AP Biology : Identify structure and purpose of carbohydrates, lipids, proteins, and nucleic acids

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #101 : Identify Structure And Purpose Of Carbohydrates, Lipids, Proteins, And Nucleic Acids

Which of the following was not present in large amounts in Earth's early atmosphere?

Possible Answers:

Carbon

Ammonia

Hydrogen 

Methane

Oxygen

Correct answer:

Oxygen

Explanation:

Earth's early atmosphere contained carbon,  (methane),  (ammonia), and , but no oxygen. 

Example Question #135 : Macromolecules

Which of the following is not true regarding RNA?

Possible Answers:

RNA contains uracil instead of thymine

RNA is single stranded

RNA is made by transcribing DNA

RNA nucleotides contain one ribose sugar

RNA nucleotides contain one deoxyribose sugar 

Correct answer:

RNA nucleotides contain one deoxyribose sugar 

Explanation:

RNA stands for ribonucleic acid, and each RNA nucleotide contains one phosphate, one nitrogenous base (either adenine, uracil, cytosine, or guanine), and one ribose sugar. RNA does not contain a deoxyribose sugar as seen in DNA.

Example Question #167 : Biochemical Concepts

A DNA sequence is read in the 5' to 3' direction, whats do these numbers refer to?

Possible Answers:

The location of the all the thymine bases

The linkages between the phosphate group and the sugar

The linkages between the sugar and the nitrogenous base

The linkages between the phosphate group and the nitrogenous base

The direction of the turn of the DNA helix

Correct answer:

The linkages between the phosphate group and the sugar

Explanation:

Nucleotides are linked together to form nucleic acids by bonds between the phosphate groups and ribose sugars. A phosphate group is bonded the 5' carbon of one ribose and the 3' carbon of the next ribose, leading to the 5' to 3 directionality of DNA.

Example Question #168 : Biochemical Concepts

What are the three parts of a nucleotide?

Possible Answers:

Afive-carbon sugar, a phosphate group, and a nitrogenous base

A glycerol head and a fatty acid tail

A five-carbon sugar, a phosphate group, and a carbon-hydrogen chain

A glycerol/phosphate head and nitrogenous base

Correct answer:

Afive-carbon sugar, a phosphate group, and a nitrogenous base

Explanation:

A nucleotide is made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base.  Lipids consist of a glycerol and fatty acid chains

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