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Flashcards in Metabolism - Lynn Rogers Deck (100):
1

- Delta G

release energy

2

+ delta G

require energy

3

Delta G

Gibbs free energy (difference between products and reactants)

4

What is ATP

Adenosine Triphosphate
Main form of energy (- delta G)
used immediately
makes reaction its coupled with, occur

5

ATP when hydrolysed (eq.)

ATP -> ADP + Pi + energy
ATP -> AMP + 2Pi + energy

6

Draw the biological cycle

Draw

7

What are catabolic pathways?

release energy and produce ATP

8

What are anabolic pathways?

use energy and require ATP

9

What happens after you eat a meal?

increase blood glucose, which increases insulin (anabolic)
Glucose -> glycogen
AA -> Proteins
excess -> adipose fats

10

What happens a couple hours after the meal?

decrease blood glucose, thus decrease insulin
Glucagon is secreted and breaks down
glycogen -> glucose
Adipose fat -> fatty acids
so that fuel is available

11

What happens in a fight or flight response?

adrenaline is released (catabolic)
glyocgen -> glucose
Adipocytes -> fatty acids

12

Name 2 types of carbs, and their digestive enzyme

Lactose - digested by lactase
sucrose - digested by sucrase

13

Describe how and why Lactose intolerance occurs

People can't produce lactase, to hydrolyse lactose.
Lactose is a disach. and so is too large to be absorbed.
Lactose is broken down to carbolites and gas, then fermented by bacteria (gas) and absorbs water (bloating)

14

What breaks down fats/lipids?

bile salts (pancreatic lipase)

15

What are fats/lipids?

insoluble triglycerides

16

What are chylomicrons?

lipoprotein particles - consist of trigylcerides, phospholipids, cholesterol and protein

17

Does the OH group move in starch/cellulose? How does this affect the structure?

Yes
OH above the plane - alpha (starch)
OH below the plane - beta (cellulose)

18

What does amylase hydrolyse?

alpha bonds

19

What is fiber?

carb which can't be absorbed by body

20

Name the 3 types of dietary fiber

1. Soluble - controls BGL, decreases chol (attracts water so softens poo)
2. insoluble - regulates bowel movements (hydrophobic so hardens poo)
3. Resistant - not digested, allows for growth of good bacteria

21

What is cholesterol?

lipid, NOT A FAT
insoluble so not a body fuel
accumulates in body (no enzymes to break it down) so blocks arteries

22

What is cholesterol essential for (3 reasons)

1. integrity of membrane
2. precursor for bile salts
3. precusors for Vitamine D and steroids

23

How is cholesterol added to body? What causes it to be high?

mostly from liver
some foods increase cholesterol
genes can increase cholesterol
age
diet and lifestyle

24

Name the 3 main types of lipoproteins

1. chylomicrons
2. LDL/VLDL
3. HDL

25

Where and it what form is glucose stored?

Liver and muscle in glycogen form

26

What is glucose used for in muscle?

fuel

27

What is glucose used for in liver?

broken down to control blood glucose levels

28

Where is fat stored, and in what form?

adipoctye as triglyceride or triacylglycerol
insoluble and neutral, so form fat conglomerates

29

Where are Amino acids stored? what are they used for?

not stored
used for proteins and enzymes

30

What does liver do

stores glucose as glycogen
makes fat from excess glucose
form glucose from AA (gluconeogenesis)
forms ketones from fat

31

What is gluconeogenesis?

formation of glucose from amino acids

32

What is glycolysis?

Form pyruvate from glucose, forming 1 ATP

33

What is glycogenolysis?

glycogen to glucose

34

What is glycogenesis?

glucose to glycogen

35

What is ketosis and where does it occur?

breakdown of fat to ketones in the liver

36

What does muscle store?

stores glycogen to be used for fuel

37

What does brain need, but can't store?

glucose

38

What does adipose tissue store?

glycogen and fat

39

What is Catabolism?

oxidation of food to supply ATP

40

What is anabolism?

conversion of simple to complex molecules (requires ATP)

41

List 2 electron and proton carriers

NAD+ (nicotinamide adenine dinucleotide) and FAD (flavine adenine dinucleotide)

42

What is NAD+ and FAD reduced to

NADH and FADH2

43

What are coenzymes

molecules which attach to enzymes (NAD+ and FAD are examples)

44

List the 3 stages of glucose oxidation

1. Glycolysis
2. Krebs cycle
3. electron transport chain

45

What is hypoglycaemia?

low blood glucose levels

46

Describe glucose

most common fuel
soluble and easily distributed
provides ATP aerobically and anaerobically

47

Aerobic equation

C6H12O6 + 6O2 -> 6CO2 + 6H20 + ATP

48

Is glycolysis an anabolic or catabolic proccess?

catabolic

49

List the 3 steps in the process of Glycolysis

1. 6 carbon glucose, with the addition of 2 ATP, produces 6 carbon sugar diphosphate and 2 ADP
2. 6 carbon sugar diphosphate converts to 2 x 3 carbon sugar phosphate
3. 2 x (3 carbon sugar phosphate, with the addition of NAD+ and 2 ADP, produces 3 carbon pyruvate, NADH and 2 ATP)

50

How is ATP formed (Name the formal name)

SLP
substrate level phosphorylation

51

What is the rate determining enzyme (RDE)
What RDE is in glycolysis?

catalyses reaction which controls the whole pathway
PFK 1 - phosphfructokinase 1 (catalyses an irreversible reaction)

52

What does ATP inactive?

RDE - PFK 1

53

Under anaerobic conditions, what does Glucose produce?

2 x lactate molecules and a small amount of ATP very quickly

54

Describe what happens when Glucose is anaerobically oxidised

Glucose, with the input of NAD+ and 2 x ADP, converts to 2 x pyruvate, NADH and 2 x ATP. Then with the input of NADH, converts to 2 x lactate and NAD+ (NADH is oxidised in reaction)

55

What is substrate level phosphorylation?

enzyme transfers a P group from phosphorylated molecule to ADP to form ATP

56

Where does glycolysis occur?

Cytoplasm, however, under anaerobic conditions, pyruvate will go to Mitochondrial matrix to produce ATP.

57

What is lactase dehydrogenase?

present in all cells to catalyse anaerobic oxidation of glucose

58

What is lactic acid responsible for?

sore muscles

59

How can tumours be seen on a PET scan?

tumours, due to rapid growth, require easy access to energy.
blood vessels that surround the tumour, cannot meet demand, thus cells grow under hypoxia conditions (anaerobic) thus anaerobic glycolysis occurs (use glucose and produce lactate)
FDG (radioactive substance) shows where tumour is
When tumour removed, excess FDG in urine, shows in kidneys and bladder

60

Why are B vitamins important?

water soluble and not stored
precursors or coenzyme components

61

Importance of B3?

precursor for NAD+
thus a deficiency leads to fatigue, and CNS problems

62

What is the warburg effect?

Cancer cells undergo anaerobic glycolysis, and produce lactate, even in the presence of oxygen. Does this so that cells can produce ATP in short amount of time

63

Does the Krebs cycle occur after anaerobic or aerobic glycolysis?

aerobic

64

Where does the Krebs cycle occur?

mitrochondrial matrix

65

Explain how pyruvate converts to Acetyl CoA

Pyruvate travels into mitochondria and, with the addition of coenzyme A and NAD+, converts to Acetyl CoA, NADH and CO2
or
CH3COCOO-H+ + NAD+ + CoA-SH
-> CH3CO-SCoA + NADH +H+ +CO2

66

Why is thiamine important?

cofactor for pyruvate dehydrogenase, which converts pyruvate to Acetyl CoA
is found in meat, legumes, etc
reduced absorption in alcoholic and caffeine addicts

67

What is Coenzyme A? What does it need to be formed?

CoA-SH
You need Pantothenate, which is from pantothenic acid
found in eggs, liver, veg

68

What happens if you have a deficiency Thiamine?

Can't convert pyruvate to Acetyl CoA, as can't produce pyruvate dehydrogenase, thus pyruvate converts to lactate in cytoplasm

69

Describe the Krebs cycle (Draw the cycle)

Draw

70

Where does electron transport chain occur?

inner mitochondrial matrix

71

Describe the electron transport chain

NADH and FADH2 gives up e- and H+ to a carrier molecule. These carrier molecules inner mitochondrial membrane) and reduced, then oxidised and give away their e- and H+ to another carrier molecule. Eventually oxygen takes up e- and converts to H20.
At the same time, H+ are translocated intermembrane space. These H+ become trapped, as membrane is impermeable, and so a proton gradient occurs.

72

How is ATP generated from proton gradient?

enzyme in membrane (F0F1 ATPase)
F0 - proton channel
F1 - enzyme
F0 allows protons to come back, which leads to a change. This leads to a change in F1 domain, and ADP phosphorylated with P to form ATP

73

Why does 02 need to be available in the e- transport chain?

So that it can accept e- in the chain

74

What is the rate of the chain determined by?

ATP demand

75

The sun is an exhaustible source of what?

energy

76

Water is an exhaustible source of what?

electrons

77

Oxygen is an exhaustible sink of what?

electrons

78

Why is ATP transported to cytoplasm?

anabolism occurs here

79

When carrier molecules are reduced, then oxidised, where does the released energy go?

energy is used to transport H+ across to the transmembrane space

80

How does cyanide work?

inhibits protein in inner mitochondrial membrane
e- cant be absorbed
H20 cant be made from O2
not proton translocation, so no gradient
NO ATP = asphyxiation

81

What is an example of uncoupling poisons?

2, 4 DNP herbicides/fungicides

82

How do coupling poisons work?

allows protons to reenter MM without capturing energy
e- still absorbed, and H+ still translocate, but H+ are absorbed, thus dissipates gradient, so no ATP
increased fuel is consumed, and increased e- absorbed, but only heat is produced

83

What is fatty acid oxidation?

fatty acids are oxidised to Acetyl CoA in the MM
beta oxidation in presence of oxygen (aerobic)

84

Reaction in ETC

02 + 4e- + 4H+ -> 2H20
or if partial oxidation occurs
02 + e- -> 02'-

85

What is ROS?

reactant oxygen species (oxidant/free radical)
Formed from partial oxidation of ETC
e- escaped from ETC, and partially oxidised oxygen becomes highly reactive

86

Why is ROS bad?

as partiall oxidised oxygen has an extra e-, it becomes extremely reactive, and destroys all molecules it meets

87

What causes ROS?

alcohol, drugs, smoking, pollution, aerobic mtabolism

88

How do you decrease free radicals?

decrease diet
antioxidants - Vit C, E and A
vegetables contain phytochemicals - destroys carcinogens

89

What are iso enzymes?

enzymes which catalyse same chemical reaction, but have a slightly different structure

90

How are isoproteins released?

When the cell is injured or dies, cell membrane becomes highly permeable and cellular contents are released, releasing enzymes

91

Where is LDH found, and name the 3 different types

in all cells
LDH1 - myocardium (HHHH)
LDH3 - brain/kidneys (MMHH)
LDH5 - skel/muscle (MMMM)

92

Name the 8 hydrophobic AA

GALVIM (glysine, alanine, leusine, valine, isoleucine, methionine)
PTT (phenylalanine, tryptophan, tyrosine)

93

Name the 3 basic AA

LAH (lysine, arginine, histidine)

94

Name the 2 acidic AA

AG (aspartic, glutamic)

95

Name the 2 amide AA

AG (asparagine, glutamine)

96

Name the 2 hydroxylated AA

ST (serine, Threonine)

97

Name the 2 special AA

Cysteine - SH group
Proline - Imino group

98

What is creatine kinase?

An enzyme which phsoprylates ATP to ADP and creatine to creatine phosphate

99

Where is creatine made?

liver, but travels to skel. muscles, where it is converted to creatine phsophate

100

What does creatine break down to?

creatinine, in the blood