Biochemistry Flashcards Preview

JazGI > Biochemistry > Flashcards

Flashcards in Biochemistry Deck (98):
1

Glycogen in the liver maintains ____ for ___
glycogenolysis fluctuates dependant on ___

glucose blood concn for RBCs and brain
meals

2

Glycogen in muscle provides ___ via __+___ during physical activity

energy
glycolysis and TCA

3

Source of glucose at night when ___ glycogen is depleted

gluconeogenesis
hepatic glycogen

4

The more ____ links = more glycogen ___ = faster release

α-1,6 links ; branches

5

To synthesis glycogen need

at least 4 glucose residues
glycogenin (primer protein)

6

activated form of glucose =
_____ link releases E on ____

UDP-glucose
phosphate ester link
hydrolysis

7

enzyme that extend glycogen chain

glycogen synthase

8

enzyme that adds α-1,6 branches roughly every ___ glucose residues =

transglycosylase
10 glucose residues

9

glycogenolysis occurs in the ___
____ is dephosphorylated by and ___ released into blood

liver
glucose-6-phosphate > glucose by glucose-6-phosphatase

10

in muscle glycogenolysis does/doesnt occur because ___

doesnt
muscle doesnt have glucose-6-phosphatase

11

Enzyme that converts glucose to glucose-6-phosphate
(1st steo in glycogenesis)

hexokinase

12

Enzyme that converts glucose -6-phosphate to glucose-1-phosphate
(2nd step in glycogenesis)

phosphoglucomutase

13

enzyme that adds UTP to glucose-1-phosphate to convert it to UDP-glucose
(3rd step in glycogenesis)

UDP- glucose pyrophosphorylase

14

Insulin stimulates and glucagon inhibits ___ in the rate limiting step of glycogenesis

glycogen synthase

15

Insulin inhibits and glucagon/adrenaline/cortisol stimulate ___ in the rate limiting step of glyconolysis __>___

glycogen phosphorylase
glycogen to glucose-1-phosphate

16

Insulins effects on glycogenesis and glycogenolysis

stimulates glycogenesis
inhibits glycogenolysis

17

Factors that stimulate glycogenolysis

glucagon
adrenaline
cortisol

18

Enzyme that converts glucose-1-phosphate to glucose-6-phosphate
(2nd step in glycogenolysis)

phosphoglucomutase

19

Enzyme that converts glucose-6-phosphate to glucose
(last step in glycogenolysis)
occurs only in the ___ and glucose enters blood via __
otherwise the glucose-6-phosphate> ___

glucose-6-phosphatase
liver > GLUT2
glycolysis

20

Synthesis of glucose from non-carb. precursors =
occurs during___

gluconeogenesis
starvation

21

precursors for gluconeogenesis

lactic acid
amino acids
glycerol

22

Energy for gluconeogenesis is supplied from __+__

oxidation of FAs from adipose tissues
body protein

23

Location of gluconeogenesis

mainly liver and some in kidneys

24

___ is synthesised from pyruvate in mitochondria and in TCA accepts ___ groups from fat breakdown

oxaloacetate
acetyl groups

25

E required for gluconeogenesis

6ATP

26

Glycolysis in muscle -> gluconeogenesis in liver (repeated) =
for each cycle ___ATP is made and ___ is used
Function:

Cori cycle
2ATP made; 6ATP used up
stop blood and muscle becoming to acidic when no O2 and buys time

27

AAs can enter TCA as intermediate/pyruvate>__
or as ____ if __ is already present

oxaloacetate
acetyl Co-A if oxaloacetate already present

28

___ stimulates gluconeogenesis and inhibits glycolysis
___ does the opposite

glucagon stimulates gluconeogenesis and inhibits glycolysis
insulin does the opposite

29

substances and their concns that stimulate glycolysis and inhibit gluconeogenesis

AMP, ADP + fructose-2,6-biphosphate high levels
citrate, ATP, alanine or acetyl Co-A low levels

30

substances and their concns that inhibit glycolysis and stimulate gluconeogenesis

ATP, citrate, alanine, acetyl-CoA high levels
fructose-2,6-biphosphate low levels

31

increased fat intake increases ____ of adipocytes

fat content and number of adipocytes

32

double bond in FAs are usually in __ format

cis

33

Most common FA in humans

palmitic acid

34

The body can't synthesise polyunsaturated FAs of more than ___ long

9C
= essential FAs

35

C next to the carboxyl group in FAs =

α carbon

36

C furthest from carboxyl group in FAs =

Ω carbon

37

Ω3 FA means that the C=C is ___

3C from Ω carbon

38

FAs of less than or equal to ___ long are liquid at temperature

8C

39

glycerol in the gut is absorbed into the ___

interstitial epithelial cells

40

short and medium FAs in the gut are absorbed into the ___ and go to the ____

mucosal cells > portal system

41

larger FAs and monoglycerides are re-synthed into ___ and absorbed into ___ where they go into the ___

triglycerides > mucosal cells where they're made into chylomicrons > lymphatics

42

FAs are oxidised in the cytoplasm by: (equation)

FA+CoA ---+2ATP--->acyl co-A

43

Carnitine shuttle is used to _____

transport acyl CoA (from FAs) into matrix for further oxidation

44

Carnitine shuttle equation:

acyl coA + carnitine = CoA and acyl carnitine
by translocase, acyl carnitine is transported into matrix
+CoA = acyl CoA + carnitine (transported back out)

45

β oxidation of FAs occurs in the ___
each cycle produces

mitochondrial matrix
1 acetyl CoA, FADH2, NADH H+, FA acyl CoA (shortened by 2C and goes back into cycle)

46

The E produced from a polyunsaturated FA of same length as a saturated one is less because

different enzymes are needed to break C=C bonds

47

odd-chain and branched FAs produce more/less E per C as saturated FAs

less

48

Sites of glycerol breakdown =

liver and kidney

49

Equation for glycerol breakdown

>glycerol-3-phosphate by glycerol kinase
dehydrogenated >dihydroxyacetone phosphate = normal intermediate of glycolysis

50

Breakdown of glycerol produces an intermediate of___

glycolysis

51

Ketone bodies are formed in ____ by _____
are then taken in blood to _+_ for E where converted to ___ for the TCA

liver mitochondria from β-oxidation
heart muscle and renal cortex
acetyl CoA

52

In starvation/diabetes gluconeogenesis uses up ___
FAs are still oxidised for E to = ____ which then form ____ as there is no _____ to combine with it for the TCA => acidosis.

oxaloacetate
acetyl-CoA> ketone bodies
oxaloacetate

53

lipogeneis occurs in the ___

liver mainly
kidney
mammary glands
adipose tissue
brain

54

___ transports FAs in the blood and take to adipose tissue where they are stored as ___

albumin
triglycerides

55

Lipogenesis is a ___ process ie. it ___ electrons

reductive
requires electrons

56

Lipogenesis occurs in excess E intake
glucose is converted to acetyl CoA in ___
which is converted to FAs in ___

mitochondria
cytoplasm

57

In lipogenesis acetyl CoA binds with ___ in the mitochondria to form ___ which is transported into the cytoplasm and then converted back to acetyl CoA

oxaloacetate > citrate

58

In lipogenesis: in cytoplasm the crucial regulatory step is:

acetyl CoA ---acetyl CoA carboxylase--> malonyl CoA (donates C to new lipid)

59

___ is electron donor to malonyl CoA in lipogenesis
Enzyme to synth sat FAs =
Lengthens acylchain by __ each cycle
needs different enzymes at ___ length or if ___ needed

NADPH
FA synthase
2C
C16 / C=C

60

____ regulates FA anabolism it is stimulated by __
inhibited by ___

acetyl CoA carboxylase
stimulators: insulin and citrate
inhibitors: glucagon, adrenaline, palmitoyl Co-A (when FAs in excess) + AMP

61

glycerol-3-phosphate is made in the liver from ___ + in adipose from ____
required in the synth of ___
and then _____ occurs to + 3 acyl CoAs

liver from glycerol
adipose from glucose
triglycerides
esterification

62

Nitrogen from AA breakdown is excreted via:

urea (80%) formed in liver
uric acid
creatinine
NH4+ ion

63

synthesis of urea, 3 steps =

transamination
deamination
urea cycle

64

In transamination for urea synth:
In all tissues: ___ move the amino group from α-AAs to α-keto acids => glutamate
Transported to liver by __ or ___

aminotransferases
alanine OR glutamine

65

Deamination and urea/___ cycle in urea synth:
In ___:amino group of ___ -> free __ ion
N from___+ N from ____ and C from ___ = ___

ornithine cycle
liver
glutamate -> NH4+
NH4+ , aspartic acid, CO2 = urea

66

The urea cycle uses _ATP as _ PO4 bonds are broken
and it produces ___ a intermediate in TCA

3ATP
4PO4
fumarate

67

C skeletons of ketogenic AAs are degraded to ___/___ and form __/___

acetyl CoA/acetoacetyl CoA
ketone bodies/FAs

68

C skeletons of glucogenic AAs are degraded to __/___ and are involved in ___

pyruvate/TCA intermediates
gluconeogenesis

69

3 inherited disorders of AA degradation:

alcaptonuria
maple syrup urine disease
phenylketonuria

70

Urea cycle disorders cause __ to increase which is toxic for the NS. Treat = ____ diet and drugs that ___

NH4+
low protein diet and N2 removing drugs

71

Plasma proteins biggest>smallest

albumin
α globulins
β globulins
γ globulins

72

α globulin eg.s

ceruloplasmin (Cu2+)
retinol binding protein (vit A transport)

73

vitamin A is converted to __ - part of ___ a visual pigment

retinaldehyde part of rhodopsin

74

α globulins functions =

transport lipoproteins, lipids, hormones, bilirubin and dietary metals

75

β globulin eg.s

transferrin (Fe3+ transport)
fibrinogen

76

50% of plasma proteins =

albumin

77

albumin is __ charged and __ soluble
is main determinant of ___

-vely charged
water soluble
plasma oncotic P

78

___ stimulates albumin synthesis

insulin

79

albumin transports ___ molecules, it has a ___ affinity but a ___ capacity

lipophilic/hydrophobic
low affinity
high capacity

80

eg.s of substances transferred by albumin (5)

thyroid hormones
sex hormones
FAs
bilirubin
exogenous substances eg. aspirin

81

Fe3+ is reduced to Fe2+ for ___ by __ being oxidised

storage
Cu2+

82

Deficiency of ceruloplasmin for Cu2+ transport =

Wilson's disease

83

Tranport exogenous tri.s =

chylomicrons

84

transport endogenous tri.s =

VLDL

85

Transport lipids to peripheral tissues =

LDL

86

Cholesterol is a precursor for (3)

steroid hormones
bile salt
vitamin D

87

cholesterol is more/less soluble in water than cholesteryl esters

more

88

__% of cholesterol circulates in free form

30%

89

Rate limiting step in cholesterol synthesis is :

HMG CoA to mevalonic acid by HMG CoA reductase

90

Cholesterol synthesis starts with ___
the reducing power is from __
and energy from ___

2 acetyl CoA
NADPH
ATP

91

vitamin D regulates __+__ metabolism
most abundant form =

Calcium and phosphorus
D3

92

Liver stores these 3 vitamins and __

A (10 months worth as retinol palmitate)
D (3 wks worth)
B12 (few yrs worth)
Iron bound to ferritin

93

β oxidation in lipid metabolism is the conversion of __ to __ in the ___

fatty acyl co-A to acetyl co-A in the mitochondrion

94

__ can't be used for gluconeogenesis

FAs

95

For saturated FAs in fat catabolism the number of oxidation cycles =

(no of Cs/2) - 1

96

acetyl coA carboxylase (in FA synthesis) is stimulated by

insulin and citrate

97

acetyl coA carboxylase (in FA synthesis) is inhibited by

glucagon, adrenaline, palmitoyl coA, AMP

98

___ AAs can be completely oxidised in TCA
___ AAs can be used to form glucose

ketogenic AAs = TCA
glucogenic AAs = glucose
all are precursore for gluconeogenesis