Answer:
c. a high percentage of very long chain saturated fatty acids
Explanation:
Saturated fatty acids do not have double bonds (they are saturated with hydrogens), so their tails are relatively straight. Unsaturated fatty acids, on the other hand, contain one or more double bonds, which often produces an elbow or bend. (You can see an example of an unsaturated bent tail in the phospholipid structure diagram that appears at the beginning of this article.) Saturated and unsaturated phospholipid fatty acid tails behave differently when the temperature drops:
- At colder temperatures, the straight tails of saturated fatty acids can be tightly bound, producing a dense and quite rigid membrane.
- Phospholipids with unsaturated fatty acid tails cannot bind so closely due to the bent structure of their tails. For this reason, an unsaturated phospholipid membrane remains fluid at lower temperatures than a saturated phospholipid membrane.
Most cell membranes contain a mixture of phospholipids, some with two saturated (straight) tails and others with a saturated tail and an unsaturated (folded) tail. <u>Many organisms — fish, for example — can adapt physiologically to cold environments by changing the proportion of unsaturated fatty acids in their membranes, that is, increasing the proportion of saturated long-chain fatty acids.</u>
In addition to phospholipids, animals have an additional component in their membrane that helps them maintain fluidity. Cholesterol, another type of lipid that is embedded between the membrane phospholipids, helps decrease the effects of temperature on fluidity.
Answer:
In relation to voltage-gated ion channels, when depolarization occurs, Na⁺ gates open while K⁺ gates remain closed.
Explanation:
Depolarization is a phenomenon that occurs in cells like neurons, and depends on the distribution of ions in extracellular spaces and intraceluar.
-
Na⁺ is a predominantly extracellular cation.
- K⁺ has a high intracellular concentration.
This distribution occurs when the membrane potential is at rest, with a negative intracellular value.
Depolarization involves opening the Na⁺ channels, so that this cation enters the intracellular space, causing a change in cell voltage. Increasing Na⁺ concentration in intracellular space progressively produces an action potential, resulting in an electrical signal.
While depolarization occurs, K⁺ channels remain closed, limiting the output of this cation to extracellular space, which would prevent the action potential from occurring.
Learn more:
brainly.com/question/4661368
The answer is all of the above. Efferent nerves carry impulses away from the central nervous system, while Afferent nerves carry impulses towards the central nervous system. I hope this helps! :)
Answer:
it turns blue
Explanation:
I learned it from Esther 2.0
