Nutrition Humans Flashcards
Topic 2 E.2
1
Q
necessary food groups for a balanced diet (7)
A
- carbohydrates
- proteins
- lipids
- fibre
- vitamins
- minerals (mineral ions)
- water
2
Q
function of carbohydrates
A
provide energy
3
Q
function of lipids
A
provides energy for insulation
4
Q
protein function
A
growth and repair of cells and tissue.
5
Q
fibre function
A
aids digestion/ movement of food through the gut
6
Q
vitamins function
A
needed in small quantities to maintain health
7
Q
minerals function
A
needed in small quantities to maintain health
8
Q
water function
A
needed for chemical reactions to take place in the body
9
Q
vitamin a function
A
helps improve vision and help keep hair and skin healthy
10
Q
vitamin C function
A
prevents scurvy
11
Q
vitamin D function
A
needed for calcium absorption
12
Q
sources of vitamin a
A
organ meats like liver, eggs, cheese
13
Q
sources of vitamin c
A
oranges, lemons, tomatoes
14
Q
vitamin d sources
A
egg yolk, cheese, oily fish
15
Q
sources of fibre
A
vegetables and wholegrains
16
Q
sources of lipids
A
butter, oil, nuts
17
Q
sources of carbohydrates
A
bread, pasta, rice
18
Q
protein sources
A
meat, egg, fish, nuts
19
Q
sources of water
A
fruit, juice, water
20
Q
function of mineral ion calcium
A
needed to make bones and teeth
21
Q
function of mineral ion iron
A
makes haemoglobin for healthy blood
22
Q
sources of iron
A
red meat
23
Q
sources of calcium
A
milk, cheese
24
Q
a balanced diet is
A
a diet which gives you all the essential nutrients in the correct proportions
25
the energy a person needs depends on : (4)
activity level
age
pregnancy
gender
26
why does activity level affect the amount of energy people need
active people need more energy than people who sit around all day as muscles are contracting more and respiring faster
27
why does pregnancy affect the amount of energy people need
energy requirements increase as energy is needed to support the growth of the developing fetus, as well as the larger mass the mother carries around. ( extra calcium and iron are also needed to help build the bones, teeth and blood of fetus)
28
why are extra calcium and iron needed when pregnant
to help build the bones, teeth and blood of fetus and produce milk for breastfeeding mothers
29
how does age affect the amount of energy people need
younger people are still growing and are most likely more active so need energy for that
30
how does gender affect the amount of energy a person needs
Male average energy requirements tend to exceed that of females due to them having a larger proportion of muscle compared to fat
31
what is the food made into at the mouth
a bolus
31
what happens at the mouth (alimentary canal)
your teeth mechanically break down food
salivary glands in the mouth produce amylase enzyme in the saliva - which chemically breaks down food
32
what happens in the oesophagus (alimentary canal)
what does the oesophagus do
peristalsis
tube that connects mouth to stomach
33
what happens in the stomach (alimentary canal)
food is mechanically digested by churning actions while protease enzymes start to chemically digest proteins
hydraulic acid kills bacteria in food and provides optimum pH for protease enzymes
34
what does hydrochloric acid do
kills bacteria in food and provides optimum pH for protease enzymes
35
what happens in the small intestine (alimentary canal)
duodenum
where digestion of the food exiting the stomach is completed by enzymes that are present in the duodenum lining and secreted by the pancreas
36
what happens in the small intestine (alimentary canal)
ileum
here the absorption of water and digested food molecules takes place; the ileum is long and lined with villi to increase the surface area over which absorption can take place
37
what happens in the large intestine ( alimentary canal)
Water is absorbed from the remaining material in the colon to produce faeces
Faeces are stored in the rectum and exit the body via the anus
38
what does the pancreas do in the alimentary canal
produces all three types of digestive enzymes
Secretes enzymes in an alkaline fluid into the duodenum for digestion; this raises the pH of fluid coming out of the stomach
39
three types of digestive enzymes and where they're found
- protease ( stomach)
- amylase (saliva)
- lipase (duodenum)
40
what does the liver do / what happens here
Produces bile to emulsify fats (break large droplets into smaller droplets), mechanical digestion
Amino acids that are not used to make proteins are broken down here, producing urea
41
gall bladder function
Stores bile to release into the duodenum
42
2 parts of the large intestine
rectum and colon
42
function of rectum
where faeces is stored before being excreted out of the anus
43
function of colon
Remaining water is absorbed from food into the blood, and the solid waste left behind in the colon forms faeces
44
order food passes through in alimentary canal
- mouth
- oesophagus
- stomach
- small intestine ( both duodenum then ilium)
- large intestine ( including colon, rectum then anus)
45
what is peristalsis
Wave-like contractions take place to push the food bolus down in the oesophagus, making sure it doesn't go back up.
46
what does peristalsis do
a mechanism that helps moves food along the alimentary canal
47
once the ball of food ( bolus) has reached the stomach, what happens to it
it is churned into a less solid form, called chyme, which continues on to the small intestine
48
what muscles is peristalsis controlled by and what do they do
circular and longitudinal muscles
circular - contract to reduce the diameter of the lumen of the oesophagus or small intestine
longitudinal- contract to reduce the length of that section the oesophagus or the small intestine
49
why is mucus produced during peristalsis
to continually lubricate the food mass and reduce friction
50
how does dietary fibre help in peristalsis
provides the roughage required for the muscles to push against during peristalsis
51
what is the purpose of digestion
to break down large, insoluble molecules into smaller, soluble molecules that can be absorbed into the bloodstream
52
food is digested partially by :
mechanical digestion (chewing, churning and emulsification)
to break large pieces of food into smaller pieces of food which increases the surface area for enzymes to work on
53
digestion mainly takes place ...
chemically
where bonds holding the large molecules together are broken to make smaller and smaller molecules
54
chemical digestion is controlled by
enzymes which are produced in different areas of the digestive system
55
proteases are and do
a group of enzymes that break down proteins into amino acids
56
pepsin is
is an enzyme made in the stomach which breaks down proteins into smaller polypeptide chains
57
protease enzymes are made in the __ and work in the ___ to break _____ chains into ___ ___
pancreas
small intestine
polypeptide chains
amino acids
58
lipases are / do
enzymes that break down lipids (fats) to glycerol and fatty acids
59
lipase enzymes are produced in the ____ and secreted into the ____ _____
pancreas
small intestine
60
what are the three main enzymes in digestion
- lipase
- amylase
- protease
61
amylase and maltase digestest
starch to glucose
61
protease digests
proteins to amino acids
62
lipases digest
lipids to fatty acids and glycerol
63
amylase is produced in
salivary glands
64
bile is produced in the
liver
65
bile is stored in the
gallbladder
66
bile is
an alkaline substance produced liver
67
from the gallbladder, bile is released into
the small intestine
68
what are the 2 main roles of bile
neutralising acidic conditions of food in the stomach ( neutralises hydrochloric acid)
breaking apart large drops of lipids into smaller ones (emulsification)
69
how does neutralising work in the bile and why is it so important
alkaline properties of bile allow for this to occur
This neutralisation is essential as enzymes in the small intestine have a higher (more alkaline) optimum pH than those in the stomach
70
how does emulsification happen in the bile
Breaking apart large drops of lipids (fats) into smaller ones (and so increasing their surface area)
71
bile allows what enzyme to increase its rate
lipase
72
what is absorption
the movement of small digested food molecules from the digestive system into the blood
73
how does the absorption of small, soluble molecules happen
by diffusion and active transport
74
how is water absorbed and where
by osmosis in the small and large intestine
75
what are the adaptations of the small intestine
- very long
- highly folded surface
- villi
76
why does the small intestine have adaptations
because they massively increase the surface area of the small intestine, allowing absorption to take place faster and more efficiently
77
adaptations of villi
- network of blood capillaries so steep concentration gradient
- permeable layer of surface cells
- microvilli to increase surface area even more
- have a one cell thick wall
78
PRACTICAL energy content of a food sample
measure out 25 cm3 of water and pour it into the boiling tube
Record the starting temperature of the water using the thermometer
Record the mass of the food sample
Set fire to the sample of food using the bunsen burner and hold the sample 2 cm from the boiling tube until it has completely burned
Record the final temperature of the water
Repeat the process with different food samples
E.g. popcorn, nuts, crisps
The larger the increase in water temperature, the more energy is stored in the sample
79
what does hydrochloric acid do
kills bacteria
