Biochemistry Quiz 1 (Class activity)

Which of the following is an incorrect statement regarding hydrogen bonds?

• Hydrogen bonds are weaker than covalent bonds

• Hydrogen bonds can occur in liquid ammonia

• Hydrogen bonds are responsible for the high boiling point of water

• Hydrogen bonds cannot form between molecules of the same type

Classically, covalent bonds are considered __________ bonds and hydrogen bonds are __________.

• intermolecular . . . intramolecular

• intramolecular . . . intermolecular

• intramolecular . . . intramolecular

• intermolecular . . . intermolecular

A student notes that a molecule forms hydrogen bonds that involve chlorine atoms. What can you conclude about this observation?

• This observation is valid

• This observation is invalid because chlorine is a halogen and cannot form hydrogen bonds

• This observation is invalid because chlorine cannot form hydrogen bonds due to its smaller electronegativity

• The observation is invalid because chlorine cannot form hydrogen bonds because it is a gas at room temperature

Grace is conducting an experiment to understand the properties of water. She learns that one water molecule can interact with other molecules through hydrogen bonds. What is the maximum number of hydrogen bonds that one water molecule can form?

• One

• Two

• Three

• Four

What is a chiral center?

• An atom with multiple isomers.

• An atom that has substituents which are unique.

• An atom with only one double bond, but other constituents are unique.

• An atom with substituents organized such that the molecule cannot be superimposed on its mirror image.

Which of the following statements about hydrophobic interactions is incorrect?

• Hydrophobic interactions are stronger in the presence of polar solvents.

• They play a crucial role in protein folding.

• Hydrophobic molecules tend to aggregate in aqueous solutions.

• These interactions can influence the structure of biological membranes.

What is the major driving force for the formation of a phospholipid bilayer?

• Nucleophilic attack

• Covalent interactions

• Hydrophobic interactions

• Hydrogen bond formation

While certain bonds within a polypeptide chain are able to rotate, the actual conformations found in nature are limited. What is a major factor limiting the available conformations?

• Steric clashes between backbones in a cis conformation.

• Steric clashes between side chains in a trans conformation.

• Steric clashes between side chains in a cis conformation.

• Steric clashes between hydrophobic and hydrophilic in a trans conformation.

What is the main blood buffer system?

What is the pOH of a 0.6 M solution of H2SO4?

• 13.78

• 12.78

• 11.28

• 16.58