CBSE Class 10 Biology Control And Coordination Worksheet Set A

Question. Plant parts show two types of movements, one dependent on growth and the other independent of growth.
Give one example of the movement in plant parts :
(a) which depends on growth
(b) which does not depend on growth
Answer : (a) Bending of stem (or shoot) towards light (b) Folding up of the leaves of a sensitive plant on touching

Question. What is a plant hormone ? Name four plant hormones. State one function of each.
Answer : The hormones that control and coordinate the activities in plants are called plant hormones. The four types of plant hormones are: i Auxins – It promotes cell enlargement and cell differentiation in plants. ii Gibberellines – It helps in breaking the dormancy in seeds and buds. iii Cytokinins – It promotes cell division in plants. iv Abscisic acid – It promotes the dormancy in seeds and buds.

Question. (a) What does a root do in response to gravity ? What is this phenomenon known as ?
(b) What does a stem (or shoot) do in response to light ? What is this phenomenon known as ?
Answer : (a) Root bends downwards in the direction of gravity ; Positive geotropism
(b) Stem (or shoot) bends towards the light; Positive phototropism

Question. (a) What does a stem (or shoot) do in response to gravity ? What is this phenomenon known as ?
(b) What does a root do in response to light ? What is this phenomenon known as ?
Answer : (a) Stem (or shoot) grows upward against the direction of gravity ; Negative geotropism
(b) Root bends away from light ; Negative phototropism

Question. (a) What does a Mimosa pudica plant do in response to touch ? What is this phenomenon known as ?
(b) What happens to the dandelion flower (i) during daytime, and (ii) at night ? What is this phenomenon known as ?
Answer : (a) In Mimosa Pudica plant, the leaves fold up in response to touch. This phenomenon is known as thigmonasty.
(b) (i) A dandelion flower opens up in the morning in bright light. This phenomenon is known as positive photonasty.
(ii) At night the dandelion flower closes and this phenomenon is known as negative photonasty.

Question. (a) What does a plant root do in response to water ? What is this phenomenon known as ?
(b) What happens to the moonflower (i) during daytime, and (ii) at night ? What is this phenomenon known as ?
Answer : a The plant root grows towards water and the phenomenon is known as the hydrotropism.
b i During the daytime the petals of moon flower close when there is bright light. ii At night when it is dark the petals of moon flower opens up. This phenomenon is known as photonasty.

Question. What is a tendril ? Name the two types of tendrils. What does a tendril do in response to the touch of a support ? What is this phenomenon known as ?
Answer : Tendrils are the thin thread-like growths on the stems or leaves of climbing plants. The two types of tendrils are stem tendrils and leaf tendrils. The tendrils grow towards the things they happen to touch. This phenomenon is known as thigmotropism.

Question. Name the five types of tropisms. How are tropic movements helpful to plants ? Explain with an example.
Answer : The five types of tropisms are: Phototropism Geotropism Chemotropism Hydrotropism and Thigmotropism. The various types of tropic movements help the plants to survive. Example even if a seed is planted upside down its root will grow downwards into earth because it is positively geotropic.

Question. Define chemotropism. Give one example of chemotropism. State whether this example is of positive chemotropism or negative chemotropism.
Answer : The growth of plant parts in response to a chemical stimulus is known as chemotropism.
The growth of a pollen tube towards the ovule induced by a sugary stimulus is an example of chemotropism. This is an example of positive chemotropism as the pollen tube grows towards the stimulus.

Question. Distinguish between tropic movements and nastic movements in plants. Give examples to illustrate your answer.
Answer : Tropic movements - These are directional movements of plants in response to the stimulus.
Example: The upward growth of a plant stem in response to sunlight.
Nastic movements - These are non-directional movements of plants in response to the stimulus.
Example: The folding up of leaves in response to touch.

Question. (a) What is meant by nastic movements in plants ? Give one example of nastic movements in plants.
(b) What is the difference between photonasty and thigmonasty ?
Answer : (a) The non-directional movement of a plant part in response to an external stimulus is known as nastic movement . The folding up of leaves in sensitive plants in response to touch is an example of nastic movement.
(b) Photonasty - It is the non-directional movement in plants in response to light.
Thigmonasty - It is the non-directional movement in plants in response to touch

Question. A potted plant is kept horizontally for a considerable time. The three positions of the parts A and B of the potted plant are shown in the following figures :
(a) Which figure shows the correct position taken by the parts A and B of the plant ?
(b) What type of phenomenon is exhibited by the figure chosen in (a) above ?
Answer : (a) Figure (ii) (b) Geotropism

Question. Name the plant hormones which are responsible for the following effects :
(a) falling of leaves (b) opening of stomata
(c) bending of stem towards light (d) closing of stomata
Answer : (a) Abscisic acid (b) Cytokinin (c) Auxin (d) Abscisic acid

Question. Name the plant organs which are :
(a) positively phototropic
(b) positively geotropic
(c) negatively geotropic
(d) positively hydrotropic
Answer : (a) Stem (or Shoot)
(b) Root
(c) Stem (or Shoot)
(d) Root

Question. Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism ?
Answer : The folding up of leaves in a sensitive plant on touching is not a tropism because it is a non-directional movement. Tropism is a directional movement where the direction of the movement of the plant part is towards the stimulus.

Question. Why is the closing of a dandelion flower at dusk (when it gets dark) not a tropism ?
Answer : • The closing of a dandelion flower at dusk is not a tropism as it is a form of non-directional movement with respect to the stimulus.
• The stimulus for the opening and the closing of petals in dandelion flowers is the intensity of sunlight (bright and dim).
• This form of non-directional movement is depicted as a nastic movement.

Long Answer Type Questions

Question. (a) What is meant by ‘tropisms’ (or tropic movements) ? Explain with an example.
(b) What are the different types of tropisms ? Define each type of tropism. Write the name of stimulus in each case.
(c) How do tropisms differ from nasties (or nastic movements) ?
Answer : (a) Tropism is the directional movement where the plant parts move in a particular direction with the response to the stimulus.
Example- Geotropism: Growth of roots towards gravity. Phototropism: Growth of stems towards the sunlight. 
(b) The different types of tropisms are:
(i) Phototropism: The movement of plant parts in response to light is called phototropism. Its stimulus is light.
(ii) Geotropism: The movement of plant parts in response to gravity is called geotropism. Its stimulus is gravity.
(iii) Hydrotropism: The movement of plant parts in response to water is called hydrotropism. Its stimulus is water.
(iv) Chemotropism: The movement of plant parts in response to chemicals is called chemotropism. Its stimulus is chemical.
(v) Thigmotropism: The movement of plant parts in response to touch is called thigmotropism. Its stimulus is touch. 

(c) Tropism is a directional movement where the parts of plant move in a particular direction with the response to stimulus. These movements are exhibited by all parts of a plant.
Nasties are the non-directional movements of plant parts in response to an external stimulus. These movements are exhibited by the flat organs (like leaves and petals of flowers) of a plant.

Question. (a) Define phototropism. Give one example of phototropism.
(b) How does phototropism occur in a plant stem (or shoot) ? Explain with the help of labelled diagrams.
(c) What is meant by positive phototropism and negative phototropism ? Give one example of each type.
Answer : (a) The growth of plant parts in response to light is known as phototropism. An example of phototropism is the growth of plant stem in the upward direction in response to sunlight.
(b) The stems of plants grow towards sunlight showing positive phototropism.
(c) The movement of plant parts towards the light source is known as positive phototropism, whereas the movement of plant parts away from light is known as negative phototropism.
The stems of plants show positive phototropism as they grow upwards. The roots of plants show negative phototropism as they grow downwards into the soil.

Question. (a) Define geotropism. Give one example of geotropism.
(b) What is meant by ‘positive geotropism’ and ‘negative geotropism ? Give one example of each type. Draw a labelled diagram to illustrate your answer indicating the plant part which shows positive geotropism and the plant part which shows negative geotropism.
(c) Name one plant part which exhibits positive thigmotropism.
Answer : Part (a): Geotropism:
The movement of plant parts in response to the direction of gravity is known as geotropism.
The growth of plant roots is an example of geotropism as it grows towards the direction of gravity.
Part (b): Positive and negative geotropism:
If the movement of the plant parts is towards the pull of gravity, it is known as positive geotropism; whereas if the movement of the plant parts is in the direction opposite to the pull of gravity, it is known as negative geotropism.
The movement of roots towards the soil is an example of positive geotropism.
The movement of plant stem away from the soil in the upward direction is an example of negative geotropism. 

Part (c): Example of thigmotropism:
Tendrils or climbing organs of a plant exhibit positive thigmotropism.
These structures are found in plants with weak stems like pumpkins.

Question. (a) How does control and coordination take place in plants ? How does it differ from that in animals ?
(b) Name five stimuli which act on plants. Name the type of tropism produced by each one of these stimuli.
(c) Define hydrotropism. Give one example of hydrotropism. State whether this example is of positive hydrotropism or negative hydrotropism. Illustrate your answer with the help of labelled diagram.
Answer : (a) Control and coordination occur in plants with the help of hormones. It differs from animals because animals have a nervous system while the plant hasn't.
(b) The five types of stimuli and the tropisms produced by each of them are:
1. Light - produces phototropism.
2. Water - produces hydrotropism.
3. Gravity - produces geotropism.
4. Touch - produces thigmotropism.
5. Chemicals - produce chemotropism.
(c) The growth or movement of plant parts in response to water is known as hydrotropism. An example of hydrotropism is the movement of plant roots towards the water. It is a positive hydrotropism because the roots move towards the stimulus (water).

Question. (a) What is meant by positive tropism and negative tropism ? Explain with examples.
(b) Define thigmotropism. Give one example of thigmotropism.
(c) What is the difference between thigmotropism and thigmonasty ? Name one plant which exhibits thigmotropism and one plant which exhibits thigmonasty. What behaviour (or responses) of these plants make you think that they exhibit thigmotropism and thigmonasty respectively ?
Answer : (a) If the movement of the response is towards the stimulus, it is known as positive tropism; whereas if the movement of the response is in the direction opposite to the stimulus, it is is known as negative tropism.
The movement of roots towards the pull of gravity is an example of positive geotropism, whereas the movement of plant stem in the direction opposite to the pull of gravity is an example of negative geotropism.
(b) The directional movement of plant parts in response to touch is known as thigmotropism. The movement of tendrils of climbing plants towards the things they happen to touch is an example of thigmotropism.
(c) Bitter gourd exhibits thigmotropism as its tendrils show directional movement towards the things they happen to touch.
On the other hand, Mimosa pudica exhibits thigmonasty as its leaflets show non-directional movement in response to touch.

Questions Based on High Order Thinking Skills (HOTS)

Question. P is a cell (or group of cells) in the human body which is sensitive to a particular type of stimulus and conveys the messages to CNS through nerves Q. On the other hand, R is a part of the human body which can respond to a stimulus according to the instructions sent from the CNS through nerves S.
(a) What is P ? Name five organs which contain cells (or group of cells) like P.
(b) Name the nerves Q.
(c) What is R ? Give two examples of R.
(d) Name nerves S.
(e) How do messages travel through the nerves Q and S ?

Answer : (a) P is a receptor ; Eyes, Ears, Nose, Tongue and Skin
(b) Sensory nerves
(c) Effector ; Muscles and Glands
(d) Motor nerves
(e) In the form of electrical impulses

Question. The human body contains a large number of cells A which are very long and branched, and look like electric wires. The longest branch of this cell is B whereas there are many small branches C. Any two A cells do not join to one another completely in the human body. There is a microscopic gap D between every pair of adjacent A cells through which electric impulses can pass by the release of a chemical substance.
(a) What are cells A ?
(b) What is the name of (i) branch B, and (ii) branches C ?
(c) What is the microscopic gap D known as ?
(d) What is the function of cells like A in the human body ?
(e) The cells A are of three types. Name the three types.

Answer : (a) Neurons (b) (i) Axon (ii) Dendrites (c) Synapse (d) Transmit messages to and from the central nervous system (e) Sensory neurons, Motor neurons and Relay neurons

Question. When we touch a hot plate unknowingly, then this heat is sensed by a receptor P present in our fingers. The receptor triggers an impulse in neuron Q which transmits the message to an organ R which is a part of the central nervous system. Here the impulse is passed on to a neuron S which in turn passes it to a yet another neuron T. The neuron T passes the impulse to a tissue U in our arm. The tissue U then contracts and pulls our hand away from the hot plate.
(a) What is the name of (i) receptor P (ii) neuron Q, and (iii) organ R ?
(b) What is (i) neuron S, and (ii) neuron T ?
(c) Name the tissue U.
(d) What name is given to the phenomenon in which hand is pulled away quickly from the hot plate ?
(e) Name the effector in this whole process.

Answer : (a) (i) Thermoreceptor (ii) Sensory neuron (iii) Spinal cord (b) (i) Relay neuron (ii) Motor neuron
(c) Muscle (d) Reflex action (e) Muscle (of arm)

Question. The gland X which is located just below the brain in the human head secretes a chemical substance Y which controls the development of bones and muscles in the body of a person. Secretion of too little of substance Y as well as the secretion of too much of substance Y by the gland X leads to abnormal development of the body of a person.
(a) Name the gland X.
(b) What is the chemical substance Y ?
(c) What happens if too little of substance Y is secreted ?
(d) What happens if too much of substance Y is secreted ?
(e) Name the system of glands in the human body of which gland X is a part.

Answer : (a) Pituitary gland (b) Human growth hormone (c) The person remains very short and becomes a dwarf (d) The person grows very tall and becomes a giant (e) Endocrine system

Question. A and B are the two systems of control and coordination in the human body. The messages in system A are transmitted in the form of chemical substances C which travel comparatively slowly through the blood stream. The substances C are made in tissues D present in the head and trunk of human body. The messages in system B are transmitted very quickly in the form of electrical impulses through fibres E. The effect of messages transmitted by system B usually lasts for a much shorter time as compared to those transmitted by
system A.
(a) Name the system A. What does system A consist of ?
(b) Name the chemical susbtance C.
(c) What is tissue D ? Name any five such tissues in the human body.
(d) Name the system B. What does system B consist of ?
(e) Name the fibres E.
(f) State whether system A controls the working of system B or system B controls the working of system A.

Answer : (a) Endocrine system ; Glands (b) Hormones (c) Endocrine
glands ; Pituitary, Thyroid, Pancreas, Adrenals, Testes (d) Nervous system ; Brain , Spinal cord and Nerves
(e) Nerve fibres(f) System B (Nervous system) controls the working of system A (Endocrine system)

Question. A cylindrical structure P in our body begins in continuation with medulla and extends downwards. It is enclosed in a bony cage Q and surrounded by membranes R. As many as x pairs of nerves arise from the structure P. The structure P is involved in the reflex actions of our body and conduction of nerve impulses to and from another organ S of our body with which it forms CNS.
(a) Name the structure P.
(b) Name (i) bony cage Q, and (ii) membranes R.
(c) How much is x ?
(d) Name the organ S.
(e) What are the reflexes involving structure P only known as ?

Answer : (a) Spinal cord (b) (i) Vertebral column (ii) Meninges (c) 31 (d) Brain (e) Spinal reflexes

Question. The pancreas is made up of two parts A and B. The part A secretes insulin whereas part B secretes pancreatic juice.
(a) Which part is functioning as an endocrine gland ? Why ?
(b) What is insulin and what effect does it have in the body ?
(c) Name the disease which can be treated by giving insulin injections.
(d) What does pancreatic juice contain ? Where does pancreatic juice go ?
(e) Name the life process in which pancreatic juice is made use of.

Answer : (a) Part A; It is secreting a hormone called insulin (b) Insulin is a hormone ; It controls the blood sugar
level (c) Diabetes (d) Pancreatic juice contains digestive enzymes like pancreatic amylase, tryspin and
lipase ; Small intestine (e) Digestion

Question. The gland A is attached to the wind pipe in the human body. The gland A makes and secretes a hormone B which controls the metabolism of carbohydrates, fats and proteins in the body. The non-metal element C is necessary for the formation of hormone B. The deficiency of C in the diet can cause a deficiency of hormone B in the body leading to a disease D in which the neck of a person appears to be swollen. People are advised to use salt E in cooking food so as to avoid disease D.
(a) Name (i) gland A, and (ii) hormone B.
(b) What is the element C ?
(c) Name one type of food which can provide sufficient C in the diet of a person.
(d) Name (i) disease D, and (ii) salt E.

Answer : (a) (i) Thyroid gland (ii) Thyroxine (b) Iodine (c) Sea-food (like
fish) (d) (i) Goitre (ii) Iodised salt

Question. A piece of thread was tied tightly around an animal’s pancreatic duct. The animal subsequently had difficulty in digesting food but did not get diabetes. Explain.
Answer : When a piece of thread is tied tightly around the animal’s
pancreactic duct, then the pancreatic duct gets closed due to which pancreatic juice containing digestive
enzymes cannot go into small intestine. In the absence of pancreatic juice, the animal has difficulty in digesting
food. The pancreas however, releases insulin hormone directly in the blood due to which the animal does
not get diabetes,

Question. Which is the target organ of both adrenaline and insulin ?
(a) heart
(b) kidney
(c) liver
(d) pancreas

Answer : (c) liver

Question. A gland W is located just below the stomach in the human body. The gland W secretes a hormone X. The deficiency of hormone X in the body causes a disease Y in which the blood sugar level of a person rises too much. The person having high blood sugar is called Z. 
(a) Name (i) gland W, and (ii) hormone X.
(b) What is the function of hormone X ?
(c) Name (i) disease Y, and (ii) person Z.
(d) What advice would you like to give to a person who is suffering from disease Y due to faulty life-style ?

Answer : (a) (i) Pancreas (ii) Insulin (b) Hormone X (insulin) controls the blood sugar level (c) (i) Diabetes (ii) Diabetic person (d) Control diet , Reduce weight, Do regular physical exercise ; Take medicines regularly

Question. There are two similar glands P which are located on the top of two similar organs Q in the human body. The glands P are often called glands of emergency and they secrete a hormone R into the blood stream. The hormone R is secreted in large amounts when a person is frightened. It brings about temporary changes in the body which allow a lot of substance S from the liver to go into blood so as to provide a lot of energy in a very short time. This helps the person concerned to fight back or run away from the frightening situation.
What are P, Q, R and S ?
Answer : P : Adrenal glands ; Q : Kidneys ; R : Adrenaline hormone ; S : Glucose

Question. The two glands A and B which occur in pairs, are present in the endocrine system of humans. The pair of glands A is found only in females whereas the pair of glands B occurs only in males. The glands A make and secrete two hormones C and D whereas glands B make and secrete only one hormone E. In addition to hormones, glands A make gametes F whereas glands B make gametes G.
(a) What are glands A ?
(b) What are hormones C and D ?
(c) What are glands B ? Name the hormone E.
(d) What are gametes (i) F, and (ii) G ?
(e) Which event in the life of males and females is associated with the secretion of hormones C, D and E ?

Answer : (a) Ovaries (b) Oestrogen and Progesterone (c) Testes ; Testosterone (d) (i) Ova
(or Eggs) (ii) Sperms (e) Puberty

Question. The organ A which is located inside the skull of our body is protected by a bony box B and it is surrounded by three membranes C. The space between the membranes is filled with a liquid D which protects the organ A from mechanical shocks. The organ A in combination with another organ E makes up the central nervous system.
(a) What is organ A ?
(b) What are (i) B (ii) C, and (iii) D ?
(c) Name the organ E.
(d) While walking barefooted, if we happen to step on a sharp piece of stone, we immediately lift our foot up. Which of the two organs, A or E, is directly involved in this action ?
(e) If we step out from a darkened room into bright sunshine, we close our eyes for a moment. Which of the two organs, A or E, is directly involved in this action ?

Answer : (a) Brain (b) (i) Cranium (Skull) (ii) Meninges (iii) Cerebro spinal
fluid (c) Spinal cord (d) Organ E (Spinal cord) (e) Organ A (Brain)

Question. Write down the following in the correct order for a simple reflex arc :
(a) impulse travels in motor fibre
(b) impulse travels in sensory fibre
(c) effector organ stimulated
(d) impulse crosses synapse

Answer :(b) → (d) → 
(a)→   (c)

Question. Explain why, the tongue may be considered to be both a receptor and an effector organS.
Answer : Tongue is considered a receptor because it has taste buds which act as receptors for tastes ; Tongue can be considered to be an effector because it is a muscular organ having muscles which can respond to a stimulus. 

Question. Explain why, the tongue may be considered to be both a receptor and an effector organ.

Answer : Tongue is considered a receptor because it has taste buds which act as receptors for tastes ; Tongue can be considered to be an effector because it is a muscular organ having muscles which can respond to a stimulus.