The Structure of DNA

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Slide 1

The Structure of DNA

Slide 2

DNA

DNA is often called the blueprint of life.

In simple terms, DNA contains the instructions for making proteins within the cell.

Slide 3

Watson & Crick’s Model

Slide 4

Why do we study DNA?

We study DNA for many reasons, e.g.,

its central importance to all life on Earth,

medical benefits such as cures for diseases,

better food crops.

Slide 5

Chromosomes and DNA

Our genes are on our chromosomes.

Chromosomes are made up of a chemical called DNA.

Slide 6

The Shape of the Molecule

DNA is a very long polymer.

The basic shape is like a twisted ladder or zipper.

This is called a double helix.

Slide 7

The Double Helix Molecule

The DNA double helix has two strands twisted together.

Slide 8

One Strand of DNA

The backbone of the molecule is alternating phosphates and deoxyribose sugar

The teeth are nitrogenous bases.

phosphate

deoxyribose

bases

Slide 9

Nucleotides

C

C

C

O

Phosphate

O

One deoxyribose together with its phosphate and base make a nucleotide.

Nitrogenous

base

Deoxyribose

ATP

Slide 10

One Strand of DNA

One strand of DNA is a polymer of nucleotides.

One strand of DNA has many millions of nucleotides.

nucleotide

Slide 11

Four nitrogenous bases

Cytosine C

Thymine T

Adenine A

Guanine G

DNA has four different bases:

Slide 12

Two Kinds of Bases in DNA

Pyrimidines are single ring bases.

Purines are double ring bases.

C

C

C

C

N

N

O

N

Slide 13

Thymine and Cytosine are pyrimidines

Thymine and cytosine each have one ring of carbon and nitrogen atoms.