biology

1.Define the difference between these pairs of terms;

1)gene and allele

2)homozygote and heterozygote

3)genotype and phenotype.

2.Color-blindness is a sex-linked, recessive trait. Two people with normal vision have two sons, one color-blind and one with normal vision. How is this possible? If the couple also has daughters, what proportion of them are expected to have normal vision? Explain your answer.

3.Using the Data Analysis Exercise at the top of page 217 in the textbook, answer the following questions:

1) Regarding the Ty2 strain of S. typhi, about how many more bacteria were able to enter normal cells (those expressing unmutated CFTR) than cells expressing the gene with the ÄF508 deletion?

2) Which strain of bacteria entered normal epithelial cells most easily?

3) The ΔF508 deletion inhibited the entry of all three S. typhi strains into epithelial cells. Can you tell which strain was most inhibited?

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Use caution when interpreting the graph. Note that the Y-axis is a log scale.