Biology exercise: Unit 3
1. Which of the following organisms can perform photosynthesis?
A) Animals B) Fungi
C) Plants D) All of the above
2. What type of energy powers photosynthesis?
A) Chemical energy B) Electrical energy
C) Thermal energy D) Light energy
3. Which two substances are the primary inputs for photosynthesis?
A) Oxygen and glucose B) Carbon dioxide and water
C) Nitrogen and phosphorus D) Sugars and minerals
4. What are the main outputs of photosynthesis?
A) Carbon dioxide and glucose B) Oxygen and sugars
C) Water and nitrogen D) Light and heat
5. Where does photosynthesis usually take place in plant cells?
A) Mitochondria B) Ribosomes
C) Chloroplasts D) Nucleus
6. What role does chlorophyll play in photosynthesis?
A) It breaks down sugars. B) It captures light energy.
C) It absorbs carbon dioxide. D) It releases oxygen.
7. How can the sugars produced in photosynthesis be utilized by the
organism?
A) Only for energy
B) Only for structural purposes
C) For energy, structure, or stored for later use
D) They cannot be used at all
8. What happens to the oxygen produced during photosynthesis?
A) It is used up by the plant.
B) It is released into the environment.
C) It is converted back to carbon dioxide.
D) It is stored in the chloroplasts.
9. What is the function of chloroplasts in photosynthesis?
A) To store water
B) To capture light energy and produce food
C) To absorb nutrients from the soil
D) To transport sugars
10. How do plants obtain their food?
A) By eating other plants
B) Through photosynthesis
C) By absorbing nutrients from the soil
D) By consuming animals
11.Which of the following is NOT mentioned as an important food
molecule?
A) Fats B) Proteins
C) Vitamins D) Sugars
12. What common element is found in fats, proteins, and sugars?
A) Hydrogen B) Nitrogen
C) Carbon D) Oxygen
13. What process do animals use to break down large food
molecules?
A) Photosynthesis B) Fermentation
C) Digestion D) Absorption
14. Where do the smaller molecules from digested food go?
A) They are excreted.
B) They enter the bloodstream.
C) They stay in the digestive system.
D) They are immediately converted to energy.
15. What happens to the smaller molecules inside cells?
A) They are stored as fat.
B) They are rearranged to form new molecules.
C) They are excreted as waste.
D) They remain unchanged.
16. What is one of the main purposes of the new molecules formed
from food?
A) To create waste
B) To help the organism grow and stay healthy
C) To produce energy directly
D) To absorb sunlight
17.What process do cells use to obtain energy from food molecules?
A) Photosynthesis B) Digestion
C) Cellular respiration D) Fermentation
18. Which of the following statements is true regarding food
molecules?
A) All food molecules are absorbed unchanged.
B) Only plants can use food molecules for energy.
C) Food molecules are essential for growth and energy in all living
organisms.
D) Animals do not need food molecules to live.
19. What is the main purpose of cellular respiration?
A) To produce food B) To release energy for the organism
C) To absorb nutrients D) To perform photosynthesis
20. What simple sugar is primarily broken down during cellular
respiration?
A) Fructose B) Sucrose
C) Glucose D) Lactose
21. Which two substances are the main inputs of cellular
respiration?
A) Glucose and nitrogen B) Oxygen and water
C) Glucose and oxygen D) Carbon dioxide and glucose
22. What are the outputs of cellular respiration?
A) Glucose and oxygen B) Carbon dioxide and water
C) Energy and heat D) Nitrogen and sugars
23. Where do the different parts of cellular respiration happen in
multicellular organisms?
A) Only in the nucleus B) In the cytosol and mitochondria
C) Only in the cytosol D) In the chloroplasts
24. What role do mitochondria play in cellular respiration?
A) They produce glucose.
B) They store waste products.
C) They are the site where some steps of cellular respiration occur.
D) They absorb oxygen.
25. What happens to glucose during cellular respiration?
A) It is stored as fat. B) It is broken down to release energy.
C) It is converted into proteins. D) It is used to form carbon dioxide.
26. Which letter best represents carbon dioxide in the model of
cellular respiration?
A B C D
27. Which sentence comparing cellular respiration in plants and
animals is true?
A) Animal cells carry out cellular respiration, but plant cells do not.
B) Cellular respiration occurs inside mitochondria in animal cells, and
inside chloroplasts in plant cells.
C) Cellular respiration releases carbon dioxide in both plant and
animal cells.
28. After a cat eats food, which of these three steps occurs second?
A) The atoms in food molecules are rearranged by chemical reactions
inside cells, releasing energy.
B) Energy from food is used to do work in the cat’s cells.
C) Large food molecules are broken down into smaller molecules in
the cat’s digestive system.
29. After a dog eats food, which of these three steps occurs last?
A) The atoms in food molecules are rearranged by chemical reactions
inside cells, releasing energy.
B) Energy from food is used to do work in the dog’s cells.
C) Large food molecules are broken down into smaller molecules in the
dog’s digestive system.
