Question

Q1) why do dicot leaves have more number of stomata on their under surface.

Q2) differencee between i )photosynthesis and chemosynthesis and ii) photosythesis and respiration

Answer 1

Respiration	Photosynthesis
It takes place in all the living cells, both green(Chlorophyllated) and non green	It takes place only in chlorophyllous cells
It occurs in light and dark, both conditions	It occurs only in light
Glycolysis: in cytoplasm Citric acid cycle or Krebs cycle: mitochondrial matrix Electron transport chain and oxidative phosphorylation: in inner mitochondrial membrane	Light reaction: grana of chloroplast Dark reaction or calvin cycle or CO2 fixation: stroma of chloroplast Water splitting complex or photolysis: thylakoid lumen
Oxygen is utilized and carbon dioxide and water are formed. C6H12O6 + 6O2-> 6CO2 + 6 H2O+ energy	Carbon dioxide and water are used while oxygen is evolved. 6CO2 + 12H2O -> C6H12O6 + 6H2O+ 6O2
It is a catabolic process and includes the destruction of stored food	It is an anabolic process and includes the manufacture food
Oxygen is absorbed in the process	Oxygen is liberated
Carbohydrates are oxidised	Carbohydrates are synthesised
Energy is released during respiration and hence it is an exothermic process.	Energy is stored during this process and hence it is an endothermic process.
Energy is liberated in the form of ATP.	Light energy is stored in the form of glucose or chemical energy.
Dry weight of plants decreases	Dry weight of plants increases
Oxidative phosphorylation occurs	Photophosphorylation occurs
During the process, potential energy is converted to kinetic energy.	Light energy is converted into potential energy

Ans (1)
All surfaces of the leaf have some amount of stomata for regulating gas exchange for photosynthesis. However, the lower epidermis (the underside of the leaf) has more, because it is more often in the shade and so it is cooler, which means evaporation won't take place as much

(2)
Photosynthesis
1. Occurs only in green plants or chlorophyllated organisms.
2. Sunlight or solar energy is essential.
3. Involves pigment systems to trap solar energy.
4. Radiant energy is fixed as chemical energy and stored in organic molecules like carbohydrates.
5. Oxygen is evolved during the process.
6.Major contribution of energy to the total biospheric energy reserve.
Chemosynthesis
1. Occurs only in some chemosynthetic bacteria.
2. Sunlight or solar energy is not essential.
3. Pigment systems are not necessary.
4. Chemical energy is released by the oxidation of inorganic molecules and is then stored in organic molecules.
5. Oxygen is not evolved during the process.
6. No significant contribution of energy to the total biospheric energy reserve.