Practice quiz 2 chapter 2

All of the above: length of the phospholipid fatty acid chains. temperature. number of double bonds in the fatty acid chains.

Common factors affecting the fluidity of a membrane include

hydrogen

Complementary base pairs form .......... bonds to direct replication of DNA.

embedded nearly randomly in the lipid bilayer.

In the fluid mosaic model of biological membrane structure, transmembrane proteins are

amphipathic.

Molecules that are partly water-soluble and partly water-insoluble are

20

Proteins are polymers of how many different amino acids?

Arginine

Proteins can be covalently modified by the addition of phosphate groups to all but which of the following amino acids?

polar

Serine, threonine, asparagine, and glutamine are all .......... amino acids.

Frederick Sanger.

The scientist who first determined the complete amino acid sequence of a protein (insulin) was

oligosaccharide.

A few sugars joined together are called a(n)

decreasing membrane fluidity at high temperatures and increasing membrane fluidity at low temperatures.

Cholesterol affects the fluidity of membranes by

peptide

In the primary structure of a protein, amino acids are joined together by .......... bonds.

kink

Introducing a double bond into a fatty acid has the effect of putting a(n) .......... into the conformation of the molecule.

increase the fluidity of membranes.

Lipids with unsaturated fatty acids

All of the above: intracellular signal molecules. carriers of chemical energy. building blocks for nucleic acids.

Nucleotides have an important function in cells as

All of the above: regulator of gene expression. catalyst or enzyme. carrier of information from the nucleus to the cytoplasm.

RNA in cells can serve as a

serine

Sphingomyelin contains two hydrocarbon chains linked to

cholesterol.

Steroid hormones are derivatives of

X-ray crystallography.

The three-dimensional structure of a protein is analyzed most definitively by

proteins.

The unique properties of different membranes are primarily a function of their

All of the above: Ionic bonds Hydrophobic interactions H bonds

Which of the following are involved in forming the tertiary structure of proteins?

glutamine

Which of the following is not a basic amino acid?

Water

Which of the following is not one of the four major classes of organic molecules in the cell?

DNA can form hydrogen bonds with complementary sequences.

Which of the following is not one of the ways in which DNA differs from RNA?

Lipids

Which of the following store most chemical energy per unit weight?

part water-soluble and part water-insoluble.

An amphipathic molecule is

estradiol.

Cholesterol, a membrane lipid in animals, has a chemical structure similar to

triacylglycerols.

Fatty acids are stored in fat droplets in the form of

G pairs with C and A pairs with T.

In DNA,

glycosidic

In polysaccharides, sugars are linked together by means of .......... bonds.

All of the above: part of the cell signaling function. components of cell membranes. a form of energy storage.

Lipids play a major role in cells as

glycerol

Phospholipids consist of a 3-carbon core to which fatty acids and a phosphate group are linked. The most common 3-carbon core is

five

Sugars can cyclize if they contain .......... or more carbons.

quaternary

The interaction of the α and β subunits to form the hemoglobin molecule is an example of .......... structure.

α(1→4)

The major bonds in glycogen are .......... glycosidic bonds.

water

The most abundant molecules in cells are

Phospholipids

The most common molecules in cellular membranes are the

proteins

Transport across biological membranes is speeded by what class of biological molecules?

It increases permeability.

What is the effect of a beta barrel on the permeability of a membrane?

starch

What is the major carbohydrate-storage molecule in plants?