Organisation Flashcards
What is the process by which cells become specialised called?
Differentiation
name these in order of size: Organs, tissues, organs systems, cells
Cells
Tissues
Organs
Organ systems
What is tissue?
A group of similar cells that work together to carry out a particular function.
give some examples of tissues in mammals
muscular tissue, glandular tissue and epithelial tissue
What is an organ?
A group of different tissues that work together to perform a certain function.
 give an example of an organ system
The digestive system
What are enzymes?
Biological catalysts.
What is a catalyst?
A substance that increases the speed of reaction without being changed or used up in the reaction.
What are enzymes made up of?
they are made up of large proteins, which are made up of chains of amino acids.
High temperatures tend to increase reactions. Why is it better that enzymes are produced?
Because increasing temperature also speeds up unwanted reactions as well. Enzymes reduce the need for high temperatures and we only have them to speed up useful chemical reactions in the body.
What is the lock and key theory?
that an active site needs to be perfectly compatible to the substrate for it to work.
what is it called when the active site changes shape a little as the substrate binds to it to get a tighter fit?
The induced fit model of enzyme action.
Why do enzymes need the right temperature?
Because at first, a high temperature increases the rate. But if it gets too hot the enzyme will denature and the shape of the active site will change so the substrate wont fit.

How does pH affect enzymes?
if the pH level is too high or too low it changes the shape of the active site in denatures the enzyme.
What is usually the optimum pH for an enzyme?
It is usually PH7, but not always e.g. pepsin an enzyme used to break down proteins in the stomach, it works best to PH2 to suit the acidic conditions.
What does the enzyme amylase do?
catalyses the breakdown of starch to maltose.
How can you detect starch?
Iodine.
Why do we need digestive enzymes?
Because Starch, proteins and fats are big molecules so they’re too big to pass through the walls of the digestive system so the enzymes break them down (e.g. into sugars).
what do carbohydrases do?
Convert carbohydrates into simple sugars. Amylase is an example of a carbohydrase. It breaks down starch.
what do proteases do?
Convert proteins into amino acids.
Where is Amylase mean?
This after glands, the pancreas, and the small intestine.
where are proteases made?
The stomach, the pancreas, and the small intestine.
what do lipases do?
they convert the lip ids into glycerol and fatty acids.
where are lipases made?
The pancreas and small intestine.
What does bile do?
Neutralises stomach acid and emulsifies fat.
Where is bile produced and stored?
Produced in the liver and stored in the gallbladder until it’s released into the small intestine
Why is bile needed?
The hydrochloric acid in the stomach makes the pH too acidic for enzymes in the small intestine to work properly. The bile is alkaline, it neutralises the acid and makes conditions alkaline. The enzymes in the small intestine work best in these alkaline conditions.
What does ‘bile emulsifying fat’ mean?
It breaks the fat down into tiny droplets.
What does hydrochloric acid do in the stomach?
Kills Bacteria
Gives it the right pH for protease to work
What Enzymes do the pancreas produce?
Protease, amylase and lipase.
What enzyme does the salivary glands produce?
Amylase
What do you use to test for sugars? yeah
Benedicts solution. You need to heat it up before it works. The colour will change from blue to anywhere between green, yellow or brick red (depending on how much sugar there is)
What do you use to test for starch?
Iodine solution. Gently shake the contents and the colour will change from browny orange to black or blue-black
What do you use to test for proteins?
Biuret solution. Shake gently and the solution will change from blue to lilac
What do you use to test for fat?
Ethanol. It will turn from colourless to cloudy.
What are alveoli?
They are millions of little air sacs surrounded by a network of capillaries that carry out gas exchange. (diffusion of oxygen and carbon dioxide)
What kind of circulatory system do we have?
A double circulatory system
What does the right ventricle do?
pump deoxygenated blood to the lungs to take in oxygen.
What does the last ventricle do?
pumps oxygenated blood around the organs and rhen back to the heart
What are the walls of the heart mostly made up of?
Muscle tissue