Unit 3 Test Practice: Biochemistry

The three subatomic particles that make up atoms are...

• protons, neutrons, and isotopes.
• neutrons, isotopes, and electrons.
• positives, negatives, and neutrals.
• protons, neutrons, and electrons.

Label the part of the helium atom known as the nucleus.

• A
• B
• C
• D

Substances formed from atoms of two or more elements are called __.

• metals
• isotopes
• ions
• compounds

A map of eastern North America, showing the pH of rainfall in the various states, indicates that the pH of rain in New York State varies from 4.22 to 4.40. According to these figures, the most acidic rainfall in New York State has a pH of ______. Use the pH scale below to help you.

• 4.22
• 4.30
• 4.35
• 4.40

What type of bond connects one water molecule to another water molecule?

• covalent bond
• ionic bond
• hydrogen bond
• peptide bond

Which property of water causes the curved surface shown in the figure below (property of water that allows it to stick to other molecules)?

• pH
• cohesion
• adhesion
• heat capacity

What factor determines that an oxygen atom can form two covalent bonds while a carbon atom can form four?

• Elemental carbon is a solid, while elemental oxygen is a gas.
• An oxygen atom has eight protons, while carbon only has six.
• An oxygen atom has two valence electrons, while carbon has four valence electrons.
• Carbon has more abundant isotopes than oxygen.

Which elements do all macromolecules have in common?

• C, H, N
• H, O, P
• C, H, P
• C, H, O

Some macromolecules are formed from one or two _________ or small molecular fragments that repeat.

• Amino acid
• Monomer
• Polymer
• String

Which of the following is NOT a monomer?

• a glucose molecule
• an amino acid
• a nucleotide
• a polypeptide