Please see the complete list of BRB prompts for unit 3. Please complete and hand in sections 3.1 and 3.2 by Friday, April 7th.

I realize that the prompts from 2.7 – DNA Replication, Transcription, and Translation are still outstanding, however Mrs. Chan and I have discussed it and it makes more sense for you to focus on unit 3 before the unit test (and my departure!) especially since many of you are just receiving your BRBs back this week!

3.1 Genes

3.1.1 Define a gene and alleles including two examples. (1)

3.1.2 Loci of a gene tells you where to find it on a particular homologous chromosome pair, and also what the protein product would be. Using the OMIM (Online Mendelian Inheritance in Man) database to give two examples of a gene loci and its respective protein product.

3.1.3 Describe what makes alleles of the same gene different from each other. (2)

3.1.4 Compare the number of genes in humans (Homo sapiens) with other species including T2 phage (virus), Escherichia coli (bacteria), Drosophila melanogaster (fruit fly) and Paris Japonica (plant). (3)

3.1.5 Discuss the advantages of sequencing the entire genome of an organism. (3)

3.1.6 Define gene mutation and give examples of mutagens that could lead to genetic diseases or cancer. (1)

3.1.7 Outline the result of the Chernobyl nuclear accident and the nuclear bombing of Hiroshima. (2)

3.1.8 Explain the consequence of a base substitution mutation in relation to the processes of transcription and translation, using the example of sickle-cell anemia.(3)

3.1.9 Explain the correlation between sickle cell anemia and the prevalence of malaria. (3)


3.2 Chromosomes

3.2.1 Compare prokaryotic and eukaryotic chromosomes in terms of shape, length and associated proteins (3)

3.2.2 State the number of genes in humans spread across homologous pairs of chromosomes. (1)

3.2.3 Define the relationship between homologous chromosomes in diploid cells. (1)

3.2.4 Describe the Cairns’ technique for measuring length of DNA molecules by autoradiography. (2)

3.2.5 Distinguish between haploid and diploid cells, giving named examples of each. (2)

3.2.6 Determine the chromosome number in human haploid cells vs human diploid cells, as well as the number of homologous pairs. (3)

3.2.7 Describe how karyograms are constructed, and their use. (2)

3.2.8 Define the number of autosomes and sex linked chromosomes in a human diploid cell. (1)

3.2.9 Compare the diploid chromosome number of Homo sapiens, Pan troglodytes, Canis familiaris, Oryza sativa, Parascaris equorum.


3.3 Meiosis

3.3.1 Define meiosis. Include the terms reduction division, diploid nucleus and haploid nucleus. (1)

3.3.2 Outline the process of meiosis, including (a) pairing of homologous chromosomes, sister chromatids, centromeres, cytokinesis to produce four haploid cells. (2)

3.3.3 State the purpose of meiosis.(1)

3.3.4 Suggest how Mendel’s law of Random Assortment relates to meiosis. (3)

3.3.5 Determine when in meiosis the chromosome number is halved. (3)

3.3.6 Outline when in meiosis non-disjunction can occur and the effect on the organism. (2)

3.3.7 Explain how crossing over, random orientation and fusion of gametes from different parents promote genetic variation. (3)

3.3.8 List factors that could influence the chances of non-disjunction. (1)

3.3.9 Describe the methods to obtain cells for karyotype analysis (via chorionic villus sampling and amniocentesis) and risks associated with each. (2)

3.3.10 Analyze a human karyotype to determine gender and whether non-disjunction has occurred. (3)


3.4 Inheritance

3.4.1 Define genotype, phenotype, dominant allele, recessive allele, codominant alleles, locus, homozygous, heterozygous, carrier and test cross. (1)

3.4.2 Draw the punnet square monohybrid crosses Mendel demonstrated with regard to pea size, texture and colour. (2)

3.4.3 Draw your own family’s pedigree chart showing the inheritance of eye colour. (2)

3.4.4 Draw and explain blood type inheritance as an example of co-dominance. (2)

3.4.5 Compare the inheritance of an autosomal recessive disorder to a sex-linked recessive disorder. (3)

3.4.6 Draw and explain an example of a disease that is inherited as autosomal dominant. (2)

3.4.7 Define the type of inheritance for each of the following diseases: red-green colour blindness, cystic fibrosis, Huntington’s disease and hemophilia. (1)


3.5 Genetic modification and biotechnology

3.5.1 Outline the use of polymerase chain reaction (PCR) to copy and amplify minute quantities of DNA(2)

3.5.2 State that, in gel electrophoresis, fragments of DNA move in an electric field and are separated according to their size. (1)

3.5.3 Explain how gel electrophoresis and PCR are used in DNA profiling. (2)

3.5.4 Describe the application of DNA profiling to determine paternity and also in forensic investigations. (2)

3.5.5 Outline a basic technique used for gene transfer involving bacterial plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes (endonucleases) and DNA ligase. (2)

3.5.6 Discuss the potential benefits and possible harmful effects of the genetic modification of crops.

3.5.7 Define clone. (1)

3.5.8 List examples of how plant species and some animal species have natural methods of cloning (including embryonic development). (2)

3.5.9 Describe the process developed to clone adult animals using differentiated cells. (2)

3.5.10 Compare therapeutic and reproductive cloning. (3)

3.5.11 Compare the ethical arguments for and against therapeutic and reproductive cloning. (3)