2.1 metabolic pathways

Question 1

Metabolic pathway definition

Answer 1

Metabolic pathways are a series of reactions inside of cells, starting with a substrate molecule and ending with a product molecule, which are controlled and integrated by enzymes.

Question 2

Types of metabolic pathway

Answer 2

Reversible, irreversible and alternative

Question 3

Reversible reactions

Answer 3

A metabolic pathway where product molecules can be converted back into substrate molecules by an enzyme.

Question 4

Irreversible reactions

Answer 4

A metabolic pathway where a product molecule can’t be converted back into its substrate by an enzyme.

Question 5

Alternative reactions

Answer 5

Metabolic pathways with a different substrate, and a different enzyme, however the same product is formed.

Question 6

Types of enzyme reactions (metabolic pathway)

Answer 6

Catabolic and anabolic

Question 7

Anabolic reactions definition

Answer 7

An enzyme controlled reaction which build up substrate molecules into larger product molecules requiring energy, in the active site.

Question 8

Catabolic reactions definition

Answer 8

An enzyme controlled reaction which breaks down the substrates into smaller product molecules releasing energy in the active site.

Question 9

Enzymes definition

Answer 9

Enzymes are biological catalysts made of protein by a living cell, meaning they speed up the rate of reaction without being used up by decreasing the activation energy.

Question 10

Enzymes type of protein

Answer 10

Globular

Question 11

Activation energy definition

Answer 11

The energy required for substrates to form products

Question 12

Rules of activation energy in relation to speed of reaction

Answer 12

The lower the activation energy the faster the reaction.

Question 13

High affinity

Answer 13

Where there is a strong attraction between the substrate and the enzyme.

Question 14

Low affinity

Answer 14

Where the active site and the product repel each other.

Question 15

Rules of affinity of enzymes

Answer 15

Low affinity of products
High affinity of substrates

Question 16

Induced fit

Answer 16

Where an enzymes active site changes shape to suit the shape of the substrate after it has bound to the active site.

Question 17

Inhibition definition

Answer 17

Where an enzyme cannot change the shape of a substrate, due to the presence of another molecule.

Question 17

Inhibition definition

Answer 17

Where an enzyme cannot change the shape of a substrate, due to the presence of another molecule.

Question 18

Types of inhibition

Answer 18

Competitive, non competitive, feedback.

Question 19

Competitive inhibitor definition

Answer 19

A molecule which binds to the active site of an enzyme and prevents the enzyme from changing the substrates shape.

Question 19

Competitive inhibitor definition

Answer 19

A molecule which binds to the active site of an enzyme and prevents a substrate from entering or binding with the enzyme’s active site, therefore preventing the substrate from being catalysed.

Question 20

Rules of competitive inhibition

Answer 20

As the concentration of substrate increases the rate of reaction increases, due to there being a higher chance of a substrate binding to the active site.
As the concentration of inhibitor increases the rate of reaction decreases due to there being a higher chance of the inhibitor binding to the enzymes active site.

Question 21

Non competitive inhibitors

Answer 21

molecules which bind to the allosteric site, which changes the shape of the active site, to prevent the substrate from binding with the active site.

Question 22

Rules of non competitive inhibitors

Answer 22

As the substrate concentration increases the rate of reaction stays constant, since the non competitive inhibitor changes the shape of the enzymes active site, preventing the chance of the substrate binding with the enzymes active site.

Question 22

Rules of non competitive inhibitors

Answer 22

As the substrate concentration increases the rate of reaction stays constant, since the non competitive inhibitor changes the shape of the enzymes active site, preventing the chance of the substrate binding with the enzymes active site.

Question 23

Feedback inhibitors

Answer 23

End product molecules, that when there is a critical concentration of the molecule, the molecule will bind with the allosteric site, in an enzyme earlier on in the process, to stop the production of the product.

Question 24

Types of proteins in membrane

Answer 24

Pores pumps and enzymes