DNA Structure & The Double Helix

What is the shape of a DNA molecule?

A double helix.

What is a nucleotide?

A molecule containing a sugar, phosphate group and nitrogenous base.

What are the four DNA bases?

Adenine (A), thymine (T), cytosine (C) and guanine (G).

Which DNA base pairs with adenine?

Thymine.

Which DNA base pairs with thymine?

Adenine.

Which DNA base pairs with cytosine?

Guanine.

Which DNA base pairs with guanine?

Cytosine.

What is complementary base pairing?

The specific pairing of A with T and C with G.

What forms the backbone of DNA?

Alternating sugar and phosphate groups.

What holds complementary DNA bases together?

Hydrogen bonds.

How many strands make up a DNA molecule?

Two.

How are the two DNA strands arranged?

They are coiled around each other to form a double helix.

What is the role of the DNA base sequence?

It stores genetic information.

Why is complementary base pairing important?

It allows accurate copying of genetic information.

What is DNA replication?

The process of making a copy of DNA before cell division.

What happens to the DNA strands during replication?

They separate, allowing new complementary strands to form.

How are new DNA strands formed?

Complementary nucleotides pair with exposed bases on each original strand.

Why is DNA replication described as semi-conservative?

Each new DNA molecule contains one original strand and one newly synthesised strand.

What is a polymer?

A large molecule made from many repeating smaller units.

Why is DNA described as a polymer?

It is made from many nucleotide units joined together.