The gene that is mutated in cases of cystic fibrosis encodes an ion transporter protein normally expressed in the respiratory and digestive tracts along with other locations. Individuals homozygous for the most common mutation in this gene (ΔF508) died at very early ages prior to the advent of advanced medical intervention. Despite this, the mutation exists at relatively high frequency in populations of European descent. One potential explanation is that heterozygotes for such mutations may be relatively immune to the lethal effects of diseases such as typhoid fever. Which statement below is most accurate?

#Question id: 2809

#Unit 2. Cellular Organization

In the human genome, one centimorgan or a 1 percent recombination frequency represents, on average, a distance of about

#Question id: 2810

#Unit 2. Cellular Organization

Which of the following steps is required to generate a knockout mouse?

a. microinjection of DNA into the pronucleus of a fertilized mouse egg

b. introduction of DNA into mouse embryonic stem cells

c. selection for cells containing the gene targeted insertion

d. expression of Cre protein during embryonic development

#Question id: 2811

#Unit 2. Cellular Organization

RNA interference is a method for inhibiting the function of specific genes using

a. single-stranded DNA.                     

b. double-stranded DNA.

c. single-stranded RNA.                     

d. double-stranded RNA.

#Question id: 2812

#Unit 2. Cellular Organization

Which of the following statements is (are) true of the human genome?

a. 1.5 percent of the genome corresponds to protein coding sequences.

b. The median length of an intron is 10 kb.

c. 10 percent of the genome is transcribed into pre mRNA precursors.

d. Most human exons contain 500–1000 base pairs.

#Question id: 2813

#Unit 2. Cellular Organization

DNA fingerprinting is a technique based on differences in the

a. length of introns.   

 b. number of tandem copies of a simple sequence repeat.

c. number of tandem ribosomal RNA genes.

d. size of protein coding genes.

#Question id: 2814

#Unit 2. Cellular Organization

LINES (long interspersed elements)