Chapter 15 Metabolism:Basic Concepts and Design

Question 1

What is the first stage of generation of energy from food?

Answer 1

Large molecules in food are broken down into smaller molecules in the process of digestion

Question 2

What is the second stage of generation of energy from food?

Answer 2

The many small molecules are processed into key molecules of metabolism, most notably acetyl CoA

Question 3

What is the third stage of generation of energy from food?

Answer 3

ATP is produced from the complete oxidation of acetyl CoA

Question 4

Energy is required to meet what three fundamental needs?

Answer 4

1.To do work: power muscle contraction, cell movement
2.Active transport
3.Biosynthesis

Question 5

What is a Phototroph?

Answer 5

Something that obtains energy by capturing sunlight

Question 6

What is a Chemotroph?

Answer 6

Something that obtains energy through the oxidation of carbon fuels.

Question 7

What are metabolic pathways

Answer 7

This is when molecules are degraded or synthesized stepwise in a series of reactions

Question 8

How can ATP be formed?

Answer 8

By oxidation of carbon fuels

Question 9

What is a metabolism?

Answer 9

It is a series of linked reactions that convert a specific reactant into specific product

Question 10

What do the Catabolic pathways do?

Answer 10

They combust carbon fuels to synthesize ATP or ion gradients

Question 11

What do Anabolic pathways do?

Answer 11

They use ATP and reducing power to synthesize large biomolecules

Question 12

In order to construct a metabolic pathway, what two criteria must be met?

Answer 12

1.The individual reactions must be specific
2.The pathway in total must be thermodynamically favorable

Question 13

What do Heterotrophs do?

Answer 13

They extract the chemical potential energy stored in sugars and other organic compounds and release CO2 and H2O

Question 14

The hydrolysis of ATP is ___________ because the triphosphate unit contains ___________________________________ that are unstable

Answer 14

Exergonic, Two Phosphoanyhdride bonds, unstable

Question 15

What is the Phosphoryl-transfer potential?

Answer 15

This is the means of comparing the tendency of organic molecules to transfer a phosphoric group to an acceptor molecule

Question 16

What factors cause ATP to have a high phosphoryl-transfer potential

Answer 16

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

Question 17

Phosphate esters are thermodynamically ______, yet they are kinetically _________

Answer 17

unstable, stable

Question 18

Why are phosphate esters stable?

Answer 18

Because the inherent negative charges resist hydrolysis

Question 19

What other roles do ATP have ?

Answer 19

ATP can function as a biological hydrotrope and it can also play a role in maintaining protein solubility

Question 20

What is the immediate donor of free energy for biological activities

Answer 20

ATP

Question 21

Why are fats more efficient food source than glucose?

Answer 21

Because fats are more reduced

Question 22

As prominent fuels, Why do we use carbs more than fatty acids when FAs store my energy

Answer 22

Its because carbs are biological more available compared to fatty acids

Question 23

The oxidation of the carbon atom may form a compound with high phosphoryl transfer potential to later form what?

Answer 23

ATP

Question 24

What two characteristics are common to activated carriers?

Answer 24

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 25

What do NAD+ and FAD carry?

Answer 25

They carry activated electrons derived from the oxidation of fuels.

Question 26

In the structure of NAD+ which H is the reactive site and in the standard form what charge does N have?

Answer 26

Top right H of the hexagon is the reactive site and the N has a positive charge.

Question 27

In the structure of FAD what Ns are the reactive site?

Answer 27

in the three hexagons in a line the bottom right N and the N at the very top are reactive sites

Question 28

The transfer of the acyl group is _____________ because the thioester is ___________

Answer 28

Exergonic,unstable

Question 29

In the structure of CoA what is the reactive site ?

Answer 29

The HS on the left of the CoA is the reactive site

Question 30

What is more stable the oxygen esters or Acyl CoA and why?

Answer 30

Its because oxygen esters are more stable because they are stabilized by resonance structure.

Question 31

What do B vitamins function as?

Answer 31

Coenzyme

Question 32

Metabolic processes are regulated in which three ways?

Answer 32

1.The amount of enzymes present
2. The catalytic activity of enzymes
3. The accessibility of substrates