D1 absorptive state

Question 1

what is glycolysis

Answer 1

seq of reactions that metabolises 1 mol of glucose to 2 mols of pyruvate
net production of 2 mols of ATP

Question 2

glycolysis eqn

Answer 2

D-glucose+2NAD+2ADP+2Pi—2 pyruvate+2 ATP+2NADH+2H+2H20

Question 3

what do the 2 phosphorylation rxns form

Answer 3

fructose 1,6-biphosphate

Question 4

what 2 mols are cleaved from each fructose 1,6-biphosphate

Answer 4

triose phosphate

Question 5

what 2 molecular rearrangements occur in glycolysis

Answer 5

• 2 phosphorylations of ADP = 2 ATP per triose phosphate
• 1 oxidation forming NADH per triose phosphate

Question 6

whats the product per glucose

Answer 6

2 mols of pyruvate

Question 7

what is phosphoryl transfer

Answer 7

transfer of a phosphoryl group from ATP to an alcohol

Question 8

what occurs after phosphoryl transfer

Answer 8

alcohol gives up the hydrogen while ADP and an organic phosphate are yielded

Question 9

what is aldose ketose isomerisation

Answer 9

conversion of an aldose (glucose) to a ketose (fructose) or a ketose to an aldose

Question 10

what is alcohol hydrogen transferred to and what does this result in

Answer 10

to the oxygen in the aldehyde group transforming the original alcohol group to a carbonyl and the original aldehyde to an alcohol

Question 11

what is aldol cleavage

Answer 11

splitting of a carbon-carbon bond

Question 12

what does aldol cleavage yield

Answer 12

an aldehyde and a ketose

Question 13

what is a phosphoryl shift

Answer 13

movement of a phosphoryl group from oxygen to an alcohol oxygen in the same mol

Question 14

result of a phosphoryl shift

Answer 14

alcohol hydrogen is removed and binds to the formerly phosphorous bound oxygen

Question 15

what is dehydration

Answer 15

removal of a water mol from an alcohol

Question 16

what does dehydration yield

Answer 16

a carbon-carbon double bond in the original mol

Question 17

how many rxns take place during glycolysis

Answer 17

10 rxns

Question 18

what balance in the cell has to be maintained during glycolysis

Answer 18

redox balance

Question 19

how is NAD* regenerated

Answer 19

through metabolism of pyruvate

Question 20

what happens without regeneration of NAD*

Answer 20

glycolysis will stop

Question 21

what is the dual role of the glycolytic pathway

Answer 21

1. degradation of glucose to generate ATP
2. provision of building blocks for synthetic reactions eg fatty acids

Question 22

what can be sites of control in glycolytic pathway

Answer 22

enzymes catalysing irreversible reactions are potential sites of control

Question 23

what are the control sites in glycolysis

Answer 23

-hexokinase
-phosphofructokinase
-pyruvate kinase

Question 24

hexokinase control site

Answer 24

inhibited by its product glucose 6-phosphate

Question 25

phosphofructokinase control site

Answer 25

committed step inhibition by; ATP, low pH, citrate;activation by; AMP and fructose 2,6-bisphosphate

Question 26

pyruvate kinase control site

Answer 26

ATP and alanine inhibit; fructose 1,6-bisphosphate activates

Question 27

origin of fructose 2,6-bisphosphate

Answer 27

generated by phosphofructokinase 2

Question 28

what is phosphofructokinase 2

Answer 28

bifunctional enzyme responsible for synthesis and hydrolysis of fructose 2,6-biphosphate into phosphofructokinase-phosphofructobisphosphatase

Question 29

how is phosphofructokinase 2 regulated

Answer 29

reciprocal control by phosphorylation of serine 460 by protein kinase a

Question 30

what is active in phosphorylated form

Answer 30

phosphatase

Question 31

what is active in dephosphorylated form

Answer 31

kinase

Question 32

what happens to pyruvate in anaerobic setting

Answer 32

converts to ethanol

Question 33

lactic acid fermentation occurs how

Answer 33

pyruvate into lactate by a reduction rxn using lactate dehydrogenase

Question 34

what is lactate produced by

Answer 34

muscles when the body cannot supply enoughoxygen

Question 35

what lacks mitochondria and so cannot oxidise glucose completely

Answer 35

erythrocytes

Question 36

body can create more ATP at a cost of what

Answer 36

creating an oxygen debt

Question 37

what must lactate be converted back into

Answer 37

pyruvate

Question 38

what does glycogen function as

Answer 38

reserve of glucose when metabolic demand for glucose outpaces the cells ability to obtain it from extracellular sources

Question 39

what does controlled release of glucose from glycogen maintain

Answer 39

blood glucose levels

Question 40

main storage of glycogen

Answer 40

liver and skeletal muscle

Question 40

main storage of glycogen

Answer 40

liver and skeletal muscle

Question 41

what is glycogen very similar to

Answer 41

amylopectin but more branches from every 10th glucose

Question 42

what are the two names of the stages of glycogen anabolism

Answer 42

initiation and elongation

Question 43

what is the initiation stage of glycogen synthesis catalysed by

Answer 43

catalysed in an autocatalytic manner by glycogenin

Question 44

what is the elongation stage of glycogen synthesis catalysed by

Answer 44

by glycogen synthase in concert with the branching enzyme

Question 45

what is glycogenin

Answer 45

enzyme involved in glycogen biosynthesis

Question 46

what is glycogenin classified as

Answer 46

glycosyl-transferase

Question 47

what does glycogenin act as

Answer 47

the primer to which further glucose monomers can be added

Question 48

how does glycogenin bind glucose

Answer 48

from UDP-glucose to a hydroxyl group of tyrosine 194

Question 49

what is glycogen synthase (GS)

Answer 49

main enzyme involved in glycogen polymerisation

Question 50

GS can only be added to what

Answer 50

an existing chain of at least 8 glucose residues (elongation stage)

Question 51

GS regulated by

Answer 51

covalent modifications and an allosteric mechanism

Question 52

what 2 things is GS phosphorylated by

Answer 52

protein kinase A glycogen synthase kinase 3 (GSK3)

Question 53

what does phosphorylation convert GS into

Answer 53

active a form into inactive b form

Question 54

when is b form still active

Answer 54

when a high level of the allosteric activator glucose 6-phosphate is present

Question 55

what is the activated form of glucose that is the immediate precursor for glycogen synthesis

Answer 55

uridine diphosphate glucose (UDP-glucose)

Question 56

what are nucleotide diphosphate sugars precursors for

Answer 56

synthesis of complex carbohydrates including oligosaccharide chains of glycoproteins

Question 57

what is UDP-glucose formed from

Answer 57

glucoses-1-phosphate

Question 58

overall eqn for UDP-glucose synthesis

Answer 58

glucose-1-phosphate+UTP=UDP-glucose+2Pi

Question 59

is the rxn for UDP-glucose reversible or irreversible

Answer 59

irreversible

Question 60

what makes the UDP-glucose rxn irreversible

Answer 60

spontaneous hydrolysis of the ~P bond in pyrophosphate PPi (P~P) drives the overall rxn

Question 61

what is the only energy cost for glycogen synthesis

Answer 61

cleavage of PPi (one~P bond per glucose residue)

Question 62

where are glucose residues added to

Answer 62

non-reducing terminal residues of glycogen

Question 63

what is the rxn product released from UDP-glucose

Answer 63

UDP

Question 64

what is the linkage formed from glycogen synthesis

Answer 64

a-1,4-glycosidic linkage

Question 65

what is amylo (1,4-1,6) transglycosylase

Answer 65

branching enzyme

Question 66

how many residues and from where is transferred to a more interior site

Answer 66

7 residues from the non reducing end of the chain

Question 67

what must the block include

Answer 67

non reducing terminus

Question 68

what linkage and where are the 7 residues attached by

Answer 68

a-(1,6) linkage at least 4 residues from the nearest branch point

Question 69

why is branching so important

Answer 69

increases solubility of glycogen

Question 70

what does branching allow

Answer 70

generation of a large osmotically inactive storage form of glucose

Question 71

what does branching create

Answer 71

large number of terminal residues

Question 72

terminal residues are at the sites of action of what 2 enzymes

Answer 72

glycogen phosphorylase glycogen synthase

Question 73

what does branching increase the rate of

Answer 73

glycogen synthesis and degradation

Question 74

where are fatty acids synthesised

Answer 74

cytoplasm

Question 75

why are fatty acids synthesised in the cytoplasm of a fed state

Answer 75

more carb (hence acetyl CoA) is available than needed for the TCA cycle

Question 76

what is required to build new fatty acids

Answer 76

ATP

Question 77

what protein remains bound to the intermediates in fatty acid synthesis

Answer 77

acyl-carrier protein (ACP)

Question 78

how does the fatty acid chain grow by

Answer 78

sequential addition of 2 carbon units derived from acetyl CoA

Question 79

what is the activated donor of fatty acid synthesis

Answer 79

malonyl-ACP

Question 80

what is the transfer driven by and what is released in fatty acid synthesis

Answer 80

a decarboxylation reaction releasing CO2

Question 81

what are fatty acids stored as

Answer 81

triacylglycerides (TG)

Question 82

what are the 2 building blocks of fatty acid biosynthesis and what does it result in

Answer 82

1 acetyl CoA 7 malonyl CoA = palmitate (C16)

Question 83

what enzyme catalyses formation of malonyl CoA

Answer 83

acetyl CoA carboxylase

Question 84

is the formation of malonyl CoA reversible or irreversible

Answer 84

irreversible committed step

Question 85

what is the bond that joins the glycerol mol to the fatty acids

Answer 85

ester bond

Question 86

is triacylglycerol high or low energy

Answer 86

high energy storage biomolecule

Question 87

how man kJ/g of fat is in a triacylglycerol mol

Answer 87

39

Question 88

components of a triacylglycerol mol

Answer 88

3 fatty acid groups glycerol-3 phosphate

Question 89

3 places that TGs are synthesised

Answer 89

liver adipose tissue intestinal tract

Question 90

how is TG synthesis carried out in the liver

Answer 90

from fatty acids made using glucose (glycolysis) or aa side chains

Question 91

TG synthesis during transport of dietary fat (what type)

Answer 91

intestines and adipose tissue

Question 92

can TG cross the cell membrane

Answer 92

no

Question 93

how does TG get in and out of cells

Answer 93

has to be broken down by lipases

Question 94

how are TG carried around the body

Answer 94

by lipoproteins in the plasma

Question 95

how is TG carried from liver to peripheral tissues

Answer 95

very low density lipoprotein VLDL

Question 96

how is TG carried from intestine to peripheral tissues

Answer 96

chylomicrons

Question 97

how is each fatty acid activated

Answer 97

thiol group of CoA forms high energy thioester bond with the carboxylic acid group of the fatty acid

Question 98

what is the energy source in activation of FA

Answer 98

ATP (2 high energy bonds used)