unit: 2 - metabolic pathways

Question 1

What is metabolism?

Answer 1

The sum of all chemical reactions in an organism, including catabolism (breakdown) and anabolism (synthesis).

Question 2

What are the two types of metabolic pathways?

Answer 2

Catabolic pathways, which break down molecules to release energy, and anabolic pathways, which build molecules and consume energy.

Question 3

What is ATP and why is it important in metabolism?

Answer 3

ATP (adenosine triphosphate) is the energy currency of the cell, providing energy for metabolic reactions.

Question 4

Why are membranes important in metabolic pathways?

Answer 4

Membranes compartmentalize processes, create concentration gradients, and house enzymes and transport proteins for metabolic reactions.

Question 5

What role does the inner mitochondrial membrane play in metabolism?

Answer 5

It hosts the electron transport chain and ATP synthase for oxidative phosphorylation.

Question 6

How do concentration gradients relate to metabolic pathways?

Answer 6

Gradients drive processes like ATP production (e.g., proton gradient in mitochondria).

Question 7

What is a metabolic pathway?

Answer 7

A series of enzymatic reactions where the product of one reaction becomes the substrate for the next.

Question 8

Give an example of a metabolic pathway.

Answer 8

Glycolysis: the breakdown of glucose into pyruvate, producing ATP and NADH.

Question 9

How are metabolic pathways regulated?

Answer 9

Through feedback inhibition, enzyme activation, and gene expression

Question 10

What is an enzyme?

Answer 10

A biological catalyst that speeds up chemical reactions by lowering activation energy

Question 11

What is the active site of an enzyme?

Answer 11

The specific region where the substrate binds and the reaction occurs.

Question 12

Explain the induced fit model of enzyme action

Answer 12

The enzyme changes shape slightly to fit the substrate more tightly, improving catalytic efficiency.

Question 13

What factors affect enzyme activity?

Answer 13

Temperature, pH, substrate concentration, and inhibitors.

Question 14

What are competitive inhibitors?

Answer 14

Molecules that compete with the substrate for the enzyme’s active site, reducing activity.

Question 15

What are non-competitive inhibitors?

Answer 15

Molecules that bind to a different site (allosteric site) on the enzyme, altering its shape and reducing activity.

Question 16

What is feedback inhibition?

Answer 16

When the end product of a metabolic pathway inhibits an earlier enzyme to prevent overproduction.

Question 17

How is enzyme activity controlled by phosphorylation?

Answer 17

Enzymes can be activated or deactivated by the addition or removal of a phosphate group.

Question 18

Do enzyme reactions take place in isolated areas or pathways?

Answer 18

Enzyme reactions do not take place in isolation but in pathways

Question 19

are pathways able to be reversed?

Answer 19

Many of these pathways are reversible, but some are not

Question 20

Is there an alternative pathway around pathways that cant be reversed?

Answer 20

Where pathways are irreversible, or energetically unfavorable, alternative pathways are usually available

Question 21

What are anabolic reactions?

Answer 21

Anabolic reactions build up large molecules from small molecules and require energy

Question 22

What are catabolic reactions?

Answer 22

Catabolic reactions break down large molecules into smaller molecules and release energy.

Question 23

Are pathways linked, and how if they’re?

Answer 23

Most of these reactions are linked; the energy given off by one pathway is used to power another

Question 24

What do proteins need to do several functions, and give examples?

Answer 24

Proteins within the membranes perform several functions, such as pores, embedded enzymes and channels

Question 25

What is the rate of metabolism dictated by?

Answer 25

The rate of metabolism is dictated by the rate at which the enzymes work