Respiratory metabolism and ATP synthesis

Question 1

What is the main function of glycolysis?

Answer 1

To split glucose into two 3-carbon compounds, ultimately pryuvate

Question 2

Where does glycolysis occur in the cell?

Answer 2

In teh cytoplasm

Question 3

At which steps of glycolysis is ATP produced?

Answer 3

Steps 7 and 10

Question 4

Which step of glycolysis produces NADH?

Answer 4

Step 6

Question 5

What happens to NADH produced during glycolysis in aerobic metabolism?

Answer 5

It is fed into the respiratory chain

Question 6

What is produced per Acetyl CoA in the Krebs cycle?

Answer 6

3 NADH
1 FADH2
1 GTP

Question 7

Where does the citric acid cycle occur?

Answer 7

In the mitochondrial matrix

Question 8

What is the role of the Krebs cycle in metabolism?

Answer 8

It captures energu from carbohydrates, amino acids, and fats and liberates CO2

Question 9

Can metabolism be added or removed from the Krebs cycle?

Answer 9

Yes, for metabolic flexability

Question 10

What is special about the outer mitochondrial membrane?

Answer 10

It is permeable to small molecules and ions, but not proteins

Question 11

What do teh cristae of the inner membrane provide?

Answer 11

A large surface for electron transport chians and ATP synthase

Question 12

How many repiratory chain sets can a liver mitochondrion have?

Answer 12

Over 10,000

Question 13

How many genes are in the mitochondrial genome?

Answer 13

37 genes

Question 14

What do mitochondrial genes encode?

Answer 14

rRNAs
22 tRNAs
13 key respiratory chain subunits

Question 15

How many mitochondria are in a typical animal cell?

Answer 15

Hundreds to thousands

Question 16

What causes heterogeneity in daughter cells during division?

Answer 16

Unequal separation of mitochondria

Question 17

How many ETC proteins are encoded by mtDNA?

Answer 17

13 out of 100 proteins

Question 18

Whichc ETC complex is not encoded by both nuclear and mitochondrial DNA?

Answer 18

Complex II

Question 19

What mutation causes MERRF?

Answer 19

A8344G in mt-tRNA^Lys

Question 20

What are the symptoms of MERRF?

Answer 20

Myoclonus
Ataxia
Hearing loss
Muscle weakness
Seizures

Question 21

What mutation causes MELAS?

Answer 21

A3243G in mt-tRNA^Leu

Question 22

What are the symptoms of MELAS?

Answer 22

Stroke-like episodes
Hemiparesis
Vomiting
Headache
Proximal limb weakness

Question 23

What syndrome results from large heterolasmic mtDNA deletions in muscle?

Answer 23

Kearns-Sayre Syndrome (KSS

Question 24

Key feature of KSS?

Answer 24

Opthalmoplegia
Retinal degeneration
Heart block
Cerebellar ataxia

Question 25

What syndrome results from large deletions in all tissues?

Answer 25

Pearson Syndrome

Question 26

What are the symptoms of Pearson Syndrome?

Answer 26

Sideroblastic aneamia Neutropenia Macrocytic anaemia (fatal in infancy)

Question 27

Which genes are associated with autosomal dominant PEO?

Answer 27

POLG1 POLG2 PEO1 (Twinkle helicase)

Question 28

What us MDS and what are some causative genes?

Answer 28

Mitochondrail DNA depletion syndrome. Genes: POLG1, DGUOK, TK2, RRM2B, TP

Question 29

What dies a PUS1 mutation cause?

Answer 29

Myopthy and sideroblastic aneamia

Question 30

What does a DARS2 mutation cause?

Answer 30

Leukoencephalopathy

Question 31

What does an MRPS16 mutation cause?

Answer 31

Fatal neonatal lactic acidosis

Question 32

What does a TSFN mutation cause?

Answer 32

Hypertrophic cardiomyopathy

Question 33

What does DCA do?

Answer 33

Inhibits pyruvate dehydrogenase kinase --> activates PDC --> lowers blood lactate

Question 34

What does L-arginine treat and how?

Answer 34

MELAS: increases nitirc oxide to dilate vessals and reduce stroke-like episodes

Question 35

What is the role of Co-enzymes Q/ Idebenone?

Answer 35

Enhances electron flux Antioxidant protection Often used with Vitamin C

Question 36

What mitohcondrial defects con riboflavin treat>

Answer 36

Transporter defects and assembly defects in Complexes I and II

Question 37

What is mitochondrial replacement therapy (MRT)?

Answer 37

IVF method replacing mutated mtDNA with donor mtDNA