Organisation Flashcards
What is the basic building block of life
Cells
What is a tissue?
A group of cells with a similar structure and function
What is an organ?
A group of different tissues working together to
carry out a function.
What is an organ system?
A group of organs working together to carry out a
function.
What is an organism?
A living thing made of organ systems working
together.
What is the digestive system?
An organ system which works to digest food and
absorb the nutrients into the bloodstream.
What are enzymes?
Catalysts, made of protein that speed up reactions.
In the digestive system enzymes break down large
molecules into small soluble ones.
How do enzymes work?
They have a specific active site that allows them to bind and react with specific substrate molecules.
What does optimum mean?
The temperature or pH that allows the enzyme to
work at it’s fastest rate.
What does denature mean?
If the shape of the active site changes, no substrate can bind. The enzyme can no longer work when it’s active site is denatured.
What can denature an enzyme active
site?
Temperatures that are too high and extreme pH can
both make the active site change shape and become
denatured. This is permanent.
Can low temperatures denature enzymes?
No, the enzyme will not change shape if cold but has
low kinetic energy so there will be a slower rate of
reaction. This is reversible.
What are the enzymes in digestion?
Amylase (and other carbohydrases), protease and
lipase.
What does amylase do?
It is a carbohydrase that breaks down starch into
sugars. It is produced in the salivary glands (in the
mouth).
What do proteases do?
Break down proteins into amino acids. They are
produced in the stomach and pancreas.
What do lipase do?
Break down lipids (fats and oils) into fatty acids and
glycerol. They are produced in the small intestine.
What do carbohydrases do?
Break down sugars into glucose. Amylase is a type of carbohydrase, but there are others in the small intestine too.
Why do we need to digest foods?
Only small soluble molecules can enter the
bloodstream. Enzymes break large molecules into
molecules small enough to be soluble.
What do we do with the digested products?
Cells build new proteins, carbohydrates and lipids with the molecules we have digested.
Some glucose is used in respiration too.
What other chemicals are in the Hydrochloric acid is found in the stomach digestive system?
Bile (made in the liver and stored in the gall
bladder) is found in the small intestine.
What does hydrochloric acid do?
Kills some bacteria on the food we ate.
Also provide the optimum pH for stomach enzymes (proteases) to work at a fast rate
What does bile do?
Bile is alkaline, so neutralises hydrochloric acid.
Also it emulsifies fat droplets, giving a larger surface area for lipase enzymes to work.
What is a qualitative food test?
A test that shows if a substance is there or not. A qualitative test doesn’t give a measurement result, just a change of colour. It can be hard to decide if one food has more of a substance than another.
What is the test for sugars?
When sugary food/drink is heated with Benedict’s reagent,
It turns from blue to brick red (or green).
This shows sugar is present.
What is the test for starch?
When iodine is added to starchy food, It turns from
orange to blue-black. This shows starch is present.
What is the test for protein?
When Biuret reagent is added to food/drink containing protein,
it turns from pale blue to lilac.
This shows protein is present.
What is metabolism?
The rate at which molecules are broken down during digestion and built into new molecules by cells.
Sometimes called metabolic rate.
What does the heart do/
It is an organ that contracts to pump blood around
the body and to the lungs. It is a double pump.
Why is the heart called a double pump?
The right ventricle pumps blood to the lungs for gas
exchange. The left ventricle pumps blood to the
of the body.
What blood vessels must you label?
Vena cava, aorta, pulmonary artery, pulmonary vein
and coronary arteries.
What lung structures must you label?
Trachea, bronchi, alveoli, and capillaries around the
alveoli.
What controls resting heart rate?
A group of cells in the right atrium acting as a
pacemaker. Some people need an artificial
pacemaker if their heart rate is irregular.