Essential Idea: Chromosomes carry genes in a linear sequence that is shared by members of a species.
- Outline answer to each objective statement for topic 3.2 (coming soon)
- Quizlet study set for this topic
At SHS, Topic 3.2 is taught in the following class unit(s):
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3.2.U1 Prokaryotes have one chromosome consisting of a circular DNA molecule.
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3.2.U2 Some prokaryotes also have plasmids but eukaryotes do not.
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3.2.U3 Eukaryote chromosomes are linear DNA molecules associated with histone proteins.
- Describe the structure of eukaryotic DNA and associated histone proteins during interphase (chromatin).
- Explain why chromatin DNA in interphase is said to look like “beads on a string.”
3.2.U4 In a eukaryote species there are different chromosomes that carry different genes.
- List three ways in which the types of chromosomes within a single cell are different.
- State the number of nuclear chromosome types in a human cell.
3.2.U5 Homologous chromosomes carry the same sequence of genes but not necessarily the same alleles of those genes.
- Define homologous chromosome.
- State a similarity and a difference found between pairs of homologous chromosomes.
3.2.U6 Diploid nuclei have pairs of homologous chromosomes.
- Define diploid.
- State the human cell diploid number.
- Outline the formation of a diploid cell from two haploid gametes.
- State an advantage of being diploid.
3.2.U7 Haploid nuclei have one chromosomes of each pair.
- Define haploid.
- State the human cell haploid number.
- List example haploid cells.
3.2.U8 The number of chromosomes is a characteristic feature of member of a species.
- State that chromosome number and type is a distinguishing characteristic of a species.
- List mechanisms by which a species chromosome number can change.
3.2.U9 A karyogram shows the chromosomes of an organism in homologous pairs of decreasing length.
- Describe the process of creating a karyogram.
- List the characteristics by which chromosomes are arranged on the karyogram.
3.2.U10 Sex is determined by sex chromosomes and autosomes are chromosomes that do not determine sex.
- Outline the structure and function of the two human sex chromosomes.
- Outline sex determination by sex chromosomes.
3.2.A1 Cairns’ technique for measuring the length of DNA by autoradiography.
- Describe Cairn’s technique for producing images of DNA molecules from E. coli.
- Outline conclusions drawn from the images produced using Cairn’s autoradiography technique.
3.2.A2 Comparison of genome size in T2 phage, Escherichia coli, Drosophila melanogaster, Homo sapiens, Paris japonica.
- Describe the relationship between the genome size of a species and the species complexity in structure, physiology and behavior.
3.2.A3 Comparison of diploid chromosome numbers of Homo sapiens, Pan troglodytes, Canis familiaris, Oryza sativa, Parascarsis equorum.
- State the minimum chromosome number in eukaryotes.
- Explain why the typical number of chromosomes in a species is always an even number.
- Explain why the chromosome number of a species does not indicate the number of genes in the species.
- Explain the relationship between the number of human and chimpanzee chromosomes.
3.2.A4 Use karyograms to deduce sex and diagnose Down Syndrome in humans.
- Distinguish between a karyogram and a karyotype.
- Deduce the sex of an individual given a karyogram.
- Describe the use of a karyogram to diagnose Down syndrome.
3.2.S1 Use of databases to identify the focus of a human gene and its polypeptide product.
- Search NCBI or OMIM for a given gene.
- Determine the gene locus, abbreviated gene name, and description of the gene.
3.2.NOS Developments in research follow improvements in techniques- autoradiography was used to establish the length of DNA molecules in chromosomes.
- Outline the advancement in knowledge gained from the development of autoradiography techniques.