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HL Bio > D1 Human nutrition > Flashcards

D1 Human nutrition Flashcards

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Biology 101 flashcards
1
Q

define nutrient

A

a chemical substance that can be used by the human body

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2
Q

what is an essential nutrient

A

cannot be synthesized by the body = has to be included in diet

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3
Q

examples of essential nutrients 4

A

minerals, vitamins, amino acids, fatty acids

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4
Q

what are non-essential nutrients + example

A

made in the body / have a replacement nutrient

eg carbohydrates as respiratory substrates

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5
Q

name the 2 types of fatty acids the body cant synthesize

A
  • omega-3 fatty acids
  • omega-6 fatty acids
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6
Q

what benefits does omega-3 fatty acids have 2

A

controlling blood clotting
building cell membranes in the brain

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7
Q

is omega-3 fatty acid saturated? why?

A

NO – has a double bond between 3rd and 4th carbon (from opp end of OOH grp)

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8
Q

where can omega-3 fatty acids be found

A

plant and fish oils (fatty fish like salmon)

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9
Q

benefits of omega-6 fatty acids 3

A
  • lower LDL (low density lipoprotein) cholestrol levels (‘bad’ cholesterol)
  • reduce inflammation
  • protect against heart disease
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10
Q

how many essential amino acids can humans not synthesize

A

nine

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11
Q

what is an essential amino acid in infants

A

arginine

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12
Q

what amino acid is essential if phenylalanine is absent

A

tyrosine

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13
Q

how many amino acids does protein synthesis require in most living organisms

A

20

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14
Q

why is calcium required in the diet

A

major constituent of structures like bones, teeth + needed for muscle contraction

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15
Q

why is iron needed in the diet

A

needed to form haemoglobin

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16
Q

why is phosphate needed in the diet

A

needed to make DNA, cell membranes

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17
Q

why are sodium and chloride ions needed in the diet

A

control of composition of body fluids, propogation of nerve impulse

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17
Q

words used to describe how much of an element a body needs: m______ vs t______

A

macro vs trace

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18
Q

why are vitamins essential nutrients?

A

they cant be manufactured in the body
- absence from diet = deficiency diseases
- complex chem structures

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19
Q

what are the 2 types of vitamins

A

water-soluble vitamins – excess=excreted in urine

fat-soluble vitamins – stored in body, excess=problems!

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20
Q

are the following vitamins soluble in water or fat?
1. B
2. C
3. D
4. E

A
  1. water
  2. water
  3. fat
  4. fat
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21
Q

define a balanced diet

A

contains accepted and defined portions of carbs, fats, proteins, vitamins, minterals, and water essential good health

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22
Q

define malnutrition

A

condition that occurs when diet does NOT contain right amt of nutrients

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23
Q

what is malnutrition caused by 3

A

deficiency – lack
imbalance – inadequate intake (not enough)
excess – disproportionate intake (too much)

(of nutrients in the diets)

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24
Q

where is appetite controlled from?

A

the hypothalamus (appetite control centre!)

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25
Q

3 hormones used in controlling appetite

A
  • Leptin
  • Ghrelin
  • PYY3-36
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26
Q

what is starvation caused by

A

a severe reduction in caloric energy intake

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27
Q

how does starvation lead to the breakdown of body tissue 5

A
  1. diets very low in energy rich foods = body exhausts glycogen stores
  2. body respires AA deprived from protein digestion (instead of building and maintaining tissues)
  3. muscle proteins break down, body wastes away – eg muscle wastage
  4. prolonged starvation = permanent organ damage and death
  5. vitamin deficiency = deficiency diseases (anaemia, beriberi, pellagra, scurvy)
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28
Q

does the number of fat cells change in adults

A

no, not significantly

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29
Q

how does leptin control appetite? 3

A
  1. overeat = fat cells fill with lipids = secrete more LEPTIN
  2. reaches appetite centre, suppressing hunger sensation
  3. fat cells empty = less leptin = hunger experienced

(long term)

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30
Q

leptin is associated with the ____-term regulation of eating

A

LONG

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31
Q

how does ghrelin work 2

A
  1. stomach empties = ghrelin secreted
  2. stimulates appetite control centre to create a WISH to FEED
32
Q

how does PYY3-36 work 4

A
  1. released after eating
  2. from upper intestines + pancreas
  3. early in digestion process – reaches appetite centre = suppresses hunger
  4. hunger is temporarily overcome

(short term)

33
Q

what diets lead to protein deficiency

A
  1. based on carbs (cassava, plantain, sweet potato)
  2. starvation: too little food intake = proteins used for energy, AAs respired
34
Q

protein-deficient malnutrition leads to?

A

lack of blood plasma proteins
= water retained in tissue

35
Q

symptoms of protein deficiency 2

A
  • fluid retention
  • swelling in abdominal area
36
Q

name the 2 types of protein deficiency

A

Kwashiorkor: swelling of legs and abdomen

Marasmus: wizened, underweight body

37
Q

can humans synthesize vitamin C?

A

NO

38
Q

why cant some animals synthesize vitamin C?

A

mutation in the GLO gene (codes for an enzyme needed for last step of synthesis of vitC)

39
Q

what is vitamin C needed for? 2

A
  • production of collagen: involved in synthesis of AA hydroxyproline (15% of collagen)
  • synthesis of lipoproteins: makes lipids soluble for transport in blood plasma
40
Q

lack of vitamin C leads to?

A
  • iron deficiency
  • anaemia (bc low blood haemoglobin lvls)
  • scurvy
41
Q

whats a good source of vitC!

A

citrus fruits

42
Q

how was vitamin C discovered? (scurvy)

A

1753: sea captain reported SCURVY could be avoided by including ORANGES AND LEMONS in the diet

1907: norwegian scientists Axel Holst and Theodor Frolich – animal model (guinea pigs) for scurvy

43
Q

case control vs cohort study

A

case control: look at outcome first, then work backwards and look at the factors

cohort study: subject normal indivs to condition to yield results

44
Q

8 symptoms of scurvy

A
  • bleeding gums
  • lack of energy
  • weight loss
  • extreme fatigue
  • mood swings depression
  • chronic join pain (bc bleeding in the joints)
  • suppressed immune system
  • slow wound healing
45
Q

what is the full name of PKU

A

phenylketonuria

phenyl keton uria

46
Q

how does phenylketonuria (PKA) work

A
  1. mutation in gene coding for phenylalanine hydroxylase (recessive)
  2. inability to convert phenylalanine into tyrosine
  3. Phenylalanine accumulates
47
Q

4 medical consequences of PKU

A
  1. intellectual disability
  2. reduced growth of head
  3. lack of skin and hair pigmentation
  4. seizures
48
Q

treatment of PKU? 2

A
  1. early diagnosis (within 24 of birth) – Heel prick test
  2. restriction of diet to supply only amt of phenylalanine that body needs for protein synthesis

(may still dev learning difficulties)

49
Q

2 important roles of Vitamin D

A
  1. maintain skeletal calcium balance – promoting calcium absorption in intestines
  2. maintain calcium and phosphate levels for bone formation
50
Q

what does a vitamin D deficiency lead to?

A

softening or malformation of bones

51
Q

names of vitamin C deficiency in adults and children

A

adult: Osteomalacia (milder)
child: Rickets (more serious)

52
Q

what foods can vitamin D be found in?

A

oily fish (salmon, herring, tuna), egg yolk, liver, dairy products

53
Q

how can the synthesis of vitamin D be triggered in humans

A

exposing human skin to UV light (wavelength 290-310) = triggers syn of vitamin D

54
Q

out of carbs, lipids, proteins, rank the amt of energy each yields

A

lipids
carbs
proteins

55
Q

what is the BMI (body mass index)

A

value used to determine if a patient is within normal parameters of weight

56
Q

how to calculate BMI?

A

weight in KG / (height in M)^2

57
Q

what BMI is clinical obesity

A

30 and over

58
Q

how do people become overweight / obese (2)

A
  1. diet w excess lipids and fatty acids = more energy rich items than body requires
  2. storage of excess fat in adipose tissue
59
Q

why does obesity lead to enhanced likelihood of type II diabetes 3

A
  1. islet of Langerhans: B cells produce sufficient insulin
  2. BUT! insulin receptors on target cells are less sensitive (insulin resistance)
  3. pateient raised blood glucose level
60
Q

symptoms of type II diabetes 4

A
  1. incr glucose levels (blood and urine)
  2. frequent need to urinate
  3. tiredness and fatigue
  4. loss of. weight
61
Q

main 3 health consequences of obesity

A

enhanced likelihood of…
1. type II diabetes
2. hypertension
3. coronary heart disease

62
Q

how does obesity lead to hypertension

A
  • persistently raised blood pressure
  • accelerates onset of atherosclerosis
  • incr workload of heart
  • makes brain haemorrhage more likely

(can be. treated using drugs)

63
Q

what is hypertension

A

persistently raised blood pressure (damages heart, blood vessels, brain, kidneys)

64
Q

what is coronary heart disease

A

plaque builds up inside coronary arteries

65
Q

how does obesity lead to coronary heart disease

A
  • saturated fatty acids deposited inside arteries
  • deposits combine with cholesterol = atherosclerosis = hypertension
66
Q

saturated vs unsaturated fatty acids

A

saturated = bad – raises LDL cholesterol
(low-density lipoprotein bc saturated = easier to arrange)

67
Q

why is cholesterol important 4

A
  • for metabolism
  • component in plasma membranes of all cells
  • needed to produce sex hormones
  • bile salts (involved in lipid transport) synthesised from cholestorl
68
Q

how does high cholestrol lead to atherosclerosis

A

strands of low-density lipoproteins are deposited under the endothelium of arteries

69
Q

cholesterol in blood is an indicator of?

A

coronary heart disease

70
Q

how is high cholesterol treated

A
  1. reducing dietary intake = limtied effect
  2. DRUGS! statins (drugs that lower cholesterol lvls) more effective
71
Q

what are statins

A

a class of drugs used to lower cholesterol levels

72
Q

how do statins/cholesterol lowering drugs work

A

inhibits ENZYME HMG-CoA reductase
(catalyses 2nd step in Acetyl CoA –> cholesterol pathway)

73
Q

how can the energy content of food be determined

A

combustion – burning a known mass of food to test

74
Q

steps to find energy content in food

A
  1. burn a known mass of food under a test tube with water
  2. heat liberated absorbed by known value of water
  3. record rise in temp
  4. energy value /g = temp rise x mass of water x 4.184 or 1 calorie
75
Q

IS units system units for energy 3

A

energy – Joules (J)
food related – kilojoule (kJ)
kilocalorie (kcal)

76
Q

kcal conversion to kJ

A

1 kcal = 4.184 kilojoules

77
Q

benefits of high fibre diet

A

maintains bowel health

lowers cholesterol levels

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