Question

Which type of membrane protein is characterized by having a unique strand of sugar molecules attached to it?

receptor protein
cell recognition protein
channel protein
carrier protein

Which statement correctly describes why the phospholipids of the cell membrane arrange the way they do in a bilayer?


The nonpolar tails are repelled by water, so they position themselves in the middle of the bilayer. The polar heads are attracted to water, so they point outward.

The polar heads are attracted to water, so they position themselves in the middle of the bilayer. The nonpolar tails are repelled by water, so they point outward.

The polar heads are repelled by water, so they position themselves in the middle of the bilayer. The nonpolar tails are attracted to water, so they point outward.

The nonpolar tails are attracted to water, so they position themselves in the middle of the bilayer. The polar heads are repelled by water, so they point outward.

Determine if the following statement is true or false. If true, choose TRUE. If false, choose the rewording that is true.

As cell size increases, the surface area-to-volume ratio increases.

TRUE
As cell size decreases, the surface area-to-volume ratio increases.
As cell size decreases, the volume of the cell increases.
As cell size decreases, the surface area-to-volume ratio decreases.

Which characteristics correctly describe prokaryotic cells?

(Select all that apply.) THERE IS MORE THEN ONE CORRECT

have a nucleus
have membrane-bound organelles
have no nucleus
have no membrane-bound organelles

Answer 1

1. The answer is; cell recognition protein

These types of proteins are categorized as a glycoprotein because they are proteins with a carbohydrate molecule attached to it. These proteins tag the cell and help the immune system to identify them so the cells are recognized and not destroyed.

2. The answer is; The nonpolar tails are repelled by water, so they position themselves in the middle of the bilayer. The polar heads are attracted to water, so they point outward.

Water is a polar molecule hence dissolves charged molecule which it can form hydrogen bonds with. Non-polar/uncharged molecule tend to be ‘water-hating’ hence form clumps when put in water and do not dissolve. Amphipathic molecules such as phospholipids tend to form the bilipid layer with the polar heads on the outside interacting with water and the non-polar carbon chains sandwiched in between away from water.

3. As cell size increases, the surface area-to-volume ratio increases is FALSE.

As cell size decreases, the surface area-to-volume ratio increases is TRUE

As cell size decreases, the volume of the cell increases is FALSE

As cell size decreases, the volume of the cell decrease is TRUE

As cell size decreases, the surface area-to-volume ratio decreases is FALSE

As cell size decreases, the surface area-to-volume ratio increases is TRUE.

4. The answer is; have no nucleus

have no membrane-bound organelles

Prokaryotes DNA is not surrounded by a nucleus membrane hence their DNA is not secluded from the cytoplasm as that of the eukaryotes. In addition, they lack membrane-bound organelles because they are primitive organisms. It is also significant to note that the membrane-bound organelles in eukaryotes were once-living prokaryotes organisms.