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.

Reading:  Review of chromosome structure

Reading:  How Cells Pack Tangled DNA into 

Chromosomes as socks analogy with blank handout

Homologous chromosomes handwritten notes

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 chromosome of each pair.

• Define haploid.

• State the human cell haploid number.

• List example haploid cells.

Class review for haploid/diploid

3.2.U8:  The number of chromosomes is a characteristic feature of members 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.A3:  Comparison of diploid chromosome numbers of Homo sapiens, Pan troglodytes, Canis familiaris, Oryza sativa, Parascaris 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.

Chromosomes notes

Chromosome number in species drawings

Chromosome number emojis

Discovery of human chromosome number

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.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.

Cairn’s Notes

Cairn’s Experiment Notes (handwritten)

Importance of Autoradiography in Cell Biology

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. 

3.3.A2:  Description of methods used to obtain cells for karyotype analysis e.g. chorionic villus sampling and amniocentesis and the associated risks.

• Describe the two procedures for obtaining fetal cells for production of a karyotype.

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. 

Karyotyping notes

Scitable Karyotyping

Karyotyping review

Karyotyping Simulation Gizmos

Simulation slides for students

Diagnosis from karyotypes activity

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. 

6.6.U5:  A gene on the Y chromosomes causes embryonic gonads to develop as testes and secrete testosterone.

• Describe the mechanism by which the SRY gene  regulates embryonic gonad development.

Sex Determination notes

Sex determination hand written 

CFU Sex Determination

Sex determination Scitable

genetic mechanisms of sex determination

Scitable XX male

Nature Sex Redefined

A&B:  chromosome haplotypes

Dutee Chand NYTimes

Dutee Chand Radiolab

TED The Weird History of Sex Chromosomes (questions)

Final knowledge audit

Kahoot is part of meiosis unit

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