Introduction to metabolism

Question 1

what is metabolism?

Answer 1

the total of all chemical reactions in the cell

Question 2

describe Catabolism (6)

Answer 2

• bio degradation
• the breakdown of a larger molecule into smaller one(s)
• Breaks covalent bonds and releases energy, so they are exergonic
• Enzyme catalyzed
• Most are also oxidations (provides reducing power)
• Generates precursors for anabolism

Question 3

describe anabolism (5)

Answer 3

• Biosynthesis
• The synthesis of a larger molecule from a smaller one or smaller ones
• Creates many new covalent bonds and requires energy input so they are endergonic (never endothermic)
• Enzyme catalyzed
• Mostly reductions

Question 4

what is chemical work?

Answer 4

synthesis of complex molecules

Question 5

what is transport work?

Answer 5

take up of nutrients; elimination of wastes, and maintenance of ion balances

Question 6

what is mechanical work?

Answer 6

cell motility and movement of structures within cells

Question 7

describe Free Energy and Reactions (3)

Answer 7

1. ) G = H - TS
2. ) Expresses the change in energy that can occur in chemical reactions and other processes
3. ) Used to indicate if a reaction will proceed spontaneously
   - if G is negative, reaction is spontaneous
   - if G is positive, reaction is not spontaneous
   * *slide 7**

Question 8

slide 8

Answer 8

KNOW

Question 9

what is an exergonic reaction?

Answer 9

chemical reactions with a negative Go′value that release free energy (if heat released it also exothermic)

Question 10

what is an endergonic reaction?

Answer 10

chemical rReactions with a positive Go′ value require an energy input (it is never endothermic in biological systems)

Question 11

slide 11-16

Answer 11

LOTS OF SHIT

Question 12

what is a redox reaction?

what does it result in?

Answer 12

• Transfer of electrons from a donor to an acceptor

- results in energy release, which can be conserved and used to form ATP

Question 13

what is oxidation?

Answer 13

the loss of an electron or electrons from an atom, or the loss of an electron, electrons or whole hydrogen atom (2 electrons and 1 proton) from a molecule

Question 14

is oxidation exergonic or or endergonic?

explain

Answer 14

Removing electrons or a hydrogen atom removes energy so oxidations are exergonic

Question 15

what is reduction?

Answer 15

the gain of an electron or electrons by an atom, or the gain of an electron, electrons or whole hydrogen atom (2 electrons and 1 proton) by a molecule

Question 16

is reduction exergonic or endergonic?

explain

Answer 16

Adding electrons or a whole hydrogen atom (bonds) adds energy so reductions are endergonic

Question 17

what is reduction potential(Eo′)?

Answer 17

tendency of a compound to donate electrons (to be oxidized) or to gain electrons (to be reduced)
(slide 23)

Question 18

slides 24-26

Answer 18

take a look

Question 19

SLIDE 27

Answer 19

look at (hard to make a flashcard for)

Question 20

describe electron carriers (where they are located in bacteria and archaea and eukaryotic cells; also give examples)

Answer 20

• Located in cell membranes of chemoorganotrophs in bacteria and archaeal cells
• Located in internal mitochondrial membranes in eukaryotic cells
• Examples of electron carriers include NAD, NADP, and others

Question 21

what does NAD stand for?

Answer 21

nicotinamide adenine dinucleotide

Question 22

what does NADP stand for

Answer 22

nicotinamide adenine dinucleotide phosphate

Question 23

slide 30

Answer 23

LOOK AT

Question 24

what does FAD stand for?

Answer 24

flavin adenine dinucleotide

Question 25

what does FMN stand for?

Answer 25

flavin mononucleotide | *riboflavin phosphate

Question 26

what does coenzyme Q (CoQ) stand for

Answer 26

a quinone | also called ubiquinone

Question 27

what do cytochromes do?

Answer 27

use iron to transfer electrons | iron is part of a heme group

Question 28

what do Nonheme iron-sulfur proteins

Answer 28

use iron to transport electrons (iron is not part of a heme group) e.g., ferrodoxin (slide 32)

Question 29

what are enzymes? what do they allow?

Answer 29

- Organic molecules that act as catalysts and increase the rate of a chemical reaction - Allow reactions to occur at physiological conditions so they proceed in a timely manner

Question 30

Some enzymes are composed solely of one or more _______________- Some enzymes are composed of one or more __________ and ________ components

Answer 30

polypeptides; polypeptides and nonprotein

Question 31

what is the protein component of an enzyme?

Answer 31

Apoenzyme

Question 32

what is a cofactor? describe

Answer 32

nonprotein component of an enzyme prosthetic group – firmly attached coenzyme – loosely attached, can act as carriers/shuttles

Question 33

Holoenzyme = _________ + __________ | + ___________

Answer 33

apoenzyme + cofactor | + coenzyme

Question 34

what is activation energy?

Answer 34

- energy required to form transition-state complex | - Enzyme speeds up reaction by lowering Ea

Question 35

how do enzymes lower Ea? (3)

Answer 35

- By increasing concentrations of substrates at active site of enzyme - By orienting substrates properly with respect to each other in order to form the transition-state complex - Induced fit model for enzyme-substrate interaction

Question 36

enzyme activity is significantly impacted by what three things?

Answer 36

substrate concentration pH temperature

Question 37

what is a competitive inhibiter?

Answer 37

directly competes with binding of substrate to active site

Question 38

what is non-competitive inhibiter?

Answer 38

binds enzyme at site other than active site | changes enzyme’s shape so that it becomes less active

Question 39

slide 42

Answer 39

meh :)

Question 40

Regulation of Metabolism is Important for _____________________________________ and for Maintenance of ____________________

Answer 40

conservation of energy and materials; metabolic balance despite changes in environment

Question 41

what are the three major mechanisms for metabolic regulation?

Answer 41

-metabolic channeling -regulation of the synthesis of a particular enzyme (transcriptional and translational) -regulation of enzyme activity direct activation or inhibition of the activity of a critical enzyme

Question 42

describe metabolic channeling (2)

Answer 42

1. ) Differential localization of enzymes and metabolites 2. ) Compartmentation - differential distribution of enzymes and metabolites -among separate cell structures or organelles - can generate marked variations in metabolite concentrations

Question 43

for regulation of enzyme activity what are the Two important reversible control measures?

Answer 43

allosteric regulation | covalent modification

Question 44

give 2 facts about allosteric regulation

Answer 44

Most regulatory enzymes | Activity altered by small molecule

Question 45

describe allosteric effector (4)

Answer 45

- binds non-covalently at regulatory site - changes shape of enzyme and alters activity of catalytic site - positive effector increases enzyme activity - negative effector inhibits the enzyme

Question 46

give 2 facts about covalent modification

Answer 46

- Reversible on and off switch | - Addition or removal of a chemical group (phosphate, methyl, adenyl)

Question 47

what are 2 advantages of covalent modification?

Answer 47

- respond to more stimuli in varied/sophisticated ways | - regulation of enzymes that catalyze covalent modification adds second level of control

Question 48

describe feedback inhibition

Answer 48

-Also called end-product inhibition -Inhibition of one or more critical enzymes in a pathway regulates entire pathway (catalyzes the slowest or rate-limiting reaction in the pathway) -Each end product regulates its own branch of the pathway -Each end product regulates the initial pacemaker enzyme (slide 50)