Lecture 301: intro to metabolism

Question 1

metabolic pathway

Answer 1

series of rxns/ pathway that begins with a specific molecule and ends with a specific product

Question 2

flow of metabolic pathways

Answer 2

only flow in one direction

Question 3

reversible rxn

Answer 3

direction of rxn depends on relative concentration of reactants/ products

Question 4

irreversible rxn

Answer 4

only flows in one direction; often regulation sites of metabolic pathways

Question 5

energy of catabolic pathways

Answer 5

releases energy

Question 6

energy of anabolic pathways

Answer 6

consumes energy

Question 7

energy metabolism

Answer 7

intermediary metabolic pathways that generates or stores energy

Question 8

central pathways

Answer 8

pathways accounting for large amounts of mass transfer and energy generation in a cell [heaviest traffic and highly conserved across organisms]

Question 9

catabolic pathways (5)

Answer 9

• glycolysis
• Krebs/ TCA cycle
• oxidative phosphorylation
• fatty acid oxidation [beta-phosphorylation]
• glycogenolysis

Question 10

anabolic pathways

Answer 10

• gluconeogenesis
• fatty acid biosynthesis
• glycogenesis

Question 11

pathways are regulated at the (endergonic/ exergonic) step

Answer 11

exergonic

Question 12

negative vs positive ΔG means what for reaction

Answer 12

-ΔG = reaction can only move forward
\+ΔG = reaction can only move backwards

Question 13

chemical heat energy

Answer 13

biological energy derived from heat energy

Question 14

electrochemical energy

Answer 14

biological energy derived from electromotive force

Question 15

majority of our energy comes from ____ stored as _____

Answer 15

electron movement; chemical energy

Question 16

free energy derived from ATP hydrolysis is coupled to (endergonic/ exergonic) process for what?

Answer 16

endergonic process to make it “exergonic” or closer to equilibrium

Question 17

ATP chelated to ___ why?

Answer 17

Mg2+ to stabilize phosphate bonds

Question 18

function of Mg2+ with ATP

Answer 18

stabilizes ATP molecules = prevents H2O from coming in and breaking the phosphate bond

Question 19

adenylate energy charge

Answer 19

• relative concentration of ATP, ADP and AMP

- overall regulator of energy metabolism

Question 20

high [ATP]

Answer 20

• high adenylate charge

- cell stops generation of ATP [stores energy]

Question 21

low [ATP]

Answer 21

• low adenylate energy charge

- generates ATP

Question 22

oxygen is a strong (reducing agent/ oxidizer)

Answer 22

• strong oxidant

- serves as ultimate electron acceptor

Question 23

energy derived from

Answer 23

oxidation of reduced organic carbon

Question 24

dehydrogenase reactions utilize

Answer 24

• NAD+ and FAD [oxidants]

Question 25

NADPH vs NADH

Answer 25

• equivalent in thermodynamic properties
• NADPH has a phosphate group; used in anabolic pathways to reduce substrates and in reductase rxns
• NAD+ used in catabolic pathways to oxidize their substrates and in dehydrogenase rxn

Question 26

direction of dehydrogenase and reductases catalyze ____ rxns; direction depends on _____

Answer 26

reversible; redox state

Question 27

complete oxidation of glucose yields ___ ATP molecules

Answer 27

32

Question 28

reductase reactions utilize

Answer 28

• NADP+ [oxidizer]

Question 29

high blood glucose

Answer 29

• glucose gets stored as glycogen
• glucose undergoes glycolysis = pyruvate = acetyl-CoA = energy
• acetyl-CoA can also convert into fat

Question 30

insulin

Answer 30

• lowers blood glucose

- turns on glycolysis and glycogenesis

Question 31

glucagon

Answer 31

• raises blood glucose

- turns on glycogenolysis and gluconeogenesis

Question 32

low blood glucose

Answer 32

• glycogen undergoes glycogenolysis = glucose
• metabolites undergo gluconeogenesis = glucose
• fats converted to acetyl-CoA = can be used as energy