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Flashcards in Mitochondria Deck (24)
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1
Q

Describe the structure of mitochondria

A
  • Double membrane (inner/outer)
  • Intermembranal space separating 2 membranes
  • Matrix: inner lumen
  • Contains membrane bound proteins
  • Cristae: inner membrane folds
2
Q

Give examples of physical stimuli that can cause morphological changes within mitochondria

A
  • apoptosis
  • Ca2+ transfer
  • Cell cycle
  • Nutrient saturation
3
Q

What is the advantage of having cristae in the mitochondria?

A

Increases the surface area of membrane so more proteins are available for oxidative phosphorylation to occur
More ATP produced faster

4
Q

What are co factors?

A

Molecules that associate with proteins/enzyme to aid their function

5
Q

Where are proteins found in the mitochondria synthesised?

A

In the cytoplasm and transported to the mitochondria

6
Q

Which other structure is closely associated with mitochondria?

A

Mitochondria associate strongly with microtubules allowing them to change shape regularly

7
Q

How is mtDNA inherited?

A

Genes are inherited cytoplasmically from the mother to offspring via the egg cell

8
Q

How can we view the 3D structure of mitochondria ?

A

Via tomograms

9
Q

What processes occur in order to generate of ATP

A

e- transport chain
oxidative phosphorylation
citric acid cycle

10
Q

What causes mitochondrial morphology to change?

A

Mitochondria changes shape in response to physical stimuli

11
Q

What are the functions of mitochondria?

A
  • Breakdown of fatty acids -> acetyl CoA
  • Decarboxylation of pyruvate -> acetyl CoA
  • Citric Acid Cycle (in matrix)
  • Oxidative Phosphorylation
  • Thermogenesis
  • Apoptosis
12
Q

What is significant about the mitochondrial genome?

A

Mitochondria have a small genome subset that are encoded for and synthesised in the mitochondrial matrix
- differs from nuclear genome

13
Q

What is Beriberi disease?

A

Neurological & cardiovascular disease

Caused by a Vit. B1 deficiency (thiamine)

14
Q

How are peroxisomes formed from the ER?

A
  1. Vesicles form off ER membrane
  2. Vesicles grow via uptake of peroxisomal proteins and lipids from cytosol
  3. fission occurs
  4. Contain peroxisomal targeting signal which binds to receptors enabling transport to peroxisome
15
Q

What induces mitochondrial tubulation?

A

Starvation causes mitochondria to elongate and fuse with each other to prevent getting degraded through the autophagy pathway

16
Q

Which cells in the body are mitochondria commonly found in?

A

Muscle cells or sites of high ATP utilisation

17
Q

Describe the structure of peroxisomes

A
  • single membrane
  • crystalline structure
  • catalase enzymes present
  • contains no DNA or ribosomes
  • ~0.2-1um in diameter
18
Q

Where are mitochondrial proteins encoded for?

A

In the nucleus

19
Q

What symptoms do patients suffering with Beriberi display?

A
  • Pain in limbs
  • Muscular weakness
  • Distorted skin sensation
  • Enlarged heart
20
Q

What are the precursors of peroxisomes?

A

The endoplasmic reticulum

21
Q

What does mtDNA encode?

A

mtDNA contains 16,569 bp encoding for

  • 2 rRNAs
  • 22 tRNAs
  • 50 proteins
22
Q

Why does a thymine deficiency cause disease?

A

Thiamine is a prosthetic group for enzymes involved in citric acid cycle
Deficiency causes higher serum levels of substrates below
1. pyruvate dehydrogenase
2. α-ketogluterate dehydrogenase

23
Q

What are the functions of peroxisomes?

A
  • cholesterol and phospholipid production
  • Hydrogen peroxide production and catalysis to H2O
  • Excess AMP & GMP purines hydrolysed to Uric acid
  • Fatty acid oxidation
24
Q

How are mitochondria thought to have come about?

A

Through the process of endosymbiosis