D1 Human Nutrition

Question 1

what is an essential nutrient?

Answer 1

chemical substance which cannot be synthesised by the body and must be ingested in diet

Question 2

what is a non-essential nutrient?

Answer 2

nutrients which can be made by the body (eg.carbs)

Question 3

what is malnutrition?

Answer 3

health condition caused by deficiency, imbalance or excess of nutrients in diet

Question 4

how can you estimate the energy content of food?

Answer 4

using a calorimetry

Question 5

how does calorimetry work? (2)

Answer 5

• combustion of food source causes stored energy to be released as heat which raises temperature of water
• amount of energy to raise 1g of water by 1 degrees is 4.18J (SHC)

Question 6

what is the calorimetry equation?

Answer 6

energy(J) = mass of water (g) x 4.2 (J/goC) x temp increase (oC)

Question 7

source of error for calorimetry?

Answer 7

energy lost to the environment

Question 8

what should be done to avoid error in a calorimetry experiment? (2)

Answer 8

• food should be burnt at constant distance from water
• initial temp and volume should be kept constant

Question 9

what are the 3 sources for energy?

Answer 9

carb - easier to transport and digest
lipids - stores more energy per gram, harder to digest and transport
proteins - produces nitrogenous waste which must be removed

Question 10

how many different types of amino acids are there?

Answer 10

20

Question 11

what 3 kinds of things can amino acids be?

Answer 11

• essentail
• non essential
• conditionally non-essential

Question 12

what are essential amino acids?

Answer 12

cannot be produced by body so must be in diet

Question 13

what are non-essential amino acids?

Answer 13

can be produced by body and are not required in diet

Question 14

what are conditionally non-essential amino acids?

Answer 14

produced by body at lower rates than certain conditional requirements

Question 15

what is PKU?

Answer 15

autosomal recessive disease caused by mutation to gene encoding phenylalanine hydroxylase

Question 16

what is the function of phenylalanine hydroxylase (PAH) and what happens to bepope with PKU? (3)

Answer 16

• converts excess phenylalanine into tyrosine
• peeps w/ PKU convert excess phenylalanine into phenylpyruvate (phenylketone)
• results in a toxic build up of phenylketone in blood and urine

Question 17

what occurs if you have untreated PKU? (3)

Answer 17

• brain damage, mental retardation

Question 18

how is PKU treated?

Answer 18

• low protein diet
• medical formula that contains precise quantities of essential amino acids

Question 19

what are 2 essential (cis)-polyunsaturated fatty acids?

Answer 19

• alpha-linolenic acids
• linoleic acids
  (humans lack enzyme required to introduce double bonds at required positions of carbon chain)

Question 20

What are vitamins?

Answer 20

Organic molecules with complex chemical substances

Question 21

What is absorbed acid?

Answer 21

Form of vitamin C
- potent antioxidant and immune function
- synthesis of collagen and lipoproteins

Question 22

What occurs if one has a deficiency in vit c? (2)

Answer 22

Scurvy
Weak immune system

Question 23

What are the symptoms if of scurvy? (6)

Answer 23

Skin discoloration
Hemorrhaging
Anemia
Dental issues
Exhaustion
Swelling joints

Question 24

What is vit D used for?

Answer 24

Absorption of calcium and phosphorus

Question 25

What occurs if you do not have enough vit D?

Answer 25

(Calcium and phosphorus are excreted by body)
- rickets
- osteamalacia

Question 26

Where is vitamin D stored?

Answer 26

In liver

Question 27

What are the symptoms of vitamin D deficiency?

Answer 27

Bone fragility
Atrophy (bone weaken)
Dental problems
Growth retardation
Enlargement of liver
Skeletal deformities

Question 28

Why are minerals important for in humans? (3)

Answer 28

• major constituents of teeth and bones
• important of body fluids
• cofactors for specific enzymes or components of proteins/hormones

Question 29

How are minerals important in plant development? (3)

Answer 29

• magnesium in chlorophyll
• potassium inorganic salt in sap
• calcium for plant root and shoot elongation

Question 30

What is the process of appetite? 4

Answer 30

From hypothalamus
- stretch receptors in stomach and intestines are activated
- adipose tissue release hormone in response to fat storage
- pancreases will release hormones in response to change in blood sugar concentrations

Question 31

What are the hormones that trigger hunger response?

Answer 31

Ghrelin (stomach)
Glucagon (pancreas)

Question 32

What are the hormones that tigger satiety response? (2)

Answer 32

• lepton (adipose tissue)
• CCK (intestine)

Question 33

How does hypertension develop in obese people? (4)

Answer 33

Suffer from hypertension (high blood pressure)
- excess weight more strain on hear to pump blood -> faster heart rate and high blood pressure
- high cholesterol lead to arthesclerosis (narrow blood veins) which raises blood pressure
- can develop CHD

Question 34

How does type II diabetes develop in obese people? (3)

Answer 34

• occurs when fat, liver and muscle cells become unresponsive to insulin (insulin insensitivity)
• result of diet rich in sugar -> causes over0stimulation of cells by insulin
• overweight individuals who have high sugar intake develop type II diabetes

Question 35

What is obesity?

Answer 35

Significant excess in body fat caused by increased energy intakes and decreased energy expenditure

Question 36

What is starvation?

Answer 36

Severe restriction of daily energy intake leading to signifiant loss of weight

Question 37

What is anorexia nervosa? (4)

Answer 37

Eating disorder which individuals severely limit food intake
- body breaks down heart muscle
- blood flow is reduced and blood pressure decreases
- heart may develop dangerous arrhythmias (get smaller)

Question 38

What is the recommended daily intake for adults?

Answer 38

8400 kJ (2000kcal)