Question

the cell membrane-practice problems
48.00 points possible | due friday 10/24/25 at 11:59 pm
0/2 points eame
the unsaturated lipid dha is an omega-3 fatty acid that is synthesized in your body or obtained from a diet containing
certain types of fish like salmon and tuna. dha is an important component of your cell membranes. recent research has
shown that, as you age, the levels of dha in your neuronal cell membranes decrease. even greater decreases have been
observed in patients with alzheimers disease, a neurodegenerative disorder that affects more than 6 million people in
the united states.
how do you predict the fluidity and permeability of neuronal cell membranes will change as dha levels decrease? select
all that apply.
fluidity will decrease because dha is an unsaturated fatty acid so its presence usually increases membrane
fluidity.
permeability will decrease because dha is an unsaturated fatty acid so its presence usually increases
membrane permeability.
fluidity will not change because dha is not a phospholipid and membrane fluidity is not affected by the
presence or absence of other types of lipids.
permeability will be altered but other changes in the membrane composition could compensate for the loss of
dha and help maintain neuronal cell function.

Explanation:

• Unsaturated fatty acids like DHA have double bonds which create "kinks" in their structure. This prevents them from packing tightly together, increasing membrane fluidity. So, if DHA levels decrease (less unsaturated fatty acid), membrane fluidity will decrease.
• Membrane permeability is related to fluidity. A less fluid membrane (more "stiff") can have altered permeability. Also, in biological systems, when one component (like DHA) changes, other membrane - component changes (e.g., changes in other lipids or proteins) can sometimes compensate to maintain function (like permeability - related functions for proper neuronal cell function).
• DHA is a lipid (a fatty acid), and membrane fluidity is affected by the types of lipids (saturated vs unsaturated) present. So the statement that fluidity will not change because DHA is not a phospholipid is incorrect.

Answer:

Fluidity will decrease because DHA is an unsaturated fatty acid so its presence usually increases membrane fluidity.
Permeability will be altered but other changes in the membrane composition could compensate for the loss of DHA and help maintain neuronal cell function.