Ch 5 Part 1.

Question 1

Define metabolism

Answer 1

The collection of all the “controlled” biochemical reactions that take part in the cell.

Question 2

Define catabolism

Answer 2

Breaking down food for energy.

Question 3

Define anabolism

Answer 3

Using energy to build cell parts.

Question 4

Define holoenzyme

Answer 4

Active form of enzyme that binds substrate to active (catalytic) site.

Question 5

Define apoenzyme

Answer 5

protein that forms an active enzyme system by combination with a coenzyme and determines the specificity of this system for a substrate.

Question 6

Define cofactor

Answer 6

a non- protein chemical compound that is bound to a protein and is required for the protein’s biological activity.

Question 7

Define catalytic (active) site

Answer 7

region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Question 8

Define induced-fit model

Answer 8

the binding of a substrate or some other molecule to an enzyme causes a change in the shape of the enzyme so as to enhance or inhibit its activity.

Question 9

Define saturation point

Answer 9

Enzymes are saturated when there is the maximum amount of substrate present and no more can be absorbed.

Question 10

Describe how pH, temperature, substrate and enzyme concentrations and inhibitors effect enzyme activity

Answer 10

Can cause an alteration to number of H-bonds which can lead to denatured proteins meaning that without their structure, they have no function.

Question 11

Distinguish between competitive, non-competitive, and feedback inhibition

Answer 11

Competitive- direct inhibitor, binds to active site on enzyme
Non-competitive- indirect inhibitor, binds to allosteric site of enzyme which causes distortion to active site so that enzyme can no longer fit properly
Feedback inhibition- metabolic product inhibits the first enzyme pathway and as a result the product “feeds back” to start of reaction. Allows for the cell to save substrate and energy as it is recycled.

Question 12

List and describe the action of the common types of enzymes used in biochemical pathways

Answer 12

1. Isomerase- rearranges atoms in a compound
2. Transferase- transfer functional group from one compound to another
3. Dehydrogenase (oxidoreductase) - remove/transfers e-
4. Polymerase (ligases) -join molecules together RNA polymerase and DNA ligase
5. Lyases and hydrolases - split molecules apart (hydrolysis)

Question 13

Distinguish between an endergonic and exergonic reaction

Answer 13

Endergonic- energy absorbed during reaction
Exergonic- energy released during reaction

Question 14

Describe a redox reaction

Answer 14

A chemical reaction that takes place between an oxidizing substance and a reducing substance. In redox reactions, energy is released when an electron loses potential energy as a result of the transfer.

Question 15

Label which component is oxidized, and which is reduced

Answer 15

Electron acceptors become reduced (reduction reaction) Reduction Is Gain
Electron donors become oxidized (oxidation reaction) Oxidation Is Loss of e-

Question 16

Describe the three types of phosphorylation
Where do they occur?

Answer 16

1. Substrate lvl- transfer phosphate from a phosphorylated organic compound to ADP (glycolysis)
2. Oxidative- energy from redox reaction of respiration is used to attach phosphate to ADP (respiration)
3. Photo- light energy is used to start redox reactions that add phosphate to ADP (photosynthesis)

Question 17

What is the goal of glucose catabolism?

Answer 17

Break down glucose completely to CO2 and release energy

Question 18

Glycolysis (glucose to pyruvate):
o Is this complete oxidation of glucose?
o How much ATP used? Gained?
o How many NADH generated?
o Does it require oxygen?
o Where does this occur?

Answer 18

In glycolysis, 2 ATP molecules are consumed, producing 4 ATP, 2 NADH, and 2 pyruvates per glucose molecule. Requires O2 (aerobic) and occurs in cytoplasm

Question 19

Respiration (Synthesis of Acetyl-CoA and Kreb’s Cycle):
o Pyruvate to CO2
▪ Is this complete oxidation of pyruvate?
▪ How much ATP is generated per glucose? How?
▪ How much NADH, FADH2 per glucose?
▪ Where does this occur?

Answer 19

The Krebs cycle takes place exactly in (the mitochondrial matrix) and converts mitochondrial pyruvate into carbon dioxide and water.

Question 20

Fermentation (pyruvate to waste product(s)):
o What are some waste products?
o Why is this done?
o How much ATP does it generate?
o Does it require oxygen?
o Where does this occur?

Question 21

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Question 22

Respiration, continued (Electron Transport Chain):
o Describe an electron transport chain.
▪ Where is it located?
o What is the final electron acceptor for aerobic respiration?
o What is the final electron acceptor for anaerobic respiration?
o What is the source of the electrons?
o How does a proton gradient form?
o How is ATP produced?
o What’s the name of the enzyme used for phosphorylation?
o What type of phosphorylation is this?

Question 23

What is the overall reaction for aerobic glucose catabolism? (Glycolysis + aerobic respiration)

Question 24

Lipid catabolism
o What kind of enzyme breaks triglycerides? (What do you get after this reaction?)
o What is beta oxidation?
o Where does this happen?

Question 25

Protein catabolism
o What do proteases do? Where are they located?
o What is deamination?