Option D.1 Human Nutrition

Question 1

What happens in our body when there are excess carbohydrates?

Answer 1

synthesizes into lipids and stored under skin around the body organs

Question 2

What is an example for a fatty acid?

Answer 2

Omega 3 fatty acids:

• group of naturally occurring polysaturated fatty acids
• have between 3 to 6 double bonds in hydrocarbon tail
• first double bond always between 3rd and 4th cabon atom

Question 3

Where can omega 3 fatty acids be found?

Answer 3

plants and fish oils

Question 4

Why are omega 3 fatty acids needed in the body?

Answer 4

needed through out body (especially brain and eye)
may prevent heart disease by reducing tendency of blood clots to form by giving healthy, well-functioning plasma membranes around cardiac muscle fibres

Question 5

Can even energy rich diets be protein deficient?

Answer 5

Yes

Question 6

Give example of energy rich diets that are protein deficient

Answer 6

diets mainly based root crops, plantain or sweet potato because energy source is low in protein

Question 7

Is starvation different from malnutrition? How?

Answer 7

Yes, starvation occurs when individual simply does not have enough to eat. nourishment occurs when a person does not have a balanced diet

Question 8

What occurs during starvation?

Answer 8

Not enough essential nutrients are absorbed body starts to break down body tissues that store carbohydrates, protein is taken from body structure for respiration

Question 9

What are clinical protein deficiencies known as?

Answer 9

marasmus

Question 10

What is phenylketonuria?

Answer 10

PKU is a genetic metabolic disorder.

Question 11

How is phenylketonuria caused?

Answer 11

mutation in a gene coding of a protein that form a liver enzyme which converts amino acid phenylalanine (often excess in diets) into non- essential amino acid tyrosine;
only occurs in individuals with two recessive mutant alleles;
can accumulate in blood when not used immediately

Question 12

What are the consequences of PKU?

Answer 12

Phenylalaline is essential for growth, but too much build up can cause brain damage; reduced growth of head/brain (with mental retardation in kids); severe learning difficulties; hyperactivity and seizuresin older children; lack of skin/hair pigmentation

Question 13

How is PKU treated?

Answer 13

eating a diet s low in protein and especially PKU for rest of the life; only in very small quantities milk and diary products, nuts, fish and meat;
tyrosine supplement may be needed;
consequences of PKU can then be avoided;

Question 14

How does a healthy diet provide energy?

Answer 14

provides metabolic energy to supply metabolic processes, growth, repair from carbohydrates and lipids

Question 15

What is the determination of energy content called?

Answer 15

calorimetry

Question 16

When are people in danger of being overweight and obesity?

Answer 16

storage of excess of fatty acids and lipids in adipose tissues, present around body organs and under skin

Question 17

Reasons for why so much of our population is quickly becoming obese?

Answer 17

• diets rich in fat/low in fibre
• junk food is cheaper
• junk food tastes good
• becoming less forced to do exercise (walking to school)

Question 18

Consequences of obesity

Answer 18

• enhanced likelihood of type II diabetes
• enhanced likelihood of hypertension ( high blood pressure)
• athersclerosis

Question 19

By what hormone is appetite controlled by?

Answer 19

hyperthalamus (in brain);
also regulates thirst and temperature;
impulse send to specific body organs/organ systems; via nerves and spinal cord;
causes release of Leptin (hormone)

Question 20

How does leptin work in our body?

Answer 20

number of fat cells does not change;
if we overeat they are filled with lipids;
more leptin released;
circulates in blood;
leptin suppresses hunger sensation
when we are short of food reserves are drawn/fat cells empty;
less leptin secreted

Question 21

How is immediate hunger controlled?

Answer 21

hormone called ghrelin;

stimulates appetite control centre to create appetite

Question 22

What are the effects of starvation?

Answer 22

severete lack of intake of essential/nonessential nutrients;
break down of body tissues;
body will exhaust glycogen stores first;
body breaks down its own muscle tissue to utilize amino acids as energy source;
amino acids sent to liver to convert to glucose; loss of muscle mass

Question 23

What is anorexia nervosa?

Answer 23

deliberate dieting developed through obsessive fear of getting fat/distorted self-image;
amounts of carbohydrates/fat are too small to satisfy body;
protein and other chemicals are broken down;
wasting of muscles;

Question 24

What are the effects of anorexia nervosa?

Answer 24

lost muscles; lost strength;
thinner hair/hair loss;
skin is dry and bruised easily;
blood pressure reduced; slow hear rate and poor circulation;
infertility (no ovulation or menstrual);
heart muscle deteriorates;
lacking protein/micronutrients cause deterioration of muscle fibres;

Question 25

What is the role of vitamin C in the body

Answer 25

builds structural proteins in connective tissues; involved in amino acid that builds collagen;
synthesis of lipoprotein that are soluble in blood plasma;
formation of bone, enamal and dentine fail to function properly without nough Vitamin C;
antioxidant

Question 26

What is an example of a falsification of theories with one theory being superseded by another?

Answer 26

scurvy was thought to be specific to humans because attempts to induce symptoms in laboratory rates/mice were unsuccessful;
then discovered that guinea pigs could also not synthesize vitamin C;
given diets vitamin C; showed symptoms of scurvy;
may be unethical

Question 27

What is role of Vitamin D?

Answer 27

needed to ensuret hat sufficient calcium is absorbed from food in intestines

Question 28

What happens when Vitamin D is lacking?

Answer 28

phosphorus and calcium pass to feaces;
affects bone mineralization;
leads to softening and malformation of bones; known as rickets in children;
in elderly deficiency of vitamin D causes osteomalacia

Question 29

Where can vitamin D be obtained from?

Answer 29

oily fish (salmon); tuna; egg yolk; liver, dairy products; can also be synthesized in the body when exposed to UV rays; liver can store vitamin D good for countries where there is little sun)

Question 30

What are the risks of too much exposure to UV light?

Answer 30

mutations (skin cancer;
melanin (light skin) in skin intercepts and absorbs light; higher rate of melanoma;
dark skin is good protection of cancer by reduce Vitamin D synthesis;

Question 31

What are normal roles of cholesterol?

Answer 31

component in plasma membrane; produce important hormones like progesterone, testosterone and estrogen, and certain growth hormones;
produces bile salts for lip transport (in blood plasma)

Question 32

Explain why there is a high correlation between CHD and high intake in saturated fatty acids

Answer 32

asian populations tend to have lower rates of CHD and less hypertension as their diet contains high intake in vegetables and whole grain and less red meat and high fat dairy products;
saturated fatty acids can be deposited in arteries; combine with cholesterol forms atherosclerosis;
reduces diameter of lumen; causes hypertension; can cause obesity in excess;

Question 33

Explain correlation between cholesterol and CHD

Answer 33

LDLs (where cholesterol is transported in) do not travel in blood stream and can clog up arteries causes atherosclerosis/CHD; occurs in high levels of saturated/trans fatty acids
HDL (good cholesterol) are carried easily (no blockage); can remove LDL from arteries

Question 34

What is a link between saturated fats and cholesterol in blood?

Answer 34

saturated fats increase cholesterol levels; increase risk of CHD; yet reducing dietry cholesterol has little effect as genetics can also cause liver to synthesize more cholesterol;
most likely saturated fats (not cholesterol) causing CHD

Question 35

How can high blood cholesterol be treated?

Answer 35

statins (a drug) substance that lowers level of blood cholesterol; provides specific inhibitor of enzyme that synthesizes cholesterol in liver; prevented heart disease caused by high LDL/cholesterol

Question 36

Example of fat soluble vitamins

Answer 36

• D (calciferol)
  Source: fish liver oil, butter, egg yolk, made by body in sunlight
  function: required for absorption of calcium
• K
  Source: dark green leafy vegetables, made by bacteria in gut
  function: blood clotting factor