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Page 1: DNA.  DNA


Page 2: DNA.  DNA



Page 3: DNA.  DNA

Animal Cell

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The difference between: DNA, Chromosomes and Genes.

DNA is a long continuous strand of genetic information.

Genes are segments of DNA which control the inheritance of specific characteristics/trait.

Chromosomes are long tightly coiled strands of condensed DNA and protein.A trick to help remember:

DNA is like a long piece of string.Genes are the knots in the string.Chromosomes are a big coilof knots.

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Another way to think of it

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How can 2 meters of genetic code fit into a

body cell? http://learn.genetics.utah.edu/content/begi


Who wants to be a volunteer!

If you were to uncoil a chromosome you would find over 2m of DNA.

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DNA to Chromosome


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What does DNA look like?

DNA is structured like a ladder that has been twisted. This twisted shape is called a double helix.

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What does DNA look like?DNA is made up of blocks called nucleotides.

Each nucleotide is made up of a phosphate, a sugar and a base.

The nucleotides are named after the bases that they are made of, Adenine, Thymine, Guanine, and Cytosine.

A always pairs with T.C always pairs with G.

A trick to help rememberAT the Cricket Ground. AT is a word. CG look similar.

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DNA game http://www.nobelprize.org/educational/medicine/dna_double_helix/

Type “Nobel Prize DNA game” into Google.

Click the first linkPlay the gamePeople with high

scores will win a prize!

The game will let you make mistakes, so remember...


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One step further Backbone (made of sugar and

phosphate the vertical part of the ladder)

Base pairs (the horizontal rungs)

made of AT – CG. Nucleotides the building blocks of

DNA are which consist of a phosphate, a sugar and a base.


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Check your knowledge challenge...

1) Where is DNA located?

2 )What is the difference between DNA a gene and a chromosome?

3 )Describe the structure of DNA.

4 )What is a nucleotide? How many are there? What are they named?

5 )Which base pairs match up?

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Mix and Match

B) Genetic material found in every

living cell. It is a chemical

compound that carries genes and it

is how we store genetic information

in our cells

A) Made of DNA and proteins coiled

tightly together.

D) Sections of DNA that control the inheritance of

certain characteristics. Ie- nose shape, ear lobe type, eye

colour, pea plant height or colour.

C) Variations of genes, ie blue eyes,

green eyes, tall, short.

1 -DNA

3 -Chromosom


2 - Genes

4 - Alleles

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Punnet square game

Revision of last lesson

Type punnet square game into Google

Select the fourth link


Remember A dominant trait is

always represented by a capital letter.

A recessive trait is represented by a small letter.

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Next lessonChromosomes!

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Chromosomes!Every living thing has

its own number of chromosomes in each body cell, normally occurring in matched pairs.

Every human cell, (whether located in your eyeball or your arm, your kidney or your blood) will have 23 chromosome pairs or 46 chromosomes in total.

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What do other animals have?Do larger

organisms have more chromosomes?

What organism has the largest number of chromosomes?

Species Number of chromosomes per cell

Kingfisher (bird)


Fruit fly






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Species Number of chromosomes per cell

Kingfisher (bird) 132

Elephant 56

Fruit fly 8

Human 46

Chimp 48

Dog 78

Snail 52

Organism with the leastAnt Myrmecia pilosula


Species Number of chromosomes per cell

Onion 16

Sugar cane 80

Wheat 42

Organism with the mostAdders Tongue Fern Ophioglossum reticulatum