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Biology Option > D1 > Flashcards

D1 Flashcards

1
Q

What is a nutrient ?

A

chemical substance found in foods that is used in the human body

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2
Q

what are the six classes of nutrients?

A

Carbohydrates / proteins / lipids / vitamins / minerals / water

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3
Q

what is the difference between essential and non-essential nutrients ?

A

Essential nutrient: cannot be synthesised by the body (water, vitamins, dietary minerals, some fa and aa)

Non-Essential nutrient: can be made by the body or replaced by another nutrient (carbohydrates, other minerals, some fa and aa)

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4
Q

State examples of essential minerals

A

Calcium (Ca)
Magnesium (Mg)
Iron (Fe)
Phosphorus (P)
Sodium (Na)
Potassium (K)
Chlorine (Cl)

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5
Q

explain the importance of minerals in human development

A
  • Major constituents in structures such as teeth and bones (Ca, P, Mg)
  • Important components of body fluids (Na, K, Cl)
  • Cofactors for specific enzymes or components of proteins and hormones (Fe, P, I)

Deficiency = illness/disorder

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6
Q

What are vitamins ?

A

Chemically diverse carbon compounds that cannot be synthesised by the body. Their functions can vary as cofactors, antioxidants, hormones, many are essential

WATER soluble vitamins: need to be constantly consumed as any excess is lost in urine (B, C)

FAT soluble vitamins: can be stored within the body (A, D, E, K)

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7
Q

What is ascorbic acid?

A

A form of vitamin C that is required in a range of metabolic activities in all animals and plants. It is produced by some mammals, but not others that need a dietary supply.
most common food sources: citrus fruits, orange juice

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8
Q

What are the functions of Vit C in mammals?

A

Potant antioxidant / Immune function / Synthesis of collagen / Synthesis of lipoproteins

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9
Q

What are the consequences of Vit C deficiency?

A

SCURVY
- Skin decoloration and bruising
- Haemorrhaging
- Anemia
- Dental issues
- Exhaustion / fatigue
- Swelling of joints (edema)

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10
Q

What is Vitamin D?

A

Naturally synthesized by the body in presence of the sun.
Involved in the absorption of calcium and phosphorus, contributing to bone mineralization.
May be stored in the liver when levels are low.
Darker skin = slower production

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11
Q

What are the consequences of Vitamin D deficiency?

A
  • Calcium and Phosphorus are not absorbed
  • Osteomalacia (bones soften)
  • Rickets (bones deform)
  • Elderly and certain ethnicities more affected
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12
Q

What are the symptoms linked to rickets?

A
  • Bone fragility & fracturing
  • Atrophy / muscle weakening
  • Dental problems
  • Growth retardation
  • Enlargement of liver / spleen
  • Skeletal deformities
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13
Q

What does “conditionally non-essential” mean?

A

can be produced by the body, but at rateslowerthan certain conditional requirements (e.g. during pregnancy or infancy)

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14
Q

What is “protein deficiency malnutrition”

A

A shortage of one or more essential amino acids in the diet will prevent the production of specific protein

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15
Q

What are the 2 (cis)-polyunsaturated essential fatty acids?

A

Alpha linolenic acid: omega 3 fatty acid
linolenic acid : omega 6 fatty acid

(humans lack the enzyme required to introduce double bonds at the required position of the carbon chain)

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16
Q

state the sources and functions of omega 3 and 6

A

Omega 3
Source: fish, vegetable oils, walnuts
Function: make hormones regulating blood clotting, part of cell membrane, movement of artery walls

Omega 6
Source: sunflower, poultry, eggs, avocado, nuts, whole grains
Function: reduce risk of heart disease and cancer, lowers cholesterol

17
Q

what are the dangers of trans fats?

A
  • easily absorbed by the body
  • cannot be used = build up
  • more risks of CHD
  • increase harmful LCL cholesterol
  • decrease useful HDL cholesterol
18
Q

What is Phenylketonuria? (PKU)

A

autosomal recessive genetic condition - caused by a mutation in the gene encoding for enzyme phenylalanine hydroxylase PAH = impaired metabolism of amino acid phenylalanine

in healthy people, PAH converts excess phenylalanine into tyrosine

19
Q

What are the symptoms and treatments of Phenylketonuria?

A

SYMPTOMS: excess phenylalanine instead converted to phenylpyruvate = toxic build up in blood and urine. Leads to brain damage & mental retardation

TREATMENTS: strict diet restricting phenylalanine, low protein diet, diet should be supplemented with medical formula containing essential amino acids

20
Q

What can cause malnutrition?

A

deficiency, imbalance or excess nutrients in a diet

21
Q

How is appetite controlled?

A
  • by a center in the hypothalamus
    –> hormones made in the pancreas, stomach, intestine, adipose tissue send messages to the appetite control center of the brain to inhibit or stimulate it
22
Q

Which hormones trigger a hunger response?

A

Ghrelin (stomach) Glucagon (pancreas)

23
Q

Which hormones trigger a satiety response?

A

Leptin (adipose tissue) CCK (intestine)

24
Q

What are the causes and consequences of overweight or obesity?

A

CAUSES
Obesity = BMI > 30
Increased energy intake
Decreased energy expenditure

CONSEQUENCES
Hypertension / Higher blood pressure = CHD
Excess weight = more strain on the heart that has to pump more blood = faster heart rate
High cholesterol = atherosclerosis = narrowing blood vessels
Type II diabetes: diet rich in sugars causing the progressive overstimulation of these cells by insulin = fat, liver and muscle cells become unresponsive to insulin (insulin insensitivity)

25
Q

What are the consequences of starvation?

A
  • significant loss of weight
  • break down of body tissue as an energy source
  • muscle loss
  • organ damage
  • breduced blood flow & blood pressure drop as heart tissue begins to starve
  • heart may develop dangerous arrhythmias and diminish in size
  • death (often due to coronary disease)
26
Q

What is “anorexia nervosa”

A

an eating disorder in which individuals severely limit the amount of food they intake

27
Q

Explain the determination of food energy content through combustion

A
  • combustion of the food source causes the stored energy to be released as heat, which raises the temp of water
  • beacause of the water’s specific heat capacity, amount of energy required to raise 1g of water by 1°C is 4.18J
28
Q

Compare the energy content of Carbohydrates, Lipids and Proteins

A

Carbohydrates: easier to digest and transport –> preferentially used as energy source

Lipids: store more energy per gram, but harder to digest and transport = long-term storage

Proteins: metabolism produces nitrogenous waste products which must be removed from cells

Biology Option (3 decks)

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