Ch 13 (Book) Catabolism, Gluc Breakdown, TCA Cycle Flashcards

1
Q

4 organic carbon sources for catabolism

A

carbohydrates (sugars)

lipids

peptides

aromatic molecules

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2
Q

carbohydrate examples

A

cellulose of plant cell walls

starch from potatoes

pectin of fruit

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3
Q

polysaccharides are ________ to products that enter central catabolic pathways like ________

A

hydrolyzed, glycolysis

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4
Q

which two polysaccharides are most widely digested

A

starches

pectins

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5
Q

out of numerous choices of substrate, why are certain ones chosen?

A

availability

energy efficiency

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6
Q

catabolic repression

A

the process of prioritized catabolism of substrates

ex. glucose over lactose for E. coli

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7
Q

sources of lipids

A

milk

animal fat

nuts

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8
Q

what are lipids catabolized to

A

glycerol

FA

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9
Q

glycerol

A

a 3 carbon sugar that enters catabolism as a glycolysis intermediate

could break down to acetate

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10
Q

how do FA enter catabolism

A

form acetyls by fatty acid degradation pathway

acetyls enter TCA cycle or fermentation

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11
Q

how are peptides catabolized

A

broken into aa that are decarboxylated or deaminated

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12
Q

lignin

A

an aromatic that makes up trees

broken down by fungi and soil bacteria to acetyl CoA –> TCA

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13
Q

in fermentation are all the e- from organic substrates returned to organic products?

A

yes

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14
Q

in respiration are the e- transferred to an inorganic electron acceptor?

A

yes

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15
Q

photoheterotrophy

A

bacteria gain energy from light and use organic carbon sources for catabolism/biosynthesis

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16
Q

fermentation

A

partial breakdown of organic food without transferring e- to a terminal e- acceptor

ethanol, lactate, acetate

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17
Q

respiration combines what 2 things

A

catabolic breakdown of organic molecules and e- transfer to a terminal e- acceptor

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18
Q

anaerobic respiration

A

use of a terminal electron acceptor other than O2

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19
Q

what are the only polysaccharides human enzymes can digest?

A

starch

lactose

sucrose

20
Q

how can humans/animals digest other polysaccharides

A

symbiotic relationship with microbes that can

ex. human gut microbes

21
Q

3 pathways to form pyruvate

A

glycolysis (embden-meyerhof-parnas EMP)

entner-doudoroff (ED)

pentose phosphate pathway

22
Q

products of glycolysis

A

glucose –> 2 ATP, 2 NADH, 2 pyruvate

23
Q

products of ED pathway

A

1 ATP, 1 NADH, 1 NADPH, 2 pyruvate

sugar acids from intestinal mucous – essential for enteric bacteria to colonize intestine

24
Q

PPP pathway products

A

1 ATP, 2 NADPH

25
Q

which steps in glycolysis are irreversible

A

the ones that consume ATP

26
Q

substrate-level phosphorylation

A

transfer of a phosphate from an organic substrate to make ATP

27
Q

enzymes of catabolism are regulated at the level of ________ of the enzyme, and by ________ regulation

A

transcription, allosteric

28
Q

why is allosteric regulation needed

A

so intermediates don’t build up

to make sure the cell doesn’t spend more energy than it has

29
Q

which step is most importantly regulated in glycolysis

A

fructose-6-P –> fructose 1,6-bisphosphate by phosphofructokinase

activated by ADP, inhibited by ATP

30
Q

amphibolic

A

if a pathway can do catabolism and anabolism

31
Q

how do ED bacteria help humans

A

prevent pathogen colonization

stimulate the immune system

32
Q

key intermediate in PPP

A

ribulose-5-P

33
Q

intermediates from PPP can be used in what biosynthesis

A

aa

vitamins

purines –> DNA/RNA

or can reenter glycolysis

34
Q

how does fermentation complete catabolism

A

recycle NADH + H+ to NAD+

ex. 2 molecules of lactic acid, 2 molecules of ethanol + 2 CO2, or 1 lactic acid, 1 ethanol, 1 CO2

35
Q

mixed-acid fermentation

A

can also form acetate, formate, lactate, succinate

36
Q

what is acetyl coA structure

A

acetyl group esterified to CoA

37
Q

can acetyl coA be converted to fermentation products

A

yes, many pathways

38
Q

what types of food products does fermentation yield

A

ethanol –> beer/wine

lactate –> cheese and yogurt

butyric acid –> butter

39
Q

phenol red broth test

A

test for fermentation

red pH indicator that turns yellow at below pH 6.8

40
Q

tricarboxylic acid cycle (TCA) Krebs Cycle

A

generates NADH and FADH2 which donate e- to a terminal electron accepton in the ETC

41
Q

pyruvate dehydrogenase complex (PDC)

A

converts pyruvate to acetyl CoA

removes CO2 and moves 2e- to NAD+

42
Q

what do some memb proteins in the ETC do with the energy

A

pump protons out to generate a gradient

43
Q

how many ATP do you get from NADH and FADH2

A

NADH: 3

FADH2: 2

44
Q

oxidative phosphorylation

A

electron transport and ATP generation

45
Q

glyoxylate bypass

A

modified TCA cycle used by some bacteria to catabolize FA –> acetyl CoA