Organic Chemistry : Biological Molecules

Study concepts, example questions & explanations for Organic Chemistry

varsity tutors app store varsity tutors android store

Example Questions

Example Question #5 : Help With Other Biological Molecules

By which characteristic do resonance structures of a molecule differ?

Possible Answers:

The position of the electrons

Rotation around sigma bonds

Molecular formula

Hybridization

Correct answer:

The position of the electrons

Explanation:

By definition, resonance structures are multiple Lewis structures that depict the same molecular compound. The only difference pertains to the way in which electrons are shared by atoms in the molecule. Molecules are weighted averages of their most stable resonance contributors.

Example Question #41 : Biological Molecules

Which of the atoms in the molecules below is/are sp2 hybridized?


Screen shot 2015 10 24 at 10.11.54 am

Possible Answers:

1, 3 and 5

1 and 5

2 and 4

1 and 4

3 only

Correct answer:

1, 3 and 5

Explanation:

The boron in 2 is sp3 hybridized because of its four  substituents and the carbon in 4 is sp hybridized because of its connection to only the nitrogen with a single .

Example Question #42 : Biological Molecules

Pinene

How many isoprene units does the given molecule, alpha-pinene, have?

Possible Answers:

None - it is not a terpene

Correct answer:

Explanation:

Alpha-pinene is a terpene, and is thus composed of isoprene units. A single isoprene unit has 5 carbon atoms. This molecule has 10 carbons, thus it contains 2 isoprene units.

Example Question #8 : Help With Other Biological Molecules

Cholic acid 3d

What class of biological molecule is the given compound? 

Possible Answers:

Fatty acid

Amino acid

Nucleic acid

Steroid

Carbohydrate

Correct answer:

Steroid

Explanation:

This is cholic acid, a steroid.  Steroids can be easily identified by their characteristic fused ring structures.

Learning Tools by Varsity Tutors