Ch. 5 Microbial Metabolism

Question 1

catabolism

Answer 1

macromolecules broken down into simpler molecules, releasing energy

Question 2

anabolism

Answer 2

simpler molecules are combined into macromolecules, using energy

Question 3

catabolic reactions provide…

Answer 3

energy needed for anabolic rxns

Question 4

ATP purpose

Answer 4

storing and releasing energy

ATP ADP + energy

Question 5

enzymes

Answer 5

catalyze all reactions in a cell; reduce activation energy

Question 6

apoenzyme

Answer 6

protein portion (inactive)
- to activate, must bond to a nonprotein cofactor (activator)

Question 7

holoenzyme

Answer 7

whole, active enzyme

Question 8

active site

Answer 8

where substrate binds; very specific to substrate. forms the enzyme-substrate complex. products are released after the enzyme catalyzes. ENZYMES ARE NOT USED UP AFTER RXN

Question 9

Factors influencing enzymatic activity

Answer 9

1) temp
2) pH
3) substrate concentration
(KNOW CURVES FOR QUIZ)

Question 10

competitive inhibitor

Answer 10

binds to active site and blocks substrate from binding

Question 11

sulfa drugs

Answer 11

prevent folic acid production through competitive inhibition

bacteria make their own folic acid but we don’t, therefore it doesn’t affect us

Question 12

allosteric/noncompetitive inhibitor

Answer 12

binds to allosteric site, altering shape of the active site (reversible)

Question 13

feedback inhibition

Answer 13

end product binds to allosteric site earlier in process (usually first enzyme), shutting down pathway. extremely common regulator of biochemical pathways.

Question 14

Ribozymes

Answer 14

made of RNA; function as enzymes, but not made of protein

Question 15

oxidation

Answer 15

removal of electrons from a molecule; often produces energy

Question 16

reduction

Answer 16

receiving electrons to a molecule; often requires energy

Question 17

common redox reaction

Answer 17

NAD+ coenzyme (electron carrier) --> NADH
FAD coenzyme (electron carrier) --> FADH2

Question 18

Generation of ATP

Answer 18

ADP + energy + Pi ATP

Question 19

What are the two pathways of energy to make ATP?

Answer 19

1) substrate-level phosphorylation

2) oxidative phosphorylation

Question 20

substrate-level phosphorylation

Answer 20

high energy bond in a phosphorylized organic molecule broken and Pi and energy are transferred directly to ADP, forming ATP

Question 21

oxidative phosphorylation

Answer 21

electron transport chain; electron is carried through each electron acceptor through repeated redox reactions. Final electron acceptor produces ATP and side product (usually O2 is acceptor and H2O)
energy is released step-wise down the electron chain

Question 22

photophosphorylation

Answer 22

energy comes from the light; excited electrons ejected from chlorophyll

Question 23

carbohydrate catabolism

Answer 23

glycolysis, then respiration (Krebs and ETC) or fermentation

commonly glucose

Question 24

Glycolysis

Answer 24

glucose (6C) + 2 ATP –> 2 pyruvic acid (3C) + 4 ATP
2 NAD+ –> 2 NADH (to ETC)

DOES NOT REQUIRE O2

Question 25

Krebs Cycle

Answer 25

2x per glucose 1) transition step: pyruvic acid --> acetyl CoA (2C) + CO2 (byproduct). reduces one NAD -> NADH (therefore two per glucose) 2) cycle x2: completely oxidizes glucose, producing: 2 FADH, 6 NADH, 2 ATP

Question 26

Electron Transport Chain

Answer 26

- high-low energy electron carriers through redox reactions - O2 is required as the final electron acceptor - occurs on the cell membrane (prokaryotes) or mitochondria membrane (eukaryotes)

Question 27

Chemiosmosis

Answer 27

process of making ATP where a proton pump uses energy from ETC to help protons out of the cell against the gradient (active transport). this creates potential energy. ATP synthase in the cell membrane has a channel for protons, fueling the synthesis of ATP

Question 28

aerobic respiration

Answer 28

O2 is the final electron acceptor

Question 29

anaerobic respiration

Answer 29

final electron acceptor can be nitrates, sulfates, or carbonate (NO3-, SO4-, CO3-). Produce methane, hydrogen sulfide, nitrogen gas

Question 30

total ATP in respiration per glucose mol

Answer 30

2 ATP (glycolysis) + 2 ATP (Krebs) + 34 ATP (ETC) = 38 ATP total

Question 31

fermentation

Answer 31

gets rid of pyruvic acid. - final electron acceptor: organic molecule - no energy is produced; only energy from glycolysis - 2 ATP per molecule of glucose

Question 32

strict fermenters

Answer 32

cannot use O2; therefore O2 is not requried

Question 33

lactic acid fermentation

Answer 33

lactic acid is final product - Lactobacillus - Streptococcus - tang in yogurt, sauerkraut

Question 34

alcohol fermentation

Answer 34

- produces 2 CO2 and 2 ethanol | - Saccharomyces (yeast: bread, wine)

Question 35

catabolism of lipids

Answer 35

lipid --> glycerol and fatty acids | intermediates in respiration

Question 36

catabolism of proteins

Answer 36

protein --> amino acids | also intermediates in carb catabolism

Question 37

photosynthesis

Answer 37

1) photophosphorylation (light --> chemical; light-dependent rxns) 2) Calvin Cycle (carbon fixation; no energy produced; light-independent rxns)

Question 38

Calvin cycle

Answer 38

3 CO2 --> glyceraldehyde 3-phosphate | NO ATP produced

Question 39

Metabolic diversity among organisms originates from...

Answer 39

how they obtain carbon and how they obtain energy

Question 40

energy source

Answer 40

energy from chemicals = chemotrophs | energy from light = phototrophs

Question 41

carbon source

Answer 41

``` organic = heterotrophs CO2 = autotrophs ```

Question 42

chemoheterotrophs

Answer 42

``` uses organic compounds, energy from chemical source final electron acceptor: - O2 = aerobic respiration - organic comp = ferment - inorganic comp = anaerobic respiration ```

Question 43

chemoautotrophs

Answer 43

use CO2 from the environment they're in

Question 44

photoheterotrophs

Answer 44

light and organic comp

Question 45

photoautotrophs

Answer 45

light and CO2

Question 46

anabolism

Answer 46

Intermediates from krebs cycle and glycolysis -- building blocks from macromolecules come from intermediates