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Year 10
Edexcel
Higher

The structure of DNA

I can describe the structure of DNA.

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New
New
Year 10
Edexcel
Higher

The structure of DNA

I can describe the structure of DNA.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. DNA is a type of biological molecule called a nucleic acid.
  2. DNA is made of two strands, each a long polymer of nucleotides.
  3. DNA is a polymer of four different nucleotides (A, C, G and T).
  4. The two strands in DNA are wound together in a double helix shape.
  5. Making a physical, representational model of DNA.

Common misconception

DNA is living and not necessarily a chemical.

Discussing that DNA is a chemical molecule and showing how it is made up of smaller chemical groups, and then modelling this chemical structure.

Keywords

  • DNA - DNA is a nucleic acid polymer made up of four nucleotides, it contains the genetic code in all living organisms.

  • Nucleic acid - A nucleic acid is a polymer made up of nucleotides, an example is DNA.

  • Polymer - A polymer is a chemical made up of smaller repeating chemical groups.

  • Nucleotide - A nucleotide is a chemical group that make up the building blocks of DNA, the four types are coded A, T, C and G.

  • Double helix - A DNA molecule is made up of two nucleic acid chains that spiral around each other to form a double helix.

Make models with pupils in class or for homework and get them to peer evaluate each other's.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Video

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Starter quiz

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6 Questions

Q1.
The drawing shows a bacterial cell. Which structure (A, B or C) contains the genetic material?
An image in a quiz
A
B
Correct answer: C
Q2.
Which is the best definition of a gene?
A large chemical molecule made of smaller groups.
All the DNA of an organism.
Correct answer: A short section of DNA carrying the genetic code for a process or feature.
All the chromosomes in the nucleus.
Q3.
All organisms have similarities in their DNA. Put these examples in order, starting with the example of two things that have the most similar DNA.
1 - two brothers
2 - a granddaughter and her grandmother
3 - a human being and a chimpanzee
4 - a human being and a lion
5 - a human being and a banana
Q4.
What do scientists call the sections of DNA in a chromosome that lie between genes?
An image in a quiz
Correct Answer: non-coding, non-coding DNA, non coding, non coding DNA
Q5.
True or false? Only genes make up the genome of an organism.
true
Correct answer: false
Q6.
Which is the best explanation for why the genomes of humans and bananas have similarities?
Humans and bananas are very closely related.
Humans and bananas share many similar features.
Humans and bananas have no similar features.
Correct answer: Humans and bananas have common life processes.

Exit quiz

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6 Questions

Q1.
In plant and animal cells, the genome is stored in the ...
Correct Answer: nucleus, nucleus.
Q2.
DNA is a nucleic acid polymer. How many nucleic acid strands make up each DNA molecule?
one
Correct answer: two
four
eight
Q3.
Put these in size order, starting with the smallest.
1 - nucleotide
2 - nucleic acid
3 - DNA molecule
4 - nucleus
Q4.
The photograph shows a model of part of a DNA molecule. It is made from liquorice and jelly babies. What would improve the model?
An image in a quiz
Add more than four colours of jelly baby.
Add more than two liquorice sticks.
Correct answer: Twist the model to form a helix.
Bend the model into a square.
Q5.
Scientists often use models such as the DNA models you have studied. Why?
Models are exact copies of things such as DNA.
Models always contain a lot of details.
Models are always much larger than the things they represent.
Correct answer: Models help to explain things that are difficult to see or understand.
Q6.
Match the word to its meaning.
Correct Answer:DNA,a polymer made of four nucleotides, which make up the genetic code

a polymer made of four nucleotides, which make up the genetic code

Correct Answer:polymer,a chemical made from many smaller chemical groups

a chemical made from many smaller chemical groups

Correct Answer:nucleic acid,a polymer made up of nucleotides, an example is DNA

a polymer made up of nucleotides, an example is DNA

Correct Answer:nucleotide,the building blocks for nucleic acids and DNA

the building blocks for nucleic acids and DNA