B3 Flashcards
Tissue
A group of similar cells working together to carry out a particular function
Muscular tissue
Contracts to move whatever it’s attached to
Glandular tissue
Makes and secretes chemicals like enzymes and hormones
Epithelial tissue
Covers some parts of the body
Cells
The basic building blocks making up all living organisms
Organ
A group of different tissues working to perform a certain function
Organ system
A group of organs working together to form a particular function
Function of small intestine
To digest food
To absorb soluble food molecules
Function of large intestine
Absorbing water from undigested food, leaving faeces
A catalyst
A substance increasing the speed of a reaction, without being changed or used up in the reaction
How does amylase break starch down
The enzyme amylase breaks starch down to maltose
Effect of PH on enzyme activity practical
1) Put a drop of iodine solution into each well of a spotting tile.
2) Place a bunsen burner on a heat-proof mat, and a tripod/gauze over the Bunsen burner. Put a beaker of water on top of the tripod and heat the water until it’s 35C(thermometer measures temperature). Keep a constant temperature of the water through the experiment.
3) Use a syringe to add 1cm3 of amylase solution and 1cm3 of buffer solution with a ph of 5 to a boiling tube. Using test tube holders, place the tube in a beaker of water and wait for five minutes.
4)Use a different syringe to add 5cm3 of starch solution to the boiling tube.
5)Mix the contents of the boiling tube and start a stop clock.
6)Use continuous sampling to record how long it takes for the amylase to break down all the starch. 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 solution remains browny-orange, starch’s no longer present.
7)Repeat the experiment with buffer solutions of different PH values - control variables include concentration and volume of amylase solution.
Rate of reaction(for something changing over time)
Amount of product formed/changed divided by time
Normal rate of reaction
1000/time
Where is amylase made
The salivary glands
The pancreas
The small intestine
Where are lipases made
Pancreas and small intestine
Where are proteases made
The stomach
The pancreas
The small intestine
Uses of products of digestion
Make new carbohydrates, proteins, lipids
Some glucose made is used in respiration
Where is bile stored before being released into the small intestine
Gall bladder
What are protease enzymes called in the stomach?
Pepsin
Functions of hydrochloric acid
To kill bacteria
To give the right PH for the protease enzyme to work(PH2- acidic)
Functions of stomach
Pummels the food with muscular walls
Produces the protease enzyme pepsin
Produces hydrochloric acid
Function of rectum
Where the faeces are stored before bidding a farewell through the anus.
Preparing a food sample(before every food test)
1)Get a piece of food and break it up using a pestle and mortar
2)Transfer the ground up food to a beaker and add some distilled water.
3)Give the mixture a good stir with a glass rod to dissolve some of the food,
4)Filter the solution using a funnel lined with filter paper to get rid of the solid bits of food
Benedict’s Test
1) Prepare a food sample and transfer 5cm3 to a test tube.
2)Prepare a water bath for 75C
3)Add 10 drops of Benedict’s solution to the test tube using a pipette
4) Place the test tube in the water bath using a test tube holder and leave it for 5 minutes: ensure the tube is pointing away from you. Solution turns green/yellow/brick-red if reducing sugars are present
How to test for presence of starch
1)Make a food sample, transfer 5cm3 to test tube.
2)Add a few drops of iodine solution fand shake the tube to mix the contents. The solution will change from browny-orange to blue-black if starch is present.
How to test for proteins(Biuret test
1)Prepare a sample of your food, add 2cm3 of the sample to a test tube.
2)Add 2cm3 of biuret solution to the sample, mix the contents of the tube by gently shaking it.
3) If the food sample contains protein, the solution will change from blue to people
How to test for lipids
1) Prepare a sample of food and transfer 5cm3 of it to a test tube.
2)Use a pipette to add 3 drops of Sudan III stain solution to the test tube, gently shake the tube.
3) If the sample contains lipids, the mixture will separate into two layers, with the top layer bright red.
Examples of simple sugars
Glucose
Sucrose
Examples of complex carbohydrates
Starch
Cellulose
What are most carbohydrates you eat broken down into?
Glucose used in cellular respiration to provide energy for metabolic reactions in your cells
Uses of lipids
Useful in nervous system
Useful as hormones in cell membrane
Structure of lipids
The glycerol is always the same, but the fatty acids vary, which affects whether the lipid will be a liquid oil or solid fat
Protein uses
Antibodies, which destroy pathogens and are part of the immune system
Enzymes, which act as catalysts
What do enzymes control?
The metabolism - sum of all the reactions in a cell or in the body
Alkaline areas in body
Mouth
Small intestine
Why are proteins broken dowm
Stomach
Small intestine
Where are lipase enzymes made
Pancreas
Small intestine
Purpose of mucus in stomach
Coats stomach walls - protects them from being digested by the acid and enzymes. If someone develops a stomach ulcer, the protecting mucus is lost and the stomach lining is attacked by the acid and protein-digesting enzymes
Gall stones
They block the gall bladder and bile duct - stop bile releasing on food, reducing the efficiency of digestion
Where is starch digested
Mouth
Small intestine
