thymine and cytosine

guanine and cytosine

uracil and guanine

thymine and adenine

adenine and guanine

adenine ... guanine

thymine ... cytosine

thymine ... guanine

adenine ... cytosine

adenine ... thymine

a covalent bond joining nucleotides together to form a nucleic acid

a covalent bond joining simple sugars together to form a polypeptide

a covalent bond joining amino acids together to form a polypeptide

a hydrogen bond joining nucleotides together to form a nucleic acid

a hydrogen bond joining amino acids together to form a polypeptide

primary structure

secondary structure

quaternary structure

pentiary structure

tertiary structure

denaturing the protein

All of the listed responses are correct.

a change in salt concentrations or pH

heating the protein

treating the protein with a chemical that breaks hydrogen bonds

Denaturation breaks the covalent bonds that hold the protein in its three-dimensional shape. Without the proper shape, the protein cannot function.

Different amino acids are substituted into the sequence, so the protein's properties change.

Denaturation breaks the intramolecular bonds, such as hydrogen bonds and van der Waals interactions, that hold the protein in its three-dimensional shape. Without the proper shape, the protein cannot function.

Denaturation destroys the primary structure of the protein, and the protein breaks down to monomers.

The protein's pH changes, and the change causes the protein to lose its functionality.

primary structure

secondary structure

quaternary structure

tertiary structure

double helix

hydrophobic ... consist of units assembled by dehydration reactions

hydrophilic ... consist of units assembled by dehydration reactions

hydrophilic ... are easily hydrolyzed into their monomers

hydrophobic ... have no charges to which water molecules can adhere

hydrophobic ... dissolve easily in water

None of the listed responses is correct.

adding hydrogen atoms to the fatty acid hydrocarbon chains, thereby converting carbon-carbon double bonds to single bonds

adding hydrogen atoms to the single-bonded carbon atoms of the fatty acid hydrocarbon chains

removing hydrogen atoms and forming additional single bonds in the fatty acid hydrocarbon chains

removing hydrogen atoms and forming additional double bonds in the fatty acid hydrocarbon chains

lipids

carbohydrates

nucleic acids

amino acids

proteins