(D) Enzymes in Action

Question 1

What are enzymes?

Answer 1

A protein molecule that acts as a catalyst in a biochemical reaction

Question 2

What are proteins made of?

Answer 2

Amino acids

Question 3

What are amino acids?

Answer 3

Molecules that can combine to make proteins

Question 4

What is the structure of an amino acid?

Answer 4

A central (Alpha) carbon atom with 4 chemical groups attached

Question 5

What chemical groups are attached to the central(alpha) carbon in a amino acid?

Answer 5

• A hydrogen atom
• An amino group
• A carboxyl group
• A variable R group (side chain)

Question 6

How many R groups and amino acids are there?

Answer 6

There are 20(multiple) different R groups so there are 20(multiple) different amino acids

Question 7

What are the main types of amino acid?

Answer 7

• Polar/Hydrophilic
• Non-polar/Hydrophobic
• Acidic/Negatively charged R group
• Basic/Positively charged R group

Question 8

Peptide bond

Answer 8

Bonds that link amino acids together

Question 9

What is a condensation reaction?

Answer 9

A reaction that occurs between two amino acids and produces water as well as a peptide bond

Question 10

What is a dipeptide?

Answer 10

When two amino acids are linked together by a peptide bond

Question 11

What is a tripeptide?

Answer 11

When three amino acids are linked together by a peptide bond

Question 12

What is a polypeptide?

Answer 12

When several amino acids are linked together by a peptide bond and a polypeptide with more than 50 amino acid is a protein

Question 13

What is a protein structure and the types of protein structure?

Answer 13

A protein structure is the structure of a protein and there are 4 types;
* Primary
* Secondary
* Tertiary
* Quaternary

Question 14

What is a primary protein structure?

Answer 14

A polypeptide chain/amino acid sequence

Question 15

What is a secondary protein structure?

Answer 15

When a polypeptide chain forms a shape (secondary structure) usually a α-helix or a beta plated sheet

Question 16

What types of secondary structures are there?

Answer 16

• α-helix
• Beta plated sheet

Question 17

What are secondary protein structures held by?

Answer 17

Hydrogen bonds between -NH of one peptide and the -C=O of another amino acid

Question 18

What are tertiary protein structures?

Answer 18

A secondary structure which folds into three dimensional shapes

Question 19

What does a tertiary protein structure do?

Answer 19

Gives an enzyme the shape of it’s active site

Question 20

What bonds hold a tertiary protein structure together?

Answer 20

• Peptide
• Hydrogen
• Ionic
• Disulphide bridge

Question 21

What is a disulphide bond?

Answer 21

A bond that forms due to a oxidization reaction

Question 22

What is an active site?

Answer 22

An active site is a a region on an enzyme that binds to a substrate

Question 23

What is a substrate?

Answer 23

The molecule that binds and is broken down by the enzyme

Question 24

What is denaturation?

Answer 24

When the tertiary structure(active site) of the enzyme is changed

Question 25

What is a catalyst?

Answer 25

A substance that speeds up a reaction, enzymes are biological catalysts

Question 26

What is catalytic activity?

Answer 26

Increase in the rate of a reaction caused by the inclusion of an catalyst

Question 27

What is collusion theory?

Answer 27

For a reaction to occur;
* Particles have to collide
* Particles must have enough energy to react

Question 28

What is activation energy?

Answer 28

The minimum energy required for a particles to react

Question 29

What is the enzyme-substrate complex

Answer 29

When a substrate enters the active site, this forms the enzyme-substrate complex. Then the reaction occurs, converting the substrate into products

Question 30

What is different(specific) about every enzyme?

Answer 30

Enzymes are specific because different enzymes have different shaped active sites
The shape of the active site is complementary to the shape of its substrate

Question 31

How does an enzyme lower the activation energy it needs?

Answer 31

• More particles have the required energy needed
• There are mores successful collisions
• There is a faster reaction

Question 32

How can the rate of reaction be measured?

Answer 32

The initial rate of reaction must be recorded
* Measuring the decrease in substrate
* Measuring the increase in product

Question 33

What are the factors that affect enzyme activity?

Answer 33

• Temperature.
• pH
• Substrate and enzyme concentration

Question 34

How does temperature affect enzyme activity?

Answer 34

The closer the temperature is to the optimum(37°C) the faster the rate of reaction

Question 35

What happen to an enzyme if the temperature is below the optimum?

Answer 35

Below this, there is less energy so less collision so slower reaction

Question 36

What happen to an enzyme if the temperature is above the optimum?

Answer 36

Above this, the enzyme starts to denature and the hydrogen bond in the enzymes start to break

Question 37

How does the pH affect enzyme activity?

Answer 37

Most enzymes have an optimum pH between 7 and 8, if the pH is outside this range then enzyme activity decreases

Question 38

How does the substrate and enzyme concentration affect enzyme activity?

Answer 38

Increase in substrate/enzyme concentration →
Increase in the rate of collisions →
Increase in the rate of reaction

Question 39

How much can the substrate and enzyme concentration affect enzyme activity?