Please help me, I am deeply confused in this class and trying so hard to underst

Question

Please help me, I am deeply confused in this class and trying so hard to understand. Please give detailed answers. I know some of these might be confusing but your help will really help me learn. The teacher requires very very detailed answers and he gives nearly no (and I mean literally nearly zero) partial credit so I'm dying here. Thank you sooooooo much, you have no idea.

Also, I am nearly leaglly blind and I am dyslexic so if you could please write clear it would help so much. I just want to learn like everyone else. SUPER SUPER THANK YOU

4. You are a member of an expedition to study bacteria X that is found living in Antarctica. In the middle of your studies of this bacteria, a colleague of yours discovers that the same species of bacteria living in the soil in Cambridge. To begin your investigation into the similarities and differences of these two bacterial populations, you decide to look at the composition of lipids in the plasma membrane of bacteria X for both samples derived from Antarctica and Cambridge. (5 pts total) a) What differences in composition do you expect to observe and why? [2 ptl You can use Activity 6.2 (www.Life11e.com/ac6.2) to help model this question. b) Why is it mpotant for cells to maintain membrane fluidity? [1 ptl c) You further observe that the membrane composition of this bacteria X that is found living in Cambridge is more similar to that of the inner membrane of the mitochondria within human cells than the outer membranes of the mitochondria. Why do you think this is the case? [1 ptl d) Moreover, why might mitochondria and other organelles maintain different lipid membrane compositions compared to one another and compared to the plasma membrane? [1 pt]

Explanation / Answer

(a) When the composition of the plasma membrane was investigate, it was observed that the bacteria residing in Antarctica displayed greater proportion of unsaturated fatty acids w.r.t. the bacteria of the same species residing in Cambridge.

this is due to the fact that at low temperatures, the membrane fluidity declines. In order to counter and adapt to the extreme environmental conditions, alteration in the ratio of unsaturated to saturated fatty acids occurs to maintain membrane fluidity. The physical state of the membrane and fluidity directly regulates the activity of the membrane bound proteins and signal-transduction events which are vital for membrane functions.

(b) Membrane fluidity is defined as the viscosity in the lipid bilayer of the membrane which affects the rotation and diffusion of ions, proteins and other biomolecules and directly affects the functions of these. The fluidity and membrane deviations are involved in multiple vital cellular functions like cell growth, division, differentiation, solute transport as well as signal transduction. Slight alterations in fluidity may lead to abberations in the normal functioning of the cell.

(c)

(d) Cell membrane possess single lipid bilayer while the mitochondria has double layered lipid membrane, outer and inner membrane where the mitochondrial membarne is largley composed of phospholipids and cardiolipin. Not much differences in the lipid composition of the two membranes exists.

Alos, the outer mitochodrial membrane is freely permeable to small molecules and ions while the inner mitochondrial membrane is selectivley permeable.

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