ATP & Energetics

Question 1

What is metabolism?

Answer 1

A set of biochemical reactions that are required to sustain life.

Foods are broken down via catabolic pathways to make cellular building blocks which then synthesize macromolecules

Question 2

From the breakdown of foods during metabolism what is happening?

Answer 2

Energy is being generated

Energy is then used to synthesize macromolecules

Question 3

What is energy

Answer 3

The capacity to do work
eg:
-mechanical, chemical

Question 4

What is energy transduction?

Answer 4

A process by which living organism:

• collects and stores energy
• releases stored energy to do work

Question 5

What do we need to make energy?

Answer 5

mitochondria
fuel (food: carbs, fats)
Helpers: O2(wo this, the cells without be able to generate the energy needed for biochemical needs), enzymes,

Question 6

What are the products during the process of making energy?

Answer 6

ATP

Question 7

What are the waste products during the process of making energy?

Answer 7

CO2, water

Question 8

What is ATP?

Answer 8

The energy currency of the cell.

Question 9

How much ATP do we synthesize

Answer 9

> 60kg daily

Question 10

What is cellular reparation?

Answer 10

Process in which sugars (glucose) are converted into usable energy (ATP)

Sugar + Oxygen –> CO2 + water + energy (stored in the form of ATP)

Question 11

Explain the ATP-ADP cycle

Answer 11

When ATP is used, ADP is generated

O2 + energy from food + O2 + Pi –> ATP

ATP used for cellular work (biosynthesis of macromolecules, muscle contraction, active ion transport, thermogenesis) and a Pi is extracted

Question 12

Why the ATP energy system is used?

Answer 12

quick and renewable
produces a rapid turnover of ATP
highly efficient
rapidly responds to energy demands

Question 13

Hydrolysis of ATP

Answer 13

-Water required to spilt phosphate bond to get energy
-The terminal phosphate (high energy gamma phosphate) bond is hydrolyzed.
- Thermostable: does not hydrolyze spontaneously
- Energy is released from ATP when the terminal phosphate bond is broken
- This release of energy comes from the chemical change to a state lower free energy, not from the P-bonds themselves
- Pi can be transferred to another molecule
- release of 1 phosphate group and formation if 1 ADP
very slow unless there is a catalyze available

Question 14

Where does the energy in ATP hydrolysis comes from?

Answer 14

Release from the chemical change to a state of lower free energy, not from the phosphate bonds themselves

Question 15

What do the different Gibbs free energy values mean?

Answer 15

• delta G = 0. means body is at equilibrium, inert
• delta G -, exergonic, favorable, the driving force is in the forward direction, releases energy
• delta G +, endergonic, meaning the driving force is in the reversible direction, requires energy, usually ATP

Question 16

How does ATP work?

Answer 16

As a coupled reaction = 2 half reactions

eg: Glucose + Pi –> G-6-P + H2O delta G = +3.3

ATP + H2O –> ADP + Pi delta G = -7.3

Glucose + ATP –> G-6-P + ADP delta G = -4.0

Question 17

ATP is not the highest energy compound. Why use ATP rather than other phosphorylated compounds?

Answer 17

It and the other nucleotide triphosphates are stable

It is quick and renewable (unlike the others)

Hydrolysis is slow and enzymatically catalyzed

Question 18

riboflavin

Answer 18

Vitamin used as a food coloring

Question 19

Where is more ATP generatied? TCA or ETC

Answer 19

ETC

TCA has little ATP

Question 20

The high energy phosphate bond in ATP is located in which of the following groups

1. Adenine and phosphate
2. Ribose and phosphate
3. Ribose and adenine
4. Two phosphate groups

Answer 20

Remember the gamma phosphate

Question 21

Where does the energy needed to drive the biochemical reactions come from?

Answer 21

The food we eat.

The larger foods are broken down into smaller molecules from which energy is extracted.

Question 22

Joules to calorie conversion

Answer 22

1J = 1/4 calorie

1 calorie is needed to raise the temperature of water by 1 degree C

Question 23

How is ATP used in transport?

Answer 23

Helps take molecules across the cell membrane against a concentration gradient.

Question 24

How is ATP used in transport in the stomach?

Answer 24

H+/K+ ATPase (proton pump; acidified the stomach)

ATP provides the energy to maintain pH levels low

Question 25

How is ATP used in transport in the heart/neurons?

Answer 25

Na+/K+ pump
ATP provides the energy to maintain Na+ levels low inside the cells

Needed for heart contractions and synaptic transmission in neurons

Question 26

What are mechanisms for synthesizing ATP?

Answer 26

1. Substrate level phosphorylation
   -Direct transfer: ADP + Pi –> ATP
   Glycolysis and TCA cycle
2. Oxidative phosphorylation (~90% of ATP is generated)
   - indirect transfer: energy in the form of e- is passed to electron carries and used indirectly to form ATP
   “ETC:

3, Photophosphorylation
occurs in plants

Question 27

What are the cofactors needed for ATP synthesis?

Answer 27

NAD+ - coenzyme.
vitamin needed: niacin
carrier of e-

FAD - prosthetic group. vitamin needed: riboflavin
carrier of e-

Coenzyme A - coenzyme
vitamin needed: pantothenic acid
carrier of acyl groups

Question 28

How does Coenzyme A work as a cofactor

Answer 28

It has a reactive thiol group at its end terminus which binds to the acyl group. When hydrolyzed, it releases energy

Question 29

What are the stages in cellular respiration

Answer 29

Glycolysis - makes few ATP

TCA cycle - provides the energy to make alot of ATP, doesn’t generate much ATP

ETC - generates the most ATP

Question 30

Total oxygen consumption takes place where?

Answer 30

mitochondria