Microbial Metabolism

Question 1

Why are two of the phosphates on ATP designated with a “squiggle P”?

Answer 1

high energy bonds

Question 2

Define oxidation and reduction

Answer 2

oxidation is the loss of an electron
reduction is gain of an electron

Question 3

What is the net ATP from glycolysis?

Answer 3

2

Question 4

What occurs at the active site of the enzyme?

Answer 4

Substrates attach

Question 5

What is meant by “reducing power”? List some molecules that act as reducing power.

Answer 5

Reducing power is the ability of a chemical species to make another chemical substance undergo reduction.
NAD+-> NADH and FAD->FADH2

Question 6

What effect do enzymes have on activation energy?

Answer 6

lower the activation energy

Question 7

In glycolysis, how many ATP molecules are utilized?

Answer 7

2

Question 8

Define exergonic

Answer 8

energy releasing

Question 9

What is meant by carbohydrate catabolism?

Answer 9

the breakdown of sugars to produce ATP or other carbon-containing macromelecules

Question 10

Define chemiosmosis

Answer 10

Chemiosmosis is the process of diffusion of ions (usually H+ ions, also known as protons) across a selectively permeable membrane. Chemiosmosis leads to a concentration gradient of the diffusing ion across the membrane. A concentration gradient is a form of potential energy that can do work.

Question 11

Why is the Kreb’s cycle a cycle?

Answer 11

goes in a circle of 8 reactions twice

Question 12

How many NADH and FADH2 is created in the Kreb’s cycle per glucose?

Answer 12

6 NADH and 2 FADH2

Question 13

What is activation energy?

Answer 13

the amount of energy needed for a reaction to occur

Question 14

How much ATP is generated per glucose molecule in the Kreb’s cycle?

Answer 14

2 ATP per glucose

Question 15

What are the two differences between chemiosmosis in prokaryotes vs eukaryotes? (hint: where it occurs and the number of ATP generated)

Answer 15

In prokaryotes it takes place on the plasma membrane, in eukaryotes it takes place in the mitochondria membrane
Eukaryotes produce 36 ATP, Prokaryotes produce 38

Question 16

How much NADH is generated in glycolysis?

Answer 16

2

Question 17

Briefly describe how enzymes are named. [i.e. what are two common suffixes (endings) that are used?]

Answer 17

named for the reaction they catalyze, end in -ase or -sin

Question 18

What is the terminal electron acceptor in fermentation?

Answer 18

organic molecule like pyruvate

Question 19

What is the terminal electron acceptor in anaerobic respiration?

Answer 19

inorganic molecule like carbonate or sulfate

Question 20

Final electron acceptor in fermentation vs aerobic respiration

Answer 20

fermentation- pyruvate
aerobic- oxygen

Question 21

What are the main three steps of aerobic respiration and in what order do they occur?

Answer 21

glycolysis, Kreb’s cycle, and electron transport chain

Question 22

Define metabolism

Answer 22

the sum of all chemical reactions of a living organism

Question 23

What is the number of ATP generated for each NADH and FADH2 in the electron transport chain?

Answer 23

NADH= 3 ATP
FADH2= 2 ATP

Question 24

Compare photosynthesis to aerobic respiration

Answer 24

Photosynthesis uses the sun’s energy. Can fix its own carbon.

Question 25

Define catabolism

Answer 25

breaking down complex molecules to produce energy. Exergonic

Question 26

In the electron transport chain, what happens to the reducing power generated in glycolysis and the Krebs cycle?

Answer 26

the electrons are passed from electron carrier to electron carrier which moves protons out of the cell

Question 27

What step happens prior to the Kreb's cycle? What 2 things happen?

Answer 27

transition step, pyruvate is converted to CoA and NAD+ is reduced to NADH (2 per glucose)

Question 28

In glycolysis, how many ATP molecules are generated per glucose molecule?

Answer 28

4, 2 used, 2 net

Question 29

Give some examples of coenzymes (a special type of cofactor)

Answer 29

FAD= flavin adenine dinucleotide FMN=flavin mononeucleotide CoA= coenzyme A Other vitamins

Question 30

Define reactants/substrates

Answer 30

starting components substrates are the reactants for enzymes

Question 31

define anabolism

Answer 31

smaller subunits combine to create macromolecules. Endergonic

Question 32

Define endergonic

Answer 32

energy absorbing/requiring energy

Question 33

define electrochemical gradient

Answer 33

a difference in charge and chemical concentration

Question 34

What are the three types of carriers found in the electron transport chain?

Answer 34

flavoproteins, cytochromes, and ubiquinones (coenzyme Q)

Question 35

Briefly describe how enzymes function.

Answer 35

substrates attach to the enzyme at the active site and are transformed into a new product

Question 36

Number of ATP produced in fermentation vs aerobic respiration

Answer 36

fermentation- 2 aerobic- 36-38

Question 37

O2 requirements in fermentation vs aerobic respiration

Answer 37

fermentation- does not need O2 but O2 can be present aerobic- needs O2

Question 38

Briefly describe how feedback inhibition works.

Answer 38

process in which the end product of a reaction inhibits or controls the action of the enzyme that helped produce it. prevents unneccesary product from being made

Question 39

What gas is being produced in the catalase test?

Answer 39

O2

Question 40

Describe four properties of enzymes.

Answer 40

biological catalyses speed up the rate of reaction by lowering activation energy reusable are not permanently changed by reaction made of protein (ribosomes are made of RNA) specific for a specific substrates need an optimal pH and temp to work best

Question 41

Define substrate and turnover number.

Answer 41

a way of expressing the number of substrate molecules converted into products in one second

Question 42

How and why do the following affect enzyme function? a. temperature b. pH c. substrate concentration d. inhibitors (competitive and allosteric)

Answer 42

temp: can affect the shape of the enzyme pH: can affect the shape of the enzyme substrate concentration: enzyme activity increases with concentration until it hits a plateau competitive inhibitors: compete with the substrate to fill the active site on the enzyme allosteric inhibitors: change the shape of the active site

Question 43

What is the terminal electron acceptor in aerobic respiration?

Answer 43

oxygen

Question 44

Describe the different parts of an enzyme.

Answer 44

holozyme- whole enzyme apoenzyme- protein part of the enzyme cofactor- ion or organic molecule that is required to make the enzyme functional active site- binding site for substrate allosteric site- site that allows molecules to either activate or inhibit enzyme activity

Question 45

What are two ways to speed up a chemical reaction?

Answer 45

increase heat and lower activation energy

Question 46

In glycolysis what is glucose converted to?

Answer 46

two molecules of pyruvate

Question 47

define proton motor force

Answer 47

the movement of H+ to the outside of the membrane that creates an electrochemical gradient

Question 48

What molecule is regenerated in the Kreb's cycle?

Answer 48

oxaloacetic acid (OAA)