Biological Molecules
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Organic Chemistry › Biological Molecules
Which element is present in all organic compounds?
Carbon
Nitrogen
Oxygen
Phosphorous
Explanation
By definition, an organic compound is a compound that contains carbon. Organic chemistry is the study of carbon-containing molecules.
Which element is present in all organic compounds?
Carbon
Nitrogen
Oxygen
Phosphorous
Explanation
By definition, an organic compound is a compound that contains carbon. Organic chemistry is the study of carbon-containing molecules.
An unknown molecule was found to have a molecular formula of . This molecule can be identified as a .
None of these
fatty acid
steroid
triaclyglycerol
Explanation
This question is a little bit tricky. At first glance, we would jump to the conclusion that this molecule is a long hydrocarbon chain attached to a carboxylic acid and, therefore, a fatty acid. The premise is correct. However, our conclusion is false because, by convention, a fatty acid must contain a carbon chain of at least 12 carbons. The given formula does not match the description for a steroid or triacylglycerol. The correct answer is none of these.
Which of the atoms in the molecules below is/are sp 2 hybridized?

1, 3 and 5
3 only
1 and 4
1 and 5
2 and 4
Explanation
The boron in 2 is sp 3 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
.
What is the name of the following carbohydrate?

Alpha-D-galactopyranose
Alpha-L-galactopyranose
Beta-D-galactofuranose
Alpha-L-glucopyranose
Beta-D-galactofuranose
Explanation
Stereochemistry from second to fifth carbon is R, S, S, R, which indicates D-galactose. The Haworth structure is a six-membered ring, so the molecule is in its pyranose form. The molecule has its anomeric hydroxyl group pointing down, so it's the alpha anomer.
What is the name of the following carbohydrate?

Alpha-D-galactopyranose
Alpha-L-galactopyranose
Beta-D-galactofuranose
Alpha-L-glucopyranose
Beta-D-galactofuranose
Explanation
Stereochemistry from second to fifth carbon is R, S, S, R, which indicates D-galactose. The Haworth structure is a six-membered ring, so the molecule is in its pyranose form. The molecule has its anomeric hydroxyl group pointing down, so it's the alpha anomer.
Which of the atoms in the molecules below is/are sp 2 hybridized?

1, 3 and 5
3 only
1 and 4
1 and 5
2 and 4
Explanation
The boron in 2 is sp 3 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
.
An unknown molecule was found to have a molecular formula of . This molecule can be identified as a .
None of these
fatty acid
steroid
triaclyglycerol
Explanation
This question is a little bit tricky. At first glance, we would jump to the conclusion that this molecule is a long hydrocarbon chain attached to a carboxylic acid and, therefore, a fatty acid. The premise is correct. However, our conclusion is false because, by convention, a fatty acid must contain a carbon chain of at least 12 carbons. The given formula does not match the description for a steroid or triacylglycerol. The correct answer is none of these.

How many isoprene units does the given molecule, alpha-pinene, have?
None - it is not a terpene
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.
What is the name of the following molecule?

Alpha-D-glucofuranose
Beta-L-glucofuranose
Alpha-D-glucopyranose
Alpha-L-galactopyranose
Beta-D-galactofuranose
Explanation
Stereochemistry from second to fifth carbon is R, S, R, R, which indicates D-glucose. The Haworth structure is a five-membered ring, so the molecule is in its furanose form. The molecule has its anomeric hydroxyl group pointing down, so it's the alpha anomer.