Lecture 4: Reg Metabolic Flux

Question 1

metabolic pathways include…

Answer 1

linked enzymatic reactions that share reactants and products

Question 2

Metabolic Flux…

Answer 2

the rate at which metabolites are converted between reactants and products

Question 3

hormones that regulate metabolic flux

Answer 3

glucagon
epi
insulin

Question 4

why do organisms need a CONSTANT input of energy?

Answer 4

in order to maintain homeostats, a condition FAR FROM EQILIBRIUM

Question 5

Linear pathways

Answer 5

each reaction generates only a single product

product is reactant for next reaction in the pathway

Question 6

forked pathways

Answer 6

gnerate TWO produts

each product has a differnt metabolic fate

Question 7

cyclic pathways

Answer 7

contain a number of metabolites that regenerate during each turn of the cycle

Question 8

easy way to tell if something is an enzyme?

Answer 8

ends in ASE

Question 9

hierarchy of metabolism

Answer 9

4 macromolecule classes (proteins, lipids, nucleic acids, carbs)
6 primary metabolite groups
7 small biomolecules

Question 10

6 primary metabolite groups

Answer 10

amino acids
nucleotides
fatty acids
glucose
pyruvate
acetyl CoA
aid in synth and degredation

Question 11

7 small biomolecules

Answer 11

NH4+
CO2
NADH
FADH2
O2
ATP
H2O
all are energy currency

Question 12

2 things that determine the flux of metabolites (through anabolic and catabolic pathways)

Answer 12

1. Avaliability of substrates (diet/stored reserves)
2. Level of enzyme activity
   a. enzyme levels (gene transcription/protein synth)
   b. catalytic activity (allosteric control/covalent mod)
   c. compartmentation (subcellular/tissue localization

Question 13

Flux ex 1 : If we had a steady state of molecular flow, and then we limit a molecule at the beginning of the pathway, what happens to the later moleculess?

Answer 13

their production decreases too

Question 14

Flux ex 1 : If we had a steady state of molecular flow, and then we eliminate an enzyme in the middle of the pathway, what will happen to the earlier molecules?

Answer 14

The conc of the earlier molecs will increase too (assuming the reactions can go both ways)

Question 15

Liver cells BEFORE breakfast

Answer 15

higher [GLUCAGON] than [insulin].

Glycogen degredation gluconeogenesis of pyruvate makes more glucose that cell can use

Question 16

Liver cells AFTER breakfast

Answer 16

higher [INSULIN] than [glucagon] (b/c lots of glucose)

glucose synthed into glycogen and converted to pyruvate by glycolysis

Question 17

photosynthetic autotrophs

Answer 17

solar nrg to oxidize H2O and make chem nrg
carbon fixation (making sugar molecs) and aerobic respiration (using sugar molecs for other stuff)

Question 18

heterotrophs

Answer 18

dependent on autotrophs or other heterotrophs
give off CO2 (which can be used in carbon fixation in autotrophs)
do aerobic resporation to get nrg

Question 19

Note about regulation of metabolic flux

Breakfast ex with glycogen and insulin

Answer 19

all pathways ARE present, but depending on how much glucose we have, some have a higher flux than others (higher flux in glycogen degretaion pathway before breakfast for example)

Question 20

Redox Reactions

Answer 20

OIL RIG

Question 21

what does redox reactions?

Answer 21

photosynth and areobic respiration to interconvert nrg

Question 22

note about electrons in redox

Answer 22

electrons CANT EXIST FREE IN SOLUTION

so they are transferred between compounds (controlled by enzymes

Question 23

what to redox reactions DO

Answer 23

catalyzed by enzymes

permit NRG to be captured as WORK

Question 24

SEE SLIDE 20

Answer 24

SEE SLIDE 20

Question 25

electron carriers

Answer 25

NAD+ and FAD and Q

Question 26

SEE SLIDE 21

Answer 26

SEE SLIDE 21