Respiration in Plants:
1. By the use of which of the following structures, plants exchange gases?
A. Stem
B. Root
C. Bark
D. Stomata
Answer: D
Explanation: Plants, unlike animals, have no specialised organs for gaseous exchange but they use stomata and lenticels for this purpose. Plants can easily get along without any specialised respiratory organs.
2. Why plants can get along without the need for specialised respiratory organs?
A. It would be an extra expense
B. They don’t like it
C. Each plant part takes care of its own needs
D. Oxygen is easily available for all the parts of the plants
Answer: C
Explanation: There are several reasons why plants can get along without respiratory organs.
i. Each plant part takes care of its own gas-exchange needs
ii. Plants do not present great demands for gas exchange
iii. The distance that gases must diffuse is not large.
3. What are lenticels?
A. Openings on the surface of the bark
B. Openings on the surface of roots
C. Pores on leaves
D. Pores on stem
Answer: A
4. Where does the photosynthesis take place in eukaryotes?
A. Mitochondria
B. Cytoplasm
C. Chloroplasts
D. Vacuoles
Answer: C
Explanation: Photosynthesis takes place within the chloroplasts in the eukaryotes whereas the breakdown of complex molecules to yield energy takes place in the cytoplasm and the mitochondria.
5. The breaking of which of the following bonds leads to release of energy?
A. P-P bonds
B. C-C bonds
C. N-N bonds
D. S-S bonds
Answer: B
Explanation: The breaking of the C-C bonds of complex compounds through oxidation within the cells, leads to the release of a considerable amount of energy. This process is known as respiration.
6. Which of the following compounds are not oxidised to release energy?
A. Proteins
B. Fats
C. Carbohydrates
D. DNA
Answer: D
Explanation: Nucleic acids like DNA and RNA are never oxidised to release energy because these are integrated parts of the cell and they are used to carry or express different genes in the human beings which carry out different functions like the formation of proteins, fats and carbohydrates.
7. During oxidation within a cell, all the energy is released into a single step.
A. True
B. False
Answer: B
Explanation: During oxidation within a cell, all the energy contained in the respiratory substrate is not released in a single step because then all the energy would be lost in a single step and the cell would not be able to store the synthesised energy for its future use.
8. Which of the following acts as the energy currency of the cell?
A. ATP
B. Enzymes
C. Proteins
D. DNA
Answer: A
Explanation: ATP or Adenosine Triphosphate acts as the energy currency of the cell. The energy which is released by the oxidation of respiratory substrates is stored in ATP so that we can use it for future purposes.
9. Which of the following is used as a precursor for the biosynthesis of other molecules?
A. Phosphorous substrate
B. Nitrogen substrates
C. Carbon skeletons
D. Sulphur skeletons
Answer: C
10. In green plants, all the cells, tissues and organs carry out photosynthesis.
A. True
B. False
Answer: B
Explanation: In green plants, not all cells, tissues and organs photosynthesise, only cells containing chloroplasts, that are most often located in the superficial layers, carry out photosynthesis.
11. What is meant by cellular respiration?
A. Breakdown of water
B. Breakdown of air to consume energy
C. Breakdown of food materials to release energy
D. Breakdown of soil to release energy
Answer: C
12. Where does the energy required to carry life processes come from?
A. Food
B. House
C. Earth
D. Galaxy
Answer: A
Explanation: All the energy required for life processes is obtained by the oxidation of some macromolecules that we call as food. All living organisms need energy to carry out daily life activities.
13. Which of the following can synthesise their food?
A. Yellow plants
B. Green plants
C. Animals
D. Mycoplasma
Answer: B
Explanation: Only green plants and cyanobacteria can prepare their food, by the process of photosynthesis. They trap light energy and convert it into chemical energy that is stored in the bonds of carbohydrates.
14. What kind of organisms are fungi?
A. Saprophytes
B. Carnivores
C. Omnivores
D. Herbivores
Answer: A
