3 - Diet and Nutrition

Question 1

What is metabolism?

Answer 1

The chemical processes that occur in an organism to maintain life

Question 2

What different pathways make up metabolism?

Answer 2

• Oxidative (food –> energy)
• Biosynthetic (produces building blocks)
• Fuel storage and mobilisation (fuels are mobilised when we are not eating)
• Detoxification (removes toxins)

Question 3

What is catabolism?

Answer 3

Breakdown of molecules to release energy (reducing power)

Question 4

What is anabolism?

Answer 4

Using energy and materials to make larger molecules for growth and maintenance

Question 5

Cells use …… …… energy to drive energy-requiring activities.

Answer 5

Chemical bond

Question 6

What is energy used for in the body?

Answer 6

Ion transport

Muscle contraction

Biosynthesis

Thermogenesis

Detoxification

Question 7

What is the SI unit of food energy?

Answer 7

Kilojoule (kJ)

Question 8

What is one kcal?

Answer 8

Amount of energy required to raise the temperature of one kg of water by one degree C

1 kcal = 4.2 kJ

Question 9

What are the dietary food groups and what do they do?

Answer 9

Carbohydrates - supply energy
Protein - energy and amino acids
Fat - energy and essential fatty acids
Minerals - essential
Vitamins - essential
Water - hydration
Fibre - normal GI function

Question 10

What is the general formula of carbohydrates?

Answer 10

(CH2O)n

Question 11

Give an example of a monosaccharide, disaccharide and polysaccharide.

Answer 11

Mono - glucose, fructose, galactose etc.
Di - sucrose, lactose, maltose
Poly - starch, glycogen, cellulose

Question 12

Sucrose is a disaccharide of which monomers?

Answer 12

Glucose and fructose

Question 13

Lactose is a disaccharide of which monomers?

Answer 13

Glucose and galactose

Question 14

What is the carbohydrate storage molecule in:

a) plants
b) animals

What monomer are they a polymer of?

Answer 14

a) starch
b) glycogen

Glucose

Question 15

How many amino acids are needed in the body? How many of these are essential (i.e. can only be obtained from the diet)?

Answer 15

20 amino acids

9 are essential amino acids

Question 16

Name an essential amino acid

Answer 16

Isoleucine, lysine, threonine, histidine, leucine, methionine, phenylalanine, tryptophan, valine

Question 17

Why are individual animal sources of protein better than plant sources?

Answer 17

Animal protein contains all 9 essential amino acids.

Plant protein is deficient in one or more essential amino acids - need to get protein from multiple plant sources.

Question 18

Lipid is composed of ……….. made up of one ……. and 3 …… ……..

Answer 18

triacylglycerol, glycerol, fatty acids

Question 19

What are the fat-soluble vitamins?

Answer 19

A, D, E and K

Question 20

Fats contain less oxygen than carbs or protein, so they yield …….. energy when oxidised.

Answer 20

More

The molecules are more reduced to give more energy when oxidised.

Question 21

Name and essential fatty acid

Answer 21

Linoleic acid, linolenic acid

Question 22

Name the primary electrolytes (minerals) that establish ion gradients and water balance

Answer 22

Sodium, potassium and chloride

Question 23

What is vitamin D deficiency known as?

Answer 23

Rickets

Question 24

Vitamin B12 deficiency causes what condition?

Answer 24

Anaemia

Question 25

Scurvy is a deficiency of which vitamin?

Answer 25

C

Question 26

Niacin deficiency leads to what condition?

Answer 26

Pellagra (diarrhoea, dermatitis, dementia and death)

Question 27

Why can cellulose not be metabolised?

Answer 27

Humans don't have required enzymes to break the B-1,4 linkages between the glucose monomers

Question 28

# Define: a) EAR b) RNI c) LRNI

Answer 28

a) estimated average requirement - 50% of a population will need more, 50% need less b) reference nutrient intake - ensures needs of 97.5% of people are met c) lower RNI - enough for the small number of people with low requirements (2.5%)

Question 29

Energy requirements vary depending on what factors?

Answer 29

Age, sex, body composition, physical activity

Question 30

Daily energy expenditure is the sum of ...

Answer 30

Basal metabolic rate Diet-induced thermogenesis (energy needed to process food) Physical activity level

Question 31

What is the energy requirement of: - A 70kg adult male - A 58kg adult female

Answer 31

- 12,000 kJ/day | - 9,500 kJ/day

Question 32

What factors affect the basal metabolic rate?

Answer 32

``` Body size Gender Environmental temperature Endocrine status Body temperature ```

Question 33

Which organs use the most of the basal metabolic rate?

Answer 33

Skeletal muscle - 30% Liver - 20% Brain - 20% Heart - 10%

Question 34

Energy demand for physical activity comes from the energy demand of which tissues?

Answer 34

Skeletal muscles Heart muscle Respiratory muscles

Question 35

Energy stores in muscles last a few ........., carbohydrate stores can last ........ - ..........., long term stores in .......... tissue lasts up to 40 days.

Answer 35

seconds, minutes to hours, adipose

Question 36

Obesity is a BMI above what value? What is the value for severely obese?

Answer 36

Obese - 30 | Severely obese - >35

Question 37

What is the calculation for BMI?

Answer 37

Weight (kg) / Height ^2 (m2)

Question 38

Underweight is a BMI of less than what value?

Answer 38

18.5

Question 39

Desirable weight is a BMI of what range?

Answer 39

18.5 - 24.9

Question 40

Fat in upper body (esp. abdomen) instead of hips is associated with increased risk of:

Answer 40

``` Insulin resistance Hyperinsulinism Type 2 diabetes Hypertension Hyperlipidaemia Stroke Premature death ```

Question 41

What barriers influence peoples food choices?

Answer 41

- Income and cost - Ability to cook - Cultural pressures - Mood and stress - Age - Physical activity - Ease of access to unhealthy foods

Question 42

How much fluid per day is required for good hydration?

Answer 42

6-8 glasses of water (~2 litres)

Question 43

Why are caffeinated drinks not a good source of hydration?

Answer 43

Caffeine is a diuretic, so increases loss of water in the urine.