Intro to respiration

Question 1

What are the 2 types of metabolic pathways?

Answer 1

Anabolic and Catabolic

Question 2

Define anabolic

Answer 2

pathways requires energy and involved in biosynthesis of complex molecules from simple molecules

Question 3

Define catabolic

Answer 3

pathway releases energy and involves the breakdown of molecules

Question 4

What are the 2 functions of oxidative catabolism of glucose?

Answer 4

1- production of free energy in the ATP form

2- Production of intermediates from glycolysis and the TCA cycle to provide materials for other metabolic pathways

Question 5

Define oxidative metabolism

Answer 5

A chemical process in which oxygen is used to make energy from carbohydrates, also called aerobic metabolism /aerobic respiration/ and cell respiration.

Question 6

Name the respiration equation.

What is the standard free energy change?

Answer 6

C6H12O6 + 6O2 → 6CO2 + 6H2O

The standard free energy change (G°´) for this reaction is -2834 kJmol-1

Question 7

Energy that is not used for work is released as what?

Answer 7

Heat

Question 8

Define Delta G°

Answer 8

Change in Gibbs free energy at pH 0 (1M [H+]) under standard conditions

Question 9

Define Delta G°´

Answer 9

Change in Gibbs free energy at pH 7 under standard conditions

Question 10

What does Delta G prime show us about the reaction?

Answer 10

Provides info on what happens to free energy. This amount is related to difference in energy level between products and reactants

Question 11

If Delta G prime is negative…..

Answer 11

free energy is released hence it is exergonic

Question 12

If Delta G prime is positive…..

Answer 12

free energy is absorbed hence it is endergonic

Question 13

Exergonic and Endergonic differ from endo and exothermic reactions- how?

Answer 13

Entropy not included in exo and endo

Question 14

What are the 4 biological uses of the release of energies?

Answer 14

Mechanical work- eg muscle contraction
Transport work -eg establish ion gradients
Heat Generation
Biochemical Work- eg energy requiring chemical reactions

Question 15

Define Kc
Define Q
what is their relationship

Answer 15

Kc= Equilibrium constant
Q= reactant quotient
Kc=Q and equilibrium

Question 16

At equilibrium
State ΔG°
Change in ΔG°
Change in [reactant] and [product]

Answer 16

Delta G=0
No change in free energy

concentrations are constant

Question 17

State the equation for ΔG°

What does this allow us to do?

Answer 17

ΔG°= -RTlnK

Predict spontaneity if K is known
To estimate if reaction lies to the left or the right if ΔG° is known

Question 18

Which equation links ΔG and ΔG prime?

Answer 18

ΔG = ΔG°´ + RT lnQ

where Q =[Products]/[Reactants]

Question 19

Endergonic or Exergonic?

Large Kc
negative ΔG prime

Answer 19

Exergonic

Question 20

Endergonic or Exergonic?

Small Kc
Positive ΔG prime

Answer 20

Endergonic

Question 21

Delta G is dependent on two parts

What are they?

Answer 21

A constant term whose value depends only on the reaction taking place
A variable term that depends on the concentration of the reactants and products

Question 22

If Delta G is negative equilibrium lies in favour of the ….?

Answer 22

Lies in favour of the products

Question 23

If Delta G is positive, equilibrium lies in favour of the……?

Answer 23

Lies in favour of the reactants

Question 24

If the Delta G is large and negative what does this mean for the reaction?

Answer 24

The reaction is irreversible

Question 25

If delta G is large and positive what does this mean for the reaction?

Answer 25

Reaction will not proceed

Question 26

In reactions with multiple steps what is the relationship between the delta Gs

Answer 26

Delta G are additive

Question 27

What are the two forms of the enzyme for glucose?

Answer 27

Glucokinase and hexokinase

Question 28

Are metabolic pathways reversible?

Answer 28

No its irreversible

Question 29

Describe feedback inhibition

Answer 29

The product of a late or last step frequently acts as an inhibitor of the first committed step. Hence, end product controls its own synthesis. All metabolic pathways are regulated.

Question 30

Each metabolic pathways have a first committed step

Answer 30

xx

Question 31

There are 2 forms of glucose- what are they?

Answer 31

D-glucose can be alpha or beta

It can also be cyclic or branched.
The branched version is CHO-ChOH-COHH-CHOH-CH2OH

The 2nd OH is on the left the rest are on the right