Contents
Key Stage 3
Meaning
Chromosomes are coils of DNA found in the nucleus.
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| This diagram shows how DNA is coiled up to make a chromosome. |
About Human Chromosomes
- Humans have 46 chromosomes.
- Chromosomes come in pairs, one from the father and one from the mother.
- 23 chromosomes are from the father and 23 chromosomes are from the mother.
- The last 2 chromosomes are called sex chromosomes and they determine if the offspring is male or female. If the human has two X Chromosomes then they are female. If the human has an X and a Y Chromosome they are male.
Key Stage 4
Meaning
A chromosome is a section of DNA that has coiled together.
About Chromosomes
- Chromosomes are found in pairs in diploid cells.
- In organisms which engage in sexual reproduction one of the chromosomes in the pair is inherited from the mother and the other from the father.
- During mitosis chromosomes have made copies of themselves that are joined by a centromere.
- In haploid cells there are half the number of chromosomes. These cells are gametes used in sexual reproduction.
About Human Chromosomes
- Humans have 46 chromosomes.
- 23 chromosomes are from the father and 23 chromosomes are from the mother.
- The last 2 chromosomes are called sex chromosomes and they determine if the offspring is male or female. If the human has two X Chromosomes then they are female. If the human has an X and a Y Chromosome they are male.