Starter quiz
This image shows a model of ...- a bacterial cell.
- DNA ✓
- a mitochondrion.
- an enzyme.
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- Which of the following is the definition of a polymer?
- A single subunit that makes up a long repeating chain.
- A long chain of repeating subunits called monomers. ✓
- A type of cell division that produces genetically identical cells.
- Individual subunits that make up DNA.
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- Match each structure to its correct definition.
- Nucleus⇔Contains DNA and controls cell activities. ✓
- Chromosome⇔Made from coiled DNA; humans have 23 pairs in their nuclei. ✓
- DNA⇔A polymer with a double helix structure; carries the genetic material. ✓
- What happens during interphase in the cell cycle?
- The cell membrane and cytoplasm divide.
- The chromatids are pulled to either end of the cell.
- The DNA and sub-cellular structures are copied. ✓
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- Which type of cell division creates two genetically identical cells?
- meiosis
- mitosis ✓
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- Which term describes a cell with a membrane bound nucleus?
- 'eukaryotic' ✓
Exit quiz
- Which words describe the structure of DNA?
- monomer
- polymer ✓
- double helix ✓
- single strand
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- DNA is made from single repeating subunits called ...
- bases.
- nuclei.
- nucleotides. ✓
- phosphates.
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- Which of these statements about DNA are true?
- The base A always pairs with G.
- Nucleotides are inverted on one strand of DNA. ✓
- The base C always pairs with G. ✓
- The sugar phosphate backbone includes the base of a nucleotide.
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- What is complementary base pairing?
- DNA is made from repeating bases.
- DNA has a double helix structure.
- DNA unwinds during interphase.
- Bases only pair in a certain way; A-T and C-G. ✓
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- Which of the following statements about copying DNA are true?
- DNA is copied during mitosis.
- The double helix DNA unwinds before copying. ✓
- Each single strand acts as a template. ✓
- Four copies of the same double helix DNA are created.
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Use the diagram to match the letter to the correct part of the nucleotide.- A⇔phosphate ✓
- B⇔base ✓
- C⇔sugar ✓
Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- DNA is made of two strands, each a long polymer of nucleotides, wound together in a double helix shape.
- DNA is a polymer of four different nucleotides (A, C, G and T).
- Nucleotides in each strand of DNA pair up in a complementary way; A pairs with T, and C pairs with G.
- The DNA in chromosomes is unwound & copied during interphase, then the copies separate and the cell divides by mitosis.
- Complementary base pairing allows an exact copy of each ‘unzipped’ DNA strand to be made from free nucleotides.
Common misconception
Students may think that each strand of DNA is the same without recognising one strand is inverted.
The slides specifically mention the second strand is inverted and this is also reinforced using diagrams of inverted nucleotides wherever possible.
Keywords
Dna - A polymer with a double helix structure that carries the genetic information.
Mitosis - A type of cell division that produces genetically identical cells.
Nucleotides - Individual subunits that make up DNA.
Polymer - A long chain of repeating subunits.
Complementary base pairing - Bases form pairs with one other base: A pairs with T, and C pairs with G.
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