Level 2 Bio: Enzymes

Question 1

What is an enzyme

Answer 1

Enzymes are a type of protein. They are long complex strands of amino acids. They are biological catalysts: that lower the activation energy of a reaction/speed up reactions.

They are not part of the reaction, they facilitate the reaction. (With protein synthesis there are enzymes that catalyze the process to make enzymes (proteins))

There are lots of different types of enzymes that are specific to the type of reaction.

Cells would not be able to survive in our body without enzymes (the reactions in our body would take too long).

Question 2

What are the parts of an enzyme

Answer 2

Active site, substrate

Question 3

What do digestive enzymes do

Answer 3

Break complex insoluble food to small soluble molecules.

Question 4

What does denatured mean

Answer 4

Enzymes become irreversibly damaged, loss of structure and shape - no active site.

Question 5

What cause enzymes to denature?

Answer 5

pH if it’s too acidic or too basic

heat/temperature if it’s too high it will denature the enzymes.

Question 6

What are the main points of enzymes

Answer 6

Enzymes are proteins!

Each chemical reaction in the body is controlled by a specific enzyme.

A reaction will only occur if that specific enzyme is present.

The molecule that an enzyme acts on is called the SUBSTRATE.

Most enzyme names end in -ase. This is usually added on to the name of the substrate it is acting on.

Question 7

What does Lipase break down?

Answer 7

Lipase breaks down lipids (fat)

Question 8

What enzyme breaks down fat?

Answer 8

Lipase

Question 9

What does Maltase break down?

Answer 9

Maltase breaks down maltose

Question 10

What enzyme breaks down maltose

Answer 10

Maltase

Question 11

What does Lactase break down

Answer 11

Lactase breaks down lactose (milk, sugar)

Question 12

What enzyme breaks down lactose

Answer 12

Lactase

Question 13

What does Amylase break down

Answer 13

Amylase breaks down starch

Question 14

What enzyme breaks down starch

Answer 14

Amylase

Question 15

What are the factors that affect enzymes

Answer 15

Enzyme & substrate concentration.

Temperature: too low=slow reaction, too high= at a point will denature.

pH: Most work best at pH 7 (stomach digestive enzymes work in acid & intestinal enzymes work in alkaline.

Question 16

What is it you need to know about the shape of an enzyme

Answer 16

The shape of an enzyme is unique to that enzyme they are like jigsaw puzzle pieces and will only fit one reaction. If the shape gets altered they don’t work.

Question 17

What is a catabolic enzyme (catabolism)?
IMPORTANT!

Answer 17

Catabolic enzyme (catabolism this is where the substrate is broken down into smaller molecules. For example:
Digestion (breaking food down)
Respiration (glucose broken down into energy)
Co factors (co-enzymes) some enzymes have 2 parts to them:
The protein (enzyme)
And a co-factor (a metal or vitamin) these enzymes that need a cofactor can’t work without them.

Question 18

Information to know about co-factors

Answer 18

Co factors (co-enzymes) some enzymes have 2 parts to them:
The protein (enzyme)
And a co-factor (a metal or vitamin) these enzymes that need a cofactor can’t work without them.

Question 19

Definition of a Catalyst

Answer 19

Something that lowers the activation energy required for a reaction, which speeds up the reaction.

Question 20

Definition of a Substrate

Answer 20

The chemicals that need to be made or broken.

Question 21

Definition of a Product

Answer 21

The result of an enzyme’s reaction with a substrate.

Question 22

Definition of Active Site

Answer 22

Part of the enzyme’s surfaces which the substrate binds to, it is where the substrate undergoes a reaction.

Question 23

Describe the process of how enzymes produce new substances

Answer 23

A substrate bonds to the activation site on the enzyme, reactions occur where the enzyme changes shape which forces the substrate molecules to combine. The end product is then released, the enzyme returns to its usual shape.

Question 24

What is meant by the activation energy of a reaction.

Answer 24

The amount of energy required for the reaction to be successful.

Question 25

Describe how enzymes lower the activation energy

Answer 25

Enzymes are biological catalysts which influence the stability of the bonds in the reactants or they provide alternative reaction pathways which lowers the activation energy.

Question 26

How does enzyme concentration affect enzyme activity

Answer 26

An increase in the enzyme concentration will mean an increase in the rate of reaction.

Question 27

How does substrate concentration affect enzyme activity

Answer 27

As the substrate concentration increases the reaction rate will also increase until the saturation is reached.

Question 28

How does temperature affect enzyme activity

Answer 28

A lower temperature will cause the reaction to be slower, when the enzyme is at it's optimum temperature the reaction is faster, however if it gets too hot it will denature.

Question 29

How does pH affect enzyme activity

Answer 29

At the optimum pH the reaction will be the most successful/faster most have an optimum pH of 7. If the pH is too low or high the reaction will not work so well.

Question 30

What is a catabolic reaction

Answer 30

Catabolic reactions cause a single substrate molecule to break apart into separate products, as chemical bonds are broken. Examples are digestion and cellular respiration.

Question 31

What is an anabolic reaction

Answer 31

Anabolic reactions combine 2 or more substrates to form a single product. Chemical bonds are formed, causing the substrate molecules to fuse together. Examples are protein synthesis and photosynthesis.

Question 32

Distinguish between an anabolic reaction & a catabolic reaction

Answer 32

Anabolic reactions combine 2 or more substrates to form a single product, creating bonds. Whereas catabolic reactions break apart a single substrate into separate products and break bonds.

Question 33

What does a cofactor do?

Answer 33

Help the enzyme to alter the shape of the enzyme to make it more reactive or to complete the active site. Cofactors can be metals (Na, K, Ca, Fe, Mg ions) or organic vitamins (called coenzymes).

Question 34

Explain the role of enzyme cofactors in enzyme activity

Answer 34

They enable enzymes to change shape to fit substrates to make it more reactive or to complete the activation site.

Question 35

Explain how inhibitors prevent substrate attachment

Answer 35

Inhibitors attach to the activation site of an enzyme stopping substrates from binding to the enzyme and therefore stopping the reaction from occurring.

Question 36

What is an enzyme inhibitor?

Answer 36

These are objects that prevent a substrate from fitting into the enzyme. Some are reversible others are irreversible. Irreversible: These are poisons (heavy metal) they are permanent inhibitors & make the enzymes useless. Hg, Cd, Pb, & A's are some. Reversible: These are inhibitors used to control the activity of an enzyme. Can be removed when the enzyme is needed.

Question 37

What is the 'lock & key' model?

Answer 37

The Enzyme & substrate both have specific complementary geometric shapes that fit exactly into one another.

Question 38

What is the 'induced fit' model?

Answer 38

The substrate doesn't bind to a rigid active site, the active site moulds itself around the substrate for a more precise fit.

Question 39

Definition of an enzyme

Answer 39

Enzymes are proteins that are biological catalysts and help to speed up chemical reactions by lowering the activation energy of a reaction.