Human nutrition Flashcards
What does iodine solution test for?
starch
If starch is present, what colour change will happen in the solution
goes from orange to blue/black
How to test for glucose
5cm3 of sample in test tube
Add around 10 drops Benedict’s solution
Heat in water bath for 5 mins at 75 degrees
Positive result of the test for glucose
solution turns blue to green/ yellow/ brick red
(red is the highest concentration of glucose)
What is the name of the test for lipids
the emulsion test
how to test for lipids
add 2cm3 ethanol to food sample in test tube
shake the test tube aggressively
colour change if lipids are present in the emulsion test
turns from colourless to cloudy white
what does biuret solution test for
protiens
colour change when protiens are present in the biuret test
solution turns from blue to lilac/purple
what is the main type of carbohydrate
starch
what is starch broken down by and what is it broken into
broken down by amylase
broken into smaller sugars called maltose
where is amylase made in the body
pancreas, small intestine, salivary glands
what are proteins broken down by, and what are they broken into
broken down by protease enzymes
into amino acids
where are proteases made
stomach (pepsin)
small intestine
pancreas
what are fats broken down by and what are they broken into
broken down by lipases into glycerol and fatty acids
where are lipases made
small intestine
pancreas
what is starch a polymer of
glucose
how are maltose molecules broken down into glucose
by maltase
examples of protease enzymes
pepsin
trypsin
what is bile
a yellow-greenish liquid released from the gall bladder that helps with lipid digestion
how does bile help with digestion of lipids
it emulsifies the lipids which increases the surface area for lipase enzymes to break them down
what type of digestion is chewing
physical
what does the stomach do during physical digestion
contracts muscular walls
produces pepsin to break down protein
produces hydrochloric acid which kills bacteria and creates right environment for pepsin
where does digested food get absorbed into the bloodstream
small intestine
which organ creates the most digestive enzymes
pancreas
what does the gall bladder release into the small intestine
bile
what are the two main roles of bile
neutralises acid from the stomach
emulsifying fats - gives the fats a bigger surface area for the digestive enzymes to work on
how does the small intestines structure help digested food to be absorbed into the bloodstream
villi - increases surface area, digested food can be absorbed into bloodstream more quickly
villi have a single layer of surface cells - nutrients only diffuse a short distance
what is released into the small intestine to mix with digested foods
pancreatic juices
bile
what are the two main functions of the digestive system
digestion
absorption
what is digestion
process of breaking down large food molecules into smaller molecules
how do teeth breaking food down into smaller pieces help digestion
makes food easier to swallow
increases the surface area for enzymes to act on
which enzyme is in saliva and what does it do
amylase - breaks down starch into maltose
what carries food from the mouth to the stomach
oesophagus
