B3 Flashcards
what is a tissue
a group of cells with a similar structure/function
what is an organ
a group of tissues with a specific function
what is an organ system
organs working together to form a system
what is an organism
made up of several organ system
what happens in the mouth when you eat
chewing - physically breaking down food
saliva is released which softens the food and contains amylase
what happens in the gullet when you eat
transports food from the mouth to the stomach
what happens in the stomach when you eat
food is churned up by the muscular stomach walls when they contract
produces pepsin and protease which breaks down starch into amino acids
contains hydrochloric (HCL) acid to kill bacteria and give an optimum temp for the digestive enzymes in the stomach
what happens in the pancreas when you eat
releases lots of enzymes like amylase, lipase and protease
what happens in the gall bladder when you eat
releases bile which was produced by the liver
what happens in the small intestine when you eat
nutrients from the food is absorbed by the small intestine
enzymes like lipase, protease and amylase are also released to help digestion
what happens in the large intestine when you eat
excess water is removed from the food
what happens after water is absorbed in the large intestine
the waste is stored in the rectum and then it’s removed by the anus
how is the small intestine adapted to its’s function
contains lots of of villi at the surface of the intestine which increases the surface area of the intestine so more molecules can be absorbed and so food molecules can be absorbed more quickly. Villi have a good blood supply and only have a single layer of surface cells so the nutrients only have to diffuse a short distance to get to the blood supply.
what is an enzyme
an enzyme is a biological catalyst and so its used to speed up chemical reactions
what is the role of bile and how does it aid digestion
it neutralises acids and emulsifies fats
what is the role of an enzyme
it breaks down large insoluble molecules into small soluble molecules
what is the role of amylase and where is it made
it breaks down starch into glucose (sugars). it’s made in the pancreas, the small intestine and the salivary glands
what is the role of lipase and where is it made
breaks down fats into fatty acids and glycerol. made in the pancreas and small intestine.
what is the role of protease and where is it made
breaks down proteins into amino acid. made in the pancreas, stomach and small intestine
the lock and key theory. what is it
substrate enters the active site of an enzyme.
the enzyme breaks up the substrate so it’s soluble
once the substrate is broken down it’s released from the enzyme
what are factors affecting the efficiency of enzymes
temperature, pH, substrate concentration, surface area
whats the test for testing foods for starch
the iodine test
how do you know if the iodine test is positive or negative
iodine turns blue-black if there is starch and if there isn’t then it’ll stay orangey-brown.
how do you test for sugars
the benedict’s test
how do you know if the benedict’s test is positive or negative
turns brick red if it’ positive and blue if it’s negative
what’s the test for proteins
the biuret reagent test
how do you know if the biuret reagent test is positive or negative
the blue biuret turns to a light purple when it reacts with proteins
what’s the test for lipids
the ethanol emulsion test
how do you know if a ethanol emulsion test is positive or negative
ethanol forms a cloudy emulsion when mixed with lipids and water
what happens to an enzyme if the temperature is over 37 degrees Celsius
it will denature so it’ll stop working
what’s the optimum temp for enzymes
37 degrees Celsius
weel
done
