Key Area 4 - Proteins Flashcards
What is an enzyme?
A biological catalyst that is made by all living cells
What do enzymes do?
They speed up chemical reactions and are unchanged in the process.
How would life be affected without the help of enzymes?
Chemical reactions would occur so slowly that life would be impossible.
What are the key characteristics of enzymes?
- They are made in all living cells
- They speed up cellular reactions
- They are unchanged in the process so can be reused
- They are protein molecules
What are enzymes?
Biological catalyst produced by all living cells: they speed up chemical reactions without taking part themselves
(e.g. Amylase breaks down starch to maltose - SAM)
What are hormones?
Chemical messengers transported in the blood from endocrine glands to target tissues.
(e.g. Insulin controls blood glucose level.)
What are antibodies?
Provides defence against specific bacteria and viruses. They bind to bacteria and viruses to allow white blood cells to recognise and destroy them.
(e.g. Immunoglobulins (IgA) IgA is found in breast milk and helps protect the new born baby from infections)
What is a structural protein?
They provide strength and support for cell structures.
e.g. Structural proteins within the cell membrane & Keratin in nails and hair.
What are receptors?
Allow cells to recognise specific chemical signals.
e.g. Liver cells have receptors for insulin.
Each enzyme has its own unique protein structure and overall shape which is designed to match and complement what?
The substance (substrate) on which it works
What is the special region on the surface of enzyme molecules called and what does it do?
The active site, where they bind to their substrate.
What is the active site unique to?
It is unique and complementary to specific substrates and don’t act on other types.
What is a summary of enzyme reactions?
Substrate(s) —>Enzyme —>Products
What is a substrate?
A particular chemical substance(s) on which a specific enzyme works.
What is a product?
Substance(s) formed by the action of an enzyme in its substrate(s).
Why is an enzyme said to be specific?
Because it can on,y work on one type of substrate.
What is the active site of an enzyme?
The place on its surface that is complementary in shape to its substrate
What are the two main types of enzyme catalysed reactions?
Degradation reactions and synthesis reactions
What is a degradation reaction?
When one substrate is broken down to form more than one product.
What is a synthesis reaction?
Several substrate molecules are bound together to form one product.
Give two examples of degradation reactions?
Hydrogen peroxide —> Catalase —> Oxygen + water
(HPCOW)
Starch —> Amylase —> maltose
(SAM)
Give an example of a synthesis reaction:
Glucose-1-phosphate —> phosphorylase —> starch
Lots of them). (G1PPS
What happens to enzymes when they are too cold?
They move slowly so the reaction takes longer to complete
What happens when an enzyme is too hot?
It’s shape changes and the rate of reaction decreases.
