U2:K1 - Metabolic pathways

Question 1

What are metabolic pathways?

Answer 1

Integrated and controlled pathways of enzyme-catalysed biochemical reactions within a cell

Question 2

What is a catabolic pathway?

Answer 2

The breakdown of complex molecules to simpler ones, this releases energy

Question 3

What is an anabolic pathway?

Answer 3

The build up of simple molecules into complex molecules, this requires energy

Question 4

What are reversible steps?

Answer 4

Steps that allow for alternative routes if there is an excess of substrate

Question 5

What are irreversible steps?

Answer 5

Steps that are a key regulatory point in the pathway

Question 6

What are alternative routes?

Answer 6

Routes that allow steps in the pathway to be bypassed

Question 7

What are plasma membranes of a cell?

Answer 7

The boundary that separates the internal contents from its external surroundings

Question 8

What does a plasma membrane do?

Answer 8

Regulates the flow of materials into and out of the cell

Question 9

What are embedded in the membranes?

Answer 9

Protein pores, pumps and enzymes

Question 10

What is diffusion?

Answer 10

The net movement of molecules or ions from a region of high concentration to low concentration down a concentration gradient

Question 11

What is active transport?

Answer 11

The movement of molecules across the cell membrane from a low to high concentration, against a concentration gradient

Question 12

What does active transport require the presence of?

Answer 12

Proteins

Question 13

How do enzymes lower the activation energy?

Answer 13

By forming an enzyme substrate complex that accelerates the rate of reaction

Question 14

What does the substrate have a high affinity for?

Answer 14

The active site of the enzyme

Question 15

What is induced fit?

Answer 15

The active sites flexible structure which changes when the substrate binds

Question 16

What do enzymes require to function efficiently?

Answer 16

Suitable temperature, appropriate pH, adequate supply of substrate

Question 17

What is an inhibitor?

Answer 17

A substance which decreases the rate of an enzyme controlled reaction

Question 18

What can inhibitors do?

Answer 18

Compete for enzyme active sites, change the shape on an active site and inhibit pathways by feedback inhibition

Question 19

What do competitive inhibitors do?

Answer 19

Bind with the enzymes active site preventing a substrate from binding

Question 20

What do non-competitive inhibitors do?

Answer 20

Bind with the allosteric site causing a reaction to occur which results in the active site changing shape so the substrate can no longer bind

Question 21

What happens in feedback inhibition?

Answer 21

The end product binds to enzyme one in metabolic pathways, blocking the pathway, this prevents further synthesis of the end product