Chapter 6

Question 1

What is metabolism?

Answer 1

Total of all reactions in a cell

Question 2

Catabolism?

Answer 2

Breaks down! Energy released!

When energy is released, it can be transferred elsewhere in the form of electrons. Is a source of reducing power.

Question 3

Anabolism?

Answer 3

Builds up! Needs energy to do so.

Needs reducing power. Is a source of electrons. Synthesizes complex organics from simple molecules.

Question 4

Phototrophs?

Answer 4

Harvest energy and use it to power synthesis of organics from inorganic CO2.

Question 5

Chemoorganotrophs

Answer 5

Harvest energy from organics

Question 6

Chemolithotrophs

Answer 6

Harvest energy from inorganics

Question 7

Exergonic reactions

Answer 7

Energy released. More free energy is present in reactants.

Question 8

Energonic reactions

Answer 8

Energy is gained. More free energy is present in the products.

Question 9

ADP + Pi —> ATP

Answer 9

Energy is used. Exergonic. Catabolic rxn.

Question 10

ATP —> Pi + ADP

Answer 10

Energy released and drives anabolic reactions. Endergonic.

Question 11

Substrate level phosphorylation

Answer 11

Exergonic. Phosphate comes directly from substrate. Free energy used to phosphorylate ADP to ATP.

Question 12

Oxidative Phosphorylation

Answer 12

Transfer of electron energy (ETC, proton motive force, ATP synthase). Coupled rxn that is driven by oxidation-reduction reactions.

Question 13

Photophosphorylation

Answer 13

Light harvested, used to create proton motive force

Question 14

Electron carriers have oxidative or reducing power?

Answer 14

Reducing power.

Question 15

True or false: number of steps and speed of reaction is irrelevant because the change in free energy is always the same.

Answer 15

True

Question 16

Why are numerous steps in metabolism advantageous?

Answer 16

More steps allows cell to have more control over energy release. Also provides variety in points at which it can release energy.

Question 17

Glucose breaks down to power respiration. Does it lose or gain electrons?

Answer 17

Lose

Question 18

Oxidation

Answer 18

Lose electrons

Question 19

Reduction

Answer 19

Gain electrons

Question 20

True or false - enzymes affect change in free energy

Answer 20

False, because some reactions would occur without enzymes, just very slowly.

Question 21

Enzymes’ primary function…

Answer 21

to reduce activation energy.

Question 22

How do enzymes lower Ea?

Answer 22

Binds substrates to active sites, orients substrates so reactive ends of compounds are in close proximity with one another, creates microenvironment (i.e. raise and lower pH to make rxn more favorable), destabilize existing bonds

Question 23

What does it mean when exergonic rxns are coupled to endergonic?

Answer 23

Energy released from exergonic rxn can be used by endergonic rxn

Question 24

Factors that affect enzyme activity?

Answer 24

ph, temperature, salt, cofactors (nonprotein)

Question 25

Cells can turn enzyme activity off and on after transcription and translation. How?

Answer 25

Allosteric regulation. It can be positive or negative. Regulatory molecule binds to the enzyme, but NOT in the active site. deeThis changes the overall shape of the substrate, and prevents or enhances substrate binding in the active site.

Question 26

Non-competitive inhibition

Answer 26

Type of negative allosteric regulation. Inhibitor binds to site other than the active site.

Question 27

Competitive inhibition

Answer 27

Prevents substrate from binding because it competitively inhibits the active site. Competitive inhibitors have similar shapes that fit to the substrate.

Question 28

ETC, proton motive force, and ATP synthase involve transport of....

Answer 28

electrons

Question 29

In central catabolism, glycolysis involves oxidation or reduction of glucose?

Answer 29

Oxidation of glucose

Question 30

Cells need to _______ and use _____ when building new cell material

Answer 30

harvest energy, sources of carbon

Question 31

Where does the reducing power of central catabolism go?

Answer 31

Respiration or fermentation