Metabolism & Bioenergetics

Question 1

Which ONE of the following systems synthesises all of its molecules from CO2?

A) Chemotrophs
B) Autotrophs
C) Heterotrophs
D) Mammalian
E) None of the above

Answer 1

A) Chemotrophs

(Could also be B)

Question 2

If the ΔG0’ value of a biochemical reaction is 25 under standard conditions the reaction:

A) Is at equilibrium
B) Is endergonic
C) Proceeds in reverse
D) Is exergonic
E) Is inhibited

Answer 2

B) Is endergonic

∆G’0 is POSITIVE

Question 3

Catabolic pathways are which of the following?

A) Reductive and divergent
B) Oxidative and convergent
C) Oxidative and divergent
D) Reductive and convergent
E) Reductive and oxidative

Answer 3

B) Oxidative and convergent

Question 4

If the ΔG0’ of biochemical reaction 1 is +5 kJ/mol and a coupled reaction 2 has a ΔG0’ value of -8 kJ/mol, what is the overall ΔG0’ for this coupled reaction?

A) 13 kJ/mol
B) 3 kJ/mol
C) -3 kJ/mol
D) -13 kJ/mol
E) 10 kJ/mol

Answer 4

C) -3 kJ/mol

+5 kJ/mol + -8 kJ/mol = -3 kJ/mol

Question 5

Which one of the following values is the nearest approximation of the ΔG0’ value for ATP hydrolysis & energy transfer?

A) -300 kJ/mol
B) -31 kJ/mol
C) -13 kJ/mol
D) -3000 kJ/mol
E) -30,000 kJ/mol

Answer 5

B) -31 kJ/mol

Question 6

ATP consists of which of the following?

A) Guanine, 2 phosphates and a ribose
B) Adenine, 2 phosphates and a ribose
C) Adenine, 3 phosphates and a ribose
D) Cytosine, 3 phosphates and a ribose
E) None of the above

Answer 6

C) Adenine, 3 Phosphates and a Ribose

Question 7

ATP is hydrolysed at which of the following bond types?

A) Phosphoanhydride
B) Thiol
C) Carboxylic acid anhydride
D) Phosphodiester
E) Hydroxide

Answer 7

A) Phosphoanhydride

Bonds between Phosphate groups

Question 8

Which of the following components of NAD accepts a hydride ion?

A) The niacin ring
B) Adenine
C) The nicotinamide ring
D) Ribose
E) The dinucleotide

Answer 8

C) The nicotinamide ring

Question 9

What happens in the following reaction AH2 + B –> A + BH2

A) A is reduced and B is oxidised
B) A is oxidised and B is reduced
C) Electrons are added to A
D) Electrons are removed from B
E) None of the above

Answer 9

B) A is oxidised and B is reduced

Question 10

FAD is derived from which ONE of the following?

A) Vitamin E
B) Niacin
C) Nicotinamide
D) Acetyl-CoA
E) Riboflavin

Answer 10

E) Riboflavin

AKA. Vitamin B2

Question 11

What is cellular metabolism?

Answer 11

All the chemical activities that support life in all cells and organsims

Question 12

What is the source of energy for Chemotrophs?

Answer 12

Chemical

Question 13

What is the source of energy for Heterotrophs?

Answer 13

Organic compounds

Question 14

What is the source of energy for Phototrophs?

Answer 14

Sunlight

Question 15

What is the source of energy for Autotrophs?

Answer 15

CO2

Question 16

What is Catabolism?

Answer 16

Transforms fuel into energy from energy-containing nutrients

Question 17

Is Catabolism Oxidative or Reductive?

Answer 17

Oxidative

Question 18

Is Catabolism Convergent or Divergent?

Answer 18

Convergent

Question 19

What is Anabolism?

Answer 19

Uses energy to synthesise macromolecules from precursor molecules

Question 20

Is Anabolism Oxidative or Reductive?

Answer 20

Reductive

Question 21

Is Anabolism Convergent or Divergent?

Answer 21

Divergent

Question 22

What is the Metabolome?

Answer 22

All the metabolites in a cell or system

Question 23

What is Metabolomics?

Answer 23

Systemic characteristics of the metabolome, including under specific conditions

Question 24

What diseases have defective metabolism?

Answer 24

• Diabetes
• Cancer
• Neurodegeneration
• Heart Disease
• Infection
• Inflammation
• Immunological Dysfunction

Question 25

What is Bioenergetics?

Answer 25

Quantitive study of **energy transductions** in living cells / organisms / systems

Question 26

How are changes in energy measured in biological systems?

Answer 26

Gibb's Free Energy (∆G'0)

Question 27

What is an Exergonic reaction?

Answer 27

If ∆G'0 is **negative** the reaction CAN spontaneously occur

Question 28

What is an Endergonic reaction?

Answer 28

If ∆G'0 is **positive** the reaction CAN'T occur spontaneously

Question 29

What equation shows how the change in free energy (∆G'0) relates to the equilibrium constant (Keq) of a reaction?

Answer 29

∆G'0 = -RTlnK'eq

Question 30

Which direction does a reaction go if K'eq is > 1.0 and ∆G'0 is negative?

Answer 30

Forward

Question 31

Which direction does a reaction go if K'eq is 1.0 and ∆G'0 is zero?

Answer 31

At equilibrium

Question 32

Which direction does a reaction go if K'eq is < 1.0 and ∆G'0 is positive?

Answer 32

Reverse

Question 33

What are the units of ∆G'0?

Answer 33

kJ/mol

Question 34

Approx. how much energy is released by complete oxidation of Glucose?

Answer 34

~ 2840 kJ/mol

Question 35

Approx. how much energy is released by complete oxidation of Palmitate?

Answer 35

~ 9,770 kJ/mol

Question 36

Where in the cell is ATP synthesised?

Answer 36

Inner membrane of Mitochondria

Question 37

Why is ATP a high energy compound?

Answer 37

Strong negative charges between Phosphate groups that repel each other

Question 38

What is the synthesis of ATP in the presence of oxygen called?

Answer 38

Oxidative Phosphorylation

Question 39

What are some examples of life processes that ATP is essential for?

Answer 39

* Cell division * Biomolecule synthesis * Muscle contraction * Transcription * Translation * Cell signalling

Question 40

What is the major reaction type responsible for cell work?

Answer 40

Oxidation / Reduction

Question 41

What is the difference between Oxidation and Reduction?

Answer 41

Oxidation - loss of electrons Reduction - gain electrons

Question 42

What is EMF?

Answer 42

Electron Motive Force | The transfer of electrons

Question 43

Does EMF relate to ∆G'0?

Answer 43

∆G'0 directly relates to the number of electrons transferred in a metabolic reaction | ∆G'0 = -nF∆E0 n = number of electrons transferred

Question 44

How are electrons transferred in biological systems?

Answer 44

Through intermediate biomolecules called **Electron Carriers** to the final electron acceptor, O2

Question 45

What are the FOUR main ways that electrons are transferred in biological systems?

Answer 45

1. Directly 2. As hydrogen atoms 3. As hydride ions 4. By direct combination of organic reductants with O2

Question 46

Why are Dehydrogenase enzymes important?

Answer 46

They **remove hydrogen atoms** in oxidations in catabolism

Question 47

What does Alcohol Dehydrogenase do?

Answer 47

Oxidises ethanol from an alcohol to an aldehyde

Question 48

What are the names of the major electron carriers in the cell?

Answer 48

* NAD * NADP * FAD * FMN

Question 49

What are the components of NAD?

Answer 49

Nicotinamide Adenine Dinucleotide | Two nucleotides joined together through their phosphate groups

Question 50

What is NAD derived from?

Answer 50

Niacin | AKA. Vitamin B3

Question 51

Which metabolic pathway does NAD generally function in?

Answer 51

Catabolism

Question 52

Which metabolic pathway does NADP generally function in?

Answer 52

Anabolism

Question 53

What disease can lack of the NAD precursor cause?

Answer 53

Pellagra | Characterised by Dermatitis, Diarrhea, and Dementia

Question 54

How does NAD work to accept and donate electrons?

Answer 54

Works with dehydrogenase enzymes to carry electrons

Question 55

What is the difference between NAD and NADP?

Answer 55

NADP has an extra phosphate group

Question 56

What is the difference between FAD and FMN?

Answer 56

FAD contains **2 nucleotides** FMN contains **one nucleotide** | FAD - Flavin Adenine Dinucleotide FMN - Flavin Mononucleotide

Question 57

How does FAD / FMN work?

Answer 57

Isoalloxazine ring accepts 1 or 2 electrons to form hydrogen atoms