DNA

Science, Grade 6

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Table Of Contents: DNA

1. DNA Shape and Composition
Double-stranded DNA (deoxyribonucleic acid) has a twisted ladder-like shape called a double helix. Each DNA strand is composed of a series of nucleotides.
2. Parts of a Nucleotide
A nucleotide contains a sugar, phosphate, and nitrogen base—adenine (A), guanine(G), cytosine(C), or thymine(T).
3. Complementary Base Pairs
The nitrogen bases pair with each other, adenine with thymine and cytosine with guanine. These are called complementary base pairs.
4. Role of DNA in Replication
The sequence of these DNA nitrogen bases provides a code. The code serves as a template when DNA is copied in a process called replication.
5. Role of DNA in Transcription
In a similar process called transcription, the DNA code is used to make RNA (ribonucleic acid).