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

Question 1

4 organic carbon sources for catabolism

Answer 1

carbohydrates (sugars)

lipids

peptides

aromatic molecules

Question 2

carbohydrate examples

Answer 2

cellulose of plant cell walls

starch from potatoes

pectin of fruit

Question 3

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

Answer 3

hydrolyzed, glycolysis

Question 4

which two polysaccharides are most widely digested

Answer 4

starches

pectins

Question 5

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

Answer 5

availability

energy efficiency

Question 6

catabolic repression

Answer 6

the process of prioritized catabolism of substrates

ex. glucose over lactose for E. coli

Question 7

sources of lipids

Answer 7

milk

animal fat

nuts

Question 8

what are lipids catabolized to

Answer 8

glycerol

FA

Question 9

glycerol

Answer 9

a 3 carbon sugar that enters catabolism as a glycolysis intermediate

could break down to acetate

Question 10

how do FA enter catabolism

Answer 10

form acetyls by fatty acid degradation pathway

acetyls enter TCA cycle or fermentation

Question 11

how are peptides catabolized

Answer 11

broken into aa that are decarboxylated or deaminated

Question 12

lignin

Answer 12

an aromatic that makes up trees

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

Question 13

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

Answer 13

yes

Question 14

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

Answer 14

yes

Question 15

photoheterotrophy

Answer 15

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

Question 16

fermentation

Answer 16

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

ethanol, lactate, acetate

Question 17

respiration combines what 2 things

Answer 17

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

Question 18

anaerobic respiration

Answer 18

use of a terminal electron acceptor other than O2

Question 19

what are the only polysaccharides human enzymes can digest?

Answer 19

starch

lactose

sucrose

Question 20

how can humans/animals digest other polysaccharides

Answer 20

symbiotic relationship with microbes that can

ex. human gut microbes

Question 21

3 pathways to form pyruvate

Answer 21

glycolysis (embden-meyerhof-parnas EMP)

entner-doudoroff (ED)

pentose phosphate pathway

Question 22

products of glycolysis

Answer 22

glucose –> 2 ATP, 2 NADH, 2 pyruvate

Question 23

products of ED pathway

Answer 23

1 ATP, 1 NADH, 1 NADPH, 2 pyruvate

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

Question 24

PPP pathway products

Answer 24

1 ATP, 2 NADPH

Question 25

which steps in glycolysis are irreversible

Answer 25

the ones that consume ATP

Question 26

substrate-level phosphorylation

Answer 26

transfer of a phosphate from an organic substrate to make ATP

Question 27

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

Answer 27

transcription, allosteric

Question 28

why is allosteric regulation needed

Answer 28

so intermediates don’t build up

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

Question 29

which step is most importantly regulated in glycolysis

Answer 29

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

activated by ADP, inhibited by ATP

Question 30

amphibolic

Answer 30

if a pathway can do catabolism and anabolism

Question 31

how do ED bacteria help humans

Answer 31

prevent pathogen colonization

stimulate the immune system

Question 32

key intermediate in PPP

Answer 32

ribulose-5-P

Question 33

intermediates from PPP can be used in what biosynthesis

Answer 33

aa

vitamins

purines –> DNA/RNA

or can reenter glycolysis

Question 34

how does fermentation complete catabolism

Answer 34

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

Question 35

mixed-acid fermentation

Answer 35

can also form acetate, formate, lactate, succinate

Question 36

what is acetyl coA structure

Answer 36

acetyl group esterified to CoA

Question 37

can acetyl coA be converted to fermentation products

Answer 37

yes, many pathways

Question 38

what types of food products does fermentation yield

Answer 38

ethanol –> beer/wine

lactate –> cheese and yogurt

butyric acid –> butter

Question 39

phenol red broth test

Answer 39

test for fermentation

red pH indicator that turns yellow at below pH 6.8

Question 40

tricarboxylic acid cycle (TCA) Krebs Cycle

Answer 40

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

Question 41

pyruvate dehydrogenase complex (PDC)

Answer 41

converts pyruvate to acetyl CoA

removes CO2 and moves 2e- to NAD+

Question 42

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

Answer 42

pump protons out to generate a gradient

Question 43

how many ATP do you get from NADH and FADH2

Answer 43

NADH: 3

FADH2: 2

Question 44

oxidative phosphorylation

Answer 44

electron transport and ATP generation

Question 45

glyoxylate bypass

Answer 45

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