Page 157 - Knowledge Organiser Yr8 24-25

Knowledge Base: Science 8.14 Variation Year 8
1. Chromosomes, Genes and DNA
1.1
Where is genetic information stored in eukaryotic cells?
Nucleus
1.2
What is DNA?
The chemical that your genetic material is made from
1.3
Give two features of DNA
DNA has a double helix shape and Is made up of 4 bases
1.4
What are chromosomes?
A coiled structure of DNA found in the nucleus of cells.
1.5
How many chromosomes in an adult human cell?
46
1.6
How many chromosomes in a human gamete
23
1.7
Why do gametes contain only half the genetic material
During fertilisation, half of each parents' genetic material is passed on
3. Genetic and Environmental Variation
3.1 What is variation? The difference between individuals of the same species
3.2
Identify two ways variation can occur
Inherited and Environmental
3.3
What is inherited variation?
Variation that is passed on from the parents to offspring, via genes during reproduction.
3.4
Give 3 examples of inherited variation
Eye colour, blood group, attached ear lobes.
3.5
What is environmental variation?
Variation that is the result of differences in the surroundings or what an individual does.
3.6
Give 3 examples of environmental variation
Tatoos, scars, language spoken.
3.7
Give 3 examples of variation because of both environmental and inherited variation
Height, weight, size of a plant
3.8
Explain one reason why variation is important
If all individuals of a species were genetically identical, they would be vulnerable to the same disease. A single disease could wipe out a species.
1.8 What is a gene? A small section of DNA that codes for a protein
1.9
Why are genes important?
They determine which traits are passed down from parent to child
2. Discovery of DNA
2.1
Who were the 4 key scientists involved in the discovery of DNA?
Watson, Crick, Wilkins and Franklin
2.2
When did work on the structure of DNA first begin?
1950s
2.3
What contribution did Rosalind Franklin make in the discovery of DNA?
She took the first photograph of the structure of DNA
2.4
What was controversial about the role of Wilkins in the discovery of DNA?
Wilkins gave Franklins photograph to Watson and Crick without permission
2.5
Which scientists received the Nobel prize for the discovery of DNA?
Wilkins, Watson and Crick
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