Membrane structure and function

Front

Which of the following macromolecule types are NOT found in the cell membrane? Glycolipids, Polysaccharides, Proteins, Nucleic Acids

Back

Nucleic Acids

Front

Which of the following best describes the structure of the phospholipids in the plasma membrane? Options: Hydrophobic phosphate heads align in the center of a double layer; hydrophilic tails point out towards the aqueous interior and exterior., Phospholipids form a single layer with the hydrophilic heads pointing towards the exterior of the cell., Phospholipids form two layers. Hydrophilic phosphate heads point to the aqueous interior and exterior; hydrophobic tails point towards each other in the center., Phospholipids form a single layer with the hydrophobic tails pointing towards the exterior environment and the hydrophilic heads pointing towards the interior of the cell.

Back

Phospholipids form two layers. Hydrophilic phosphate heads point to the aqueous interior and exterior; hydrophobic tails point towards each other in the center.

Front

Certain membrane proteins connect the extracellular matrix to the internal cytoskeleton. Which of the following must be true about this type of protein?

Back

It must be an integral protein.

Front

Why do we describe the membrane as a “fluid mosaic”?

Back

The membrane is made out of phospholipids, proteins, cholesterol, and carbohydrates which all float fluidly around the membrane.

Front

The diagram below shows the trans-membrane portions of a membrane-bound protein. Which of the following could be said about parts A, B, and C of the protein?

Back

A and C are hydrophilic, B is hydrophobic.

Front

Which of the following play a role in providing stability and fluidity at BOTH warm and cold temperatures? Saturated fatty acids, Unsaturated fatty acids, Cholesterol, Glycoproteins

Back

Cholesterol

Front

How do larger substances like amino acids, sugars, and ions enter and leave the cell?

Back

They pass through the membrane barrier with the help of protein channels, transporters, and/or pumps.

Front

Which molecule helps Rina's immune system differentiate her own cells from microbes after cutting her finger? Options: Glycoproteins, Unsaturated fatty acids, Cholesterol, Receptor proteins

Back

Glycoproteins

Front

To which of the following would insulin need to bind to first to initiate the uptake of glucose by these cells?
Options: Directly to genes in the nucleus., Unsaturated fatty acids in membrane phospholipids., Cholesterol in the cytoplasm of the cell., Receptor proteins on the cell membrane.

Back

Receptor proteins on the cell membrane.

Front

Which of the following descriptions is most likely to be the structure of phospholipids in milk fat globules?
A single layer of phospholipids surrounds the globule of triglycerides with the heads pointed towards the water and tails to the lipid center,
Phospholipids form a bilayer with the heads in the middle and the tails pointed towards the fats on one side and the water on the other,
A single layer of phospholipids surrounds the globule of triglycerides with the head oriented to the lipid center and the tails towards the water.
Phospholipids form a bilayer with the heads pointed towards the water on the outside and the lipids in the middle.

Back

A single layer of phospholipids surrounds the globule of triglycerides with the heads pointed towards the water and tails to the lipid center.