Chapter 8 - Enzymes Flashcards
What is a catalyst?
A substance that increases or speeds up the rate of a chemical reaction without partaking in the reaction and is not changed by the reaction.
What the difference between a catabolic and a anabolic reaction?
Catabolic - reactions which break down larger molecules into smaller molecules
Anabolic - reactions which build larger molecules from smaller molecules
What is an enzyme?
It is a globular protein that functions as a biological catalyst to increase the rate of a chemical reactions without itself being changed at the end of the reaction.
What are enzyme properties?
Enzymes are very specific.
They are unchanged by the reaction they catalyzed.
They are affected by temperature and pH.
They are needed in small quantities because they can be used over and over again.
What is a substrate?
The molecule/substance the enzyme acts on.
What is an active site?
The dent which is exactly the correct shape for a substrate to fit into.
What is the product of an ESC?
The new molecules that leave the active site after the enzyme acted on the substrate.
Explain the enzyme activity.
A substrate molecule collide with a specific enzyme at the active site.
The substrate has a complimentary shape and an induced fit occur between the active site and the substrate.
Enzymes are very specific and the substrate molecule fits perfectly into the active site and forms a enzyme-substrate-complex (ESC).
The enzyme catalyses the substrate and releases new products from the active site.
The enzyme remains unchanged and free to form another ESC.
What is the effect of changes of enzyme activities in high temperatures?
When the temperature becomes too high, too much kinetic energy causes the enzyme to vibrate too much this causes bonds to break and the active site changes shape. The substrate will not fit into the active site and no ESC will form. The enzyme will denature and the reaction rate will decrease/stop.
It is a permanent change and the enzymes will never work again.
What is the effect of changes of enzyme activities in low temperatures?
At low temperatures, the rate of enzyme activity is very slow, enzymes can become inactive.
Less kinetic energy causes molecules to move slowly and few collisions occur between enzymes and substrates and so few ESCs will form. This is reversible and the enzyme is not denatured and still works.
What is the effect of pH changes of enzyme activities?
Different enzymes work best at different pH levels.
Too high or too low pH levels could cause the enzyme to be denatured irreversibly.
Describe the role of enzymes in the process of germination.
Water activates enzymes that change insoluble nutrients into soluble nutrients, in the aleurone layer that is absorbed by seeds through the micropyle.
Gibberellic acid is formed in the embryo plant and goes to the aleurone layer of the seed, to activate the enzymes.
State the enzymes and the products of the following substrates:
- polypeptides
- sucrose
- maltose
- lipids
- proteins
- starch
- trypsin / amino acids
- sucrase / glucose + fructose
- maltase / glucose + glucose
- lipase / fatty acids + glycerol
- pepsin / polypeptides
- amylase / maltose
Describe the role of enzymes in biological washing powders.
Biological washing powders contain detergents with enzymes to help breakdown stains and dirt in fabrics.
Detergents are water-soluble cleansing agents that combine with impurities and dirt to make them soluble to be removed from clothes.
Enzymes removes stains by dissolving them.
Name other other processes which involves enzyme activity. (7)
- baking bread
- production of baby foods
- brewing industry
- production of fruit juices
- dairy industry
- spice industry
- syrup industry
