Questions and Answers

State the role of mitosis in growth, repair of damaged tissues, replacement of cells and asexual reproduction

Describe mitosis as nuclear division giving rise to genetically identical cells (details of the stages of mitosis are not required)

State that in a diploid cell, there is a pair of each type of chromosome and in a human diploid cell there are 23 pairs

Describe a diploid nucleus as a nucleus containing two sets of chromosomes

Explain that most body cells in an organism contain the same genes, but many genes in a particular cell are not expressed because the cell only makes the specific proteins it needs

Explain how a protein is made, limited to: • the gene coding for the protein remains in the nucleus • messenger RNA (mRNA) is a copy of a gene • mRNA molecules are made in the nucleus and move to the cytoplasm • the mRNA passes through ribosomes • the ribosome assembles amino acids into protein molecules • the specific sequence of amino acids is determined by the sequence of bases in the mRNA (knowledge of the details of transcription or translation is not required)

Explain that DNA controls cell function by controlling the production of proteins, including enzymes, membrane carriers and receptors for neurotransmitters

Explain that different sequences of amino acids give different shapes to protein molecules

State that the sequence of bases in a gene determines the sequence of amino acids used to make a specific protein (knowledge of the details of nucleotide structure is not required)

Describe the inheritance of sex in humans with reference to X and Y chromosomes