Q4. Mitochondrial fission is important for healthy mitochondrial function. Mitoc

Question

Q4.

Mitochondrial fission is important for healthy mitochondrial function. Mitochondrial fission allows for old, defective components from one mitochondrion to be replaced with new ones. Mitochondrial fission facilitates this replacement of old mitochondrial parts by isolating them in small membrane-bound vesicles that are then degraded by the cell.

What is the expected consequence for mitochondrial energy production in a pathological condition where mitochondrial fission is reduced?

Select ONE option:

A. The rate of mitochondrial replacement will increase and ATP levels will increase.

B. The rate of mitochondrial replacement will decrease and ATP levels will decrease.

Q5.

The figure below shows fission (division) of one mitochondrion into two mitochondria. For this process to occur, the mitochondrion has to grow to a certain size by synthesizing the necessary components to increase its volume.

Part 1. In order for a mitochondrion to divide, it must first make more membrane. What are the major components that need to be made by the mitochondrion during this first step?

(Select ALL that apply.)

A. Outer membrane lipids

B. ATP synthase

C. Inner membrane lipids

D. Mitochondrial DNA

E. Cardiolipin

F. Pyruvate

G. Drp1

Part 2: Where is this type of enzyme likely to be located in the mitochondria?

Select ONE option:

A. Matrix

B. Inner mitochondrial membrane

C. Intermembrane space

D. Outer mitochondrial membrane

Q6.

Porins are integral membrane proteins that serve as channels for water molecules to go through a lipid bilayer. An example of a porin is shown below. The grey spheres indicate the phosphate heads of the phospholipid bilayer in which the porin is embedded. The cyan spheres indicate water molecules.

Part 1. Identify the region (A, B, or C), where you would expect to find the hydrophobic tails of the phospholipid bilayer.

Select ONE option:

1. A

2. B

Part 2. Given the images above, the red regions of the protein are most likely to be ____________.

Select ONE option for the blank:

1. hydrophobic

2. hydrophilic

Q7.

Transport along a microtubule is especially important in delivering mitochondria from the cell body of a motor neuron to the end of an axon, where there is a high energy demand for neurotransmission. Miro is an adaptor protein that binds mitochondria to the motor proteins responsible for carrying mitochondria along microtubules.

Part 1. What symptom(s) would you expect to see in a patient carrying a deletion to the miro gene?

(Select ALL that apply.)

1. Difficulty walking because the sciatic nerve, which is the longest cell in the body, will be impaired.

2. Vision loss due to impairment of short retinal neurons.

3. Deficiencies in neurons across entire nervous system, regardless of size.

Part 2. Disrupting which of the following processes would result in similar symptoms?

(Select ALL that apply.)

1. Microtubule organization

2. Motor protein interaction with microtubules

3. Actin filament oligomerization

Q8.

Recall that the inside of a phospholipid bilayer is hydrophobic, such that hydrophilic molecules cannot readily diffuse through a cell membrane. Which of the following would require a protein channel to cross a cell membrane?

(Select ALL that apply.)

1. chloride ions (Cl-)

2. sugar molecules

3. oxygen (O2)

4. amino acids

Q9.

Part 2. What will happen to an ATP molecule bound to a beta subunit in the T (tight) conformation when the gamma subunit rotates and causes the beta subunit to adopt the O (open) conformation?

Select ONE option:

1. The ATP molecule will be released.

2. The ATP molecule will be broken down to ADP and inorganic phosphate. incorrect

3. Nothing happens to either molecule yet.

Q10.

A single ATP synthase is capable of generating about 30 ATP molecules for every 100 protons that flow through its F0 complex. If we isolated a mutant ATP synthase in which one of its three beta-subunits could not bind ADP, how many ATP molecules would this mutant be expected to generate for every 100 protons that flow through it?

Select ONE option:

1. 30 ATP molecules

2. 20 ATP molecules

3. 10 ATP molecules

4. 0 ATP molecules

Explanation / Answer

answer ro question 4: option B , simply because , when due to some pathological issue , mitochondrial fission is reduced ( given in question ) , so this will reduce the amount of replacment of old , defective mitochondrial components will also reduce , which will give reduced levels of ATP beacuse less working , perfect mitochondrias in the cell , less production of energy or ATP.

answer to question 5: PART 1 : A, C, E , these are the major components required for first step in mitochondrial fission , which are A - outer mitochondrial membrane lipids . B- inner mitochondrial membrane .lipids

E - cardiolipin ,( major componnet of inner mitochondrial membrane )

because in order to expand or make new membrane , the cell would require more inner and outer membrane lipds .

PART 2 : drp1( dynamin related protein 1) an enzyme which is usually located in cytosol and then move to the outer membrane ,for maturation .

so in oorder to select one option .- option d - outer membrane is correct.

answer to question 6: PART 1 option B is correct

because ,hydrophobic tails will be just vertically beneath the phosphate heads .( reagion B)

PART 2 :option B , the red beads are hydrophobic tails . because they are just below the phosphate headsarranged vertically .

answer to question 7 : PART 1 , option 1 and 2 are correct ,

option 1 , which is difficulty in walking , because the sciatic nerve ( longest in body is impaired , is correct beacuse when miro gene is deleted , there will be no transmission of signals properly through the axon of neuron .

option 2, which is , vision loss due to impairment of short retinal neurons is also correct because , when no atp will be present no more transmission of image signals from retina to brain , no more vision .

PART 2:   OPTION 1, 2 are correct because , if there will be no motor protein fusion with microtubules then no , transmission of signal through axons , to another neuron , and all such capabilities will be lost .

ANSWER TO QUESTION 8:   option 1, and option 2 are correct , tnhat is both chloride ions and sugar molecules ( such as glucose )pass through these special protein channels in the membrane , reason because chloride is not required all the time in the cell, so its entry and exit has to be regulated , and also because of the large size of choride ions , cant really diffuse , also because they carry a negitive charge on them .

sugar moleculs also pass through special transport proteins , not channels exactly , but cant diffuse simply through membrane .

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