Genetics Ch. 20 Homework

Which of the following DNA sequences is one strand of a restriction enzyme recognition sequence?

X-Gal is included in the growth medium on which cells transformed with bacterial plasmids are grown. The reason X-Gal is included is to

Within a six-base DNA recognition sequence, an enzyme that cuts between the 3rd and 4th bases from the 5' end will generate blunt ends.

What is the function of restriction endonucleases in bacteria?

Restriction endonucleases cut DNA at specific recognition sequences and then bond two strands covalently with the same "sticky ends."

BamHI cuts the sequence 5′ G|GATCC 3′. Which of the following sequences would not be recognized by this enzyme?

Why are filters overlaid with X‑ray film when screening a cDNA library?

Chromosome walking is used mainly to isolate a gene when the sequence of the gene is known.

The role of the primers in PCR is _______.

If there are five molecules of DNA containing the target region at the beginning of a PCR reaction, how many copies of the target will be present after three rounds of amplification?

Immediately after the primers have annealed to the target sequence, _______.

Which of the following molecules is not required for a PCR reaction?

The thermostability of Taq polymerase is required during the annealing phase of PCR.

What is the purpose of raising the temperature to 90-95°C at the beginning of each cycle of PCR?

Phage λ can carry larger DNA fragments than plasmids.

Which of the following elements is not found in a plasmid?

A DNA fragment is introduced into the lacZ gene of a plasmid, which also contains a tetracycline resistance gene. What is the appearance of bacteria transformed with this plasmid if they are spread on plates containing tetracycline and Xgal?

Which enzyme(s) will produce a DNA fragment that contains the entire vgp gene (shown in red) and has "sticky ends"? Select all that apply.

Which of the following statements about ddNTPs is true?

DNA fragments that are 600 bp long will migrate more quickly through a sequencing gel than fragments that are 150 bp long.

Which of the following statements about manual Sanger sequencing is true?

How are dideoxynucleotides (ddNTPs) structurally different from deoxynucleotides (dNTPs)?

How does this structural difference make ddNTPs valuable in chain-termination methods of DNA sequencing?

If you performed a PCR experiment starting with only one copy of double-stranded DNA, approximately how many DNA molecules would be present in the reaction tube after 25 cycles of amplification?