AQA A-Level Biology – Mitosis 2023 EXAM QUESTIONS WITH COMPLETE SOLUTIONS

AQA A-Level Biology – Mitosis 2023 EXAM QUESTIONS WITH COMPLETE SOLUTIONS PMAT - CORRECT ANSWERS Abbreviation of the four stages of mitosis Prophase - CORRECT ANSWERS The chromosomes thicken and condense, becoming visible. The nuclear envelope breaks down Metaphase - CORRECT ANSWERS The chromosomes align in the centre of the cell. Spindle fibres begin to attach to each sister chromatid Anaphase - CORRECT ANSWERS The sister chromatids are pulled apart to opposite poles of the cell. The centromeres divide in two and move to opposite poles of the cell, pulled by microtubules Telophase - CORRECT ANSWERS The start of the cell division where the spindle fibres disintergrate and the nucleolus reforms Cytokinesis - CORRECT ANSWERS The process by which the cell splits into two at the end of mitosis, forming a new nuclear envelope and plasma membrane Chromatid - CORRECT ANSWERS Half a chromosome Homologous Chromosomes - CORRECT ANSWERS Identical chromosomes Centromere - CORRECT ANSWERS The central region of a chromosome that holds the two chromatids together Mitosis - CORRECT ANSWERS The process that produces two daughter cells and have the same number of chromosomes as the parent cell Binary Fission - CORRECT ANSWERS The process of cell division in prokaryotic cells First Stage of Binary Fission - CORRECT ANSWERS The circular DNA replicates, both copies attach to the cell membrane. The plasmid also replicates Second Stage of Binary Fission - CORRECT ANSWERS The cell membrane grows between the replicated DNA and begins to pinch inwards which splits the cytoplasm in two. The new cell wall forms, forming the complete daughter cells The Importance of Mitosis - CORRECT ANSWERS Used for growth, repair and reproduction Interphase - CORRECT ANSWERS The DNA replication that occurs before mitosis. This takes up 90% of the cell cycle Growth 1 Stage - CORRECT ANSWERS The first part of interphase. Parts of the cell reproduce, such as organelles and the cytoplasm Synthesis Stage - CORRECT ANSWERS The second part of interphase. The DNA packaged into chromosomes replicate. This forms sister chromatids Growth 2 Stage - CORRECT ANSWERS The final part of interphase. The stage by which the cell checks that the replication process has been a success before the cell undergoes mitosis, further growth may occur to ensure everything has been replicated correctly Chemotherapy - CORRECT ANSWERS A type of cancer treatment that; prevents DNA replication or inhibits metaphase by damaging spindle fibres so the chromosomes cannot travel to the poles of the cell Cancerous - CORRECT ANSWERS What a tumour is called when it goes from benign to malignant Benign - CORRECT ANSWERS Where a tumour grows to a certain size and then stops growing any further; does not spread Malignant - CORRECT ANSWERS A tumour that can spread around the body, is often life threatening The Cell Cycle - CORRECT ANSWERS The process of interphase, mitosis and cytokinesis