Samacheer Kalvi Class 10 Science Solutions Chapter 14 Transportation in Plants and Circulation in Animals

I. Choose the Best Answer:

 

Question 1. Active transport involves:
(a) movement of molecules from lower to higher concentration
(b) expenditure of energy
(c) it is an uphill task
(d) all of the options
Answer: (d) all of the options
In simple words: Active transport is like moving things uphill; it needs energy to push molecules from an area where there are fewer of them to an area where there are more. This process is vital for cells to take in necessary substances against their concentration gradient.

🎯 Exam Tip: Remember that "active" transport always implies the use of energy (ATP) because it moves substances against their natural flow or concentration gradient.

 

Question 2. Water which is absorbed by roots is transported to aerial parts of the plant through _______.
(a) cortex
(b) epidermis
(c) phloem
(d) xylem.
Answer: (d) xylem.
In simple words: Xylem acts like a pipeline in plants, carrying water and minerals from the roots all the way up to the leaves. This is different from phloem, which moves food.

🎯 Exam Tip: Differentiate clearly between xylem (water and minerals from roots up) and phloem (food from leaves to other parts) as this is a common point of confusion.

 

Question 3. During transpiration there is loss of:
(a) carbon dioxide
(b) oxygen
(c) water
(d) none of the options
Answer: (c) water
In simple words: Transpiration is when plants release water vapor into the air, mainly from their leaves. This loss of water helps pull more water up from the roots, similar to how drinking from a straw works.

🎯 Exam Tip: Transpiration is a key process for water movement in plants and for cooling the plant, involving the evaporation of water from leaves.

 

Question 4. Root hairs are _______.
(a) cortical cell
(b) projection of the epidermal cell
(c) unicellular
(d) both b and c.
Answer: (d) both b and c.
In simple words: Root hairs are tiny, single-celled extensions that grow out from the epidermal cells of plant roots. They greatly increase the surface area, helping the plant absorb more water and minerals from the soil.

🎯 Exam Tip: Focus on the dual characteristics of root hairs: they are both extensions of epidermal cells and they are unicellular, which maximizes their efficiency in absorption.

 

Question 5. Which of the following process requires energy?
(a) active transport
(b) diffusion
(c) osmosis
(d) all of them
Answer: (a) active transport
In simple words: Only active transport needs energy to move substances, because it pushes them against their natural flow. Diffusion and osmosis are passive movements and do not require energy.

🎯 Exam Tip: Remember that active transport is the only process among these that consumes cellular energy (ATP) to move substances, especially from an area of lower concentration to higher concentration.

 

Question 6. The wall of the human heart is made of _______.
(a) Endocardium
(b) Epicardium
(c) Myocardium
(d) All of the options.
Answer: (d) All of the options.
In simple words: The heart wall has three main layers: the inner endocardium, the middle myocardium (which is the muscle), and the outer epicardium. All these layers work together for the heart to pump blood.

🎯 Exam Tip: When asked about the heart wall, remember all three layers- endocardium (inner), myocardium (middle, muscular), and epicardium (outer)- contribute to its structure.

 

Question 7. Which is the sequence of correct blood flow?
(a) ventricle – atrium – vein – arteries
(b) atrium – ventricle – veins – arteries
(c) atrium – ventricle – arteries – vein
(d) ventricles – vein – atrium – arteries
Answer: (c) atrium – ventricle – arteries – vein
In simple words: Blood first enters an atrium, then goes to a ventricle, which then pumps it into arteries. After circulating through the body, it returns to the heart through veins. This ensures blood flows in one direction.

🎯 Exam Tip: Always remember the sequence: Atrium receives blood, Ventricle pumps blood out. Arteries carry blood away from the heart, Veins carry blood towards the heart.

 

Question 8. A patient with blood group O was injured in an accident and has blood loss. Which blood group the doctor should effectively use for transfusion in this condition?
(a) O group
(b) AB group
(c) A or B group
(d) all blood group.
Answer: (a) O group
In simple words: People with blood group O can only receive O blood because their body has antibodies against A and B blood types. Giving them any other type would cause a harmful reaction. Group O-negative is the universal donor.

🎯 Exam Tip: In emergencies, always consider the patient's specific blood group and the compatibility rules to avoid dangerous transfusion reactions. O-negative is a universal donor, but O-positive individuals can only receive O-positive or O-negative blood.

 

Question 9. 'Heart of heart' is called:
(a) SA node
(b) AV node
(c) Purkinje fibres
(d) Bundle of His
Answer: (a) SA node
In simple words: The SA node is like the natural pacemaker of the heart; it generates electrical signals that make the heart beat rhythmically. This tiny cluster of cells sets the pace for your heartbeat.

🎯 Exam Tip: The SA node is crucial for initiating the heart's electrical activity, acting as the primary pacemaker that sets the heart rate.

 

Question 10. Which one of the following regarding blood composition is correct?
(a) Plasma – Blood + Lymphocyte
(b) Serum – Blood + Fibrinogen
(c) Lymph – Plasma + RBC + WBC
(d) Blood - Plasma + RBC + WBC + Platelets.
Answer: (d) Blood - Plasma + RBC + WBC + Platelets.
In simple words: Blood is made of several parts: plasma (the liquid part), red blood cells (RBCs) that carry oxygen, white blood cells (WBCs) that fight infection, and platelets that help blood clot. All these components work together.

🎯 Exam Tip: Understand the major components of blood and their primary functions. Plasma is the liquid matrix, while RBCs, WBCs, and platelets are the formed elements.

 

II. Fill in the blanks:

 

Question. 1. ___________ involves evaporative loss of water from aerial parts.
Answer: 1. Transpiration
In simple words: Transpiration is the process where plants lose water vapor from their leaves, which helps to pull water up from the roots.

🎯 Exam Tip: Remember that transpiration is the main way plants release water into the atmosphere, helping to drive water movement through the plant.

 

Question. 2. Water enters the root cell through a ___________ plasma membrane.
Answer: 2. Semipermeable
In simple words: Water moves into root cells through a semipermeable membrane, which allows water to pass but controls other substances.

🎯 Exam Tip: The semipermeable nature of cell membranes is vital for regulating what enters and leaves plant cells, like water absorption in roots.

 

Question. 3. Structures in roots that help to absorb water are ___________.
Answer: 3. Root hairs
In simple words: Tiny extensions called root hairs on plant roots are responsible for soaking up water and minerals from the soil.

🎯 Exam Tip: Root hairs significantly increase the surface area available for absorption, making them crucial for a plant's water uptake.

 

Question. 4. Normal blood pressure is ___________.
Answer: 4. 120 mm / 80 mm Hg
In simple words: A healthy adult's normal blood pressure is around 120 over 80 mmHg. The top number is during heartbeats, and the bottom is between beats.

🎯 Exam Tip: Remember the two values for normal blood pressure: 120 (systolic, when the heart contracts) and 80 (diastolic, when the heart rests between beats).

 

Question. 5. The normal human heartbeat rate is about ___________ time per minute.
Answer: 5. 72-75
In simple words: A typical human heart beats about 72 to 75 times every minute when at rest. This rate can change during activity or stress.

🎯 Exam Tip: Know the average resting heart rate for humans, as it's a basic indicator of cardiovascular health.

 

III. Match the Following:

 

Question. Match the Column I with Column II. Section I

Answer:
A. (ii)
B. (i)
C. (iv)
D. (iii)
In simple words: These matches link terms about plant water movement to their correct definitions or related concepts. For instance, the symplastic pathway uses plasmodesmata to move water through cells, while root pressure creates a push in the xylem.

🎯 Exam Tip: When matching, understand the core relationship between each term in Column I and its best fit in Column II to ensure accuracy.

 

Question. Match the Column I with Column II. Section - II

Answer:
A. (iv)
B. (i)
C. (ii)
D. (iii)
E. (viii)
F. (vii)
G. (v)
H. (vi)
In simple words: This section connects different blood components, conditions, and their functions or characteristics. For example, leukemia is a type of blood cancer, and eosinophils are involved in allergic reactions.

🎯 Exam Tip: Pay close attention to the specific roles and properties of each blood cell type and related medical conditions for accurate matching.

 

IV. State Whether True or False. If False Write the Correct Statement:

 

Question 1. The phloem is responsible for the translocation of food.
Answer: True
In simple words: Phloem is indeed the part of a plant that carries food, like sugars, from where it's made (leaves) to other parts of the plant. This is a correct statement about its function.

🎯 Exam Tip: Remember that phloem transports food (sugars) throughout the plant, whereas xylem transports water and minerals.

 

Question 2. Plants lose water by the process of transpiration.
Answer: True
In simple words: Transpiration is exactly how plants release water vapor into the air from their leaves. This helps water move up through the plant.

🎯 Exam Tip: Transpiration is a vital process for plants, driving water movement and cooling the plant, but excessive transpiration can lead to dehydration.

 

Question 3. The form of sugar transported through the phloem is glucose.
Answer: False – The form of sugar transported through the phloem is sucrose.
In simple words: When plants move sugar through the phloem, they use sucrose, not glucose. Sucrose is a more stable form of sugar for transport.

🎯 Exam Tip: Know that sucrose is the primary sugar transported by phloem in plants, as it is less reactive than glucose and thus more suitable for long-distance transport.

 

Question 4. In apoplastic movement the water travels through the cell membrane and enter the cell.
Answer: False – Apoplastic movement does not involve crossing the cell membrane.
In simple words: In apoplastic movement, water moves around the cells through cell walls and spaces, not by passing through the cell membranes. It's an external path.

🎯 Exam Tip: Distinguish between apoplastic (through cell walls and intercellular spaces) and symplastic (through cytoplasm and plasmodesmata) pathways of water movement in plants.

 

Question 5. When the guard cells lose water the stoma opens.
Answer: False – When the guard cells lose water the stoma closes.
In simple words: Guard cells control the opening and closing of stomata. When they lose water, they become soft and the stoma closes, preventing further water loss.

🎯 Exam Tip: Remember that turgid (full of water) guard cells cause stomata to open, while flaccid (losing water) guard cells cause stomata to close.

 

Question 6. Initiation and stimulation of heart beat take place by nerves.
Answer: False - Initiation and stimulation of heart beat take place by Sino-atrial node.
In simple words: The heart's beat starts in a special part called the Sino-atrial (SA) node, which acts as the natural pacemaker. Nerves can only change this rate, not start it.

🎯 Exam Tip: Understand that the heart is myogenic (generates its own beat), with the SA node initiating the impulses, and the nervous system only regulating this inherent rate.

 

Question 7. All veins carry deoxygenated blood.
Answer: False – All veins carry deoxygenated blood except the pulmonary veins.
In simple words: Most veins carry blood that has lost its oxygen, but the pulmonary veins are special. They carry oxygen-rich blood from the lungs back to the heart.

🎯 Exam Tip: Always remember the exception: pulmonary arteries carry deoxygenated blood, and pulmonary veins carry oxygenated blood, contrary to the general rule for arteries and veins.

 

Question 8. WBC defend the body from bacterial and viral infections.
Answer: True
In simple words: White blood cells (WBCs) are like the body's soldiers, actively fighting off germs like bacteria and viruses to keep us healthy. This statement is accurate.

🎯 Exam Tip: White blood cells are a crucial part of the immune system, with different types specializing in different forms of defense against pathogens.

 

Question 9. The closure of the mitral and tricuspid valves at the start of the ventricular systole produces the first sound 'LUBB'.
Answer: True
In simple words: The first heart sound, 'LUBB', happens when the valves between the atria and ventricles close tightly. This prevents blood from flowing backward when the ventricles contract.

🎯 Exam Tip: Remember that the 'LUBB' sound signals the closing of the atrioventricular valves (mitral and tricuspid) and the beginning of ventricular contraction (systole).

 

V. Answer in a Word or Sentence:

 

Question 1. Name two layered protective covering of human heart.
Answer: Pericardium is the two layered protective covering of human heart.
In simple words: The human heart is protected by a two-layer sac called the pericardium. This sac helps cushion and protect the heart.

🎯 Exam Tip: The pericardium not only protects the heart but also prevents over-expansion and keeps it anchored within the chest cavity.

 

Question 2. What is the shape of RBC in human blood?
Answer: The shape of RBC in human blood is biconcave and disc-shaped.
In simple words: Human red blood cells are shaped like flattened discs with indentations on both sides, making them biconcave. This shape helps them carry oxygen better.

🎯 Exam Tip: The biconcave shape of RBCs increases their surface area for oxygen binding and allows them to squeeze through narrow capillaries.

 

Question 3. Why is the colour of the blood red?
Answer: The blood is red in colour due to the presence of respiratory pigment-haemoglobin.
In simple words: Blood is red because it contains haemoglobin, a special protein that carries oxygen and gives blood its color. This protein is rich in iron.

🎯 Exam Tip: Haemoglobin is responsible for the red color of blood and plays a critical role in oxygen transport throughout the body.

 

Question 4. Which kind of cells are found in the lymph?
Answer: Lymphocytes in the lymph, which defend the body from infection.
In simple words: Lymph, which is a fluid in our body, mainly contains lymphocytes. These are a type of white blood cell that fights off infections.

🎯 Exam Tip: Lymphocytes are key immune cells found in lymph, involved in specific immunity against pathogens.

 

Question 5. Name the heart valve associated with the major arteries leaving the ventricles.
Answer: Aortic valve present at the base of aorta.
In simple words: The aortic valve is located where the aorta (the body's largest artery) leaves the left ventricle. This valve ensures blood flows out to the body and doesn't flow back into the heart.

🎯 Exam Tip: The aortic valve, along with the pulmonary valve, are semilunar valves that prevent backflow of blood from the major arteries into the ventricles.

 

Question 6. Mention the artery which supplies blood to the heart muscle.
Answer: Coronary arteries.
In simple words: The heart muscle itself needs a constant supply of blood to work, and this blood is provided by special arteries called coronary arteries. These arteries ensure the heart gets the oxygen and nutrients it needs.

🎯 Exam Tip: Coronary arteries are critical because they supply blood to the heart muscle. Blockages in these arteries can lead to serious heart conditions.

 

VI. Short Answer Questions:

 

Question 1. What causes the opening and closing of guard cells of stomata during transpiration?
Answer: The general mechanism of stomatal movement is based on entry and exit of water molecules in guard cells. When the turgidity increases within the guard cells the stomata open. When the guard cells lose water it becomes flaccid and the stomata closes.
In simple words: Stomata open and close because of how much water is inside the guard cells. When guard cells swell up with water, they open the stomata. When they lose water and shrink, the stomata close. This helps control water loss.

🎯 Exam Tip: The turgor pressure within guard cells is the primary factor controlling stomatal opening and closing, directly influencing transpiration rates.

 

Question 2. What is cohesion?
Answer: The force of attraction between molecules of water is called Cohesion.
In simple words: Cohesion is like water molecules sticking to each other very tightly. This force helps create a continuous column of water in plants, allowing it to move up from the roots to the leaves.

🎯 Exam Tip: Cohesion, along with adhesion (water sticking to other surfaces), is crucial for the continuous column of water in the xylem during transpiration pull.

 

Question 3. Trace the pathway followed by water molecules from the time it enters a plant root to the time it escapes into the atmosphere from a leaf.
Answer: Soil
\( \rightarrow \) root hair
\( \rightarrow \) cortex
\( \rightarrow \) endodermis
\( \rightarrow \) Pericycle
\( \rightarrow \) xylem
\( \rightarrow \) stem
\( \rightarrow \) leaves.
In simple words: Water enters the plant from the soil through root hairs, then moves through the cortex, endodermis, and pericycle to reach the xylem. From there, it goes up the stem and finally to the leaves, where it leaves the plant as vapor.

🎯 Exam Tip: Memorize the specific tissues and layers water travels through in the plant, starting from the root and ending at the leaf, to fully understand water transport.

 

Question 4. What would happen to the leaves of a plant that transpires more water than its absorption in the roots?
Answer: When transpiration exceeds water absorption by roots, the plant dehydrates. It affects plant processes such as growth, Photosynthesis and transpiration.
In simple words: If a plant loses more water from its leaves than it can absorb through its roots, it will dry out and wilt. This dehydration harms its growth and ability to make food.

🎯 Exam Tip: Understanding the balance between water uptake and loss is crucial. Prolonged imbalance leads to wilting and can severely impact plant survival and productivity.

 

Question 5. Describe the structure and working of the human heart.
Answer: The heart is thick muscular organ located in the thoracic cavity. It is covered by a two layered sac called pericardium. The heart is four chambered with two auricles and two ventricles. Right Auricle receives deoxygenated blood from superior and inferior vena cava and passes to right ventricles from right ventricles impure blood passes to pulmonary artery and reaches the lungs.
In simple words: The human heart is a strong muscle in the chest, protected by a sac called the pericardium. It has four chambers: two upper atria and two lower ventricles. The right side receives oxygen-poor blood from the body and pumps it to the lungs, while the left side receives oxygen-rich blood from the lungs and pumps it to the rest of the body. This continuous pumping keeps blood flowing.

🎯 Exam Tip: Detail the number of chambers, the protective sac, and the general pathway of blood (deoxygenated to lungs, oxygenated to body) for a complete answer.

 

Question 6. Why is the circulation in man referred to as double circulation?
Answer: The blood circulates twice, through the heart in one complete cycle, in the circulation of blood in man. So it is called double circulation.
In simple words: In humans, blood goes through the heart two separate times for each full round trip through the body and lungs. First, it goes to the lungs, then back to the heart. Then, it goes to the rest of the body and back to the heart again. This ensures efficient oxygen delivery.

🎯 Exam Tip: Clearly state that "double circulation" means blood passes through the heart twice in one complete circuit- once for pulmonary circulation (to lungs) and once for systemic circulation (to body).

 

Question 7. What are heart sounds? How are they produced?
Answer: 'Lubb' and 'Dupp' are the sounds of the heart. 'Lubb' is produced by the ventricle-contraction. It arises due to closing of mitral and tricuspid valve. 'Dupp' is produced by ventricular diastole. This arises due to the closing of the semi-lunar valves of two auricles.
In simple words: The heart makes two main sounds, "Lubb" and "Dupp." The "Lubb" sound comes from the closing of the valves between the upper and lower heart chambers when the ventricles start to squeeze. The "Dupp" sound happens when the valves leading to the main arteries close after the ventricles relax, stopping blood from flowing back.

🎯 Exam Tip: Associate 'Lubb' with the closure of AV valves and ventricular systole, and 'Dupp' with the closure of semilunar valves and ventricular diastole.

 

Question 8. What is the importance of valves in the heart?
Answer: The valves are the muscular flaps, that regulate the flow of blood in a single direction and prevent backflow of blood.
In simple words: Valves in the heart are like one-way doors that make sure blood always flows forward and never backward. They open and close to keep the blood moving in the right direction.

🎯 Exam Tip: Emphasize that the primary role of heart valves is to ensure unidirectional blood flow, preventing regurgitation.

 

Question 9. Who discovered Rh factor? Why was it named so?
Answer: Landsteiner and Wiener discovered Rh factor of blood in 1940. Rh factor is a protein CD antigen present on the surface of the red blood cells in majority of humans. This protein is similar to the protein present in Rhesus monkey, hence the term Rh.
In simple words: The Rh factor was found by Landsteiner and Wiener in 1940. It's named "Rh" because it's a protein on red blood cells that is also found in Rhesus monkeys. This factor is important for safe blood transfusions and in pregnancy.

🎯 Exam Tip: Remember the discoverers and the origin of the name "Rh" (Rhesus monkey), as it's a common point in questions about blood groups.

 

Question 10. How are arteries and veins structurally different from one another?

Answer:
Arteries have thick, elastic walls to handle high pressure as they carry blood away from the heart, mostly oxygenated (except pulmonary artery). Veins have thinner walls and often have valves to help carry blood back to the heart under lower pressure, mostly deoxygenated (except pulmonary vein). This difference in structure helps them perform their specific roles efficiently.
In simple words: Arteries have thick walls and carry blood away from the heart, usually with oxygen. Veins have thinner walls and carry blood back to the heart, usually without oxygen.

🎯 Exam Tip: Focus on the thickness of walls, presence of valves (in veins), and the direction of blood flow to distinguish between arteries and veins. Don't forget the pulmonary exceptions.

 

Question 11. Why is the Sinoatrial node called the pacemaker of the heart?
Answer: Sinoatrial node is called the pacemaker of the heart because it is capable of initiating impulse, which can stimulate the heart muscles to contract.
In simple words: The Sinoatrial (SA) node is called the heart's pacemaker because it creates the electrical signals that make the heart muscle contract on its own. It starts each heartbeat.

🎯 Exam Tip: The key function of the SA node is its intrinsic ability to generate electrical impulses, setting the rhythm for the entire heart's contractions.

 

Question 12. Differentiate between systemic circulation and pulmonary circulation.

Answer:
Systemic circulation carries oxygenated blood from the left side of the heart to all body tissues and returns deoxygenated blood to the right atrium. Pulmonary circulation, on the other hand, carries deoxygenated blood from the right ventricle to the lungs and brings oxygenated blood back to the left atrium. These two circuits ensure efficient gas exchange and nutrient delivery.
In simple words: Systemic circulation sends fresh blood to your body and brings used blood back to the heart. Pulmonary circulation sends used blood to your lungs to get oxygen and brings fresh blood back to the heart.

🎯 Exam Tip: Remember that systemic circulation delivers oxygen and nutrients to the body, while pulmonary circulation is responsible for gas exchange in the lungs.

 

Question 13. The complete events of the cardiac cycle last for 0.8 sec. What is the timing for each event?
Answer:
1. Atrial Systole: Contraction of auricles (0.1 sec)
2. Ventricular Systole: Contraction of ventricles (0.3 sec)
3. Ventricular diastole: Relaxation of Ventricles (0.4 sec).
In simple words: A full heartbeat, called a cardiac cycle, takes about 0.8 seconds. The upper chambers (atria) contract for a very short time (0.1 sec), then the lower chambers (ventricles) contract for a bit longer (0.3 sec), and finally, all chambers relax for the remaining time (0.4 sec).

🎯 Exam Tip: Note the specific durations for atrial systole, ventricular systole, and ventricular diastole, and ensure their sum equals the total duration of the cardiac cycle (0.8 sec).

 

VII. Give Reasons for the Following Statements:

 

Question 1. Minerals cannot be passively absorbed by the roots.
Answer: All minerals cannot be passively absorbed by the roots because, minerals are present in the soil as charged particles that cannot move across the cell membranes and the concentration of minerals in the soil is usually lower than the concentration of minerals in the root. So, the minerals enter the root by active absorption through the cytoplasm of epidermal cells which needs energy.
In simple words: Minerals often can't just float into plant roots on their own because they are charged and the soil has fewer minerals than the root cells. So, plants have to use energy to actively pull these important minerals into their roots. This process ensures the plant gets enough nutrients.

🎯 Exam Tip: The two main reasons for active absorption of minerals are their charged nature (preventing passive diffusion) and their lower concentration in soil compared to root cells.

 

Question 2. Guard cells are responsible for opening and closing of stomata.
Answer: Guard cells are responsible for the opening and closing of stomata because, during transpiration, the movement of ions (Potassium) in and out of the guard cells causes the opening and closing of Stomata. When the water moves inside the guard cells, causing them to swell up and become turgid making the stomata open. When guard cells cause water to move out of the cell and make guard cells shrunk and stomata pores close.
In simple words: Guard cells control the stomata, which are tiny pores on leaves. When water flows into guard cells, they swell and open the stomata, allowing gases to pass. When water leaves them, they shrink, and the stomata close. This action regulates gas exchange and water loss.

🎯 Exam Tip: The turgor changes in guard cells, driven by the movement of water and ions, directly regulate stomatal aperture, which is vital for photosynthesis and transpiration.

 

Question 3. The movement of substances in the phloem can be in any direction.
Answer: Phloem transports food from the source to sink. The source is part in which plant synthesize food, sink is the part that needs or stores food. Since the source-sink relationship is variable, the direction of movement in the Phloem can be upwards or downwards, i.e., bidirectional.
In simple words: Food moves through the phloem from where it's made (the "source") to where it's needed or stored (the "sink"). Since these source and sink areas can change, depending on the plant's needs, food can move up or down, making the flow bidirectional.

🎯 Exam Tip: Unlike xylem, which typically moves water upwards, phloem can transport sugars in any direction (bidirectionally) depending on the metabolic needs and growth stages of the plant.

 

Question 4. Minerals in the plants are not lost when the leaf falls.
Answer: Minerals like Phosphorus, Sulphur, Nitrogen and Potassium are remobilised in the soil from older dying leaves to younger leaves. This phenomenon is seen in deciduous plants. So minerals in the plants are not lost, when the leaf falls.
In simple words: When a plant's leaves are about to fall off, especially in deciduous trees, the plant cleverly moves important minerals like phosphorus and nitrogen from these old leaves into its younger, growing parts. This way, the valuable minerals are recycled and not wasted when the old leaf drops.

🎯 Exam Tip: This remobilization of nutrients from senescing (aging) leaves to younger, actively growing parts is an important adaptation for nutrient conservation in plants.

 

Question 5. The walls of the right ventricle are thicker than the right auricles.
Answer: Because the right ventricle has to pump out the deoxygenated blood with force away from the heart through pulmonary artery to lungs.
In simple words: The right ventricle has thicker walls than the right atrium because it needs to pump blood with enough force to the lungs. The atrium only pushes blood to the ventricle, so it doesn't need to be as strong.

🎯 Exam Tip: The thickness of a heart chamber's wall directly relates to the amount of force needed to pump blood; ventricles always have thicker walls than atria.

 

Question 6. Mature RBC in mammals does not have cell organelles.
Answer: Mature RBC in mammals does not have cell organelles because

• The lack of Nucleus in RBC makes the cells, biconcave and disc-shaped. RBC involved in the transport of oxygen from lungs to tissues.
• They do not have cell organelles in order to accommodate maximum space for haemoglobin.
• The loss of endoplasmic reticulum allows more flexibility, for RBC to move through narrow capillaries.

In simple words: Adult red blood cells in mammals lack a nucleus and other cell parts. This special design gives them more space to carry haemoglobin, which transports oxygen. It also makes them flexible, so they can squeeze through tiny blood vessels.

🎯 Exam Tip: The absence of a nucleus and organelles in mature mammalian RBCs is a key adaptation for their primary function: maximizing oxygen transport efficiency.

 

VIII. Long Answer Questions:

 

Question 1. How do plants absorb water? Explain.
Answer: Water present in the soil must reach the xylem of roots. Root hair is in contact with soil water. Their cell wall is thin and water easily diffuses in the passage of water from the soil to leaf is
Soil water
\( \rightarrow \) Root hair
\( \rightarrow \) Epidermis
\( \rightarrow \) Cortex
\( \rightarrow \) Endodermis
\( \rightarrow \) Pericycle
\( \rightarrow \) Xylem
\( \rightarrow \) Stem and leaf.
Once water is absorbed by the root hairs, it can move deepers into root layers by two pathways. Apoplast and Symplast.
1. Apoplast : This is the non living path in plants. It occurs through the intercellular spaces and walls of the cells. This movement dependent on the gradient.
2. Symplast : This is the living passage. The movement of water from cell to cell through plasmodesmato and cytoplasm, Movement is again down a potential gradient.
In simple words: Plants take in water from the soil through tiny root hairs. The water then moves through different layers of the root, like the epidermis and cortex, until it reaches the xylem, which carries it up the stem and to the leaves. There are two main ways water moves inside the root: the apoplast pathway, which goes through cell walls and spaces, and the symplast pathway, which moves through the cells themselves. Both pathways ensure water reaches all parts of the plant.

🎯 Exam Tip: Remember the pathway of water absorption from soil to xylem and differentiate between the apoplast (non-living, cell walls) and symplast (living, cytoplasm) pathways.

 

Question 2. What is transpiration? Give the importance of transpiration.
Answer: Transpiration is the evaporation of water in plants through stomata in the leaves. Importance of Transpiration

• Creates transpirational pull for the transport of water.
• Supplies water for photosynthesis.
• Transports minerals from the soil to all parts of the plant.
• Cools the surface of the leaves by evaporation.
• Keeps the cells turgid; hence, maintains their shape.

In simple words: Transpiration is when plants release water vapor into the air from tiny pores, mostly on their leaves. This process is very important because it helps pull water up from the roots, supplies water needed for making food (photosynthesis), carries minerals to different parts of the plant, cools the leaves, and helps keep plant cells firm.

🎯 Exam Tip: Define transpiration accurately and list its multiple benefits to the plant, including water transport, nutrient distribution, cooling, and turgor maintenance.

 

Question 3. Why are leucocytes classified as granulocytes and agranulocytes? Name each cell and mention its functions.
Answer: Leucocytes (WBCs) are grouped into two main types, granulocytes and agranulocytes, based on whether they have granules in their cytoplasm.
Granulocytes have granules in their cytoplasm. These include neutrophils, eosinophils, and basophils.
1. Neutrophils: These are the most common WBCs (about 60-65%). They have many-lobed nuclei and eat harmful bacteria and viruses (phagocytic). They gather in large numbers around infected tissues to fight off germs.
2. Eosinophils: These make up about 2-3% of WBCs. They have a two-lobed nucleus and increase during parasitic infections and allergic reactions. They also help remove toxins from the body.
3. Basophils: These are the least common (about 0.5-1.0%) and have a lobed nucleus. They release chemicals that cause inflammation.
Agranulocytes do not have granules in their cytoplasm. They include lymphocytes and monocytes.
1. Lymphocytes: These are about 20-25% of all leucocytes. They create antibodies to fight bacterial and viral infections.
2. Monocytes: These are the largest leucocytes and are amoeboid in shape. They make up 5-6% of total leucocytes. They are phagocytic, meaning they can engulf and digest bacteria. These different types of white blood cells play unique roles in the body's defense system.
In simple words: White blood cells are split into two groups: those with tiny dots (granules) inside them and those without. Each type has a special job, like fighting germs, stopping allergies, or causing swelling.

🎯 Exam Tip: Remember the two main categories (granulocytes and agranulocytes) and associate each cell type with its primary function to score full marks.

 

Question 4. Differentiate between systole and diastole. Explain the conduction of the heartbeat.
Answer: A single heartbeat involves one complete cycle of contraction (systole) and relaxation (diastole) of the heart's atria and ventricles. The human heart's rhythm is myogenic, meaning it generates its own beat.
The heartbeat begins at the sino-atrial (SA) node, located in the wall of the right atrium near where the superior vena cava opens. The SA node is wider at the top and narrows downwards, consisting of thin fibers. This SA node is known as the heart's "pacemaker" because it can start electrical impulses that make heart muscles contract. These impulses spread like a wave across the right and left atrial walls, pushing blood into the ventricles through the atrioventricular valves. The same wave from the SA node then reaches the atrioventricular (AV) node, which also sends an impulse of contraction to the ventricular muscle, spreading through the atrioventricular bundle and Purkinje fibers. The expansion of an artery each time blood is pushed into it is called pulse. A normal pulse rate is usually between 70 to 90 beats per minute. The heart's efficient conduction system ensures synchronized pumping of blood throughout the body.
In simple words: Systole is when the heart squeezes, and diastole is when it relaxes. The heart's beat starts at a special spot called the SA node, which sends electrical signals that make the heart muscles contract in a proper order.

🎯 Exam Tip: Clearly define systole and diastole as contraction and relaxation. For conduction, list the key components (SA node, AV node, Bundle of His, Purkinje fibers) in the correct sequence.

 

Question 5. Enumerate the functions of blood.
Answer: Blood performs several vital functions in the body:
1. It carries respiratory gases, such as oxygen (O2) and carbon dioxide (CO2).
2. It transports digested food materials to all the different cells in the body.
3. It carries hormones to their target organs.
4. It moves nitrogenous waste products like ammonia, urea, and uric acid for excretion.
5. It protects the body and helps in defense against diseases.
6. It acts as a buffer, helping to keep the body's pH and temperature regulated.
7. It helps maintain the proper water balance within the body. Blood is essential for maintaining homeostasis and proper body function.
In simple words: Blood carries oxygen, food, and hormones around the body. It also takes away waste, fights off sickness, keeps body temperature steady, and balances water.

🎯 Exam Tip: When listing functions of blood, categorize them into transport, defense, and regulation for a comprehensive answer.

 

IX. Assertion and Reasoning:

 

Question 1. Assertion: RBC plays an important role in the transport of respiratory gases. Reason: RBC do not have cell organelles and nucleus.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (b) If both A and R are true but R is not the correct explanation of A.
In simple words: The statement that red blood cells (RBCs) carry breathing gases is true. The statement that RBCs don't have cell parts or a nucleus is also true. However, these two facts are not directly related to each other as a reason and explanation.

🎯 Exam Tip: For assertion-reason questions, first check if both statements are individually true. Then, confirm if the reason actually explains the assertion, not just states another fact.

 

Question 2. Assertion: Persons with AB blood group are called an universal recipients, because they can receive blood from all groups. Reason: Antibodies are absent in persons with AB blood group.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (a) If both A and R are true and R is correct explanation of A.
In simple words: It's true that people with AB blood can get blood from anyone (universal recipients) because they don't have antibodies against other blood types. This lack of antibodies is the direct reason why they can receive any blood.

🎯 Exam Tip: For blood group questions, remember that "universal recipient" is due to the absence of antibodies, while "universal donor" (O group) is due to the absence of antigens.

 

X. Higher Order Thinking Skills (Hots):

 

Question 1. When any dry plant material is kept in water, they swell up. Name and define the phenomenon involved in this change.
Answer: The phenomenon involved is called 'imbibition'. Imbibition is a type of diffusion where a solid material absorbs water and increases in volume, causing it to swell up. This process is important for seed germination and initial water absorption by plant roots. The plant material acts as an adsorbent, drawing water molecules into its structure.
In simple words: When dry plant stuff gets wet and swells up, it's called imbibition. This is when a solid soaks up water and gets bigger.

🎯 Exam Tip: Define imbibition clearly by mentioning a solid absorbing liquid and increasing in volume, and give an example like seed swelling.

 

Question 2. Why are the walls of the left ventricle thicker than the other chambers of the heart?
Answer: The walls of the left ventricle are about three times thicker than those of the right ventricle, and much thicker than the atria. This is because the left ventricle's job is to pump oxygen-rich blood into the aorta, which then carries this blood to all the various organs throughout the entire body. It needs significant force to push blood over such a long distance, overcoming high resistance in the systemic circulation. This demanding task requires stronger, thicker muscular walls compared to other heart chambers, which pump blood over shorter distances or with less force.
In simple words: The left side of the heart has thicker walls because it has to pump blood with a lot of force to every part of the body, unlike the other parts of the heart.

🎯 Exam Tip: Focus on the "distance" and "force" needed for systemic circulation when explaining the left ventricle's thicker walls.

 

Question 3. Doctors use stethoscope to hear the sound of the heart. Why?
Answer: Doctors use a stethoscope because it is a special tool that helps them listen to the sounds made by the internal organs of the human body, especially the heart and lungs. By listening carefully to these sounds, doctors can identify and locate health problems and diagnose diseases. The distinct "Lubb" and "Dupp" sounds of the heart, for instance, give clues about the health of the heart valves. This non-invasive method is a fundamental part of a medical examination.
In simple words: Doctors use a stethoscope to hear sounds from inside the body, like the heart. This helps them find out if there are any health problems.

🎯 Exam Tip: Explain that a stethoscope helps in listening to internal body sounds and diagnosing diseases, making it a crucial diagnostic tool.

 

Question 4. How do the pulmonary artery and pulmonary vein differ in their function when compared to a normal artery and vein?
Answer: Normally, most arteries carry oxygenated blood away from the heart, and most veins carry deoxygenated blood back to the heart. However, the pulmonary artery and pulmonary vein have opposite functions:
• All other arteries carry oxygenated blood, but the pulmonary artery carries deoxygenated blood from the right ventricle to the lungs to pick up oxygen.
• All other veins carry deoxygenated blood, but the pulmonary vein carries oxygenated blood from the lungs back to the left atrium of the heart. This exception is vital for the pulmonary circulation, which allows blood to be re-oxygenated.
In simple words: Most arteries carry clean blood, and most veins carry dirty blood. But the pulmonary artery takes dirty blood to the lungs, and the pulmonary vein brings clean blood back from the lungs, which is the opposite of the usual job.

🎯 Exam Tip: Clearly state the general rule for arteries and veins, then highlight the pulmonary artery and vein as the key exceptions, explaining their specific roles in lung circulation.

 

Question 5. Transpiration is a necessary evil in plants. Explain.
Answer: Transpiration is often called a "necessary evil" because while it causes plants to lose a lot of water through their leaves, it's also essential for their survival. As water evaporates from the leaves through stomata, it creates a pulling force, or 'transpiration pull', which draws more water up from the roots through the xylem. This continuous flow of water is crucial for several reasons: it supplies water for photosynthesis, transports minerals from the soil to all parts of the plant, cools the leaf surface through evaporation, and helps maintain the turgidity (firmness) of plant cells. So, despite the water loss, transpiration is a vital process that supports the plant's overall health and functions.
In simple words: Transpiration means plants lose water from their leaves, which seems bad. But this water loss also helps pull water and food from the roots up to the leaves, cools the plant, and keeps it firm, so it's a necessary process.

🎯 Exam Tip: When explaining "necessary evil," make sure to balance the negative (water loss) with the positive and essential functions (water transport, cooling, nutrient uptake).

 

Samacheer Kalvi 10th Science Transportation in Plants and Circulation in Animals Additional Important Questions And Answers

 

I. Choose The Correct Answer:

 

Question 1. Seed swells when placed in water due to:
(a) osmosis
(b) imbibition
(c) hydrolysis
(d) all of the options
Answer: (b) imbibition
In simple words: When a dry seed gets wet and grows bigger, it's because it's soaking up water through a process called imbibition.

🎯 Exam Tip: Imbibition is a specific type of absorption, characteristic of solids like seeds, and often involves swelling without forming a solution.

 

Question 2. Root hairs occurs in:
(a) Meristematic zone
(b) Cell elongation zone
(c) Cell maturation zone
(d) Old root
Answer: (c) Cell maturation zone
In simple words: Root hairs, which help plants soak up water, are found in the area of the root where cells are fully grown and developed.

🎯 Exam Tip: Remember that root hairs are found in the zone of maturation because this is where cells fully differentiate and become specialized for absorption.

 

Question 2. The other name for Red blood corpuscles (RBC) is called __________.
Answer: Erythrocytes.
In simple words: Red blood cells are also known by another scientific name: erythrocytes.

🎯 Exam Tip: It is important to know alternative scientific names for common biological structures, as they are often used interchangeably in questions.

 

Question 3. Water in plants is transported by ascent of sap takes place through:
(a) cambium
(b) xylem
(c) phloem
(d) epidermis
Answer: (b) xylem
In simple words: In plants, water moves from the roots all the way up to the leaves through special tubes called xylem.

🎯 Exam Tip: Distinguish between xylem and phloem: xylem transports water and minerals, while phloem transports food (sugars).

 

Question 4. Absorption of water is increased when:
(a) transpiration is increased
(b) photosynthesis is increased
(c) respiration is increased
(d) root pressure is increased
Answer: (a) transpiration is increased
In simple words: When a plant loses more water through its leaves (transpiration), it creates a stronger pull to absorb more water from the soil.

🎯 Exam Tip: Connect transpiration to water absorption by understanding the concept of transpiration pull, which drives water movement up the plant.

 

Question 5. Opening of stomata is due to:
(a) Turgidity of guard cells
(b) Size of guard cells
(c) Number of guard cells
(d) Amount of CO2 in the atmosphere.
Answer: (a) Turgidity of guard cells
In simple words: The small pores on leaves, called stomata, open up when the guard cells around them fill with water and become firm or turgid.

🎯 Exam Tip: Remember that increased turgidity in guard cells causes them to bow outwards, opening the stomata, while flaccidity closes them.

 

Question 6. Guard cells help in:
(a) Fighting against infection
(b) Guttation
(c) Protecting against grazing
(d) Transpiration
Answer: (d) Transpiration
In simple words: Guard cells are like tiny doors on plant leaves that control how much water vapor leaves the plant, a process called transpiration.

🎯 Exam Tip: The primary role of guard cells is to regulate the opening and closing of stomata, directly controlling gas exchange and transpiration.

 

Question 7. Photosynthetic food material is transported in the form of:
(a) Glucose
(b) Sucrose
(c) Starch
(d) Fructose
Answer: (b) Sucrose
In simple words: The food made by plants through photosynthesis is moved around the plant in the form of a sugar called sucrose.

🎯 Exam Tip: While glucose is the initial product of photosynthesis, sucrose is the main sugar transported in plants because it is more stable and less reactive.

 

Question 8. Coronary artery supplies blood to:
(a) Mammary glands
(b) Rib muscles
(c) Skin
(d) Heart
Answer: (d) Heart
In simple words: The coronary artery is responsible for carrying blood and nutrients directly to the heart muscle itself, ensuring it has enough energy to pump.

🎯 Exam Tip: The term "coronary" specifically refers to the heart; remember that coronary arteries are crucial for the heart's own blood supply.

 

Question 9. All arteries carry oxygenated blood except:
(a) systematic
(b) hepatic
(c) pulmonary
(d) cardiac
Answer: (c) pulmonary
In simple words: Usually, all arteries carry blood full of oxygen, but the pulmonary artery is different because it carries blood without oxygen to the lungs.

🎯 Exam Tip: Always remember that the pulmonary artery is the exception among arteries, carrying deoxygenated blood to the lungs for re-oxygenation.

 

Question 10. The colour of lymph is:
(a) white
(b) pale yellow
(c) colourless
(d) milky
Answer: (c) colourless
In simple words: Lymph is a clear liquid that helps our body fight germs and carry waste away, and it does not have any color.

🎯 Exam Tip: Lymph is colorless because it lacks red blood cells and hemoglobin, which give blood its red color.

 

Question 11. An artery can be distinguished from a vein in having:
(a) thicker wall
(b) elastic vessels
(c) no valves
(d) All of the options
Answer: (d) All of the options
In simple words: Arteries are different from veins because they have thicker, more stretchy walls, and they usually don't have valves inside them, unlike veins.

🎯 Exam Tip: Remember these key differences: arteries have thicker, more muscular, and elastic walls to withstand high pressure, and typically lack valves (except at the heart), while veins are thinner-walled and have valves to prevent backflow.

 

Question 12. Purkinje fibres mainly help in contraction of:
(a) right auricle
(b) left auricle
(c) ventricles
(d) Aorta
Answer: (c) ventricles
In simple words: Purkinje fibers are special cells that help the lower chambers of the heart, called ventricles, squeeze and pump blood effectively.

🎯 Exam Tip: Purkinje fibers are the final part of the heart's electrical conduction system, ensuring rapid and coordinated contraction of the ventricles.

 

Question 13. The 'Lubb' and 'Dupp' heart sound are due to:
(a) opening of heart valves
(b) action of papillary' muscles
(c) closing of heart valves
(d) activity of pace maker
Answer: (c) closing of heart valves
In simple words: The "Lubb" and "Dupp" sounds you hear from a heart are made when the heart's valves snap shut.

🎯 Exam Tip: The "Lubb" sound comes from the closing of the atrioventricular valves, and the "Dupp" sound from the closing of the semilunar valves.

 

Question 14. The closed circulatory system occurs in:
(a) cockroach
(b) fish
(c) mosquito
(d) house fly
Answer: (b) fish
In simple words: Animals like fish have a closed circulatory system, which means their blood always stays inside blood vessels like tubes, never flowing freely in the body cavity.

🎯 Exam Tip: Remember that in a closed circulatory system, blood is always confined within vessels (arteries, veins, capillaries), typical of vertebrates like fish.

 

Question 15. Normal pulse rate is:
(a) 80 mm Hg
(b) 120 mm Hg
(c) 40 mg Hg
(d) 90 mm Hg
Answer: (d) 90 mm Hg
In simple words: A normal pulse rate is when your heart beats a certain number of times, and in this case, the typical measurement given is 90 mm Hg.

🎯 Exam Tip: Be mindful of units: pulse rate is usually beats per minute, while mm Hg is a unit for blood pressure, though options may sometimes combine them in questions.

 

Question 16. In the ABO system of blood groups, of both antigens are present but no antibody, the blood group of the individual would be?
(a) B
(b) O
(c) AB
(d) A
Answer: (c) AB
In simple words: If someone has both type A and type B antigens on their red blood cells but no antibodies in their blood plasma, their blood type is AB.

🎯 Exam Tip: Remember the rule: if both A and B antigens are present, the blood group is AB. If no antibodies are present, it means the person can receive blood from all types (universal recipient).

 

Question 17. Arteries are branches of:
(a) capillaries
(b) veins
(c) aorta
(d) none of these
Answer: (c) aorta
In simple words: The large blood vessels called arteries branch out from the main artery, which is known as the aorta.

🎯 Exam Tip: The aorta is the largest artery in the body, directly receiving blood from the left ventricle and distributing it to smaller arteries.

 

Question 18. Which type of WBCs are found in maximum number?
(a) Monocytes
(b) Basophils
(c) Eosinophils
(d) Neutrophils
Answer: (d) Neutrophils
In simple words: Among the different types of white blood cells, neutrophils are the most common and are found in the largest numbers in our blood.

🎯 Exam Tip: Neutrophils are typically the most abundant type of white blood cell and are usually the first responders to infection or inflammation.

 

Question 19. Which of the following are granular WBCs?
(a) Neutrophils, Basophils, Lymphocytes
(b) Eosinophil, Basophil, Monocytes
(c) Basophils, Monocytes, Lymphocytes
(d) Neutrophils, Eosinophil, Basophil
Answer: (d) Neutrophils, Eosinophil, Basophil
In simple words: The white blood cells that have tiny granules inside them are neutrophils, eosinophils, and basophils.

🎯 Exam Tip: Granulocytes are easily remembered by the "phil" suffix: Neutrophils, Eosinophils, and Basophils, all having granules in their cytoplasm.

 

Question 20. RBCs are concerned with carriage of gases.
(a) CO2
(b) O2
(c) Respiratory
(d) CO2 and SO2
Answer: (c) Respiratory
In simple words: Red blood cells (RBCs) are mainly in charge of carrying all the gases that our body breathes in and out, which are called respiratory gases.

🎯 Exam Tip: While RBCs primarily carry oxygen and carbon dioxide, the option "Respiratory" encompasses both, making it the most accurate general answer if specific gases aren't combined.

 

II. Fill In The Blanks:

 

Question 1. (1) __________ involves evaporative loss of water from aerial parts.
(2) Water enters the root cell through a __________ plasma membrane.
(3) Structures in roots that help to absorb water are __________.
(4) Normal blood pressure is __________.
(5) The normal human heartbeat rate is about __________ time per minute.
(6) The life span of RBC in human is __________ days.
(7) Pulmonary artery carry __________ blood.
(8) __________ discovered the circulation of blood in man.
(9) Semilunar valve is present at the base of __________.
(10) Human heart beats __________ times in a minute at rest.
(11) Red blood pigment is __________.
(12) Transpiration helps in the absorption and __________ movement of water and minerals.
(13) Water in plants is transported by ascent of sap takes place through __________.
(14) The absorption water due to expenditure of energy is called __________.
(15) In plants, the translocation of organic solutes takes place through __________.

Answer:
(1) Transpiration
(2) Semipermeable
(3) Root hairs
(4) 120 mm / 80 mm Hg
(5) 72-75
(6) 120
(7) deoxygenated
(8) William Harvey
(9) Pulmonary artery
(10) 72
(11) Haemoglobin
(12) upward
(13) xylem
(14) active absorption
(15) phloem
In simple words: These answers fill in the missing words to complete sentences about how plants take in water, how blood moves in our bodies, and how our heart works. They cover topics like water loss in plants, blood pressure, heart rate, and what makes blood red.

🎯 Exam Tip: Pay close attention to keywords in fill-in-the-blanks, especially units (mm Hg vs. beats per minute) and specific scientific terms for processes and structures.

 

III. Match The Following:

 

Question 1. Match the Column I with Column II.

Answer:
A. (iv)
B. (iii)
C. (i)
D. (ii)
In simple words: This matching exercise connects different parts of the circulatory and transport systems to their specific functions, like how blood flows in and out of the heart and lungs, and a pathway for water in plants.

🎯 Exam Tip: Review the major blood vessels and their functions, especially the exceptions like pulmonary arteries and veins, and plant transport pathways to ace matching questions.

 

Question 2. Match the Column I with Column II.

Answer:
A. (iv)
B. (iii)
C. (i)
D. (v)
E. (ii)
In simple words: This exercise matches important parts of the body, like blood, white blood cells (WBC), red blood cells (RBC), small blood vessels (capillaries), and heart sounds (heartbeat), to their main jobs or features.

🎯 Exam Tip: Understand the primary function or classification of each component: blood as connective tissue, WBCs for immune defense, RBCs for gas transport, capillaries as exchange vessels, and heart sounds from valve closures.

 

IV. State Whether True Or False. If False Write The Correct Statement:

 

Question 1. (1) The human heart beats 72 times per minute.
(2) Right half of heart receives and pumps off oxygenated blood.
(3) Between right auricle and right ventricle seen Mitral valve.
(4) The force of attraction between water molecule is cohesion.
(5) By passive transport sucrose moves into the cells where it is utilised or stored.

Answer:
(1) True
(2) False – The right half of the heart receives and pumps deoxygenated blood.
(3) False – The tricuspid valve is found between the right auricle (atrium) and the right ventricle.
(4) True
(5) False – Sucrose is moved into cells by active transport, not passive transport, for use or storage. This requires energy.
In simple words: This section checks if statements about the heart and plant processes are true or false. For false statements, it also gives the correct information, explaining things like which side of the heart carries which blood type, and how sugar moves in cells.

🎯 Exam Tip: For true/false questions, identify the core concept in each statement. If false, pinpoint the incorrect detail and provide the accurate information clearly and concisely.

 

V. Creative Question:

 

Question 1. Origin of heart beat and its conduction is represented by:
(a) AV node → Bundle of His → SA node → Purkinje fibres
(b) SA node → Purkinje fibres → AV node → Bundle of His
(c) Purkinje fibres → Purkinje node → AV fibres → Bundle of His
(d) SA node → AV node → Bundle of His → Purkinje fibres
Answer: (d) SA node → AV node → Bundle of His → Purkinje fibres
In simple words: The electrical signal for a heartbeat starts at the SA node, then goes to the AV node, then through the Bundle of His, and finally to the Purkinje fibers to make the heart contract.

🎯 Exam Tip: Memorize the correct sequence of electrical impulse conduction in the heart, starting from the SA node as the natural pacemaker.

 

Question 2. The cardiac pacemaker in a patient fails to function normally. The doctors find that an artificial pacemaker is to be grafted in him. It is likely that it will be drafted at the site of:
(a) Purkinje system
(b) Sinu atrial node
(c) Atrio ventricular node
(d) Atrio ventricular bundle
Answer: (b) Sinu atrial node
In simple words: If a person's natural heart pacemaker (SA node) stops working right, doctors will put an artificial one in its place, which is where the SA node usually is.

🎯 Exam Tip: The SA (Sino-atrial) node is the heart's natural pacemaker; therefore, an artificial pacemaker would replace its function and likely be placed at that anatomical site.

 

Question 3. Doctor use stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when:
(a) AV node receives signal from SA node
(b) AV valves open up
(c) Ventricular walls vibrate due to rushing in of blood from atria
(d) Semi lunar valves close down after the blood flows into vessels from ventricles
Answer: (d) Semi lunar valves close down after the blood flows into vessels from ventricles
In simple words: The second sound of the heart, "Dupp," happens when the valves that lead out of the heart's pumping chambers (ventricles) close after blood has left.

🎯 Exam Tip: Remember that heart sounds are caused by the closing of valves. The second heart sound ("Dupp") specifically indicates the closure of the semilunar valves (aortic and pulmonary valves).

VI. Assertion and Reason:

 

Question 1. Assertion: RBC plays an important role in the transport of respiratory gases. Reason: RBC do not have cell organelles and nucleus.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.
Answer: (b) If both A and R are true but R is not the correct explanation of A.
In simple words: Red blood cells (RBCs) carry oxygen, so the assertion is true. RBCs also don't have cell parts like a nucleus, which is a true statement. However, the reason (lacking organelles) is not why they transport gases, but it helps them carry more oxygen.

🎯 Exam Tip: For assertion-reason questions, first check if both statements are true. Then, see if the reason directly explains *why* the assertion is true. If both are true but the reason doesn't explain the assertion, choose option (b).

 

Question 2. Assertion: Persons with AB blood group are called an universal recipients, because they can receive blood from all groups. Reason: Antibodies are absent in persons with AB blood group.
(a) If both A and R are true and R is correct explanation of A.
(b) If both A and R are true but R is not the correct explanation of A.
(c) Assertion is true, but the reason is false.
(d) Assertion is false, but the reason is true.
Answer: (a) If both A and R are true and R is correct explanation of A.
In simple words: People with AB blood can get blood from any other group (universal recipients) because their blood does not have antibodies that would attack other blood types. This means both the statement and the reason are true and the reason explains the statement.

🎯 Exam Tip: Remember that universal recipients (AB blood type) lack antibodies, while universal donors (O blood type) lack antigens. This helps in understanding blood transfusions.

VII. Answer in a Sentence:

 

Question 1. Name the components of circulatory system.
Answer: The circulatory system is made up of circulating fluids (blood and lymph), the heart, and blood vessels such as arteries, veins, and capillaries. This system works together to move essential substances throughout the body.

🎯 Exam Tip: List all three main components: pump (heart), fluid (blood/lymph), and channels (vessels) for a complete answer.

 

Question 2. What is the Ascent of Sap?
Answer: Ascent of sap is the process where water and minerals move upwards from the roots to different parts of the plant, including stems and leaves. This is a vital process for plant survival.

🎯 Exam Tip: Define "ascent of sap" by clearly stating *what* moves (water and minerals) and *where* it moves (from roots up to other plant parts).

 

Question 3. Mention the composition of plasma.
Answer: Plasma contains organic substances like protein, glucose, urea, enzymes, hormones, vitamins, and minerals. These components are essential for various bodily functions.

🎯 Exam Tip: Focus on listing the key categories of organic substances found in plasma, such as proteins, nutrients, and waste products.

 

Question 4. Define Adhesion?
Answer: Adhesion is the force of attraction that exists between molecules of *different* substances. This attraction allows water to stick to other surfaces, like the walls of plant vessels.

🎯 Exam Tip: Clearly differentiate adhesion (attraction between *different* molecules) from cohesion (attraction between *similar* molecules).

 

Question 5. Why are auricles and ventricles separated by auricular and ventricular septum?
Answer: Auricles and ventricles are separated by a septum to prevent the mixing of oxygenated and deoxygenated blood. This separation ensures efficient blood circulation and oxygen delivery to the body.

🎯 Exam Tip: The main reason for the septum's presence is to maintain separate flows for oxygen-rich and oxygen-poor blood, ensuring higher efficiency.

 

Question 6. What is Single Circulation?
Answer: Single circulation occurs in animals like fish, amphibians, and some reptiles, where oxygenated and deoxygenated blood mix and pass through the heart only once in a complete circuit. This means the blood is pumped to the gills for oxygen and then directly to the body, without returning to the heart before going to the body parts.

🎯 Exam Tip: Key points for single circulation are: blood passes through the heart once, mixing of blood, and examples of animals.

 

Question 7. Name the instruments used to measure blood pressure.
Answer: A sphygmomanometer is a medical instrument used to measure blood pressure, typically when a person is relaxed. A normal human blood pressure reading is around 120/80 mm Hg.

🎯 Exam Tip: The term "sphygmomanometer" is the correct scientific name for the blood pressure cuff and gauge; spell it accurately.

 

Question 8. Which blood group is called as 'Universal Donor' and 'Universal Recipient'.
Answer: The 'O' blood group is known as the Universal Donor, while the 'AB' blood group is called the Universal Recipient. This is because O-type blood can be given to anyone, and AB-type blood can receive from anyone.

🎯 Exam Tip: Remember: O for donor (O-ne for all), AB for recipient (A-B-le to receive all).

 

Question 9. What is Pulse?
Answer: Pulse is the rhythmic expansion of an artery that can be felt each time blood is forced into it due to the heart's pumping action. It reflects the heartbeat rate.

🎯 Exam Tip: Focus on "expansion of the artery" and "blood being forced" as key elements in defining pulse.

 

Question 10. What is transpiration pull?
Answer: Transpiration pull is a suction force created within the plant's xylem when water evaporates from the leaves through stomata. This vacuum-like effect helps draw water upwards from the roots.

🎯 Exam Tip: Emphasize "suction" and "water evaporating from leaves" as the core components of transpiration pull.

 

Question 11. What are Rh antibodies?
Answer: Rh antibodies are protective proteins developed against the Rh antigen found on the surface of red blood cells (RBCs) in Rh-negative individuals. These antibodies are formed when an Rh-negative person is exposed to Rh-positive blood, for instance, during a transfusion or pregnancy, to fight against the foreign Rh antigen.

🎯 Exam Tip: Explain that Rh antibodies are not naturally present but *develop* in Rh-negative individuals after exposure to Rh-positive blood, leading to an immune response.

 

Question 12. What is Adhesion?
Answer: Adhesion is the force of attraction that exists between molecules of *different* substances. This property allows water to stick to things other than itself, like the inner walls of plant vessels.

🎯 Exam Tip: Clearly define adhesion as the attraction between dissimilar molecules, distinguishing it from cohesion (similar molecules).

VIII. Short Answer Question:

 

Question 1. What is blood pressure?
Answer: Blood pressure is the force that blood exerts against the walls of blood vessels as it flows. It is highest in arteries and decreases as blood moves into smaller vessels like arterioles and capillaries, becoming very low in veins. Blood pressure changes with physical activity, emotions, and sleep; high blood pressure is called hypertension, and low blood pressure is called hypotension. It is a critical indicator of cardiovascular health.

🎯 Exam Tip: A comprehensive answer should include the definition, its variation across vessel types, influencing factors, and the terms hypertension and hypotension.

 

Question 2. Distinguish between open and closed circulation.
Answer:

In simple words: In open circulation, blood flows out into body spaces, while in closed circulation, it always stays inside blood vessels.

🎯 Exam Tip: When distinguishing between two concepts, use a table format to clearly highlight corresponding differences for each feature, such as the presence of capillaries or the path of blood flow.

 

Question 3. Explain the phenomenon of Guttation.
Answer: Guttation is the process where water droplets are released from the edges of plant leaves, often seen in the early morning. This phenomenon is caused by root pressure and occurs when the soil is humid and has excess water, pushing water out through special cells called hydathodes. It's like the plant releasing extra water it absorbed.

🎯 Exam Tip: Focus on the conditions (humid, excess water), the mechanism (root pressure), and the specific structures involved (hydathodes) for a complete explanation of guttation.

 

Question 4. What is Coronary circulation?
Answer: Coronary circulation is the system that supplies blood to the heart muscles themselves. Cardiac muscles receive oxygenated blood from the coronary arteries, which branch off the aorta. Deoxygenated blood from the heart muscles then returns to the right atrium through the coronary sinuses. This ensures the heart muscle gets the oxygen and nutrients it needs to pump blood effectively.

🎯 Exam Tip: Remember that coronary circulation is specifically about the blood supply *to the heart muscle*, not the blood being pumped *by* the heart to the rest of the body.

IX. Long Answer Questions:

 

Question 1. What is lymph? Write its functions.
Answer: Lymph is a clear, colorless fluid that forms when plasma, proteins, and some blood cells leak out of capillaries into the spaces between tissue cells. It is similar to blood plasma but with fewer proteins.
Functions of Lymph:

• It supplies essential nutrition and oxygen to those parts of the body that blood cannot directly reach.
• It helps in draining away extra tissue fluid and metabolic waste products, returning proteins to the blood from tissue spaces.
• The lymph system, especially lymphatic capillaries in the small intestine (lacteals), helps carry absorbed fats to the blood.
• Lymphocytes, a type of white blood cell present in lymph, play a key role in defending the body against infections.

In simple words: Lymph is a clear fluid that carries food and oxygen to cells, takes away waste, transports fats, and fights germs in the body.

🎯 Exam Tip: When describing lymph, remember to include its composition (colorless fluid from plasma) and its critical roles in nutrient delivery, waste removal, fat absorption, and immune defense.

 

Question 2. (a) Name the main two components of blood. (b) What does plasma contain?
Answer:
(a) The main two components of blood are:
1. The fluid plasma
2. Formed elements (blood cells), which include:

• RBC (Red Blood Cells)
• WBC (White Blood Cells)
• Blood platelets

(b) Plasma is a slightly alkaline, non-cellular fluid that makes up about 55% of the blood. It contains organic substances such as proteins, glucose, urea, enzymes, hormones, vitamins, and minerals. These components are vital for maintaining the body's internal balance and transporting substances.

🎯 Exam Tip: For blood composition, clearly distinguish between the liquid part (plasma) and the solid parts (formed elements). For plasma composition, list major organic and inorganic components.

 

Question 3. Demonstrate the process of osmosis with thistle funnel.
Answer:
Aim: To show how osmosis works using a thistle funnel.
Materials Required: Beaker, Thistle funnel, a semi-permeable membrane, and sucrose solution.
Procedure: Cover the wide mouth of a thistle funnel with a semi-permeable membrane. Fill the funnel with sucrose solution and invert it into a beaker containing pure water. Ensure the water level in the beaker is below the level of the sucrose solution in the funnel.
Observation: Over time, the level of the solution inside the thistle funnel will rise. This happens as water moves into the funnel.
Inference: The rise of liquid in the funnel shows that water has moved across the semi-permeable membrane from an area of higher water concentration (beaker) to an area of lower water concentration (funnel), which is the process of osmosis. This demonstrates the movement of water through a semi-permeable barrier.
In simple words: When a sugar solution in a special funnel is put into water with a thin skin over its end, the water moves into the funnel, making the sugar solution rise. This shows water moving from where there's more water to where there's less water through a special filter.

🎯 Exam Tip: When describing an experiment, include a clear aim, list all materials, describe each step of the procedure, state the expected observation, and then provide a clear inference that explains the scientific principle demonstrated.

 

Question 4. Explain Double circulation.
Answer: Double circulation is a type of blood circulation where blood passes through the heart twice in one complete circuit of the body. In this system, there are two separate loops: the pulmonary circulation (blood goes from the heart to the lungs and back) and the systemic circulation (blood goes from the heart to the rest of the body and back). This ensures that oxygenated and deoxygenated blood do not mix, making the blood supply to the body much more efficient. Many animals, including humans, have double circulation, which is often best understood with a diagram showing the two separate pathways.
In simple words: Double circulation means blood goes through the heart two times for every full trip around the body. One trip sends blood to the lungs to get oxygen, and the other sends oxygen-rich blood to the whole body. This keeps clean and dirty blood separate.

🎯 Exam Tip: When explaining double circulation, clearly name and describe the two distinct pathways: pulmonary circulation (heart-lungs-heart) and systemic circulation (heart-body-heart). Highlight its advantage in preventing blood mixing and increasing efficiency.

 

Question 5. Explain the steps involved in Ascent of sap.
Answer: Ascent of sap is the upward movement of water and minerals from the roots to all other parts of a plant. Several factors work together to achieve this:

• Root Pressure: Water enters the root hairs from the soil through osmosis, creating pressure that pushes water up the stem's base. This initial push helps water move a short distance.
• Capillary Action: Water rises in thin tubes (like plant xylem vessels) due to physical forces. This happens because water molecules are attracted to each other and to the walls of the tubes, helping water climb upwards.
• Adhesion-cohesion of Water Molecules: Water molecules stick together (cohesion) and also stick to the walls of the xylem vessels (adhesion). This creates a continuous column of water in the xylem, preventing breaks in the water flow.
• Transpiration Pull: The evaporation of water from the leaves (transpiration) creates a strong suction force, or pull, that draws the continuous column of water upwards, much like drinking through a straw. This is the main force driving water to the highest parts of a plant.

In simple words: Water and minerals move from roots up to leaves through a few steps: roots push water a little, tiny tubes pull water up by capillary action, water molecules stick to each other and the tubes, and finally, water evaporating from leaves pulls the whole column up like a strong suction.

🎯 Exam Tip: For ascent of sap, remember the four key mechanisms: root pressure (push from below), capillary action (water climbing in narrow tubes), cohesion-adhesion (water column integrity), and transpiration pull (major pulling force from above).

 

Question 6. Explain the causes of the sound of the Heart.
Answer: The rhythmic "Lubb" and "Dupp" sounds of the heart are caused by the closing of its valves, which regulate blood flow. Each sound marks a specific event in the cardiac cycle:

• The first sound, 'Lubb', is produced by the closure of the tricuspid and bicuspid (mitral) valves at the start of ventricular systole (when the ventricles contract). This sound is longer and softer.
• The second sound, 'Dupp', is produced by the closure of the semilunar valves at the end of ventricular systole (when the ventricles relax). This sound is shorter and sharper.

In simple words: The "Lubb-Dupp" sounds of the heart happen when its valves close. The first sound, "Lubb," is from the valves between the atria and ventricles closing, and the second sound, "Dupp," is from the valves leaving the heart closing.

🎯 Exam Tip: Associate 'Lubb' with the closing of AV valves (tricuspid and bicuspid) and ventricular contraction, and 'Dupp' with the closing of semilunar valves and ventricular relaxation.

X. Higher Order Thinking Skills (HOTS)

 

Question 1. An unconscious patient is rushed into the emergency room and need a fast blood transfusion. Because there is no time to check her medical history or determine her blood type, which type of blood should you as her doctor, give?
Answer: As a doctor, in an emergency without time to determine the patient's blood type, you should give O-negative blood. O-negative is considered the universal donor because it lacks A, B, and Rh antigens, meaning it is compatible with all other blood types and is least likely to cause a severe reaction. O-positive blood is also a universal donor but only for Rh-positive patients, so O-negative is safer when the Rh factor is unknown.

🎯 Exam Tip: Remember that O-negative blood is the safest choice for emergency transfusions when blood type is unknown, as it is truly the universal donor.

 

Question 2. What are the factors affecting the Ascent of Sap?
Answer: The ascent of sap, which is the upward movement of water in plants, is affected by several environmental factors:

• High Temperature: Warmer temperatures increase transpiration (water loss from leaves), which in turn increases the transpiration pull, drawing water up faster.
• Atmospheric Pressure: Lower atmospheric pressure can indirectly affect transpiration rates, though its direct impact on sap ascent is less significant than other factors.
• Wind Velocity: Increased wind speed removes water vapor from around the leaves more quickly, boosting transpiration and thus enhancing transpiration pull.
• Low Atmospheric Humidity: Dry air (low humidity) causes more water to evaporate from leaves, increasing the transpiration rate and the upward pull of water.
• Soil Water Deficit: If there is not enough water in the soil, the plant cannot absorb enough water to replace what is lost through transpiration, which will slow down or stop the ascent of sap.

In simple words: How fast water moves up a plant is affected by things like high heat, strong wind, and dry air because they make the plant lose water faster. If there's not enough water in the soil, the plant can't pull water up properly.

🎯 Exam Tip: Connect each factor to how it influences the rate of transpiration, as transpiration pull is the primary driver for the ascent of sap.

 

Question 3. Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements.
Answer: Both water vapor exiting and carbon dioxide entering the plant through the same stomatal opening can happen simultaneously because the diffusion coefficients of water and carbon dioxide are different. This means they move at different rates and can pass through the small opening without significantly hindering each other. The plant manages these gas exchanges efficiently due to the partial pressure gradients of each gas.

🎯 Exam Tip: The key to answering this is understanding that different gases can diffuse independently and at different rates based on their concentration gradients and molecular properties.

 

Question 4. Write a few Strategies, to prevent heart disease.
Answer: Here are several strategies to help prevent heart disease:

• Engage in moderate exercise for at least 30 minutes every day to keep your heart strong.
• Completely avoid smoking and using tobacco products, as they severely damage the heart and blood vessels.
• Adopt a heart-healthy diet by limiting salt and sugar, and consuming plenty of vegetables and fruits.
• Maintain a healthy weight to reduce strain on your heart.
• Ensure you get enough quality sleep each night, as poor sleep can affect heart health.
• Learn to manage stress effectively through techniques like meditation or hobbies.
• Undergo regular health screenings, including blood pressure monitoring, cholesterol level checks, and diabetes screening, to catch potential issues early.

In simple words: To keep your heart healthy, you should exercise daily, avoid smoking, eat healthy foods like fruits and vegetables, keep a healthy weight, get enough sleep, manage stress, and have regular health check-ups.

🎯 Exam Tip: Provide a mix of lifestyle advice, dietary recommendations, and medical preventative measures when listing strategies for heart disease prevention.

XI. Give Reason:

 

Question 1. Valves are important in human heart. Give reason.
Answer: Valves are very important in the human heart because they prevent the backflow of blood. They ensure that blood flows in only one direction, from the atria to the ventricles and from the ventricles into the arteries, ensuring efficient and unidirectional circulation. Without valves, blood could flow backward, making the heart less effective at pumping.

🎯 Exam Tip: The primary function of heart valves is to ensure one-way blood flow, preventing backflow. This is the core reason for their importance.

 

Question 2. During rainy season wooden door generally swells up - Give reason.
Answer: Wooden doors swell up during the rainy season due to imbibition. Imbibition is a type of diffusion where solid materials, such as wood, absorb water molecules from the humid air and swell. This happens because the wood cells have a strong attraction to water. The absorbed water fills the tiny spaces within the wood, causing it to expand.

🎯 Exam Tip: Explain imbibition by stating it's a specific type of water absorption by solids, leading to swelling, and directly link it to the humidity of the rainy season.

 

Question 3. Para sympathetic neural signals affects the working of the heart. Give reason.
Answer: Parasympathetic neural signals affect the working of the heart because they reduce both the heart rate and the cardiac output. These signals release a chemical that slows down the heart's natural pacemaker, helping the body to rest and conserve energy after stressful situations. This is part of the "rest and digest" response.

🎯 Exam Tip: Remember that the parasympathetic nervous system generally *slows down* bodily functions, including heart rate and cardiac output, promoting relaxation.

 

Question 4. Grapes placed in salt solution shrink. Give reason.
Answer: Grapes placed in a salt solution shrink due to exosmosis. When a grape, which has a higher water content, is put into a concentrated salt solution (which has a lower water concentration), water moves out of the grape cells and into the salt solution. This movement of water from an area of higher concentration to lower concentration across the grape's semi-permeable skin causes the grape to lose water and shrink.
In simple words: Grapes shrink in salt water because water moves out of the grape and into the salty solution. This happens because there is less water outside the grape than inside it, and water always moves to where there is less of it.

🎯 Exam Tip: Explain exosmosis clearly: water moves *out* of a cell (or grape) into a surrounding solution with a *lower* water concentration (higher solute concentration), causing shrinking.