GCSE B.3 Flashcards
What is a tissue
A group of specialised cells of similar structure and function working together
What is an organ
An organ is a collection of tissues all working together to carry out a function.
What is an organ system.
A group of multicellular organs working together to carry out a function
What is an organism
A all the organ systems working together to support an stable, living entity.
What is the function of the liver
To produce bile that breaks down fat and neutralises the acids in the stomach
What enzyme is produced by the slavary glands (in the mouth)
Amylase
What enzyme is found in the stomach
Protease
What enzyme is found in the small intestine
Lipase
Protease
Carbohydrase
How do enzymes break down food
Enzymes have an active site that can fit into the type of food it can break down. When the food enters this active site, the enzyme acts as a catalyst and breaks up the substrate into pieces that can easily be absorbed by the body.
How does temperature effect enzyme rate of reaction
As the enzymes get more and more kinetic energy from heat they get faster and as a result have more collisions with substrates it needs to break up meaning more product is produced speeding up the rate of reaction. However, after a certain point, the heat breaks up the bonds holding the chains of proteins in the enzyme which allows them to move and changes the shape of the active site. This denatures the enzymes and makes them unable to act as a catalyst causing a longer the rate of reaction
How does pH effect enzymes rate of reaction
Different enzymes need different pH to work efficiently and so your body produces different chemicals to allow them to work at their fastest rate of reaction. If the pH is too high or too low then they will break the forces holding the chains of proteins in place which changes the shape of the active site. This denatures the enzyme as it cant catalyse reactions and causes a longer rate of reaction
Which pH does carbohydrase such as amylase need?
A slightly alkaline solution, such as in the mouth
Which pH does protease need
Very acidic conditions such as in the stomach
Which pH does lipase need
Alkaline solution which is why bile is added to food in the small intestine.
What is the role of bile in the body
Bile is added in the small intestine to neutralise the acidic food that has just come from the acidic conditions in the stomach needed for protease to work efficiently. It also provides better conditions for carbohydrase and lipase to work more efficiently.
Bile also breaks up fad molecules that are too big for lipase to break down themselves, this allows the lipase to catalyse food more effectively as it can handle the smaller chunks of lipids more easily.
