2.6-Cell Division and Cellular Organisation Exam Questions And Answers Graded A+

2.6-Cell Division and Cellular Organisation Exam Questions And Answers Graded A+ Discuss the ways in which genetic variation is produced, including the role of nuclear division.(6 marks) - ANSWER-Independent assortment of chromosomes in metaphase 1 Homologous chromosomes have different alleles Produce a large number of allele combinations Crossing over in prophase 1 Chromatids wrap around each other and swap bits of chromatids Chromatids contain the same gene but different combination of alleles A mutation Which changes the DNA base sequence-result in an abnormal protein Occur if the cell didn't check the DNA correctly during interphase Describe two examples of communication between cells that occur during the life cycle of D. discoideum.(2 marks) - ANSWER-1 attraction of cell to folic acid from bacteria 2 attraction of cells to each other by cAMP 3 coordinated movement in grex 4 differentiation / described, of (grex / slime mould) cells in response to DIF Fig. 3.2, on the insert, shows the stump of a tree with new branches growing from the stump. New growth in a stem or trunk comes from the cambium, which is situated between the xylem and phloem tissues. Explain why the new branches in Fig. 3.2 are seen growing from a position just under the bark of the cut surface.(2 marks) - ANSWER-this is where cambium found mitosis occurs in cambium (to produce new cells for growth) new cells, differentiate , (into xylem and phloem) ; xylem supplies water for (cell) elongation / (cell) growth phloem supplies, sugars / assimilates, for, energy / growth /respiration Meiosis is used in many organisms for the production of gametes. Explain why meiosis needs to have twice as many stages as mitosis.(2 marks) - ANSWER-to, halve chromosome number reduce from 2n to n to separate homologous pairs (of chromosomes) and sister chromatids because, DNA (previously) replicated / chromosomes are two chromatids at start Discuss the possible effects that mutation can have on the structure and function of a protein(3 marks) - ANSWER-different, primary / secondary / tertiary, structure ; (protein ) shorter due to, deletion / stop codon OR longer due to, insertion / duplication ; (protein) unchanged due to, silent mutation / non-coding DNA altered ; (function is) lost / worse / better ; name the process of asexual reproduction in yeast (1 mark) - ANSWER-budding Outline the process of asexual reproduction in yeast (2 marks) - ANSWER- mitosis