Metabolic Pathways Unit 1

Question 1

What name is given to the thousands of biochemical reactions that occur in living cells ?

Answer 1

Metabolism

Question 2

The quantity of energy consumed by an organism per unit time is measure of what rate ?

Answer 2

Metabolic rate

Question 3

Name two types of metabolic pathways involves the breakdown of complex molecules to simpler ones

Answer 3

Anabolic and Catabolic pathways

Question 4

Which type of metabolic pathway involves the breakdown of complex molecules to simpler ones ?

Answer 4

Catabolic

Question 5

Which type of metabolic pathway involves the build up of complex molecules to simpler ones ?

Answer 5

Anabolic

Question 6

Which type of metabolic pathway releases energy as it is breaking complex molecules down ?

Answer 6

Catabolic

Question 7

Which type of metabolic pathway requires energy as it builds up small molecules to complex molecules ?

Answer 7

Anabolic

Question 8

In a metabolic pathway, what do two opposing arrows means ?

Answer 8

The reaction is reversible

Question 9

Metabolic reactions sometimes have places where steps can be bypassed, what are these pathways known as ?

Answer 9

Alternative routes

Question 10

Give three properties of a catalyst

Answer 10

• Lowers the activation energy
• Remains unchanged at the end
• It increases the rate of reaction

Question 11

What name is given to biological catalysts ?

Answer 11

Enzymes

Question 12

What state is reached when two reactants have bonds broken and they are in a position that is unstable and ready to form a product ?

Answer 12

Translation state

Question 13

What substance are enzymes made of ?

Answer 13

Protein

Question 14

What name is given to the area on an enzyme that meets with the substrate ?

Answer 14

Active site

Question 15

What determines the shape of the active site ?

Answer 15

The sequence of amino acids in the polypeptide that makes up the enzymes molecule

Question 16

Give the word that is used to describe the fact that one enzyme fits one substrate

Answer 16

Specific

Question 17

Give the term that is used to describe the fact that the active site has a strong attraction for the substrate

Answer 17

High affinity

Question 18

Once the enzyme has broken the substrate down/ built it up and formed the product, how is the attraction for the active site described ?

Answer 18

Low affinity

Question 19

In order for the enzyme’s active site to fit the substrate more closely, the shape of the active site and enzyme changes slightly. What is this called ?

Answer 19

Induced fit

Question 20

The shape of the active site determined the what of reactants ?

Answer 20

Orientation

Question 21

In an enzyme controlled reaction, the reaction rate will increase as the substrate concentration increases up until a certain point. After that, the rate of reaction does not increase, why is this ?

Answer 21

Because all of the active site on the enzyme are occupied

Question 22

What can be done to increased the rate of an enzyme controlled reaction once all of the active sites on the enzyme are occupied and substrate has already been increased ?

Answer 22

Add more of the enzyme to the reaction

Question 23

In a metabolic pathway, if there if a fault in the gene that makes enzyme 2, which metabolite would build up ?

Answer 23

Metabolite X

Question 24

What name is given to a substance that decreases that rate of an enzyme controlled reaction ?

Answer 24

An inhibitor

Question 25

Name two types of inhibitor

Answer 25

Competitive inhibitor and non competitive inhibitor

Question 26

Which inhibitor binds to the active site and competes with the substrate in an enzyme controlled reaction ?

Answer 26

Competitive inhibitor

Question 27

Why is the competitive inhibitor able to join to the active site of an enzyme ?

Answer 27

Because it has a similar shape to the substrate

Question 28

What happens to the rebate of reaction in an enzyme controlled reaction that is affected by a competitive inhibitor ?

Answer 28

It decreases the rate of reaction, but doesn’t stop it altogether because the substrate can still bind sometimes

Question 29

How could the effects of a competitive inhibitor be reversed ?

Answer 29

Increase the substrate concentration

Question 30

Where does a non competitive inhibitor bind to ?

Answer 30

An allosteric site (site away from the active site)

Question 31

What does a non competitive inhibitor do to the shape of an enzyme active site ?

Answer 31

Changes the shape of the active site

Question 32

Why does a reaction affected by a non competitive inhibitor stop altogether ?

Answer 32

Because the shape of the active site has changed permanently and it no longer recognises the substrate

Question 33

When an end product is made in a metabolic pathway some of the product goes back and inhibits an enzyme at the start of the pathway, what is this called ?

Answer 33

End product inhibition