human nutrition

what elements do carbohydrates contain

carbon

hydrogen

oxygen

what elements do proteins contain

carbon

hydrogen

oxygen

nitrogen

what elements do lipids contain

carbon

hydrogen

oxygen

what are proteins made out of

long chains of amino acids

what are carbohydrates made up of

simple sugars

what are large, complex carbohydrates made out of

many smaller units joined together in a long chain

what are examples of smaller units of carbohydrates

glucose

maltose

what are examples of large, complex carbohydrates

starch

glycogen

what are lipids made out of

fatty acids and glycerol

how to prepare a food sample

break of a piece of food using pestle and mortar

add distilled water

mix

filter the solution

use the filtrate

how to test for glucose

prepare food sample

prepare water bath at 75c

add benedict solution

leave it there for 5 minutes

what happens if glucose is present

changes from blue to green to yellow to brick red

depending on concentration

how to test for starch

prepare food sample

add iodine solution

shake

what happens if starch is present

changes from brown-orange to blue-black

how to test for proteins

prepare food sample

add biuret solution

shake

what happens if proteins are present

changes from blue to pink to purple

how to test for lipids

prepare food sample without filtering

add Sudan III stain solution

gently shake

what happens if lipids are present

mixture will separate into two layers

top layer will be bright red - staining the lipids

balanced diet definition

provides the essential nutrients we need

in the right proportions

what is the function of carbohydrates

provides energy

what is the function of lipids

provides energy

provides insulation

acts as energy store

what is the function of proteins

growth and repair of tissue

provides energy in emergencies

what is the function of vitamin a

improves vision

keeps skin and hair healthy

what is the function of vitamin c

prevents scurvy

what is the function of vitamin d

needed for calcium absorption

what is the function of calcium

makes bones and teeth

what is the function of iron

makes haemoglobin for healthy blood

what is the function of water

need a constant supply of water for every bodily function

what is the function of dietary fibre

aids movement of food through the gut

what happens if there isnt enough dietary fibre

constipation

what are carbohydrates found in

pasta

rice

sugar

what are lipids found in

butter

oily fish

what are proteins found in

meat

fish

what is vitamin a found in

liver

carrots

what is vitamin c found in

fruits

what is vitamin d found in

eggs

what is calcium found in

milk

cheese

what is iron found in

red meat

what is dietary fibre found in

fruit

wholemeal bread

what does energy requirement depend on

age

activity level

pregnancy

why do pregnant women need for energy

support fetal growth and development

what happens if there is a deficiency of iron

causes anaemia

leading to fatigue and weakness due to lack of oxygen transport

what happens if there is a deficiency of vitamin d

causes rickets

small weak bones for children

what does starch, proteins and fats have in common

large molecules

insoluble

what does amylase do

converts starch into maltose

what does maltase do

converts maltose into glucose

what do proteases do

converts proteins into amino acids

what do lipases do

converts lipids into glycerol and fatty acids

where is amylase found

salivary glands

pancreas

where is protease found

stomach

pancreas

small intestine

where is lipase found

pancreas

mouth

stomach

functions of bile

neutralizes stomach acid

emulsifies fat

function of hydrochloric acid in stomach

kills bacteria

creates acidic environment for pepsin

why does bile neutralize stomach acid

to make sure the pH is optimum for enzymes to work in

emulsification definition

breaks down fat into tiny droplets

gives it a bigger surface area for lipase to work with

digestion is faster

where is bile produced

liver

where is bile stored

gall bladder

where is bile released

small intestine

peristalsis

series of wave-like muscle contractions that move food through the digestive track

what is the function of the mouth

salivary glands produce amylase in saliva

teeth mechanically break down food

difference between mechanical and chemical breakdown of food

mechanical digestion involves physically breaking down foo (via chewing or stomach churning)

chemical digestion involves enzymes and bile

what is the function of the oesophagus

muscular tube connecting mouth and stomach

what is the function of the stomach

pummels food with its muscular walls

produces the protease enzyme pepsin

produces hydrochloric acid

what is the function of hydrochloric acid

kill bacteria

give optimum pH for protease enzyme to work (acidic)

what is the function of the pancreas

produces protease, amylase and lipase

releases them into small intestine

what is the function of the small intestine

produces protease, amylase and lipase enzymes to complete digestion

nutrients are absorbed here

what is the first part of the small intestine called

duodenum

what is the last part of the small intestine called

ileum

what is the function of the large intestine

excess water is absorbed from the food

what is the function of the rectum

faeces are stored before excreted through the anus

assimilation

process where absorbed nurtients are used to build new tissues and cells

adaptions of villi

single permeable layer

good blood supply

long

microvilli

what does a good blood supply and single-permeable layer help with villi

assists in quick absorption

small distance for diffusion

what does microvilli and being long help with villi

there is a large surface area

more diffusion into bloodstream

roles of lacteals in villi

absorb fatty acids and glycerol into the lymphatic system

how is glucose absorbed from the small intenstine to the bloodstream

via active transport