A.1.2.6 DNA Structure and Composition

Front

What are the components of DNA?

Back

DNA is composed of strands or polymers of nucleotides. Each nucleotide contains a pentose sugar (deoxyribose) and bases (adenine, cytosine, guanine, and thymine).

Front

What is the structure of a DNA molecule?

Back

A DNA molecule consists of two strands of nucleotides linked by their bases through hydrogen bonds, forming a double helix.

Front

What is complementary base pairing in DNA?

Back

Adenine (A) forms hydrogen bonds with thymine (T), and guanine (G) forms hydrogen bonds with cytosine (C), resulting in complementary base pairing.

Front

What does it mean for DNA strands to be antiparallel?

Back

The two strands of nucleotides run in opposite directions, with one ending in a phosphate group and the other in a deoxyribose, allowing base pairing.

Front

What is the role of hydrogen bonds in the structure of DNA?

Back

Hydrogen bonds between complementary bases (A-T and G-C) hold the two DNA strands together, stabilizing the double helix structure.

Front

How does DNA replication ensure accuracy?

Back

DNA replication is highly accurate due to the proofreading ability of DNA polymerases, which correct errors by removing mismatched nucleotides.

Front

What is the significance of the 5' and 3' ends in DNA?

Back

The 5' and 3' ends refer to the directionality of the DNA strand, with the 5' end having a phosphate group and the 3' end having a hydroxyl group, crucial for DNA replication and transcription.

Front

What is the function of DNA polymerase in DNA replication?

Back

DNA polymerase synthesizes new DNA strands by adding nucleotides complementary to the template strand, and it also has proofreading abilities to ensure replication accuracy.

Front

What is the role of the enzyme helicase in DNA replication?

Back

Helicase unwinds the DNA double helix, separating the two strands to allow each to be copied during replication.

Front

What is a replication fork in DNA replication?

Back

A replication fork is the area where the DNA double helix is unwound to allow replication of each strand, forming a Y-shaped structure.