Frank Brothers Solutions for ICSE Class 9 Biology Chapter 10 Respiration In Plants

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Answer 1:
(a) Respiration is the process of oxidation and decomposition of organic compounds like simple carbohydrate glucose in the living cells with the release of energy.
(b) Respiratory substrate is a substance which is oxidized to yield energy necessary for cell maintenance and growth. Example - Carbohydrates and fats
(c) C6H1₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 673 t{ kcal energy (38 ATP)
(d) Alcoholic fermentation is a biological process in which hexose sugars such as glucose and fructose are converted into cellular energy and thereby produce ethanol and carbon dioxide as metabolic waste products.
(e) Glycolysis
(f) Cytoplasm of cell
(g) Mitochondria
Respiration is the essential life process that provides the energy needed for every activity in a plant. It happens day and night in every living cell to keep the organism alive.
Teacher's Tip: Think of glucose as the "battery" and respiration as the process of "plugging it in" to get power.
Exam Tip: Always write the complete balanced chemical equation for aerobic respiration to score full marks.

Solution 2:
Answer 2:
(a) Fermentation: It occurs in microorganisms and yeast.
Anaerobic respiration: It occurs in higher plants.
(b) Aerobic respiration:
Occurs in presence of oxygen
Complete oxidation of glucose takes place
More energy is liberated
End-products are water and carbon dioxide
It takes place in cytoplasm and mitochondria
Anaerobic respiration:
Occurs in absence of oxygen
Incomplete oxidation of glucose takes place
Less energy is liberated
End-products are ethyl alcohol and carbon dioxide
All the reactions occur in cytoplasm.
(c) Respiration:
It takes place in living cells only.
Food material is oxidized stepwise, accompanied with stepwise release of energy.
Most of the energy released is stored in the form of ATP.
It is a continuous process
Combustion:
It does not occur in living cells only.
The substrate is oxidized at random and energy is released from the spontaneous breakdown of foodstuff.
The energy released is lost in the form of light and heat.
It is not a continuous process
These comparisons show how living things release energy in a controlled and efficient way compared to simple burning. While combustion is fast and hot, respiration is slow and safe for cells.
Teacher's Tip: Remember "Aerobic" sounds like "Air," which contains the oxygen needed for this process.
Exam Tip: When asked for differences, use clear headings and align matching points for better presentation.

Answer 3:
Take two thermos flasks. In the first flask, keep some germinating seeds and a little water to keep them moist. In the second flask, keep some boiled seeds. Place corks fitted with thermometers on both the flasks. Keep the flasks airtight. Note the temperature in both the thermometers. Leave the flasks for sometime and again record the temperature. It is observed that the temperature of the first set increases and in the second case, it is not affected. The rise in temperature is because during respiration, germinating seeds release some energy in the form of heat energy.
This experiment demonstrates that energy is released as heat during the process of respiration. Boiled seeds do not show a temperature rise because their cells are no longer living and respiring.
Teacher's Tip: Germinating seeds are like tiny engines working hard to grow, which is why they get warm.
Exam Tip: Mention that boiled seeds are used as a "control" to prove that only living tissues respire.

Answer 4:
Yes, respiration is the reverse of photosynthesis.
Photosynthesis builds food by taking in carbon dioxide and water, while respiration breaks down food to release them. They are two sides of the same coin that balance the gases in our atmosphere.
Teacher's Tip: Think of Photosynthesis as "making a sandwich" and Respiration as "eating the sandwich."
Exam Tip: To explain this well, compare the equations of both processes side by side.

Answer 5:
1. - (b) nutrients are oxidized without using molecular oxygen by the process of fermentation.
2. - (c) is the best organic substrate for respiration.
3. - (a) partial breakdown of food substance.
4. - (e) the series of change from glucose to pyruvic acid in respiration.
5. - (d) the intermediate substance in the breakdown of glucose.
Matching these terms helps us understand the specific chemicals and steps involved in cellular energy release. Each term describes a specific part of the complex biological machinery inside a plant.
Teacher's Tip: Associate "Pyruvic acid" as the halfway point for glucose during its breakdown.
Exam Tip: Double-check that your matched pairs correspond correctly to the numbers in the question.

PAGE NO: 88

Answer 6:
(a) Aim - To show that carbon dioxide is released during respiration.
(b) To prevent photosynthesis
(c) To absorb carbon dioxide from incoming air.
(d) C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 673 { kcal energy (38 ATP)}
(e) The respiratory chamber should be covered with a black cloth to prevent photosynthesis. The lime water in Flask A turns milky as the plant respires and gives out carbon dioxide which turns the lime water milky. The lime water in Flask B remains clear as the incoming air is free from carbon dioxide.
Lime water is the standard test for identifying Carbon Dioxide gas in a laboratory setting. If the plant were allowed to photosynthesize, it would use up the CO₂ it produces, making the experiment fail.
Teacher's Tip: "Black cloth = No Light = No Photosynthesis," allowing us to see only respiration.
Exam Tip: When describing this experiment, always state that the lime water turns "milky" specifically.

Answer 7:
(a) Anaerobic
(b) Glycolysis
(c) Pyruvic acid
(d) Oxygen
(e) Cytoplasm
These terms identify the specific types of respiration and the locations where they occur in the cell. Knowing the difference between the cytoplasm and mitochondria is vital for biology students.
Teacher's Tip: Glycolysis always starts in the "Cytoplasm," no matter what type of respiration follows.
Exam Tip: Be careful with the spelling of "Mitochondria" and "Glycolysis" to avoid losing marks.

Answer 8:
(a) False
(b) False
(c) False
(d) False
(e) False
Identifying false statements helps correct common misconceptions about how plants and cells breathe. For example, it is a myth that respiration only happens at night; it happens all the time.
Teacher's Tip: If a cell stops respiring even for a minute, it will die!
Exam Tip: For "True/False" questions, read the statement twice to look for "tricky" words like "only" or "never."

Answer 9:
(a) To show that heat is evolved during respiration
(b) In flask A, moist seeds respire and produce heat that increases the temperature.
(c) If formalin was not used, bacteria will grow on the dry seeds and respire anaerobically to produce a little heat.
Formalin acts as a disinfectant to ensure that any heat measured comes only from the seeds and not from microscopic bacteria. This makes the experiment more accurate and scientific.
Teacher's Tip: Formalin is like a "germ-shield" that keeps the experiment clean and valid.
Exam Tip: Explain that moisture is necessary because dormant dry seeds respire very slowly compared to moist ones.

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Answer 10:
glucose ATP
Glucose is the fuel used by cells, and ATP is the energy "currency" they spend to do work. Without converting food into ATP, the cell cannot use the energy stored in glucose.
Teacher's Tip: Think of Glucose as a "Gold Bar" and ATP as "Cash" that is easier to spend.
Exam Tip: Use the full name "Adenosine Triphosphate" along with "ATP" for an impressive answer.

Answer 11:
(a) C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + 21 { kcal energy (2 ATP)}
(b)
Respiration:
Respiration is a catabolic process during which food material is broken down and energy is released.
The dry weight of plant decreases.
Oxygen is used here.
Carbon dioxide is released.
Photosynthesis:
Photosynthesis is an anabolic process during which food material is synthesized and energy is stored.
The dry weight of plant increases.
Oxygen is released.
Carbon dioxide is used up.
Respiration and photosynthesis are the two major chemical cycles that keep life on Earth in balance. One stores the sun's energy in food, and the other releases it for use by living things.
Teacher's Tip: "Catabolic" sounds like "Catastrophe" (breaking down), and "Anabolic" sounds like "Adding" (building up).
Exam Tip: Mention "dry weight" changes to show you understand the physical impact of these processes.

Answer 12:
(a) To absorb carbon dioxide produced during respiration
(b) If these are not soaked in disinfectant, the bacterial growth may be there in the tube Y and accurate result may not be obtained due to bacterial respiration.
(c) The germinating peas respire and oxygen is used which create a vacuum in the tube. So coloured water has risen in tube1.
(d) Respiration
(e) It is defined as the stepwise oxidation of glucose in the living cells to release energy.
This experiment shows that plants consume oxygen during respiration, which creates a change in air pressure inside the tube. By measuring the rise in water, we can actually see how much oxygen is being used.
Teacher's Tip: The "Vacuum" created is just like sucking air through a straw, which pulls the water up.
Exam Tip: Be very specific that the vacuum is created because CO₂ is absorbed and O₂ is used up.

Answer 13:
(a) mitochondria
(b) Fermentation
Mitochondria are the powerhouses of the cell where most of the ATP is produced during aerobic respiration. Fermentation is the alternative pathway cells use when they run out of oxygen.
Teacher's Tip: No Oxygen? No problem! Some organisms just switch to fermentation to keep going.
Exam Tip: Label mitochondria clearly in any cell diagram to show you know their role in respiration.

Answer 14:
Glycolysis:
It occurs in both aerobic and anaerobic respiration.
It occurs in the cytoplasm of cell.
Kreb's cycle:
It occurs only in aerobic respiration, but not in anaerobic respiration.
It occurs in mitochondria of cell.
Glycolysis is the first step in breaking down sugar, and it can happen anywhere in the cell without oxygen. The Kreb's cycle is the more advanced second step that requires oxygen and special organelles.
Teacher's Tip: Glycolysis is the "starter motor," while Kreb's cycle is the "main engine."
Exam Tip: Make sure to specify that the Kreb's cycle cannot happen during anaerobic respiration.

Answer 15:
Aerobic respiration: End-products are water and carbon dioxide.
Anaerobic respiration: End-products are ethyl alcohol and carbon dioxide.
The products of respiration differ depending on whether oxygen is present to fully break down the glucose. Aerobic respiration is much cleaner and more efficient than anaerobic respiration.
Teacher's Tip: Think of "Ethyl Alcohol" as the signature product of anaerobic respiration in plants/yeast.
Exam Tip: You can also mention that anaerobic respiration in animal muscles produces lactic acid instead of alcohol.

Answer 16:
(a) Respires
(b) Day and night
(c) Aerobic respiration
(d) Rises
(e) Controlled manner
Filling in these blanks correctly shows a solid understanding of how and when respiration happens. It highlights that respiration is a constant and carefully managed process within living organisms.
Teacher's Tip: Remember that plants don't take "breaks" from respiring, even when they are making food.
Exam Tip: Use the term "controlled manner" to describe how enzymes manage the release of energy in cells.

PAGE NO: 90

Answer 17:
(a) Respiration
(b) ATP
(c) Aerobic respiration
(d) Anaerobic respiration
(e) Caustic potash and KOH
(f) Lime water
(g) Carbon dioxide and water
(h) Ethyl alcohol and carbon dioxide
These one-word answers cover the fundamental concepts and chemicals involved in plant biology. They represent the "vocabulary" you need to discuss respiration accurately.
Teacher's Tip: KOH and Caustic Potash are the same thing; they are very hungry for Carbon Dioxide!
Exam Tip: When writing chemicals like KOH, make sure your capitalization is correct (K and O and H are all capital).

Answer 18:
(i) (c) Glucose is converted to carbon dioxide and water, releasing energy.
(ii) (d) Glycolysis, Kreb's cycle, electron transfer
(iii) (c) Energy is left in alcohol.
(iv) (d) To accept hydrogen and form water.
(v) (b) CO₂ and alcohol
(vi) (c) mitochondria
(vii) (b) Hans Krebs
(viii) (d) fermentation
(ix) (b) ATP
(x) (c) ATP
(xi) (b) Two
(xii) (a) In cytoplasm
(xiii) (c) 673 Kcal
Multiple-choice questions test your ability to recognize precise facts about biological processes. These answers confirm details about the history, chemistry, and location of respiration steps.
Teacher's Tip: Hans Krebs is the scientist who mapped out the cycle named after him—he's a biology hero!
Exam Tip: Read every option in an MCQ before choosing, as two answers might look similar at first glance.