Energy Reactions in Cells Flashcards Preview

Z OLD ESA 1- Metabolism > Energy Reactions in Cells > Flashcards

Flashcards in Energy Reactions in Cells Deck (134):
1

Define metabolism

The set of processes which derive energy and raw materials from food stuffs, and use them to support repair, growth and activity of the tissues of the body to sustain life.

2

Where does food go after it’s eaten?

GI tract

3

What is the overall purpose of food?

To supply the energy needs of the cell

4

What is food broken down into?

Nutrients

5

What happens once food has been broken down into nutrients in the GI tract?

They pass into the blood

6

What happens to food not absorbed into blood?

It is lost as faeces

7

What happens to the nutrients in the blood?

They are taken up by the tissues

8

What happens to nutrients in the tissue?

- Interconversion
- Storage (packaging nutrients into stores)
- Synthesis 
- Utilisation

9

What happens to utilised nutrients in the tissues?

They can pass back into blood for transport

10

How can nutrients be used for energy?

They can be oxidised

11

What happens to any waste produced from the oxidation of nutrients?

It’s passed back into the blood, and then lost from the kidneys or lungs

12

How does biological chemistry occur?

In small, controlled, step-wise chemical changes

13

What are metabolic reactions organised into?

Metabolic pathways

14

Describe the nature of the metabolic pathways

Distinct but integrated

15

What allows for the interconnectivity of metabolism?

Staging points on pathways where nutrients can enter or leave

16

Do the metabolic pathways occur in all cells?

Some do, but some restricted to certain cell types, or compartments of cells

17

Give an example of a pathway that occurs in all cells

Glycolysis

18

What is which metabolic pathways occur in which cells related to?

Function

19

What do all pathways have?

- Start point
- End point
- Interconnections 
- Intermediates

20

What are the intermediates in metabolic pathways known as?

Metabolites

21

What are the two main types of metabolic pathway?

#NAME?

22

What do catabolic pathways do?

Break down larger molecules into smaller ones

23

What are smaller molecules produced in catabolic processes known as?

Intermediary metabolites

24

What do catabolic processes release?

Large amounts of free energy

25

How do catabolic processes release free energy?

Breaking chemical bonds

26

Are catabolic processes oxidative or reductive?

#NAME?

27

What is meant by catabolic processes being oxidative?

They release H atoms- ‘reducing power’

28

What are the H atoms released by oxidative processes used for?

Can be used to fuel production of energy currency, or fuel biosynthesis in another pathway

29

What is the result of the metabolic steps being small?

Release small amounts of energy per step

30

What is the advantage of releasing small amounts of energy per step?

It can be captured for the future

31

What do we need catabolism for?

To allow synthesis within cells

32

What do anabolic processes do?

Synthesise larger cellular components from intermediary metabolites

33

What do anabolic processes need?

Energy in the form of ATP released from catabolism

34

Are anabolic processes oxidative or reductive?

#NAME?

35

What is meant by anabolic processes being reductive?

They use H's

36

Give the 4 products of catabolic metabolism

- Building block materials 
- Organic precursors
- Biosynthetic reducing power
- Energy for cell function

37

Give 3 examples of building block materials

#NAME?

38

What is meant by there being a dynamic state of cellular components?

There is interconversion between each other to meet cells needs

39

What are building block materials needed for?

- Cell growth
- Division 
- Repair

40

Give an example of an organic precursor

Acetyl CoA

41

What is Acetyl CoA required for?

Interconversion of building block materials

42

Give two examples of molecules that capture biosynthetic reducing power

#NAME?

43

What do molecules that capture biosynthetic reducing power do?

Capture H atoms

44

What is the energy content of fat?

37kJ/g

45

What is the energy content of carbohydrate?

17kJ/g

46

What is the energy content of protein?

16kJ/g

47

What is the energy content of alcohol?

29kJ/g

48

What is the basal metabolic rate for a 70kg man/ 58kg woman?

1700/1400kcal

49

What is meant by basal metabolic rate?

The energy required by an awake individual during physical, emotional and digestive rest at 18ºc by all the body tissues

50

How much energy is required for activity?

1000-3000kcal

51

How much energy is required for the specific dynamic action of food?

150kcal

52

What is the specific dynamic action of food?

The energy cost of ingestion, digestion and absorption of food- extracting molecules in a form that we can get into body

53

How long can we survive without food?

20-70 days, if given water

54

What do food regulatory mechanisms do?

Govern supply, storage and utilisation of energy

55

What can happen to the different forms of energy?

They’re all interconvertible

56

What type of energy does biology predominantly use?

Chemical bond energy

57

How is chemical bond energy used?

#NAME?

58

What is meant by man being isothermal?

They cannot use heat energy for work

59

What are all cellular activities expressions of?

Chemical reactions in which chemical bonds are broken or formed

60

What is meant by exergonic?

Releases energy

61

Are exergonic reactions catabolic or anabolic?

#NAME?

62

What is the sign for ∆G in exergonic reactions?

Negative

63

Are exergonic reactions spontaneous?

Yes

64

What is meant by endergonic?

Requires energy

65

What is the sign for ∆G in endergonic reactions?

Positive

66

Are endergonic reactions spontaneous?

No

67

What do endergonic reactions require?

Energy input

68

What is the intermediate energy position?

The high energy as a result of activation energy, caused by the necessity to bring things together

69

What are the conditions for standard free energy change (∆Gº)?

25ºc, 101kPa, 1 molar concentrations of reactants and products

70

What additional condition exists for ∆Gº ’ ?

At pH 7.0

71

What is ∆G equal too in non-standard conditions?

∆Gº + RT . log n ([products]/[reactants])

72

Where may non-standard conditions be found?

In a cell

73

What determines free energy?

The ratio of products to reactants in the body

74

What does the ∆G sign indicate?

If the reaction is spontaneous or not

75

Why does the ∆G sign not indicate rate?

It may be that a reaction has a very high activation energy, or a very low rate.

76

How is the chemical bond energy of fuel molecules released?

Oxidation reactions

77

What is oxidation?

Removal of e - or removal of H + atoms

78

What are all oxidation reactions accompanied by?

Reduction

79

Why do oxidation reactions have to be accompanied by reduction reactions?

H atoms must be passed on

80

What happens when fuel molecules are oxidised?

e - and H + are transferred on to carrier molecules

81

Why does the cell have a choice of how to use reduced power?

Because it’s not in a linear pathway

82

Give the 3 major H carrier molecules in their oxidised forms

- NAD +
- NADP +  
- FAD

83

Give the 3 main H carrier molecules in their reduced forms

- NADH + H +
- NADPH + H +
- FADH 2

84

Why is NAD(P)H and H + formed?

One H + quickly dissociates

85

How does the total concentration of oxidised and reduced carriers vary?

It doesn’t- it remains constant

86

Why does the total concentration of oxidised and reduced carriers remain constant?

The carriers are converted back and forth so they can pick up more energy in a cycle

87

What does NADH + H + act as the reducing power for?

ATP production

88

What does NADPH act as the reducing power for?

Biosynthesis

89

What do H carrier molecules contain?

Certain components from B vitamins

90

How are oxidised H carriers converted to their reduced form?

Adding 2 H atoms

91

What happens to H + in solution with H carriers?

It dissociates, leaving one electron behind on the carrier

92

What does NAD(P) + contain?

#NAME?

93

Why is the nicotinamide group with conjugated ring important?

Because the ring can pick up electrons to redistribute them

94

What is the result of the conjugated ring’s ability to redistribute electrons?

It allows the H atom to bind

95

How does FAD + differ from the other two carrier molecules?

It is similar, but has different electron capturing structure

96

What kind of process is the release of energy from food?

Exergonic

97

How has the oxidation of food captured bond energy?

Onto reducing equivalents

98

How can reducing equivalents drive energy requiring activities?

By coupling systems

99

What is meant by coupling systems?

Coupling carriers to other processes

100

Give an example of when coupling systems can be used directly

The use of NADPH drives biosynthesis

101

Give an example of where coupling systems can be used indirectly?

In the mitochondria electron transport system

102

What happens in the mitochondrial electron transport system?

NADH is coupled to production of ATP- electrons are fed into system, energy stripped out to drive ATP production

103

What bond in ATP is hydrolysed?

The bond between the terminal phosphate and the rest of the molecule

104

What happens when the terminal phosphate bond is hydrolysed?

It releases a phosphate and energy

105

What can be used to drive ATP synthesis?

Energy released in an exergonic reaction

106

How is part of the free energy released in a exergonic reaction conserved?

As chemical bond energy in the terminal phosphate of ATP

107

How much supply of ATP does a cell have?

A few seconds

108

What is the consequence of only having a few seconds supply of ATP?

It must cycle

109

Is ATP stable?

Yes, in the absence of a specific catalyst

110

What is the result of ATP being stable?

In controls the energy flow to prevent wasteage

111

When does catabolism slow?

When there is nowhere for the energy to go

112

What happens to catabolism when the energy has been used?

It restarts

113

What happens when [ATP] is high?

Anabolic pathways are activated

114

Why are anabolic pathways activated when [ATP] is high?

It is a high energy signal, so they know they have enough energy for biosynthesis

115

What happens when [ATP] is low, and [AMP] and [ADP] is high?

Catabolic pathways are activated

116

What is the effect of adenylate kinase (myokinase)?

2 ADP are converted to AMP and ATP

117

Give 4 high energy signals

- ATP
- NADH
- NADPH
- FADH 2

118

Give 5 low energy signals

- ADP
- AMP
- NAD +
- FAD +
- NADP +

119

What happens when supply > demand?

Energy most often stored in form of polymer macromolecules of fuel molecules

120

Give an example of a cell type that may need to increase metabolic activity very quickly?

Skeletal muscle

121

What is required for cell types that may need to increase their metabolic rate very quickly?

A high energy store reserve for emergencies

122

What is the high energy store reserve for emergencies?

Creatine phosphate

123

When is creatine phosphate produced in cells?

When ATP levels are high

124

Give the equation for the formation of creatine phosphate

Creatine + ATP -> Creatine Phosphate + ADP

125

What enzyme is required for the production of creatine phosphate?

Creatine kinase

126

What happens if [ATP] suddenly drops?

The creatine phosphate reaction reverses, producing a short term boost of [ATP]

127

How can creatine kinase (CK) be used clinically?

As a myocardial infarction (MI) marker

128

Why can CK be used as a MI marker?

CK is made up of 2 sub units. Different isoform combinations are found in different tissues, as there are 2 different proteaceous sub units of 2 genes that could form CK. One of the isoform combinations is CK-MM at 70% and CK-MB at 25-30%, which is specific to heart muscle. Normally CK is not in the muscle, so if it is present in a blood test in that isoform combination, it shows you there has been heart muscle damage, as CK is released from myocytes when damaged in MI.

129

Other than MI, what can CK be used as a clinical marker for?

Muscle infarction

130

What isoform is found in blood if there has been a muscle infarction?

98% MM and 1% MB

131

What happens to creatine and phosphocreatine spontaneously?

They break down slowly, at a steady rate, to creatinine

132

When is the breakdown of creatine and phosphocreatine not slow and steady?

In the case of muscle wasteage

133

How is creatinine excreted?

Via the kidneys

134

How can creatinine measurements be used clinically?

- Excretion per 24 hours is proportional to muscle mass
- Concentration in urine can be a marker of urine dilution
- Can be used to standardise other tests