Which statements are correct about lac operator;

I. The site bound by the Lac repressor.

II. The lac operator overlaps the promoter, and so the repressor bound to the operator physically prevents RNA polymerase from binding to the promoter and thus inhibit the RNA synthesis.

III. Have 21-bp sequence with twofold symmetric and is recognized by four subunits of Lac repressor, two binding to each half-site.

IV. CAP binds as a dimer to a site similar in length to that of the lac operator, but different in sequence. This site is located some 60 bp upstream of the start site of transcription.

#Question id: 4253

#Unit 3. Fundamental Processes

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. What is the result of this type of mutation?

#Question id: 4254

#Unit 3. Fundamental Processes

Which of the following statements is the most current description of a gene?

#Question id: 4255

#Unit 3. Fundamental Processes

How might a single base substitution in the sequence of a gene affect the amino acid sequence of a protein encoded by the gene?

#Question id: 4256

#Unit 2. Cellular Organization

With respect to CpG islands in our genomic DNA, which, if any, of the following descriptions do not apply?

1) frequently occurring (there are about 30,000 in the human genome).

2) long DNA sequences (typically from 10 kb to 100 kb in length).

3) low CG dinucleotide frequency.

4) frequently associated with transcriptional start sites.

#Question id: 4257

#Unit 3. Fundamental Processes

An original section of DNA has the base sequence AGCGTTACCGT. A mutation in this DNA strand results in the base sequence AGGCGTTACCGT. What type of mutation does this change represent?

#Question id: 4258

#Unit 3. Fundamental Processes

A single base substitution mutation is likely to have a less deleterious effect when the base change exhibits which of the following results?