Test 2, 17. mitochondrial genetics

Question 1

What feature makes mitochondria dynamic?

Answer 1

1. mitochondria associate with microtubular cytoskeleton

2. also interact with ER and fuse with other organelles

Question 2

What changes when mitochondria are in high energy cells?

Answer 2

1. loss of dynamic; become more fixed

2. pack tightly between myofibrils and around sperm flagellum

Question 3

What is the path that mitochondria evolved from?

Answer 3

1. bacteria–> photosynthesis–> cellular respiration

2. also evolved to retain own DNA

Question 4

What is the major driving force for fission or fusion?

Answer 4

1. energy needs of the cell.

Question 5

What is fission?

Answer 5

1. division of the mitochondria

2. activated during times of high stress

Question 6

What is fusion?

Answer 6

1. joining together of mitochondria

2. helps maintain cell survival and helps fix damaged mitochondria.

Question 7

What is the protein required for the fission of the mitochondria?

Answer 7

1. dynamin-1

Question 8

What amount of GTP is required for fusion of mitochondria?

Answer 8

1. outer membrane requires a small amount of GTP

2. Inner membrane fusion requires higher amounts of GTP due to increased amount of transmembrane proteins

Question 9

What do most mitochondrial mutations affect?

Answer 9

1. tRNA aminoacylation

Question 10

What is the Mother’s curse?

Answer 10

1. accumulation of mitochondrial genomes that are harmful to men but can be neutral or beneficial to females

Question 11

What are the most common compounds that will damage the mitochondria and increase the rate of aging?

Answer 11

1. ROS. From the respiratory chain damages the mtDNA, which reduces the DNA replication and repair mechanisms.
2. ROS increase with age
3. most common in brain due to high amount of aerobic respiration

Question 12

What is parkinson’s disease?

Answer 12

1. progressive neurodegenerative disease that results in disrupted motor function
2. loss of dopaminergic signaling in the midbrain and this contributes to reduced information processing

Question 13

What is most likely to contribute to memory loss and dementia associated with the late stages of PD?

Answer 13

1. loss of dopamine signaling

Question 14

What are the effects of losing dopaminergic neurons, that forms lewy bodies?

Answer 14

1. alpha-synuclein which becomes insoluble aggregates

Question 15

Familial PD is caused from what?

Answer 15

• mutations associated with linkage analysis

- autosomal recessive or dominant

Question 16

How does sporadic PD differ from familial?

Answer 16

1. subject to genetic susceptibility and environmental factors
2. affect mitochondrial aspects such as bioenergetics, dynamics, transport and quality control

Question 17

What are proteins that can lead to mitochondrial cell damage or death?

Answer 17

1. rotenone
2. MPP+
3. 6-OHDA

Question 18

How do rotenone, MPP+, 6-OHDA cause damage to mitochondria?

Answer 18

1. inhibition of complex I.

2. this leads to formation of ONOO- which causes damage to DNA and cell death.