Topic 2:organisation Flashcards
what are cells?
The basic building blocks that make up all organisms
what is differentiation?
the process in which cells become specialized
what is a tissue?
a group of similar cells
what is an organ?
a group of different tissues that work together to function
what tissues is the stomach made of?
1) muscular tissue- churns up food
2) Glandular tissue- makes digestive juices
3) Epithelial tissue- cover the outside and inside of the stomach
what is an organ system?
A group of organs working together to perform a particular function
what organs is the digestive system made of?
1)Glands- produce digestive juices
2)stomach and small intestine- digests food
3)liver- produces bile
4)small intestine- absorbs insoluble food molecules
5)the large intestine- absorbs water from undigested
food
6) gullet - esophagus
7)pancreas- produces protease, amylase and lipase enzymes for the small intestine
8) rectum- where the faeces are stored
9) Gall bladder- where bile is stored before it is released into the small intestine
what are enzymes?
catalysts produced by living things
what is a catalyst?
a substance that increases the speed of the reaction
what are proteins made from?
chains of amino acid
what is the active site of the enzyme?
a unique part of the enzyme that fits onto the substance involved in the reaction
why do enzymes normally only work on one substance?
because the active site has to fit the shape of the substance involved in the reaction
what happens if you change the temperature of a enzyme-catalyzed reaction?
it will speed up the reaction until a certain point in which it gets to hot and some of the bonds holding the enzyme together break and the active site changes state. the enzyme is now denatured
what happens if you change the ph of a enzyme-catalyzed reaction?
if the ph is the optimum ph it will speed up the reaction. if it is not it will break bonds in the enzyme causing the active site to change shape. the enzyme is now denatured
how do you detect starch?
using iodine. if the iodine changes to a blue/black there is starch
REQUIRED PRACTICLE: how to work out the rate of enzymatic reaction
1) put a drop of iodine solution into every spotting tile
2) place 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 until 35 degrees (use a thermometer to measure temperature. try to keep the temperature of the water constant throughout the experiment
3) use a syringe to add 1cm cubed of amylase solution and 1 cm cubed of a buffer solution with ph 5 to a boiling tube. put the tube into a beaker of water (using test tube holders) and wait 5 minutes
4) next use a different syringe to add 5 cm cubed of starch solution to the boiling tube
5) immediately mix the the contents of the boiling tube and start a stop clock
6) use continuous sampling to record how long it takes amylase to break down all the starch. To do this use a dropping pipette to take a fresh sample from the boiling tube every 30 seconds and put a drop into a well. when the iodine remains brow/orange starch is no longer present
7) Repeat the experiment with buffer solutions of different ph values
8) remember to contril and variables each time (eg concentration and volume of amylase solution) to make it a fair test
how do you calculate rate of reaction?
RATE = CHANGE / TIME
at ph 6 the time taken was 90s work out the rate of reaction?
1000/90=11s to -1 significant figure
when ph is given use this formula RATE = 1000 / TIME
24cm3 of oxygen was released in 50s. what is the rate of reaction?
rate in reaction= change/time 24/50=0.48
how are big molecules broken down in the digestive system?
by digestive enzymes as they are two big to pass through the walls of the digestive system
how are small molecules broken down in the digestive system?
they pass through the walls of the digestive system
what are the three places where amylase is made?
1) salivary glands
2) the pancreas
3) The small intestine
what is amylase an example of?
carbohydrase
what does amylase break down?
starch
what are the three places where protease is made?
1) the stomach ( although it is called pepsin there)
2) The pancreas
3) The small intestine
what does proteases convert?
proteins into amino acids
what do lipases convert?
lipids into glycerol and fatty acids
what are the two place where lipases are made?
1) the pancreas
2) the small intestine
where is bile produced?
in the liver it is stored in the gall bladder
why is the stomach to acidic for enzymes in the small intestine?
it contains hydrochloric acid HCL
what ph is bile?
alkaline
why is it important that bile is alkaline?
because it neutralizes acid so the enzymes in the small intestine can work best
where are enzymes in the digestive system produced?
in glands and gut lining
list the order of parts in the digestive system?
salivary glands, gullet, stomach, liver, gall bladder, pancreas, large intestine, small intestine, rectum
what is the use of salivary glands?
produce amylase into saliva
why is the stomach important?
1) it pummels the food with its muscular walls
2) it produces protease enzyme pepsin
3) it produces HCL for 2 reasons:
a) to kill bacteria
b) to give the right ph for protease enzyme to work
why is the liver important?
where bile is produced
why is the gall bladder important?
where bile is stored before its released into the small intestine
why is the pancreas important?
produces protease, amylase and lipase enzymes and releases them into the small intestine
why is the large intestine important?
where excess water is absorbed from food
why is the small intestine important?
1)produces protease, amylase and lipase enzymes2) where digested food is absorbed out of the digestive system and into blood
why is the rectum important?
where the faeces are stored before they exit the anus
how can you identify what food molecule a sample contains?
1) get a piece of food and break it up using a pestle and mortar
2) transfer the food to a beaker and add distilled water
3) stir the mixture with a glass rod to help it dissolve
4) filter the solution using a funnel lined with filter paper to get rid of the solid bits of food
what solution do you use to test for sugars?
benedict’s solution
it will turn from blue to green, yellow or brick red if sugar is present
REQUIRED PRACTICLE: how do you test for sugars?
1) prepare a food sample and transfer 5cm3 to a test tube
2) prepare a water bath and set it to 75degrees
3) add benedict’s solution to the test tube using a pipette
4) place it in the water bath for 5mins using a tube holder to keep it in place
5) it will turn green, yellow or brick red if there is sugar
what solution do you use to test for starch?
iodine
it will turn from browny-orange to dark blue or black if starch is present
REQUIRED PRACTICLE: how do you test for starch?
1) make a food sample and transfer 5cm3 of your sample to the test tube
2) add iodine solution and gently shake to mix the contents
3) if starch is present the solution will turn dark blue or black
what solution do you use to test for proteins?
biuret solution
it will turn from blue to pink or purple if protein is present
REQUIRED PRACTICLE: how do you test for protein?
1) prepare a sample of your food and transfer 2cm3 of your sample to a test tube
2) add 2cm3 of biuret solution to the sample and mix the contents of the tube by gently shaking it
3) it will change to pink or purple if protein is present
what solution do you use to test for lipids?
sudan III
it will separate into two layers the top one being bright red if lipids are present
REQUIRED PRACTICLE: how do you test for lipids?
1) prepare a sample of the food you are testing transfer 5cm3 to a test tube
2) use a pipette to add 3 drops of sudan III stain solution to the test tube and gently shake the tube
3) if lipids are present it will separate into 2 different layers the top one being bright red
what region of your body are the lungs found in?
thorax region
what separates the lungs from the bottom half of the body?
the diaphragm
what protects the lungs?
the ribcage
