D.1 HUMAN NUTRITION

Question 1

DIET CONSISTS OF

Answer 1

carbohydrates

lipids

proteins

dietary minerals

vitamins

water

fibre

Question 2

CARBOYDRATES

Answer 2

these are a source of energy but can be replaced by lipids

Question 3

LIPIDS

Answer 3

most fatty acids can be synthesised in the body

Question 4

GLYCEROL

Answer 4

lipid

can be synthesised from glucose

Question 5

ESSENTIAL FATTY ACIDS

Answer 5

omega 3 (fish oils)
omega 6

linoleic acid (sunflower seeds)

Question 6

ESSENTIAL AMINO ACIDS

Answer 6

• Histidine
• Valine
• Leucine
• Lysine
• Methionine
• Phenylalanine
• Tryptophan

Question 7

CONDITIONALLY ESSENTIAL AMINO ACIDS

Answer 7

threonine

arginine

Question 8

ARGININE

Answer 8

can be syn if AA phenylalanine is present

Question 9

THREONINE

Answer 9

essential AA for infants but adults can syn it

Question 10

LACK OF ESSENTIAL AA MEANS

Answer 10

that certain proteins cannot be synthesised

Question 11

NUTRIENT

Answer 11

chemical substances found in foods use in human body

Question 12

ESSENTIAL

Answer 12

foods are the only possible source of the nutrient-calcium/water

Question 13

NON-ESSENTIAL

Answer 13

another nutrient can be used for the same purpose or can be made in the body from another nutrient-glucose/starch/carbohydrates

Question 14

CONDITIONALLY ESSENTIAL

Answer 14

vitamin K produced by metabolism of symbiotic bacteria in the intestine in adults only

Infants do not have colonies of such bacteria= require supplementary injections

Question 15

MALNUTRITION CAUSES

Answer 15

deficiency of nutrients (proteins)

imbalance of nutrients (insufficient vitamins/ minerals)

excess of nutrients

Question 16

FIBRE

Answer 16

cellulose cannot be digested but is imported for maintaining the strength of the gut muscles for peristalsis

Question 17

ESSENTIAL VITAMINS

Answer 17

A B C

Question 18

CONDITIONALLY ESSENTIAL VITAMINS

Answer 18

D

can be synthesised in the skin in sunlight

Question 19

NON-ESSENTIAL VITAMINS

Answer 19

K H

syn in large intestine

Question 20

DIETART MINERALS

Answer 20

essential

calcium-bones/teeth

Na/K/Cl

Question 21

APPETITE CONTROL CENTRE

Answer 21

in hypo makes us feel satiated

When APCC receives insulin, PYY3 and leptin

it reduces desire to eat: avoid overeating

Question 22

ACC AND SI

Answer 22

S.I secretes hormone PYY3-36 when full

Question 23

ACC AND PANCREAS

Answer 23

Pancreas: insulin when blood glucose > conc

Question 24

ACC AND ADIPOSE TISSUE

Answer 24

Adipose tissue: hormone leptin when amount of stored fat increases

Question 25

OVERWEIGHT CAUSES

Answer 25

Diets rich in fat/ low in fibre overeating lack of exercise genetic factors-metabolic R

Question 26

OVERWEIGHT AND TYPE I

Answer 26

➢ Auto-immune destruction of insulin-secreting cells in the pancreas (type 1)

Question 27

OVERWEIGHT AND TYPE II

Answer 27

➢ Decreased responsiveness of body cells to insulin due to ‘burn-out’ (type 2) o Elevated blood glucose o Glucose in urine o Dehydration an thirst resulting from excretion of large volumes of urine

Question 28

OVERWEIGHT AND ATHEROSCLEROSIS

Answer 28

narrowing of arteries by fatty deposits

Question 29

OVERWEIGHT AND HYPERTENSION

Answer 29

Raised blood pressure Weight gain→ higher cardiac output which can raise blood pressure Abdominal obesity can increase vascular resistance which can raise blood pressure Weight gain is associated with arteries becoming stiffer and narrower→ raise blood P

Question 30

OVERWEIGHT AND CHD

Answer 30

narrowing of the coronary arteries with risk of <3 attack Link between high cholesterol, high conc of LDL and low conc of HDL Clear correlation between excessive weight gain and hypertension abnormally >blood P

Question 31

STARVATION EFFECTS

Answer 31

1. Body access glycogen stores 2. Break down its own muscle to utilise the resulting AA as E a. If no glucose is available 3. AA → liver→ converted to glucose 4. Loss in muscle mass = BREAKDOWN OF BODY TISSUE

Question 32

STARVATION CAUSES

Answer 32

due to severe lack of intake of essential nutrients

Question 33

PKU CAUSES

Answer 33

⇒ Genetic disease caused by mutation of a gene coding for the enzyme that converts phenylalanine into tyrosine ⇒ Mutation produces alleles of the gene that code for enzymes unable to catalyse the conversion reaction ⇒ Only occurs with 2 recessive mutant alleles→ RECESSIVE MUTATION ⇒ Phenylalanine accumulates in body→ deficiency in tyrosine

Question 34

PKU CONSEQUENCES

Answer 34

⇒ Reduced growth of head/brain ⇒ Mental retardation of young children ⇒ severe learning difficulties/ hyperactivity/ seizures ⇒ lack of skin/ hair pigmentation

Question 35

PKU TREATMENTS

Answer 35

⇒ early diagnosis/treatment: test 24 hours after birth ⇒ diet low in phenylalanine for the rest of person’s life (meat/fish/nuts/cheese/peas/beans only in small quantities) ⇒ tyrosine supplements may be needed

Question 36

ANOREXIA

Answer 36

Voluntary starvation and loss of body mass → Amounts of carbohydrates and fat consumed are too small to satisfy the body’s energy requirements → so protein/other chemicals are broken down

Question 37

ANOREXIA CONSEQUENCES 6

Answer 37

⇒ Wasting of muscles = loss of strength ⇒ Hair becomes thinner/drops out/ Skin becomes dry/bruises easily ⇒ Blood pressure is reduced→ slow heart rate and circulation ⇒ Females: infertility→ no ovulation/ menstrual cycle ⇒ Skeletal muscle is digested + heart muscle deteriorates ⇒ Lack of protein/micronutrients= deterioration of muscle fibres ⇒ Both skeletal/cardiac muscle do not contract normally

Question 38

VITAMIN D DEFICIENCY

Answer 38

Lack of vitamin D or calcium can affect bone mineralization and cause rickets or osteomalacia

Question 39

VITAMIN D SOURCE

Answer 39

oily fish/eggs/liver

Question 40

VITAMIN D SYNTHESIS

Answer 40

⇒ Can be synthesised by the skin o Only when light is 290-310 nm ⇒ Enough time spent outside = no diet supplement

Question 41

VITAMIN D USE

Answer 41

r calcium absorption from food in intestines → similar symptoms as calcium lack

Question 42

VITAMIN D DEFICIENCY SOL

Answer 42

Children/pregnant/elderly = daily supplement

Question 43

CHOLESTEROL

Answer 43

normal component of plasma membranes

Question 44

CHOLESTEROL AS HARMFUL

Answer 44

because research has shown a correlation between high levels of cholesterol in blood plasma and an increased risk of coronary heart disease CHD

Question 45

LDL

Answer 45

• Much research has involved total blood cholesterol levels but only cholesterol in LDL is implicated in CHD

Question 46

REDUCING DIETARY CHOLESTEROL

Answer 46

• Reducing dietary cholesterol often has a very small effect on blood cholesterol levels and therefore has little effect on CHD rates

Question 47

CHOLESTEROL LEVELS AND LIVER

Answer 47

Liver can synthesise cholesterol so dietary cholesterol is not the only source

Question 48

GENETIC AND CHOLESTEROL LEVELS

Answer 48

Genetic factors are more important than dietary intake

Question 49

DRUGS AND CHOLESTEROL LEVELS

Answer 49

Drugs can be more effective at reducing blood cholesterol levels

Question 50

CHD AND SATURATED FATS

Answer 50

There is a +ve correlative between dietary intake of saturated fats and intake of cholesterol Saturated fats, not cholesterol, cause the increased risk of CHD