Biochem 2

Question 1

chemotrophs

Answer 1

use energy from chemical bonds

Question 2

heterotrophs

Answer 2

use organic molecules

Question 3

facultative anaerobes

Answer 3

can be anaerobic but prefer O2 like yeast and E. coli

Question 4

reversible reactions

Answer 4

have delta G near 0

occur near equilibrium conditions

Question 5

essentially irreversible reactions

Answer 5

very high delta G

cannot be easily reversed through concentration changes alone

Question 6

committed step

Answer 6

irreversible step in a pathway

Question 7

catabolism is oxidative or reductive

Answer 7

oxidative

Question 8

anabolism is oxidative or reductive

Answer 8

reductive

Question 9

regulation of enzymes

Answer 9

feedback inhibition
allostery
covalent modification- phosphorylation, ribosylation
regulatory proteins
substrate cycles- flux
genetic control- transcription and translation

Question 10

flux equation

Answer 10

J=Vfwd - Vrev
reversible flux J=0
irreversible flux J is +

Question 11

phosphoester bond

Answer 11

bond closest to sugar

versus phosphoanhydrde which is next

Question 12

standard free energy of ATP from AMP and 2P

Answer 12

-45.6 kj/mol

Question 13

standard free energy of ATP form ADP and P

Answer 13

-30.5 kj/mol

Question 14

NAD+ becomes _____ when it accepts 2 electrons to become NADH

Answer 14

reduced

catabolism

Question 15

FAD is fully oxidized/reduced

Answer 15

oxidized (reduced is FADH2)

Question 16

irreversible steps of glycolysis

Answer 16

1: hexokinase
3: PFK
10: PK

Question 17

what does Mg do in glycolysis

Answer 17

stabilize PO4s and make P more electrophillic

Question 18

dehydrogenase means

Answer 18

redox reaction

oxidizes a substrate by a reduction reaction that removes one or more hydrogens from a substrate to an electron acceptor

Question 19

why are RBCs less efficient at making ATP

Answer 19

they skip the step of 1,3-BPG to 3-PG which makes an ATP

instead they make 2,3-BPG

Question 20

what does 2,3BPG do in RBCs

Answer 20

locks hemoglobin tight so there is less O2 binding in the tense conformation

Question 21

what is the overall G’ of phosphoenol-pyruvate to pyruvate in veto form

Answer 21

-61.9 kj/mol

Question 22

what inhibits PK

Answer 22

alanine, bc can make pyruvate from alanine so inhibits last step of glycolysis

Question 23

lactic acid fermentation

Answer 23

pyruvate and NADH to Lactate and NAD+ with lactate dehydrogenase

Question 24

anaerobic metabolism of glucose in yeast

Answer 24

1. pyruvate to acetaldehyde with pyruvate decarboxylase

2. acetaldehyde to ethanol with alcohol dehydrogenase

Question 25

TPP is what vitamin

Answer 25

B1, thiamine

Question 26

lower Km in glucose transporters mean ____

Answer 26

binds tighter

Question 27

irreversible reactions have high -G because why

Answer 27

that means they are very favorable so irreversible

Question 28

PFK is inhibited by what

Answer 28

ATP

Question 29

PFK is activated by what

Answer 29

F-2,6-BP

AMP and ADP

Question 30

in liver, PFK is regulated by what

Answer 30

glucagon

Question 31

what inhibits PK

Answer 31

ATP and Alanine (bc high alanine means high pyruvate)

Question 32

what stimulates PK

Answer 32

F-1,6-BP

Question 33

what enzyme of glycolysis is most highly regulated

Answer 33

PFK

Question 34

what is the break even point in presence of O2

Answer 34

step 6, when NADH is made GAP to 1,3BPG

Question 35

what is the break even point without O2

Answer 35

step 7, when ATP is made from 1,3BPG to 3PG