The fluid-mosaic model of membrane structure includes the following: A Option A: a lipid bilayer. B Option B: membrane proteins. C Option C: mobile components that can engage in transient or semi permanent interactions. D Option D: all of the choices are correct.

Option D

Explanation:

In 1972, the fluid mosaic model was proposed by S. J. Singer and G. L. Nicolson to describe the structure of the plasma membrane found I living cells. The model describes the plasma membrane to possess components including phospholipid, proteins and cholesterol.

The phospholipid is arranged in two layers comprising of glycerol, two fatty acids and a phosphate group. The fatty acids which forms the tail are hydrophobic (water-fearing) while the phosphate group is water-loving (hydrophobic) giving the plasma membrane an AMPHIPATHIC nature. The other component as proposed by the model are membrane proteins and cholesterol, all responsible for the fluidity of the membrane.

amber has allowed scientists to study dna that has been preserved over millions of years.

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.