AP Biology Unit Two

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?

• The two strands of the double helix would separate.

• The pyrimidines would be separated from the deoxyribose sugars.

• All bases would be separated from the deoxyribose sugars.

• The phosphodiester linkages of the polynucleotide backbone would be broken.

Which of the following best describes the relationship between the atoms described in Figure 2.1?

• They are isotopes.

• They each contain 1 neutron.

• They are compounds.

• They are polymers.

• They contain 1 and 3 protons, respectively.

Tags

NGSS.MS-PS1-1

The reactivity of an atom arises from

• the sum of the potential energies of all the electron shells.

• the potential energy of the valence shell.

• the average distance of the outermost electron shell from the nucleus.

• the existence of unpaired electrons in the valence shell.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following statements correctly describes any chemical reaction that has reached equilibrium?

• The reaction is now irreversible.

• The rates of the forward and reverse reactions are equal.

• Both forward and reverse reactions have halted.

• The concentrations of products and reactants are equal.

Tags

NGSS.HS-PS1-6

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their

• number of molecules.

• number of atoms.

• volume

• mass

The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound.

• H₃S₂

• H₂S

• HS₂

• HS

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Choose the term that correctly describes the relationship between these two sugar molecules:

• cis-trans isomers

• enantiomers

• structural isomers

• isotopes

Which functional group is not present in this molecule?

• amino

• carboxyl

• hydroxyl

• sulfhydryl

Which chemical group is most likely to be responsible for an organic molecule behaving as a base?

• carbonyl

• amino

• phosphate

• hydroxyl

Which of the following categories includes all others in the list?

• carbohydrate

• polysaccharide

• disaccharide

• starch