Option D.1 Human Nutrition Flashcards Preview

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Flashcards in Option D.1 Human Nutrition Deck (36)
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What happens in our body when there are excess carbohydrates?

synthesizes into lipids and stored under skin around the body organs


What is an example for a fatty acid?

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


Where can omega 3 fatty acids be found?

plants and fish oils


Why are omega 3 fatty acids needed in the body?

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


Can even energy rich diets be protein deficient?



Give example of energy rich diets that are protein deficient

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


Is starvation different from malnutrition? How?

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


What occurs during starvation?

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


What are clinical protein deficiencies known as?



What is phenylketonuria?

PKU is a genetic metabolic disorder.


How is phenylketonuria caused?

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


What are the consequences of PKU?

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


How is PKU treated?

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;


How does a healthy diet provide energy?

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


What is the determination of energy content called?



When are people in danger of being overweight and obesity?

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


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

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


Consequences of obesity

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


By what hormone is appetite controlled by?

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)


How does leptin work in our body?

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


How is immediate hunger controlled?

hormone called ghrelin;
stimulates appetite control centre to create appetite


What are the effects of starvation?

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


What is anorexia nervosa?

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;


What are the effects of anorexia nervosa?

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;


What is the role of vitamin C in the body

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;


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

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


What is role of Vitamin D?

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


What happens when Vitamin D is lacking?

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


Where can vitamin D be obtained from?

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)


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

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;