1.2.1: Chromosomes
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Chromosome: a thread-like structure made of tightly coiled DNA (wrapped around proteins).
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Each chromosome carries a large number of genes (sections of DNA that code for proteins).
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Chromosomes occur in pairs (diploid = 2n) in body cells; humans have 23 pairs = 46 chromosomes.
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Gametes (sex cells): one chromosome from each pair (haploid = n); humans have 23 chromosomes in each gamete.
Common exam mistakes
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Say DNA or chromosomes — 'genetic information' is too vague and will not be credited.
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Chromosomes are made of DNA — DNA is not made of chromosomes.
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Stating that gametes have 46 chromosomes or body cells have 23 is a very common number error — body cells = 46, gametes = 23.