ABC Chapter 6 (Genetics)

If a liver cell has 10 chromosomes, how many does a sperm cell have from the same species?

• 20
• 10
• 5
• 40

When an area of a chromatid is exchanged with the matching area on a chromatid of its homologous chromosome, _________________ occurs

• crossing over
• mutagenesis
• hybridization
• fertilization

Why is meiosis important for sexual reproduction?

• It allows the zygote formed from fertilization to have triple chromosome number of the organism.

• It allows gametes to have twice the original number of chromosomes of the organism

• It allows gametes to have half the original number of chromosomes of the organism.

• It allows the zygote formed from fertilization to have half the original number of chromosomes of the organism.

Which would most likely produce a mutation that is passed on to offspring?

• radiation changing the DNA sequence in skin cells

• a gamete with an extra chromosome forming

• tobacco smoke altering the genes in lung cells

• exposure to chemicals altering nerve cell function

Failure of homologous chromosomes to separate properly during meiosis; results in gametes with too many or too few chromosomes.

• nondisjuction 
• crossing over
• trisomy 
• genetic recombination 

Sexual reproduction is vital to the propagation of the human race. Which of the following sequences represents the correct order of events in the formation of a human fetus?

• Zygote → Fetus→ Embryo → Fertilization
• Fertilization → Zygote → Embryo → Fetus
• Fetus → Embryo → Differentiation → Zygote
• Fertilization → Growth → Differentiation → Fetus

In a certain fish, blue (BB scales and red (RR) scales are codominant. When a fish has the genotype BR it has a patchwork of blue and red scales. Cross two heterozygous. What are the chances of an offspring being patchwork?  

• 1 out of 4 or 25%
• 2 out of 4 or 50%
• 3 out of 4 or 75%
• 4 out of 4 or 100%

Colorblindness is a recessive, X chromosome sex-link disorder. Cross the parents to figure out which percentage of their offspring will be colorblind.

• 25%
• 0%
• 75%
• 50%

Which genetic abnormality is shown in this karyotype?

• Turner Syndrom

• Klinefelter's Syndrome

• Down Syndrome

• Trisomy 18

This is a pedigree for a recessive genetic disorder.
What is the genotype of the person in III-2?

• HH
• Hh
• hh
• XY