B2b - part 1 Flashcards
What are enzymes?
Biological catalysts
What 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 from?
proteins
proteins are made up chains of amino acids.
These chains create the unique shapes
Normally what happens in a chemical reaction?
Things are split up or joined together
Explain lock and key
All enzymes have a unique shape and only fit one type of molecule. so for reaction to work, enzymes have to fit with this unique shape.
The molecule will fit into the enzymes active site (key) and the enzyme will then split the molecule.
How do enzymes work best?
At the right temp and pH
Temp - if too hot then the bonds holding the enzyme together will break and the enzymes special shape will change - denatured - best is around 37 degrees
pH - if too high or too low the pH will break the enzeymes bonds that hold it together and change the special shape - denatured - optimum is 7 (stomach acid - would be 2)
What do digestive enzeymes do? (plus e.g)
Break big molecules into small ones
starch,proteins and fats into sugars, amino acids and glycerol.
What is amylase?
Converts starch into sugar
Where is amylase made?
Salivary glands
pancreas
small intestine
What is protease?
Converts protiens into amino acids
Where is protease made?
Stomach (known as pepsin)
pancreas
small intestine
What is lipase?
Converts lipids into glycerol and fatty acids
Where is lipase made?
pancreas
small intestine
Job of bile
Prodcued in liver. stored in gall bladder
It neutaralises the acidic hydrochloric acid in the stomach as it is an alkaline
Also breaks down fats so lipase can work on them.
Enzeymes in the digestive system
slivary glands - amylase in saliva
Stomach - protease
Pancreas - protease, lipase and amylase
Small intestine -protease, lipase and amylase
What is respiration?
The process of releasing energy from glucose which goes on in every cell
Equation for aerobic respiration
Glucose + oxygen ——-> CO2 + water + energy
What is aerobic respiration?
Respiration using oxygen
happens all the time in plants and animals
happens in mitochondria
What is energy made in respiration used for?
- To build up large molecules from small ones (proteins from amino acids)
- In animals, to allow the muscles to contract
- in mammals and birds the energy is used to keep their body temp steady
- In plants to build sugar, nitrates and other nutrients into amino acids which are built into proteins.
How does exercise increase heart rate?
More oxygen used to release energy from glucose which is used to contract muscles. More muscle activity requires more glucose and oxygen so the blood then has to flow at a faster rate.
this is why we breath more / deeper and heart pumps faster.
Why is glycogen used in exercise?
Glycogen is a form of glucose that has been stored
Each muscles has a supply of it
During exercise muscles need more glucose so glycogen is converted back
What happens if the body doesn’t have enough oxygen (what process used)
Muscles start using anaerobic respiration
glucose is used to produce energy however as a consequence lactic acid forms in muscles which causes muscle fatigue
this doesn’t release a lot of energy but keeps muscles going for a little longer.
What is anaerobic respiration?
anaerobic means without oxygen
glucose ——-> energy + lactic acid
What is oxygen debt
happens after anaerobic respiration
You have to repay the oxygen that you didn’t get to your muscles in time
This is why you breath harder after you stop exercising to get more oxygen in blood
Only reduce when pulse and breathing rate are low.
