III. Metabolism

Question 1

structure of protein enzyme?

Answer 1

4 polypeptides hold together by hydrophobic interactions, hydrogen bonds, ionic bonds and disulfide bridges

Question 2

state the route of enzymatic catalysis

Answer 2

substrate —-enzyme—> product

Question 3

which are the factors influencing enzyme activity?

Answer 3

pH
temperature
substrate concentration
salts

Question 4

methodes of regulation of enzyme activity - competitive inhibitation

Answer 4

competes with the substrate (has similar shape) to bind to the active site of the enzyme. Competitive inhibitors are substances that alter catalytic actions of the enzyme and consequently slows down, or in some cases stops catalysis.

• the lock-and-key model
• if the inhibitor wins agains the substrate, the reactions slows down

Question 5

methodes of regulation of enzyme activity - non-competitive inhibitation

Answer 5

substances which when added to the enzyme alter the enzyme in a way that it cannot accept the substrate, so it binds on the surface. It changes the shape of the enzyme so other substrates cannot bind to the active site

Question 6

methodes of regulation of enzyme activity - phosphorylation

Answer 6

the addition of phosphate group to protein or other organic molecule. It turns many protein enzymes on or off, thereby altering their function and activity

Question 7

methodes of regulation of enzyme activity - dephosphorylation

Answer 7

the removal of phosphate group from an organic compound by hydrolysis. Dephosphorylation acctivates and deactivates enzymes by cleaving phosphoric esters and anhydrides. It is the conversion of ATP to ADP and inorganic phosphate

Question 8

methodes of regulation of enzyme activity - activation of proenzymes

Answer 8

it is an inactive enzyme ancestor. A proenzyme requires a biochemical change (such as hydrolisis -> to reveal the active site) for it to become an active enzyme

Question 9

What is anabolism? (metabolism)

Answer 9

• It includes constructive or building up processes
• Energy is used and stored as potential energy
• Examples: photosynthesis in plants, assimilation in animals

Question 10

What is catabolism? (metabolism)

Answer 10

• It includes destructive or breaking down processes
• energy is released as kinetic energy
• enamples: cell respiration, digestion, excretion

Question 11

What are the major energetic compounds in the cell and how is the energy derived?

Answer 11

Major energetic compounds:
- carbohydrates
- lipids
- water
- nucleotides
The energy is derived from the chemical bond energy of the food molecules, which thereby sereve as fuel for cells.
e.g. glucose ->digestion->mitochondrion->cytosol->energy

Question 12

Compare the enrgy values of aerobic resporation and feremntation

Answer 12

aerobic respiration: produce 38ATP

Fermentation: produce 2ATP

Question 13

Wath is the biggest difference between aerobic resporation and fermentation (substrate)?

Answer 13

Aerobic respiration use oxygen to convert it into ATP and fermentation converts sugar into ethanol.

Question 14

Transcription of photosynthesis

Answer 14

• photosynthesis is the process where carbon dioxide is teken to produce energy in plants
• It occurs in the chloroplast (thylakoid membranes)
• In phothosynthesis 2 different reaction occure: Light-independent reaction and Light-dependent reactions.
• Oxyen and water are the waist products

Question 15

Pigments involved in photosynthesis?

Answer 15

gree - the radiation is mostly reflected
red - good pigment
blue - the best pickment of absorbing radiation

Question 16

What are the substrate and products of photosynthesis?

Answer 16

Substrate: carbon dioxide, water and light
Product: glucose, oxygen and water