Lecture 17: The Genetic System of Mitochondria Flashcards

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1
Q

Mitochondria are dynamic and make up ___ % fo cytoplasmic volume. They are even often associated with microtubular cytoskeleton. They are able to move up and down the microtubules and interact directly with the ___ in a unique fasion

A

20%, ER

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2
Q

Mitochondria are much less dynamic in ___ cells

A
  • high energy cells
  • They are much mor fixed
  • they can pack tightly between myofibrils (cardiac muscle) and around the flagellum of sperm cells
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3
Q

evolution of mitochondria

A

from fermenting bacteria to photosynthesis- to cellular respiration

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4
Q

in the reducing atmosphere bacteria where fermenting bacteria but then when oxygen increased in the atmosphere bacteria split and formed the

A

cyanobacteria (which later became chloroplasts), and purple nonsulfur bacter such as alpha proteobacteria (which later became mitochondria)

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5
Q

Mitochonrial DNA is what shape

A

circular

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6
Q

do mitochondria still require protiens form the cytosol

A

yes

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7
Q

when healthy what is the shape of mitochonria

A

long and slender

(this makes sense because it increases the surface area nd thus increases the ability for electron transport)

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8
Q

What cytoplasmic proteins can aid in the process of mitochondrial fission

A

Dynamin-1 (not this does require GTP)

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9
Q

Does it take more energy to fuse the inner or outer membrane of mitochondria

A

It takes more to fuse the inner membrane

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10
Q

Fusion of mitochondria is often used in times of stress to save some mitochondria but explain hwo it can be used in times of healthy bacteria

A

fusion can occur to increase the surface area of Mitochondrion. Then if one spot is damaged it is fused out and mitophagy occurs. (thus both a fusion and fission event can occur in times of stress)

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11
Q

How many base pairs is human mitochondrial DNA

A

16,569bp

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12
Q

Are there DNA repair mechanisms in the mtDNA

A

no

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13
Q

what is largely coded for in the mtDNA

A

tRNA (20 transfer amino acids)

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14
Q

changes in mt tRNAs have been linked to over 200 disease states and often these mutations prevent

A

tRNA aminoacylation

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15
Q

Mitochondrial DNA is inherited by

A

maternal side

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16
Q

Accumulation of ROS-generated by the respiratory chain-can cause

A

mitochondrial DNA damage

17
Q

ROS increase with

A

age

18
Q

The _____ is particularly susceptible due to the high amount of “combustion”

A
  • brain (because it uses 20% of your glucose and O2)
19
Q

Parkinson’s disease is treated with

A

L-DOPA, agonists

20
Q

Parkinson’s disease is a result of loss of dopamine signaling in the midbrain due to the

A

diminishment of the substantia nigra this can also lead to memory loss and demntia associated with the progression of PD

21
Q

Give an example of a genetic correlation that is found in 15% of Parkinson’s disease patients

A

alpha-synuclein

22
Q

Parkinson’s disease pathology

A
  • Loss of dopaminergic neurons
  • formation of lewy bodies?
    • alpha-synuclein becomes insoluble and aggregates
      • similar to beta-amyloid in AD
    • seen early in olfactory bulb without symptoms
  • Neurofibrillary tangles and phospho-Tau
    • also similar to AD
    • usually seen when a person reaches stage of dementia
23
Q

Etiolgy of Parkinson’s disease and links to mitochondrial integrity

A
  • Familial PD is caused by mutations
    • genes identified by linkage analysis
    • autosomal recessive or dominant manner
  • Sporadic PD is more complex
    • both genetic susceptibility and environmental factors contribute
  • both genetic and envrionmental factors influence various mitochondrial aspects, such as bioenergetics, dynamis, transport, and quality control
24
Q

increasing Nampt as therapy for PD alters ___, ____, ____, and ____ levels in skeletal muscle of aged rats

A
  • SIRT1
  • SIRT6
  • NAD
  • NAMPT
  • (note that a glucose restriction increases Nampt mRNA)