OPTION D.1-Human Nutrition

Question 1

Why is Threonine conditionally essential?

Answer 1

Can be synthesised by the body if phenylalanine is present

Question 2

Why is Arganine essential?

Answer 2

Can normally sufficiently be made by healthy individuals

→ BUT synthesis pathway isn’t active in prematurely born infants = MUST get from diet!

Question 3

If there’s a shortage of one essential aa what happens to the bodu?

Answer 3

Can’t make enough proteins = can cause malnutrition

Question 4

Protein deficiency malnutrition

Answer 4

+ Causes lack of blood plasma proteins
→ fluid retained in the tissues
+ Causes swelling (edema) most obvious in abdomen
+ Child =dev. both mentally and physically retarded
+ Adult = wasting = serious weight loss

Question 5

Why is iodine needed?

Answer 5

+ Thyroid gland to synthesis hormone = thyroxin
→ Stimulates metabolic rates
→ ensures energy = released in the body

Question 6

IDD (Iodine Deficiency Disease) consequences

Answer 6

+ Women = pregnant = IDD = baby may be born w/ permanent brain damage
+ Child = IDD = after birth
→ mental dev. and intelligence impaired

Question 7

Starvation (Malnutrition)

Answer 7

+ linked to poverty
+ consequence of diet lacking in adequate protein and carbs
→ unbalanced and fail to provide essential nutrients

Question 8

Obesity

Answer 8

+ diet contains excess fats and refined carbs
+ observed in developing countries
= unhealthy diet

Question 9

What is the Hypothalamus responsible for?

Answer 9

Making us feel satisfied when we hv. eaten enough food (satiated)

Question 10

When the appetite control centre receives what hormones and what proportion of them do they then tell body to reduce appetite?
→ Helps body avoid health problems

Answer 10

1) Small intestine secretes hormone PYY3-36 when it contains food
2) Pancreas secretes insulin when blood glucose conc. is too high
3) Adipose tissues secrete hormone = leptin when amt of fats stored increase

Question 11

Diabetes Mellitus what is it and symptoms (3)

Answer 11

Condition where sugar is present in the urine! When it is NOT suppose to be present
+ Elevated levels of blood glucose
+ Glucose in urine
+ dehydration and thirst resulting from excretion of large vol. of urine

Question 12

Type I Diabetes

Answer 12

+ Auto-immune destruction of insulin-secreting β-cells in the PANCREAS
+ Early onset

Question 13

Type II Diabetes

Answer 13

+ Decreased responsiveness of body cells to insulin due to “burn-out”
+ Late onset

Question 14

Risk Factors of Type II Diabetes (3)

→ increase blood conc. of fatty acids

Answer 14

+ diets rich in fats and low in fibre
+ Obesity due to overweight and lack of exercise
+ Genetic factors which affect FAT metabolism

Question 15

What are the 2 consequences of Obesity?

Answer 15

1) Hypertension

2) Type II Diabetes

Question 16

Other problems stemming from Diabetes (3)

→ related to cardiovascular system

Answer 16

1) Atherosclerosis = narrowing of arteries by fat deposits
2) Hypertension (high bp)
3) CHD = narrowing of coronary arteries

Question 17

What can weight gain cause that lead to hypertension? (5)

Answer 17

+ Increase the release of several hormones
+ Cause changes in body physiology and anatomy
+ Lead to higher cardiac output = increase bp
+ Abdominal obesity = increase vascular resistance = increase bp
+ Associated w/ arteries becoming stiffer and narrower = increase bp

Question 18

What can hypertension also be caused by? (other than weight gain)

Answer 18

HIGH salt intake

→ salt has osmotic effect

Question 19

What is the effect of starvation?

Answer 19

+ Leads to breakdown of body tissue
+ When there is no dietary intake of energy source
→ body will resort to glycogen stores
→ break down own muscles and tissues to use resulting aa’s as energy (sent to liver to convert to glucose)
LOSS OF MUSCLE MASS

Question 20

Anorexia Nervosa

Answer 20

Psychiatric illness → complex causes
+ voluntary starvation
+ loss of body mass

Question 21

What happens when a person has Anorexia Nervosa?

Answer 21

+ amt of carbs and fats consumed = too small to satisfy the body’s energy requirements → proteins and other chemicals in body broken down instead

Question 22

What are the consequences of Anorexia Nervosa? (4)

Answer 22

+ Wasting of muscle
+ Skin dries and bruises easily
+ Females= lead to infertility
+ Hair becomes thin and can drop out

Question 23

Why does having Anorexia Nervosa lead to low bp and poor circulations/ slower heart rate/ lower heart output?

Answer 23

+ Heart muscle can also deteriorate
+ lack of dietary intake can alter electrolyte balance
→ leads to skeletal and cardiac muscle not contracting normally

Question 24

Phenlyketonuria (PKU) what is it?

Answer 24

Genetic disease caused by mutation of a gene coding for enzyme that converts
Phenylalanine → Tyrosine
+ Allele needed for the conversion is dominant
+ symptoms only occur in individuals that have 2 recessive alleles

Question 25

Phenlyketonuria (PKU) what happens?

Answer 25

Mutations produce alleles of gene that code for enzymes = unable to catalyse the conversion!
+ Phenylalanine build up in body
+ shortage of Tyrosine = essential aa!