Q: Write a comparative account of photosynthesis and respiration. (4 Marks)
Photosynthesis
1. Occurs only in plants and some photosynthesis bacteria
2. Takes place in the presence of sunlight only
3. A plant can survive without performing photosynthesis for a few days
4. In plants, only few cells perform photosynthesis
5. It occurs in the chloroplast and is dependent on light.
6. In this process light energy is fixed
7. Raw materials are carbon dioxide and water.
8. Oxygen is liberated in this process and carbon dioxide is utilized
9. Adds on weight to the organism
10. Converts radiant light energy into chemical energy
11. Produces ATP by use of light energy.
12. NADP is reduced to NADPH2 using hydrogen of water molecule.
13. ATP and NADPH2 are mainly used for synthesis of organic compounds.
14. Anabolic process.
Respiration
1. Occurs in all living organisms.
2. Takes place throughout the day.
3. No organism can survive without respiration for few minutes
4. All living cells of an organism perform this process.
5. Aerobic respiration takes place in cytoplasm and mitochondria and is independent of light.
6. In this process energy is released
7. Uses carbohydrates or organic substance and oxygen.
8. Oxygen is utilised and carbon dioxide is released.
9. Decreases the weight of organism
10. Releases chemical or potential energy for several other functions.
11. Produces ATP by oxidation of energy glucose.
12. NADH2 is formed hydrozen of carbohydrates.
13. NADH2 and ATP are made available for cellular activities.
14. Catabolic process
Two Mark Questions
Q: What is the difference between photophosphorylation and oxidative phosphorylation?
A: In Photosynthesis, ADP is changed to ATP by using the light energy. This is called (photosynthesis) photophosphorylation. In respiration, ADP is changed to ATP by oxidation of glucose. This is called oxidative phosphorylation.
Q: What is epiglottis?
A: the cartilagenous flap which acts as a lid over the glottis preventing the food from entering the larynx is called the epiglottis.
Q: How trachea is prevented from collapsing?
A: The walls of trachea are supported by several “C” shaped cartilagenous rings which prevent the trachea from collapsing and closing.
One-mark Questions
Q: In which part of the cell, photosynthesis and respiration occur?
A: ‘Photosynthesis’ occurs in chloroplasts. In ‘Respiration’ glycolysis occurs in cytoplasm and Krebs cycle occurs in mitochondria.
Q: What is the type of respiration in amoeba?
A: In amoeba, respiration occurs by diffusion.
Q: What are alveoli?
A: Lungs in all vertebrates are made up of several thousands of small chambers called alveoli.
I. Important bits
1. The energy stored in photosynthesis is obtained from
A) sunlight B) oxidation of glucose
C) break down of proteins
D) break down of glucose
2. The rate of respiration per minute in a new born child
A) 18 times B) 32 times C) 26 times D) 16 times.
3. Respiration takes place in the presence of-
A) light B) chlorophyll
C) optimum temperature D) moisture
II. Fill in the blanks:
1. The raw materials for photosynthesis are …… of respiration.
2. The scientific name for the wind pipe of man is ……
3. “C” shaped cartilagenous rings are present in …… of man.
4. Rate of …….. decreases when fruits are kept in cold storage.
Answers:
I. 1-A; 2-B; 3-C. II. 1. product; 2. bronchi; 3. trachea; 4. respiration.