Microbial Metabolism (E2)

Question 1

The 1st law of thermodynamics is a concept called the { }, while the 2nd law is called { }.

Answer 1

1) Conservation of energy
2) Entropy

Question 2

The direction/favorability of a reaction can be predicted by the { } and { }.

Answer 2

1) Gibbs free energy change (delta G)
2) Equilibrium constant (Keq)

Question 3

Catabolic reactions are { }, meaning they have a negative Gibbs free energy change.

Answer 3

Exergonic

Question 4

Anabolic reactions are { }, meaning they have a positive Gibbs free energy change.

Answer 4

Endergonic

Question 5

Why are catabolic reactions favorable, while anabolic reactions aren’t?

Answer 5

With catabolic reactions, the breaking down of molecules means energy is being released, and this is favorable because that energy can be used by other metabolic processes, such as anabolism

Question 6

An equilibrium constant (Keq) greater than 1 indicates a(n) { } reaction.

Answer 6

Catabolic

Question 7

An equilibrium constant (Keq) less than 1 indicates a(n) { } reaction.

Answer 7

Anabolic

Question 8

If energy transformations are not 100% efficient, what happens to the energy that is lost?

Answer 8

It is released as heat

Question 9

Catalysts { } reaction rate.

Answer 9

Speed up

Question 10

Enzymes are biological catalysts that speed up reaction rates by { } the required activation energy.

Answer 10

Lowering

Question 11

What are the 5 main characteristics of an enzyme discussed in lecture?

Answer 11

1) Protein/protein component
2) Structure determines function
3) Substrate-specific
4) Don’t create reactions
5) Not permanently altered or used up by reaction

Question 12

The induced model fit dictates that if a substrate does not fit into an enzyme, then the enzyme…

Answer 12

Fits around the substrate to accomodate

Question 13

What are 2 factors that influence enzyme activity?

Answer 13

1) Denaturing stress
2) Substrate concentration

Question 14

The measure of the affinity an enzyme has for its substrate.

Answer 14

What is the Michaelis constant (Km)?

Question 15

What is the main difference between how competitive and noncompetitive inhibitors affect enzyme activity?

Answer 15

Competitive - Prevents substrate from binding to the active site

Noncompetitive - Changes enzyme shape to alter active site shape and, thus, its function

Question 16

What type of feedback is a common way that cells regulate metabolism?

Answer 16

Negative feedback

Question 17

Normal mechanism cells use this to control the amount of product in a complex metabolic pathway.

Answer 17

What is feedback inhibition?

Question 18

In feedback inhibition, the final product is a temporary { } that binds to the starting enzyme’s { } site.

Answer 18

1) Inhibitor
2) Allosteric

Question 19

The reversible phosphorylation of ADP.

Answer 19

What is ATP synthesis?

Question 20

Does aerobic respiration generate ATP at the substrate or oxidative level?

Answer 20

Both

Question 21

Does anaerobic respiration generate ATP at the substrate or oxidative level?

Answer 21

Both

Question 22

Does fermentation generate ATP at the substrate or oxidative level?

Answer 22

Substrate-level

Question 23

In substrate-level phosphorylation, the substrate donates a { } group to { } to form { }.

Answer 23

1) Phosphate
2) ADP
3) ATP

Question 24

Why is substrate-level phosphorylation so much less efficient than oxidative phosphorylation?

Answer 24

Substrate-level produces much less ATP than oxidative phosphorylation

Question 25

Name 3 ways ATP can transfer energy.

Answer 25

1) Hydrolysis-releasing phosphate (Pi)
2) Hydrolysis-releasing pyrophosphate (PPi)
3) Phosphorylation of organic molecule

Question 26

Name 3 molecules other than ATP that carry energy.

Answer 26

1) GTP
2) NADH
3) FADH2

Question 27

Coupled reactions that liberate energy.

Answer 27

What are redox reactions?

Question 28

The tendency for a chemical species to be reduced.

Answer 28

What is standard reduction potential?

Question 29

The potential of a substance to reduce another.

Answer 29

What is reducing power?

Question 30

What is the relationship between standard reduction potential & electronegativity?

Answer 30

As standard reduction potential increases, so does electronegativity