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Structure + Function 1 > Cells alive 2- mitochondria > Flashcards

Cells alive 2- mitochondria Flashcards

1
Q

describe the structure of mitochondria

A
  • oragnelles bound by a double membrane
  • outer membrane
  • inner membrane forms invaginations called cristae
  • space between membranes is intermembrane space
  • inside of mitochondrion is mitochondrial matrix
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2
Q

what are the functions of mitochondria

A
  • generates most of the energy a cell requires
  • Most nutrients delivered to cell are broken down in cytoplasm to simple constituents which are transported to the mitochondria
  • Constituents are further oxidised producing CO2 and H2O which releases energy as ATP
  • Mitochondria often located close to sites of high ATP utilisation
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3
Q

adenosine triphosphate (ATP) energy release is by hydrolysis of what bonds?

A

phosphoanhydride bonds

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4
Q

Which stages of aerobic respiration occur in the cell cystoplasm?

A

Glycolysis

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5
Q

Which stages of aerobic respiration occur in the mitochondria?

A

Link reaction

TCA/Krebs cycle

Oxidative phosphorylation

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6
Q

Describe the metabolism of fatty acids

A

B oxidation

can be in peroxisome also

2 C removed from hydrocarbon tail at a time
- used to produce acetyl-coA

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7
Q

how is glucose converted to pyruvate?

A

glycolysis

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8
Q

How and where is pyruvate converted into acetyl coA?

A
  • Link reaction -in mitochondria
  • Decarboxylated
    *remove a C = CO2

Leaves acetate
*2 C molecule

Actetate combines with coenzyme A = acetyl- CoA

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9
Q

How are amino acids used in aerobic respiration?

A
  • Deamination
    *removal of amino group
  • Leaves a carbon skeleton
  • can enter at different points depending on the amino acid it was
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10
Q

What does acetyl coA feed into?

A

TCA/Krebs/Citric acid cycle

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11
Q

what are the end products of acetyl- CoA oxidation ( Krebs) and how many

A

3 x NADH
1 x FADH2

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12
Q

what is produced as waste from acetyl-CoA oxidation (Krebs) and how many

A

2 x CO2

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13
Q

What are NADH and FADH2 needed for?

A

Carrying electrons to be used in the electron transport chain

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14
Q

What is oxygen’s role in aerobic respiration?

A

Final electron acceptor in oxidative phosphorylation, it is reduced to H2O

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15
Q

Describe the movement of electrons in the ETC

A

Move from areas of low affinity to high

3 protein complexes in the mitochondria inner membrane

Each has higher affinity for electron than the previous

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16
Q

Energy released from the movement of electrons in the ETC causes what?

A

H+ to be pumped from matrix to intermembranal space

Creates an electrochemical gradient across the inner membrane

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17
Q

How does ATP synthase generate ATP in oxidative phosphorylation?

A

Uses energy from H+ diffusing back into matrix

chemiosmosis - H flow down electrochemical gradient

H+ rotates transmembranous rotor domain stalk attached to ATP synthase

Enzymatic head held still by arm attached to membrane

Mechanical energy generated as stalk grinds against head

Mechanical converted to chemical

ADP + PI -> ATP

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18
Q

Theoretically how many ATP are made in aerobic respiration?

how many are actually produced?

A

36 -38

glycolysis 2
krebs 2
oxidative phosphorylation - 34

30-32

Some are used for active transport within the mitochondria

19
Q

How many ATP made per:

NADH

FADH2

A

NADH - 3

FADH2 - 2

20
Q

Describe transport in and out of the mitochondria’s outermembrane

A
  • Has porins that are permeable to molecules less that 5kDa
  • gases oxygen and carbon dioxide freely diffuse across the membranes down their concentration gradients- no energy or transporters needed
21
Q

Describe transport in and out of the mitochondria’s innermembrane

A
  • electrochemical gradient
  • pyruvate and inorganic phosphate transport driven by H+ gradient, they are co-transported in the same direction- SYMPORTER
  • ATP and ADP are co-transported in opposite directions using charge gradient- ANTIPORTER
22
Q

Where are most mitochondrial proteins encoded and produced?

How do they get to the mitochondria?

A

Encoded - nucleus

Produced - cytosolic ribosomes

Transported by hsp70 chaperones across cytosol to nucleus

23
Q

Importance of chaperones?

A

Keeps mitochondrial protein unfolded

N terminal signal peptides target them to mitochondria

24
Q

When does transport of mitochondrial proteins occur?

A

After translation

25
Q

What mediates the passage into the mitochondria?

A

Translocases of inner+ outer membranes
(TOM - translocases of the outer)
( TIM - translocases inner mitochondrial )

26
Q

Are mitochondria maternally or paternally inherited?

A

Maternally

27
Q

Role of mitochondria in apoptosis?

A

Release cyctochrome C from intermembrane space to trigger apoptosis

28
Q

pH of intermembrane space

A

7

29
Q

pH of matrix space

A

8

30
Q

Describe mitochondrial DNA

A

Mitochondria have own genome

Circular

Vary in size and number of genes encoded

Translation and transcription of genes occurs in matrix

31
Q

With dogs, mitochondrial DNA can be used to..

A

Determine breed origin

32
Q

What is endosymbiosis?

A

Theory that mitochondria were once independent entities

At one point in time became associated with eukaryotic cells

33
Q

Evidence of endosymbiosis?

A

Grow and divide by fission

Own genome

Own translation and transcription processes

have own DNA and ribosomes

34
Q

Mitochondria can act as stores of what mineral?

A

Calcium

35
Q

2 things mitochondria help to synthesis (other than ATP)

A

Haeme

Steroids

36
Q

What do mitochondria in hepatocytes contain?

A

Enzymes to detoxify NH3

37
Q

Examples of TCA inhibitors?

A

Arsenite
- inhibit pyruvate dehydrogenase

2-fluorocitrate
- irreversibly inhibits aconitase, used in 2nd step TCA

38
Q

How do rotenone and cyanide inhibit oxidative phosphorylation?

A

Block electron transfer

Rotenone binds to complex I

Cyanide binds to Fe of complex IV

39
Q

How does Bongkrekic acid affect mitochondria?

A

Inhibits the transporter bringing ADP into the mitochondria and ATP out

40
Q

How does 2,4 DNPH affect mitochondria?

A

Uncoupling agent

Uncouples electron transport from ATP synthesis

weak acid +lipid soluble

sits in the H+ carrier in the inner membrane

dissipates the electrochemical gradient

41
Q

Where does FADH2 donate its electrons first?

A

complex II

42
Q

Where does NADH donate its electrons first?

A

complex I

43
Q

What are mitochondrial respiratory complexes?

A

electron transport complexes that work together to harness energy

44
Q

Where are mitochondrial proteins synthesised?

A

cytoplasm
mitochondrial matrix

Structure + Function 1 (18 decks)

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