Module 2 - Enzymes

Question 1

What is an active site?

Answer 1

an indented area on the surface of an enzyme molecule, with a shape that is complementary to the shape of the substrate molecule.

Question 2

What is a catalyst?

Answer 2

chemical the speeds up the rate of the reaction and remains unchanged and reusable at the end of the reaction

Question 3

What is extracellular?

Answer 3

outside of the cell

Question 4

what is intracellular?

Answer 4

inside of the cell

Question 5

What is metabolism?

Answer 5

the chemical reactions that take place inside living cells/organisms

Question 6

what is a product?

Answer 6

a molecule that produces from substrate molecules, by an enzyme catalyzed reaction

Question 7

what is a substrate?

Answer 7

a molecule that is altered by en enzyme - catalysed reaction

Question 8

what is an enzyme?

Answer 8

Enzymes are biological catalysts because they speed up metabolic reactions in living organisms.

Question 9

Can enzymes be used again and again?

Answer 9

Yes, they remain unchanged

Question 10

Do you need a lot of enzymes to produce a large amount of substrate?

Answer 10

No, a small number of enzymes molecules can convert a large number of substrate molecules into a product per second

Question 11

what is a turnover number of an enzyme?

Answer 11

the amount of substrate converted of an enzyme

Question 12

advantages of enzymes?

Answer 12

• they function well in conditions that sustain life.
• they are more specific - usually one enzyme catalyses one specific reaction

Question 13

What structure does enzymes have?

Answer 13

• they are proteins with a tertiary or quaternary structure

Question 14

How is the enzyme structure determined?

Answer 14

determined by the sequence of amino acids in the primary protein structure, which they twists and folds in a specific way.

Question 15

What is different about each amino acid?

Answer 15

• they have different R-groups which determines how they fold

Question 16

Why is the active shape of the enzyme important?

Answer 16

As the active site will be complementary to the shape of on type of substrate

Question 17

what happens when the enzyme has kinetic energy?

Answer 17

the enzymes and the substrate randomly collide with each other

Question 18

what do the enzymes do to the activation energy?

Answer 18

• they reduce the activation energy.
• chemical reactions need to the energy to start them

Question 19

An example of activation energy can be provided?

Answer 19

It can be provided by heat

Question 20

Why can the temperature not be raised to high?

Answer 20

The proteins will denature and the lipid structure in cell membrane will fall apart

Question 21

What is an anabolic reaction?

Answer 21

• If 2 substrates join to form a product, the enzymes hold the 2 molecules close together at the active site
• the necessary bonds can then join together

Question 22

what is a catabolic reaction?

Answer 22

• if 1 substrate needs to break down into 2 productsm the active site holds the substrate in the correct positions to put a strain on certain bonds
• these then break, giving 2 products

Question 23

an example of an intracellular enzyme?

Answer 23

catalase which breaks down hydrogen peroxide

Question 24

what is a metabolic pathway?

Answer 24

when a lot of enzyme catalysed reactions inside the cell do not occur in isolation, they are part of a series of reactions

Question 25

what are metabolites?

Answer 25

all of the substrate and products

Question 26

what are extracellular enzymes?

Answer 26

These are secreted out of the cell to act somewhere else

Question 27

what is an example of an extracellular enzyme?

Answer 27

Digestive enzymes

Question 28

what do salivary amylase enzymes break down?

Answer 28

breaks down starches into sugar

Question 29

what does the enzyme pepsin do?

Answer 29

digests proteins found ingested food

Question 30

what does the enzyme lactase do?

Answer 30

breaks down lactose into smaller sugars (glucose and galactose)

Question 31

what does the enzyme maltose do?

Answer 31

converts maltose into glucose

Question 32

what are decomposers?

Answer 32

they are bacteria and fungi which live on dead organic matter, digesting large organic molecules into smaller ones - which they absorb for their own nutrition

Question 33

what is the lock and key model?

Answer 33

• the enzyme has an active site
• the substrate shape fits into the active site like a key fits into a lock
• this is complementary shape on the substrate

Question 34

what is the induced fir model ?

Answer 34

• The enzyme and its active site (and sometimes the substrate) can change shape slightly as the substrate molecule enters the enzyme
• These changes in shape are known as conformational changes
• The conformational changes ensure an ideal binding arrangement between the enzyme and substrate is achieved
• his maximises the ability of the enzyme to catalyse the reaction