topic 2- organisation Flashcards
what is a tissue
group of similar cells that work together to carry out a particular function
organ definition
a group of different tissues that work together to perform a particular function
organ system definition
a group of organs that work together to perform a particular function
catalyst definition
a substance that increases the speed of a reaction without being changed or used up in the process
how do enzymes work
they take a substrate and break it down to smaller pieces called products
all enzymes do here is speed up the process
what is the active site in an enzyme
part of the enzyme that has a unique shape that is complimentary to the substrates
how the enzyme “lock and key model”actually works
the enzyme changes shape slightly as it binds to the substrate so the active site is complimentary to the substrate
how does temperature affect the rate of reaction
the higher the temperature the faster the rate of reaction but too high of a temp the bonds start to break apart that hold the enzyme together so the active site starts to change and if it changes shape enough the enzyme wont be able to bind with the substrate so the enzyme has been denatured.
what is optimum temperature?
optimum temperature is where the rate of reaction is at its highest point.
how does ph affect the rate of reaction
ph can speed up the rate of reaction but too high of a ph or too low of a ph can cause some of the bonds to break holding the enzymes together. the active site starts ti change shape active site changes so much that substrate cant fit.
what is optimal ph
where rate of reaction is at its highest where ph causes this
why do we need carbohydrates?
they are an energy source to carry out chemical reactions and for us to function e.g. move around
role of lipids
provide energy but they are longer term store of energy
keep us warm by insulating us
and protecting organs
role of proteins
grow
repair damaged tissue
what breaks down carbohydrates
it is broken down by amylase
where is amylase made
salivary glands
pancreas
small intestines
how are proteins broken down
broken down by protease
where is protease made
stomach
pancreas
small intestine
what are breaks down fats (lipids)
broken down by lipase
where are lipases made
pancreas
small intestine
what is the point of digestion
to break down food into tiny pieces so we can absorb it into our bodies cells
digestive system roles of each part of the system
mouth-break down food physically by chewing then salivary glands produce amylase to break down carbohydrates
stomach-contracts muscular walls to mix food. produces pepsin to break down proteins. produce’s hydrochloric acid to kill bacteria and provide environment for pepsin to work.
small intestine- digested food absorbed into blood stream. produces enzymes to aid digestion
pancreas- lots of digestive enzymes which is juiced into the small intestine
gall bladder- produces bile to neutralise acid from stomach so digestive enzymes can function. also emulsifies fats by giving big surface area for enzymes to work on.
how is small intestine adapted to its function
it is an example of an exchange surface
small intestine walls have villi which increase surface area of wall so digestive food can be absorbed into blood stream quickly.
villi only have a single layer of surface cells so nutrients diffuse in a short distance. they have a very good blood supply.
what are the food tests practical
benedict test for sugars
biuret test for proteins
iodine test for starch
sudan III test for lipids
how to prepare food test practical
break up the food
put crushed food in a beaker with distilled water
stir with glass rod till some dissolves
filter out solution with funnel and filter paper to get rid of solid bits of food we dont need
how to do benedicts test
benedicts test- transfer 5cm^3 of the solution to the test tube and prepare water bath and have it at 75 degrees add 10 drops of benedicts solution to test tube and place in water bath for 5 mins. use test tube holder to place in bath. if no reducing sugars are present the solution will stay blue but if they are reducing sugars present it should turn to green yellow or brick red.