Exam 2: 14A (incomplete) Flashcards

1
Q

What is chemiosmotic coupling?

A

Chemiosmotic coupling is the idea that the proton concentration gradient across the inner mitochondrial membrane, which is generated by the electron transport chain, is ultimately what drives ATP production via ATP synthase.

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2
Q

What drives ATP synthase?

A

The proton gradient between the intermembrane space and matrix in the mitochondria.

The electrochemical gradient in ETC:
High proton conc. in intermembrane space
Lower proton conc. in matrix

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3
Q

What makes up the phosphoanhydride bond of ATP?

A

ADP + Pi —> ATP

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4
Q

What generates the proton gradient in mitochondria?

A

The electron transport chain

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5
Q

How many protons does ATP synthase require to produce one ATP molecule?

A

3 H+ protons

(Proton translocation causes a rotation of the F0 subunit and the central shaft γ. Translocation of three protons fuels synthesis of one ATP.)

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6
Q

What organelle converts food into chemical energy known as ATP?

A

Mitochondria are the organelles that function as the powerhouse of the cell. They convert the chemical energy from the food into an energy in the form of ATP in which the cells can use in order to do its work.

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7
Q

What is the anatomy of the mitochondra?

A

Outer membrane: seperating intermembrane space and cytosol

Inner membrane: separating inter-membrane space and matrix

Cristae: invaginations of inner mitochondrial membrane

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8
Q

Mitochondria have to capacity to divide and fuse.

True
False

A

True, this is called fission.

(Mitochondria are dynamic organelles with the ability to fuse and divide (fission), forming constantly changing tubular networks in most eukaryotic cells. These mitochondrial dynamics, first observed over a hundred years ago are important for the health of the cell, and defects in dynamics lead to genetic disorders.)

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9
Q

How do mitochondrion travel?

A

along microtuble tracks,

(to increase efficiency mitochondria can move about to where it is most needed in the cell.)

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10
Q

Do mitochondria move unidirectionally or bidirectionally?

A

Among all the transported cargoes that had been described in the past, the mitochondrion appears to be the most frequently reported organelle that can be unidirectionally or bidirectionally transferred

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11
Q

Mitochondria interacts with late endosomes.

True
False

A

True, it is speculated that mitochondria and late endosomes interact to exchange lipids

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12
Q

Explain mitochondria’s movement in neurons.

A

Mitochondria is dynamic, and can move both directs on neuronal processesies

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13
Q

What determines a mitochondria’s ability to move long distances like in neurons.

A

Mitochondria can move long distances in highly polarized cells, like neurons.

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14
Q

Where can mitochondria be observed in fixed points of high energy demand?

A

skeletal or cardiac muscle cells (packed between myofibrils)
sperm cells (wrapped tightly around flagellum)

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15
Q

What is the highly dynamic relationship between mitochondria and the endoplasmic reticulum?

A

facilitation of lipids, and calcium exchange between membrane systems.

(occurs at sites of mitochondrial fission)

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16
Q

What if mitochondria did not exist in present-day animal cells?

A

Animal cells would have to generate all of their ATP through glycolysis.

17
Q

Where are membrane proteins of the electron transport chain located?

A

In the cristae of the mitochondria. (invaginations of the folded matrix)

18
Q

What is the crista junction?

A

where the crista membrane and the inner membranes join and forms a narrow membrane tube.

19
Q

What does cryo-electron tomography do?

A

allows you to create 3d images made up of multiple scans. (used to visualize cristae)

20
Q

What is the permeability of bacterial or mitochondrial outer membrane?

A

freely permeable to ions and to small molecules as large as 5000 daltons. Causes the intermembrane space to have a pH and ionic composition similar to the cytoplasm. Causing no electrochemical gradient across the outer membrane.

21
Q

What is mitochondrial fission?

A

pinching off networks of mitochondria to allow the transfer of gene products between other distinct mitochondria.

(Fission is needed to create new mitochondria, but it also contributes to quality control by enabling the removal of damaged mitochondria and can facilitate apoptosis during high levels of cellular stress.)

22
Q

What is mitochondrial fusion?

A

physically merging the outer and then inner membrane of two distinct mitochondria

23
Q

What are the steps of mitochondrial division?

A