PHYSIOLOGY - Aerobic and Anaerobic Metabolism

Question 1

What is the structure of mitochondrial DNA?

Answer 1

Circular double stranded DNA

Question 2

How many proteins are encoded by mitochondrial DNA?

Answer 2

37 proteins

Question 3

(T/F) Mitochondrial DNA are inherited from the paternal lineage

Answer 3

FALSE. Mitochondrial DNA are inherited from the maternal lineage

Question 4

What facilities particle transport across the mitochondrial membrane?

Answer 4

The outer mitochondrial membrane has porin proteins which allow for passive transport and translocator outer membrane (TOM) complexes which allow for active transport. Furthermore, the inner mitochondrial membrane has translocator inner membrane (TIM) complexes which also allow for active transport

Question 5

What is reflected by the number of mitochondria in a cell?

Answer 5

The number of mitochondria in a cell reflects the metabolic demand of the tissue

Question 6

How are mitochondria highly dynamic organelles?

Answer 6

Mitochondria can undergo cellular migration, fusion, fission and turnover depending on the metabolic demands of the cell

Question 7

What is the primary function of the mitochondria?

Answer 7

Production of ATP

Question 8

What is the net production of ATP per unit of glucose?

Answer 8

38 ATP per unit of glucose

Question 9

Where does glycolysis occur?

Answer 9

Cytosol

Question 10

Where does the citric acid cycle occur?

Answer 10

Mitochondria

Question 11

Briefly describe the process of glycolysis and the citric acid cycle

Answer 11

Glycolysis is the breakdown of glucose into pyruvate. Pyruvate is then converted into acetyl CoA which enters the citric acid cycle which produces both ATP and high energy electron donors (NADH and FADH2)

Question 12

Where does the electron transport chain occur?

Answer 12

Mitochondria

Question 13

Briefly describe the electron transport chain

Answer 13

Electrons from NADH and FADH2 enter the electron transport chain and are passed along the protein complexes. As the electrons move along, protons are pumped across the inner mitochondrial membrane, creating a proton gradient which stores potential energy. When the protons flow back through ATP synthase, the stored energy is released to drive the production of ATP

Question 14

What is the main benefit of anaerobic respiration?

Answer 14

Anaerobic respiration allows for quicker ATP production without the need for oxygen which is beneficial for short-duration intense exercise

Question 15

What are the three disadvantages of anaerobic respiration?

Answer 15

Lactic acid accumulation
Less efficient ATP production compared to aerobic respiration
Oxygen dept

Question 16

What is oxygen dept?

Answer 16

Following anaerobic respiration, the body must replenish the oxygen levels to break down the lactic acid that has accumulated in the blood and to restore normal metabolic function

Question 17

What causes type A lactic acidosis?

Answer 17

Lactic acidosis caused by tissue hypoperfusion

Question 18

List three possible causes of type A lactic acidosis

Answer 18

Hypovolaemia
Cardiac failure
Sepsis

Question 19

What causes type B lactic acidosis?

Answer 19

Lactic acidosis caused by cellular dysfunction and localised tissue hypoperfusion

Question 20

List three possible causes of type B lactic acidosis

Answer 20

Mitochondrial disease
Excessive exercise
High grain diet in ruminants

Question 21

Describe the process of non-shivering thermogenesis

Answer 21

Uncoupling protein 1 (UPC 1) found in the inner mitochondrial membrane of brown adipose tissue is activated and forms a preferential pathway for protons to cross the inner mitochondrial membrane and generate heat

Question 22

Why are pigs at such high risk of neonatal hypothermia?

Answer 22

Pigs lack a functional uncoupling protein 1 (UPC1) for non-shivering thermogenesis

Question 23

Which method is used by piglets for thermogenesis?

Answer 23

Uncoupling protein 3 (UPC 3) in skeletal muscle for muscle based thermogenesis

Question 24

What causes malignant hyperthermia is pigs?

Answer 24

Inherited Ryanodine mutation

Question 25

(T/F) Mitochondrial function increases with ageing

Answer 25

FALSE. Mitochondrial function decreases with ageing

Question 26

What is the role of reactive oxygen species in ageing?

Answer 26

Reactive oxygen species can cause damage to lipids, proteins and nucleic acids - these damages can accumulate and contribute to ageing

Question 27

What is fanconi syndrome?

Answer 27

Dysfunction of the proximal convoluted tubule causing malabsorption of electrolytes and nutrients

Question 28

What is the cause of fanconi syndrome?

Answer 28

Mutation in the gene encoding for enoyl-CoA

Question 29

What are the five clinical signs of fanconi syndrome?

Answer 29

Stunted growth
Diarrhoea
Hypokalaemia
Hyponatraemia
Hypochloraemia

Question 30

What is maple syrup urine disease?

Answer 30

Inherited aminoacidopathy (dysfunctional amino acid metabolism)

Question 31

What is the cause of maple syrup urine disease?

Answer 31

Dysfunction in the branch chain keto acid dehydrogenase (BCKDH) enzyme which breaks down branch-chain amino acids leading to an accumulation of leucine, valine and isoleucine

Question 32

What is the most distinctive clinical sign of maple syrup urine disease?

Answer 32

Urine has a sweet odour