Lesson 9: Introduction to Metabolism

Question 1

some types of metabilism

Answer 1

• glycolysis, TCA, fermentation
• transcription, translation, purine recycling

Question 2

linear pathways

Answer 2

A <> B <> C <> D

Question 3

branched pathways

Answer 3

A <> B <> C <> D –> E and –> F

Question 4

catabolism

Answer 4

• breakdown pathways. high energy molecules –> low energy molecules (ex: glucose -> CO2)
• oxidative, produce energy, strip H+ and e- away from reduced “fuels”

Question 5

anabolism

Answer 5

• biosoyntheic pathways. Low energy molecules –> high energy molecules
• reductive, consume energy, utilize H+ and e- from catabolism

Question 6

more on catabolism

Answer 6

• produces energy
• generates monomers
• produces reduced coenzymes
• (e-)

OVERALL: net oxidative

Question 7

more on anabolism

Answer 7

• uses energy
• uses monomers
• uses reduced coenzymes
• (e-)

OVERALL: net reductive

Question 8

are many biomolecules and primary metabolites shared

Answer 8

YES

Question 9

near equilibrium rxn

Answer 9

easily reversible under cellular conditions

Question 10

far from equilibrium rxn

Answer 10

essentially irreversible under cellular conditions
— big delta G

Question 11

what could be the advantage of having both near and far from equilibrium rxns in the cell

Answer 11

sharing enzymes –> minimizing # of enzymes that the cell needs to have

Question 12

if delta H is negative (favorable) and delta S is positive (favorable) then

Answer 12

delta G will be negative/exergonic and will be spontaneous because its negative at all temperatures

Question 13

if delta H is positive (unfavorable) and delta S is negative (unfavorable) then

Answer 13

delta G will be positive/endergonic and will not be spontaneous because delta G is positive for temperatures

Question 14

if delta H is negative (favorable) and delta S is negative (unfavorable) then

Answer 14

delta G will be negative when T is low (T< DeltaH/DeltaS) and positive when T is high (T > deltaH/DeltaS)
– spontaneous when delta G is negative

Question 15

if delta H is positive (unfavorable) and delta S is positive (favorable) then

Answer 15

delta G will be negative when T is high and positive when T is low
- spontaneous only when delta G is negative (when T > delta H/delta S

Question 16

K’eq far

Answer 16

10^2 and up
10^-2, 10^-3 (keep getting neg) and so on…..

Question 17

K’eq near

Answer 17

between 10^1 and 10^-1

Question 18

kJ/mol near

Answer 18

around -6 to 6 Kj

Question 19

unfavorable rxns (endergonic) occur in cells by

Answer 19

coupling them to favorable reactions

Question 20

source of Gibbs free energy in terms of molecular structure

Answer 20

• repulsive forces between negatively charged phosphate groups (more stable: negative charges allowed to get further away)
• resonance stabilixation of phosphate = having good leaving group resulting in low E of products compared to reactants

Question 21

high energy compounds

Answer 21

adenosine triphosphate (ATP; thioesters, acyl-phosphates, GTP

Question 22

hydrolysis

Answer 22

• relieves electrostatic repulsion between negative charges between B and Y phosphoryl group
• the hydrolysis products are better resonance stabilized and therefore lower in energy

Question 23

free energy of hydrolysis for thioesters and oxygen esters:

Answer 23

another ay to visualize the concept of “high energy” compounds
– add H2O across bond — increases stability

Question 24

electron carrying compounds

Answer 24

NAD+ and FAD
— electrons have to go somewhere when they are being stripped away => they go to these reducing agents

Question 25

NAD+ reducing

Answer 25

NAD+ (ox) + 2 e- + 2 H+ –> NADH )red_ + H+

Question 26

FAD reducing

Answer 26

FAD (ox) + 2e- + 2H+ –>? FADH2 (red)