Describe the significance of DNA replication and meiosis in fertilisation, and how the resulting foetus is protected and nourished in the uterus Content: 17 Synthesis: 3 THE SIGNIFICANCE OF DNA REPLICATION Since DNA replication occurs just before cell division, it allows for a doubling of genetic material. This is to ensure that sufficient genetic material is available to form 4 haploid gametes from one diploid cell. SIGNIFICANCE OF MEIOSIS Meiosis leads to exchange of genetic material and adds to genetic variation. The reduction of chromosome number to haploid number keeps the chromosomes number constant form generation to generation. Meiosis forms four haploid cells, which function as gametes. Independent assortment adds to genetic variation PROTECTION OF FOETUS The foetus is protected from injury as well as against temperature changes by the amniotic fluid. NOURISHMENT OF THE FOETUS The foetus received nutrition via the placenta. Nutrients and compounds from the maternal blood pass into the foetal blood. These substances read the foetus via the umbilical vein SYNTHESIS An extra 3 marks if the essay is well constructed, demonstrates insight and understanding of the question Zero if the essay is not attempted or nothing is written other than the question number, or if there is no correct information
Posted on: Sun, 09 Mar 2014 16:41:39 +0000
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