FINAL EXAM CHAPTER 15 Metabolism

Question 1

What are the three stages of catabolism?

Answer 1

1. Large molecules in food are broken down into smaller molecules in the process of digestion
2. The many small molecules are processed into key molecules of metabolism most notably acetyl CoA
3. ATP is produced from the complete oxidation of acetyl CoA

Question 2

Where does energy come from in Phototrophs and Chemotrophs?

Answer 2

Phototrophs - Obtain energy by capturing sunlight

Chemotrophs - Obtain energy through the oxidation of carbon fuels

Question 3

What is energy used for?

Answer 3

-To do work : power muscle contraction, cell movement

-Active transport

-Biosynthesis of macromolecules

Question 4

Define Metabolism

Answer 4

A series of linked reactions that convert a specific reactant into a specific product

Question 5

Define catabolism

Answer 5

the break down of complex molecules

Question 6

Define anabolism

Answer 6

the simple molecules combine to generate complex molecules

Question 7

What are catabolic pathways?

Answer 7

Combustion of carbon fuels to synthesize ATP or ion gradients

Question 8

What are anabolic pathways?

Answer 8

Uses ATP and reducing power to synthesize large biomolecules

Question 9

How can we perform thermodynamically unfavorable reactions?

Answer 9

by coupling these reactions to a more favorable one

Question 10

What is the importance of ATP as a common intermediate in all of metabolism ?

Answer 10

It is the energy currency if the cell and it is used for building cell constituents and doing cellular work such as muscle contraction and active transport of molecules against concentration gradients

Question 11

Why are Delta G sequential reactions additive?

Answer 11

Because delta G is path independent

Question 12

Why does ATP have a high phosphoryl transfer potential?

Answer 12

1. Charge repulsion
2. Resonance stabilization
3. Increase in entropy
4. Law of Mass action
5. Stabilization by hydration.

Question 13

What are the two molecules that we discussed have high phosphoryl transfer potential

Answer 13

-Phosphoenolpyruvate(PEP)
-1,3-Biphosphoglycerate

Question 14

Explain the concept of being thermodynamically unstable but kinetically stable

Answer 14

in things like Phosphate esters you would see this, as the inherent negative charge resist hydrolysis and this happens in things where the condition in where the reaction should happen isn’t met

Question 15

Why is the oxidation of carbon fuel important?

Answer 15

Because it helps regenerate ATP and ATP is limited so it has to be recycled.

Question 16

Explain how carbon oxidation is paired with a reduction?

Answer 16

The carbon atoms in fuels are oxidized to yield CO2 and the electrons are accepted by oxygen to form H2O

-The more reduced a carbon atom is the more free energy is released upon oxidation

Question 17

why are fats more efficient food source than glucose ?

Answer 17

Because fats are more reduced

Question 18

What are the two common characteristics of activated carriers?

Answer 18

1. The carriers are kinetically stable in the absence of specific catalysts

2.The metabolism of activated groups is accomplished with a small number of carriers

Question 19

What is the activated carrier of phosphate?

Answer 19

ATP

Question 20

What are the activated carriers of electrons?

Answer 20

-NAD+
-FAD
both carry activated electrons derived from the oxidation of fuels

Question 21

What is the activated carrier of Acetyl groups?

Answer 21

-Coenzyme A (CoA or CoA-SH)

Question 22

what carriers are often derived from vitamins?

Answer 22

Coenzymes are usually derived from vitamin B