Flashcards in Organisation Deck (35):
Describe how cells are organised in a human starting from the smallest
What is a tissue?
They are a group of smaller specialized cells that work together to perform a particular function. It can contain more than one type of cell
State 3 examples of tissue and their function
Muscular tissue-which contracts to move wherever its attached to
Glandular tissue-which makes and secretes chemicals like enzymes and hormones
Epithelial tissue-which covers some parts of the body e.g. inside of the gut
What is an organ? Define
An organ is a group of tissues that work together to perform a particular function
State an examples of an organ and their function based on their tissues
Muscular tissue-moves the stomach wall to churn up food
Glandular tissue-Which makes digestive juices to digest food
Epithelial tissue-which covers the outside and inside of the stomach
State a organ system and the organs that consist in it and their part in the organ system
The digestive system, which breaks down and absorbs food.
Glands like the pancreas and the salivary glands as they make digestive juices
The stomach and small intestine which digest food
the liver which produces bile
small intestine which absorbs soluble food and molecules
large intestine which absorbs water from undigested food leaving faeces
What is an enzyme?
An enzyme is a biological catalyst.
Why do we have enzymes?
to speed up the rate of useful chemical reactions in the body. As we cant raise the temperature or any other method of speeding the reaction rate
Define what a catalyst is
A catalyst is a substance which increases the speed of a reaction, without being changed or used up in the reaction
What are enzymes made up of?
they are made of large proteins that are made up of chains of amino acids, and are folded up to unique shapes which enzymes need to fulfil their job
Describe simply how enzymes work using the lock and key diagram
Enzymes have active sites that are a specific shape to match a specific substrate
Only the substrate with the right shape will fit the enzyme and catalyse the reaction
once the substrate goes into the active site the enzyme tightens the fit a bit.
When the reaction is complete the substrate will be split or joined
How can temperature affect an enzyme?
The increase of temperature will increase the reaction at first like most reactions, however after a certain point the rate of reaction will decrease. If too cold the enzyme may not work well
the heat breaks the bonds in the enzyme and
the active site changes
the enzyme DENATURES
What do all enzymes have in terms or reaction rate?
They have a optimum temperature and ph where the rate of reaction is the fastest
What happens to an enzyme when its not in the optimum ph?
It will denature and not work as effectively
Most work best at Ph 7 but not all e.g. pepsin which works best at ph 2 in the stomach due to the conditions of it
Describe how you would test the effect that ph has on enzymes?
You would use the enzyme amaylase, and iodine to detect starch the solution will go from browny-orange to blue-black
1 Put a drop of iodine solution into every well of a spotting file
2 get a Bunsen burner on a heat -proof mat and a tripod and gauze over the Bunsen burner. Put a beaker of water on top of the tripod and heat the water until 35 degrees, and use a thermometer to measure this, try and keep the water temp as constant as possible
3 Then use a syringe to add 1cm cubed of amylase solution and 1 cm cubed of a buffer solution with a ph of 5 to a boiling tube. Using a test tube holders put the tube into the beaker of water and wait 5 minutes
4 next use another syringe to add 5cm cubed of starch solution to the boiling tube
5 immidiatley mix the contents of the boiling tube and start a stop clock
6 then sample the solution every 30 seconds using a pipette and put the drop into a well. When the solution eventually stays a browny orange colour stop as no starch is present and record the time
7 Then repeat the whole experiment at different ph's to see how ph effects the time taken to break things down
8 Remember to control variables each time
What is the equation for rate of reaction for the amylase experiment?
-------------------- = rate (s to the -1)
What do carbohydrates provide us with? And what do we need them for?
Cellular respiration and energy for metabolic reactions in your cells
What forms of carbohydrates are there?
How do you test for a starch? and sugars
Iodine test for starch turns blue black when present
Bénédicts solution to test for sugars turns brick red if sugar is present
How do you test for sugars?
prepare food sample ad put 5cm3 in a test tube
prepare a water bath so that its set to 75 Celsius
add 10 drops of benedicts solution to the test tube using a pipette
Place the test tube in the water bath using a test tube holder and leave it there for another 5 minutes make sure the tube is pointing away from you
If the sample contains sugar it will turn from blue-green-yellow-brickred
How do you test for starch?
Make a food sample of 5cm3 and put into a test tube
then add a few drops of iodine solution and gently shake the tube to mix the contents
if solution contains starch the solution should turn from browny-orange to black or blue-black
How do you test for proteins?
Prepare 2cm3 of you sample and put into a test tube
add 2cm3 of biuret solution
mix by gently shaking
if the food sample contains protein the solution will change from blue to pink or purple
What colour does protein go when tested with what?
biuret solution is used to test and makes the solution go from blue to pink or purple
or stay blue if none is present
How can you test for lipids?
Prepare a sample of your food put 5cm3 into a test tube(don't filter)
Use a pipette and add 3cm3 of Sudan III solution into the test tube and gently shake the tube
Sudan III stains lipids so if lipids is in sample the mixture will separate into two layers. The top layer will be bright red, if not present no red layer will be present at the top
what chemical would you use to test for lipids and what would happen if it was present
a red layer will form on the top of the solution
How do you prepare food as a sample?
break it up using a pestle and mortar
put the food into some distilled water and put in a beaker
stir the mixture
Filter the solution using a funnel lined with filter paper to get rid of the solid bits of food
What does the salivary glands do for digestion
produce amylase enzyme in the saliva
What does the gullet do for digestion?
Move food down to the stomach
What does the stomach do for digestion?
pummels food with its muscular walls
produces protease enzyme pepsin
produces hydrochloric acid to kill bacteria and be the right Ph for the protease enzyme
What does the liver do for digestion?
It produces bile which emulsifies fats and neutralises stomach acid
What does the Gall Bladder do for digestion?
It is where bile is stored before its released into the small intestine
What does the pancreas do in digestion?
Produces protease, amylase and lipase enzymes. It releases these into the small intestine
What does the large intestine do for digestion?
Where excess water is absorbed from the food
What does the small intestine do for digestion?
produces lipase, amylase and protease to complete digestion
also absorbs nutrients and puts them into blood