cellular respiration

Question 1

what is aerobic respiration?

Answer 1

• it occurs in presence of oxygen and results in the complete breakdown of respiratory substrates

Question 2

what is anaerobic respiration?

Answer 2

it occurs in absence of oxygen and results in partial breakdown of respiratory substrates

Question 3

what is the purpose of respiration?

Answer 3

the chemical energy released during respiration is used by cells to synthesise ATP from ADP and inorganic phosphate
- subsequently during hydrolysis of ATP to ADP and inorganic phosphate releases energy which is used in cellular work

Question 4

ATP:
what is the role of ATP

Answer 4

• it is a short term carrier of energy which provides a ready source of chemical energy
• it transfer energy from energy yielding reactions to energy requiring reactions
• hence, ATP is a small and water-soluble molecule which can move easily between cytosol and organelles by diffusion
• the rapid conversion of ATP to ADP and back to ATP again ensures that ATP is continuously recycled in cells

Question 5

ATP:
what is the structure of ATP?

Answer 5

• a ribose sugar
• an adenine base
• a chain of three phosphates
• the two end phosphate groups of each ATP are attached by phosphoanhydride bonds which are high energy bonds

Question 6

ATP:
what happens during the hydrolysis of ATP?

Answer 6

• phosphoanhydride bonds can be hydrolysed to release a large amount of free energy to do cellular work
• most energy exchanges in cells involve cleavage of only the endmost phosphate group
• the hydrolysis of ATP to ADP and an inorganic phosphate ion involves the breaking of the phosphoanhydride bond, by the addition of water which releases a large amount of energy for cellular work

Question 7

SYNTHESIS OF ATP:
- the addition of an inorganic ____ group to ADP to from ATP is a ___ reaction which requires the input of ___
- the enzymes which catalyses this reaction includes ___ and a class of enzymes known as kinases

the three types of phosphorylation reactions that can occur to synthesize ATP from ADP and inorganic phosphate group:
1. photophosphorylation
2. substrate-level phosphorylation
3. oxidative phosphorylation