Nutrition, Body Weight and Homeostasis Flashcards Preview

Z OLD ESA 1- Metabolism > Nutrition, Body Weight and Homeostasis > Flashcards

Flashcards in Nutrition, Body Weight and Homeostasis Deck (214):
1

Define metabolism

The chemical process that occur within living organisms in order to maintain life.

2

What does metabolism consist of?

#NAME?

3

What do oxidative pathways do?

Convert food to energy

4

What do fuel storage and mobilisation pathways do?

Allow food to be mobilised when we are not eating or need to increase energy

5

How to fuel storage and mobilisation pathways allow fuel to be mobilised?

Through interconversion of glycogen and fat stores

6

What do biosynthetic pathways do?

Produce basic building blocks for cells

7

What do detoxification pathways do?

Remove toxins

8

What are catabolic processes?

They break down molecules to release energy in form of reducing power

9

What are anabolic processes?

They use energy and raw materials to make larger molecules for growth and maintenance

10

Define energy

The capacity to do work

11

What kind of energy to cells use?

Chemical bond energy

12

How do cells use chemical bond energy?

Through the utilisation of ATP

13

What kind of work do cells do?

#NAME?

14

What biosynthetic work do cells do?

Synthesis of cellular components

15

What transport work do cells do?

Movement of ions and nutrients across membranes

16

Why is the movement of ions across membranes important?

For neuronal communications

17

What mechanical work do cells do?

Muscle contraction

18

What electrical work do cells do?

Nervous conduction in the form of action potentials

19

Where does osmotic work occur?

In the kidney

20

Describe the structure of ATP

Adenine base linked to ribose sugar and 3 phosphates- alpha, beta and gamma.

21

How does ATP release energy?

Bond between beta and gamma phosphate breaks

22

Give the equation for ATP hydrolysis

ATP ↔ ADP + Pi

23

Give 5 examples something that pushes ATP hydrolysis in the forward direction

#NAME?

24

What pushes ATP hydrolysis in the backwards direction?

Energy production by oxidation

25

Give 4 examples of things oxidised for energy production

#NAME?

26

How is ATP generated?

By breaking down the chemical bonds in food

27

Give 3 processes that generate ATP

#NAME?

28

What is the official SI unit of energy?

kJ

29

How many kJ’s are there in 1 kcal (calorie)?

4.2

30

Give the 6 essential components of the diet

#NAME?

31

Which of the essential components of the diet can’t be digested?

Fibre

32

What are carbohydrates required for?

Mostly supply energy

33

What are proteins required for?

Energy and amino acids

34

When are proteins utilised for energy?

In starvation

35

What are fats required for?

Energy and essential fatty acids

36

What are minerals required for?

Cofactors of enzymes

37

What is water required for?

Hydration

38

What is fibre required for?

Normal GI function

39

Why can’t fibre be digested?

Because humans can’t digest the 1,4-ß glycosidic bonds in cellulose, as they don’t have the enzyme

40

Give 4 examples of carbohydrates

#NAME?

41

What is starch

A glucose polymer that is the carbohydrate storage molecule in plants

42

What are the monomers of sucrose?

Glucose and fructose

43

What are the monomers of lactose?

Glucose and galactose

44

What is the purpose of digestion of carbohydrates

To break larger carbohydrates into monosaccharides

45

Why must larger carbohydrates be broken down into monosaccharides?

So they can be absorbed in the blood

46

What are proteins composed of?

Amino acids in linear chains

47

How are amino acids in proteins linked?

Peptide bonds

48

What effect does digestion have on proteins?

Breaks them down into constituent amino acids

49

What happens to the amino acid products of digestion?

They are absorbed into the blood

50

How many amino acids are used for protein synthesis in the body?

20

51

How do amino acids differ from one another?

They each have a different side chain

52

How many essential amino acids are there?

9

53

Why are essential amino acids so called?

They cannot be synthesised by the body

54

What is the result of the inability of the body to synthesise essential amino acids?

They must be obtained from diet

55

How must protein hormones enter the body

Injected

56

Why must protein hormones be injected?

Otherwise the body would break them down

57

What are the 9 essential amino acids?

- Isoleucine
- Lysine
- Threonine
- Histidine
- Leucine
- Methionine
- Phenylalanine 
- Tryptophan 
- Valine

58

What is meant by conditionally essential?

Some amino acids are only essential in extreme circumstances

59

When may amino acids be conditionally essential?

In children and pregnant women

60

Why might amino acids be conditionally essential in children and pregnant women?

High rate of protein synthesis as rapid growth rate

61

What 3 amino acids are conditionally essential in children and pregnant women?

#NAME?

62

What is the difference between protein of animal origin and plant origin?

Protein of animal origin ‘high quality’- contains all amino acids. Proteins of plant origin usually deficient in 1+ essential amino acids

63

What is the result of protein of plant origin being of lower quality?

Vegetarians need proteins from wide variety of sources

64

What are lipids composed of?

Triacylglycerols

65

What are triacylglycerols composed of?

3 fatty acids esterified to 1 glycerol

66

What are the 2 types of lipids?

#NAME?

67

What is the result of a double bond in a lipid?

Allows more flexibility

68

How do fats differ from carbohydrates or protein?

They have much less oxygen

69

What is the result of fats having less oxygen than carbohydrates or protein?

They are more reduced, so yield more energy when oxidised

70

What are fats required for?

#NAME?

71

What are the 4 fat soluble vitamins?

#NAME?

72

What are the two essential fatty acids?

#NAME?

73

What kind of constituent are minerals in the diet?

Microconstituent

74

What is the role of electrolytes in cells?

They establish ion gradients across membranes and maintain a water balance

75

Give an example of an electrolyte required in the body

Cl -

76

Why is Cl - required in the diet?

It is an essential electrolyte for sodium potassium ATPase, needed to establish ion gradients

77

Give two examples of macrominerals

#NAME?

78

What are macrominerals essential for?

Structure, e.g. bones and teeth

79

Other than structure, what is calcium important for?

Important signalling molecule

80

Give 7 examples of enzyme cofactors

#NAME?

81

Give an example of a process that requires an enzyme cofactor

Glutathione peroxidase, required to combat oxidative stress, requires selenium

82

What is iron essential for?

Component of haemoglobin

83

From high to low amount, how much of a mineral is needed?

Electrolytes → minerals → trace minerals → ultratrace

84

In what quantity are vitamins required?

Very small

85

Are vitamins fat or water soluble?

Can be either

86

What happens if someone has incorrect vitamin intake?

If too little, can get deficiency diseases 
Can also have vitamin excess

87

Give an example of a vitamin excess disease, and it’s effects

#NAME?

88

Give 4 examples of fat soluble vitamins

#NAME?

89

Give 10 examples of water soluble vitamins

- B1 (Thiamine)
- B12
- B6
- Biotin
- C 
- Choline
- Folate
- Niacin
- Pantothenic acid
- Riboflavin

90

What disease is caused by a deficiency in vitamin A?

Xerophthalmia

91

What disease is caused by a deficiency in vitamin D?

Rickets

92

What is caused by a deficiency in vitamin E?

Neurological abnormalities

93

What is caused by a deficiency in vitamin K?

Defective blood clotting

94

What disease is caused by a deficiency in vitamin B1?

Benberi

95

What disease is caused by a deficiency in vitamin B12?

Anaemia

96

What diseases are caused by a deficiency in vitamin B6?

Dermatitis, anaemia

97

What is caused by a deficiency in biotin?

Alopecia, scaly skin, CNS defects

98

What disease is caused by a deficiency in vitamin C?

Scurvy

99

What is caused by a deficiency in choline?

Liver damage

100

What is caused by a deficiency in folate?

Neural tube defects, anaemia

101

What disease is caused by a deficiency in niacin?

Pellagra

102

What is caused by a deficiency in pantothenic acid?

Fatigue, apathy

103

What disease is caused by a deficiency in riboflavin?

Ariboflavinisis

104

What vitamins have an antioxidant role?

A and C

105

What antioxidant role do vitamins A and C have?

They are free radical scroungers

106

Give 4 examples of dietary fibres

#NAME?

107

What is dietary fibre essential for?

Normal GI function

108

Can dietary fibres be broken down by human digestive enzymes?

No

109

What is the recommended intake of dietary fibre?

18g/day

110

What is the consequence of low dietary fibre?

#NAME?

111

What is the result of high dietary fibre intake?

Reduced cholesterol

112

Why does a high dietary fibre intake reduce cholesterol?

Bile salts are secreted into the stomach, which requires cholesterol. Fibre absorbs bile salts, so if there is high fibre intake, more bile salts are absorbed, so less bile salts reabsorbed into liver. This means that more bile salts must be made, so more cholesterol used.

113

What is the advantage of lower cholesterol?

Lower risk of diabetes

114

Who publishes dietary reference values (DRV’s)?

SACN

115

What are DRVs?

A series of estimates of amount of energy and nutrients needed by different groups of the UK population

116

What is the reference nutrient intake (RNI)?

The level of protein, vitamins and minerals that would meet the needs of 97.5% of the population

117

When is the estimated average requirement (EAR) used?

For energy

118

What is the EAR?

The energy requirement for 50% of the group

119

What is the lower reference nutrient value (LRNI)?

The level that would be enough for 2.5% of the population- the majority need more

120

When is safe intake used?

When there is insufficient data

121

What do nutrient requirements depend on?

#NAME?

122

How are nutrient requirements established?

By review of scientific evidence and frequency distribution for groups

123

Are nutrient requirements applicable to individuals?

No- groups.

124

Give 4 things that daily energy requirements depend upon

- Age
- Sex
- Body composition 
- Physical activity

125

What is daily energy expenditure equal too?

Basal metabolic rate + diet induced thermogenesis + physical activity level

126

What is the basal metabolic rate?

The energy used to keep the body going, e.g. for liver function, brain etc.

127

What is diet induced thermogenesis?

Energy required to process food

128

Give two examples of things required for the maintenance of cells

- Ion transport across membrane 
- Biochemical reactions

129

What percentage of the BMR is accounted for by the skeletal muscle?

30

130

What percentage of the BMR is accounted for by the brain?

20

131

What percentage of the BMR is accounted for by the heart?

10

132

What percentage of the BMR is accounted for by other organs?

20

133

Give 5 factors that affect BMR

#NAME?

134

How does body size affect BMR?

Depends on surface area

135

How does gender affect BMR?

It is higher in males

136

How does environmental temperature affect BMR?

It increases when it’s cold

137

How does endocrine status affect BMR?

It is increased in hyperthyroidism

138

How does body temperature affect BMR?

It increases by 12% per degree

139

What does energy required for voluntary physical activity depend on?

Intensity

140

What systems does voluntary physical activity increase energy demand for?

#NAME?

141

What happens to the heart and breathing rate with physical activity?

They increase

142

What does an increase in energy demand with activity reflect?

An increase in demand on skeletal muscle

143

Why does skeletal muscle require more energy with activity?

Skeletal muscle hydrolyses ATP to form cross bridges that underlie skeletal muscle contraction.

144

How does skeletal muscle contraction work?

Muscle contraction is determined by myosin in the thick filament and actin in the thin filament. Myosin head binds to thin filament, hydrolyses ATP (chops off gamma phosphate). Energy released used to change the myosin head, which draws the filaments over each other.

145

What is the very short term energy store?

Creatine phosphate

146

Where is creatine phosphate found?

In the muscles

147

How much creatine phosphate do the muscle contain?

A few seconds worth

148

What energy store is used for immediate use?

Carbohydrate stores

149

What form are the carbohydrate stores in?

Glycogen

150

What is the time scale for glycogen utilisation?

Minutes to hours

151

Where is glycogen stored?

Muscles and liver

152

Where are the long term energy stores?

Adipose

153

How much energy is stored in adipose?

About 40 days worth

154

Where does energy come from in emergency situations?

Muscle protein converted to carbohydrate

155

Why is muscle protein only used as an energy source in emergency situations?

The body wants to conserve muscle mass

156

What is the main difference in body composition between men and women?

Fat

157

What happens to body composition in obesity?

Not everything in body increases, just adipose tissue

158

What happens if energy intake = expenditure?

The body weight is stable

159

What happens if energy intake > expenditure?

Energy stores increase

160

What happens if energy intake

Body components, e.g. protein, utilised to provide energy

161

What is obesity?

Excessive fat accumulation in adipose tissues

162

What is the result of obesity?

It impairs health

163

How is obesity usually measured?

In BMI

164

What BMI would be considered obese?

Over 30

165

What is the problem with obesity?

It is the major preventable cause of death in developed countries, with an increasing prevalence

166

What health issues is obesity associated with?

- Increased risk of some cancers
- Cardiovascular disease
- Type 2 diabetes

167

What is the unit for BMI?

kg/m 2

168

How is BMI calculated?

Weight (kg) / Height 2 (m 2 )

169

What is BMI used for?

To clinically evaluate a patients weight

170

What BMI is considered underweight?

Under 18.5

171

What BMI is considered normal?

18.5 - 24.9

172

What BMI is considered overweight?

25 - 29.9

173

What BMI is considered severely obese?

Over 35

174

Under what conditions is BMI measured?

#NAME?

175

What is the advantage of a BMI measurement?

Good correlation with body fat measurement

176

What is the disadvantage of a BMI measurement?

Very muscular individuals may be classified as obese

177

What is an alternative to BMI?

Hip-to-waist ratio

178

What has been evidenced to be clinically important?

Distribution of body fat

179

Why is distribution of body fat clinically important?

Greater proportion of fat in upper body (especially abdomen) compared with hips is associated with increased risk of- 
- insulin resistance
- hyperinsulinism
- type 2 diabetes
- stroke
- hypertension
- hyperlipidaemia
- premature death

180

What is a major preventable cause of death in developing countries?

Malnutrition

181

What are the two main types of malnutrition?

- Kwashiorkor 
- Marasmus

182

What is kwashiorkor?

Protein deficiency

183

What is marasmus?

Insufficient energy

184

Why does malnutrition cause death?

Due to damage from low energy intake and deficiency diseases of other nutrients

185

What can low protein intake result in?

Insufficient blood protein synthesis

186

Why does low protein synthesis result in insufficient blood protein synthesis?

Inhibition of the liver to create proteins such as albumin

187

What is the result of insufficient blood protein production?

A decrease in plasma osmotic pressure and oedema

188

What is Starlings Law of the Capillary?

Flow net = (P c - P i ) - (π c - π i ) 

When 
- P x = hydrostatic pressure
- π x = oncotic pressure
- X c = of capillary
- X i  = of interstitial fluid

189

Using Starling’s Law of Capillary, what causes oedema?

π c decreases because of decrease in plasma protein, therefore increased net flow of fluid into interstitial fluid

190

What does fluid oedema lead to?

Distended abdomen

191

Give 6 functions of blood

- Transport
- Coagulation
- Immune functions
- Regulation of body pH 
- Regulation of core body temperature 
- Hydraulic functions

192

What are the transport functions of blood?

- O 2 and nutrient supply 
- Removal of waste products
- Signalling

193

What are the nutrients supplied by the blood used for?

#NAME?

194

Give 3 waste products removed by the blood

- CO 2
- Urea
- Lactic acid

195

How is the blood used for signalling?

By transporting hormones

196

Why is metabolite measurement in the blood used rather than using actual tissue samples?

Difficult to examine actual tissues with metabolic problem, as could be dangerous or expensive to biopsy

197

What are the advantages of using blood to measure metabolite concentrations?

- Blood readily obtainable 
- Tests inexpensive

198

What could an increase or decrease in concentrations of substances found in blood mean?

Could be used as diagnostic tool to help indicate nature of problem

199

Give an example of where a change in concentration of substances in blood could be used as a diagnostic tool

An increase in ketone bodies could be indicative of diabetes

200

Are normal ranges of substances found in blood absolute or typical?

Typical - they vary within a range

201

What does the concentration of substances in the blood depend on?

#NAME?

202

What can happen when the skeletal muscle, liver and adipose tissue release the substances they store?

Can change the concentrations of nutrients in the blood plasma

203

Which organs can interconvert substances?

#NAME?

204

Which tissues can utilise nutrients?

All

205

What do homeostatic mechanisms do?

Act to counteract changes in the internal enviroment

206

Are body systems in a steady state?

No, in a dynamic equilibrium

207

What is the result of homeostatic failure?

Disease

208

What levels do homeostatic mechanisms exist on?

All- cell, tissue, organ, organism

209

Are homeostatic mechanisms independent or interdependent for the variable being regulated?

#NAME?

210

What are the 4 main aspects of a homeostatic mechanism?

#NAME?

211

What does the receptor do?

Monitors and responds to changes in environment

212

What does the control centre do?

- Sets range where variable is maintained 
- Determines appropriate response 
- Sends signal to effector

213

What does the effector do?

Brings about desired changes

214

What does negative feedback do?

Corrects deviation