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IGCSE Biology > human nutrition > Flashcards

human nutrition Flashcards

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1
Q

what is a balanced diet

A

getting all the right nutrients in correct proportions

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2
Q

how is diet related to age/sex/activity

A

Children Below 12: Require more calcium

Teenagers: Highest calorie Intake

Adults: Balanced meal with less calories

Pregnant Women: more iron, calcium and folic acid

Males: Generally, require more energy

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3
Q

what is malnutrition

A

A condition caused by eating an unbalanced diet.

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4
Q

forms of malnutrition

A

Overnutrition: balanced diet but eating too much of everything

Undernutrition: having too little food

Eating foods in incorrect proportions

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5
Q

effects of malnutrition

A

Starvation: losing strength & finally dying because of lack of food

Coronary heart disease: eating too much fats which are rich in saturated fatty acids and cholesterol, may lead to heart attack

Constipation: lack of roughages in food causes constipation because roughages are indigestible and form bulks. Friction between bulks and walls of intestine stimulate the peristalsis

Obesity: Eating too much fats and carbohydrates leads to their storage in storage in the body mainly in the forms of fats and causing an increase in body weight. This can cause; heart attack, stroke, joint pain, mobility impairment, high blood pressure

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6
Q

use of carbohydrates

A

energy

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7
Q

use of fats

A

Source of energy, building materials, energy store, insulation, buoyancy, making hormones

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8
Q

use of proteins

A

Energy, building materials, enzymes, haemoglobin, structural material (muscle), hormones, antibodies

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9
Q

use of vitamin c

A

Protect cells from ageing, production of fibres

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10
Q

use of vitamin d

A

Absorption of calcium

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11
Q

use of calcium

A

Development and maintenance of strong bones and teeth

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12
Q

use of iron

A

Making haemoglobin

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13
Q

use of fiber

A

Provides bulk for faeces, helps peristalsis

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14
Q

use of water

A

Chemical reactions, solvent for transport

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15
Q

what are the deficiencies

A

Vitamin C: Scurvy; loss of teeth, pale skin & sunken eyes

Vitamin D: Rickets; weak bones and teeth

Calcium: Rickets; weak bones and teeth, also poor clotting of blood, spasms

Iron: Anaemia: Fatigue (less iron → less haemoglobin → less oxygen transported → less respiration → less energy)

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16
Q

ingestion alimentary canal

A

taking substances (e.g. food, drink) into the body through the mouth.

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17
Q

egestion alimentary canal

A

passing out of food that has not been digested, as faeces, through the anus.

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18
Q

digestion alimentary canal

A

the break-down of large, insoluble food molecules into small, water soluble molecules using mechanical and chemical processes

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19
Q

mouth alimentary canal

A

contains teeth used for mechanical digestion, area where food is mixed with salivary amylase & where ingestion takes place

20
Q

salivary glands alimentary canal

A

produce saliva which contains amylase and helps food slide down oesophagus

21
Q

oesophagus alimentary canal

A

tube-shaped organ which uses peristalsis to transport food from mouth to stomach

22
Q

stomach alimentary canal

A

has sphincters to control movement into and also has pepsin (a protease) to break down proteins into peptides, it also kills bacteria with hydrochloric acid. They also have elastic walls.

23
Q

small intestine alimentary canal

A

tube shaped organ composed of two parts the:

Duodenum: fats are emulsified by bile, and digested by pancreatic lipase to form fatty acids and glycerol. Pancreatic amylase and trypsin (a protease) break down starch and peptides into maltose and amino acids

Ileum: Maltase breaks down maltose to glucose. This is where absorption takes place; adapted by having villi and microvilli.

24
Q

pancreas alimentary canal

A

produces pancreatic juice which contains amylase, trypsin and lipase and hydrogencarbonate.

25
Q

liver alimentary canal

A

produces bile, stores glucose as glycogen, interconverting them to keep glucose concentration constant. Also carries out interconversion of amino acids (transamination), deamination and removal of old red blood cells and storage of their iron. Also, site of breakdown of alcohol and other toxins.

26
Q

gall bladder alimentary canal

A

stores bile from liver

27
Q

bile alimentary canal

A
  • produced by liver and stored in gall bladder, its role is to emulsify fats, to increase surface area for the action of enzymes
  • in neutralising the acidic
    mixture of food and gastric juices entering the
    duodenum from the stomach, to provide a
    suitable pH for enzyme action
28
Q

large intestine alimentary canal

A

tube shaped organ composed of two parts:

Colon: organ for absorption of minerals and vitamins, and reabsorbing water from waste to maintain body’s water levels

Rectum: where faeces are temporarily stored

29
Q

anus alimentary canal

A

ring of muscle which controls when faeces is released.

30
Q

diarrhoea cause and cure

A

Diarrhoea: when not enough water is absorbed from the faeces

To cure this is to give oral rehydration therapy

One of these this infectious by a bacterium causing the diseases cholera (spreads rapidly)

The cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water into the gut, causing diarrhoea, dehydration and loss of salts from the blood

31
Q

incisor

A

Rectangular shape, sharp for cutting and biting

32
Q

canine

A

Sharp-pointed for holding and cutting

33
Q

premolar

A

Blunt for chewing and crushing

34
Q

molar

A

Blunt chewing and crushing. Two roots

35
Q

structure of a tooth

A

Enamel: the strongest tissue in the body made from calcium salts

Cement: helps to anchor tooth

Pulp cavity: contains tooth-producing cells, blood vessels, and nerve endings which detect pain.

Dentine: calcium salts deposited on a framework of collagen fibres

Neck: in between crown and root, it is the gums

36
Q

tooth decay stages

A
  • plaque hardens to form tartar
  • acid wears out surface of the enamel (takes time/not painful)
  • erosion is faster in the dentine because it is softer (faster))
  • erosion hits the pulp, where nerves and blood vessels are (very painful)
37
Q

prevention of tooth decay

A

Eating food with low sugar content

Regular and effective teeth brushing to remove plaque

Finishing a meal with a crisp vegetable and a glass of water`

38
Q

what is chemical digestion

A

Where enzymes are used to break down large insoluble substances such as proteins into smaller soluble substances like amino acids so that they can be absorbed.

39
Q

use of amylase

A

breaks down starch into maltose, it is produced in the pancreas (but also in the salivary gland)

40
Q

use of protease

A

breaks down proteins to peptides (done by pepsin) then into amino acids (done by trypsin). Pepsin comes from the stomach and trypsin comes from the pancreas.

41
Q

use of lipase

A

breaks down lipids into fatty acids and glycerol, produced by the pancreas.

42
Q

use of hydrochloric acid

A

Denaturing enzymes in harmful microorganisms in food

Giving the optimum pH for pepsin activity

43
Q

what is absorption

A

Movement of digested food molecules through wall of the intestine into the blood or lymph.

The small intestine is the region for absorption of digested food.

44
Q

adaptations of small intestine

A

The small intestine is folded into many villi which increase the surface area for absorption. One villus will have tiny folds on the cells on its outside called microvilli.

More surface area means more absorption can happen

45
Q

structures in villi

A

Capillary: transports glucose and amino acids

Vein: delivers absorbed products to liver via hepatic portal vein.

Gland: produces enzymes

Lacteal: absorbs fatty acid and glycerol

Epithelium: only one cell thick for faster transport. The cells of the epithelium are folded to form microvilli.

46
Q

function of small intestine and colon

A

Small intestine and colon absorb water

The small intestine absorbs 5–10 dm3 per day

The colon absorbs 0.3–0.5 dm3 per day

47
Q

digestion of starch in the alimentary canal

A

amylase is secreted into the alimentary canal
and breaks down starch to maltose
– maltose is broken down by maltase to
glucose on the membranes of the epithelium
lining the small intestine

IGCSE Biology (21 decks)

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