DNA and RNA Nucleotides: Components, Structures, and Nomenclature

What are the 3 components that can make up a nucleotide?

Nitrogenous base + sugar + phosphate(s)

What is a nitrogenous base by itself called?

A base, e.g. adenine, guanine, cytosine, thymine, or uracil.

What is a nucleoside?

Base + sugar

What is a nucleotide?

Base + sugar + phosphate(s)

Nucleoside vs. nucleotide

Nucleoside = base + sugar; Nucleotide = base + sugar + phosphate(s)

What does the prefix "deoxy-" tell you?

The sugar is deoxyribose rather than ribose.

What is a ribonucleotide?

A nucleotide containing ribose: base + ribose + phosphate(s).

What is a deoxyribonucleotide?

A nucleotide containing deoxyribose: base + deoxyribose + phosphate(s).

What type of nucleotides make up RNA?

Ribonucleotides

What type of nucleotides make up DNA?

Deoxyribonucleotides

Adenine vs. adenosine

Adenine = base only; Adenosine = adenine + ribose.

What is adenosine?

Adenine + ribose; it is a nucleoside.

What is cytidine?

Cytosine + ribose; it is a nucleoside.

What is uridine?

Uracil + ribose; it is a nucleoside.

What is deoxyuridine?

Uracil + deoxyribose; it is a deoxynucleoside.

What is thymidine?

Thymine + deoxyribose in the usual biological convention; it is a nucleoside found in DNA.

What does adding phosphate(s) to a nucleoside produce?

A nucleotide

What is AMP?

Adenosine monophosphate = adenine + ribose + 1 phosphate.

What is ATP?

Adenosine triphosphate = adenine + ribose + 3 phosphates; a ribonucleotide.

What is dATP?

Deoxyadenosine triphosphate = adenine + deoxyribose + 3 phosphates; a DNA nucleotide.

What does the "d" in dATP, dCTP, dGTP, and dTTP mean?

Deoxy-; the nucleotide contains deoxyribose.

What does "triphosphate" tell you about a nucleotide?

It has 3 phosphate groups.

What is the key structural difference between ribose and deoxyribose?

Ribose has a 2′-OH; deoxyribose has a 2′-H.

What is the key structural difference between deoxyribose and dideoxyribose?

Deoxyribose has a 3′-OH; dideoxyribose has a 3′-H.

What groups are at the 2′ and 3′ positions of ribose?

2′-OH and 3′-OH

What groups are at the 2′ and 3′ positions of deoxyribose?

2′-H and 3′-OH

What groups are at the 2′ and 3′ positions of dideoxyribose?

2′-H and 3′-H

What does "dideoxy-" mean?

Two OH groups found in ribose are replaced by H: the 2′-OH and 3′-OH.

What is a dideoxyribonucleotide (ddNTP)?

A nucleotide containing a dideoxyribose sugar, which lacks both the 2′-OH and 3′-OH.

Why does a dideoxyribonucleotide terminate DNA synthesis?

It lacks the 3′-OH needed to attach the next nucleotide.

Decode "dideoxycytidine triphosphate" (ddCTP).

Cytosine base + dideoxyribose sugar + 3 phosphates.

Decode "deoxyadenosine triphosphate" (dATP).

Adenine base + deoxyribose sugar + 3 phosphates.

What naming pattern should you use to decode DNA/RNA molecules?

Base + sugar = nucleoside; nucleoside + phosphate(s) = nucleotide.