chapter 18

25問 • 1年前

問題一覧

You grow a culture of bacteria and split it into two culture tubes. One sample of bacteria you treat with calcium and the other is not treated. When you transform both samples with a plasmid, only the samples treated with calcium take up the plasmid. Which of the following best explains your results?

The calcium makes the bacterial membrane more porous to DNA

A plasmid vector and chromosomal DNA are treated separately with the same restriction enzyme. The digested plasmid and chromosomal DNA were incubated together with DNA ligase and transformed into bacteria. Plasmids isolated from some of the colonies do not contain inserted chromosomal DNA. Which of the following could explain this observation?

The two sticky ends of the plasmid could hybridize back together, recircularizing.

What is an advantage of cDNA libraries over genomic libraries?

cDNA only contains protein coding exons.

Which. of the following vectors undergo transformation to get into bacterial cells?

Plasmid

The lacZ gene encodes _______

B-galactosidase

Why is Tag polymerase used in a polymerase chain reaction (PCR)?

Unlike other DNA polymerases, Taq polymerase is heat stable and survives the 94 degree denaturation step in PC.

What is TRUE of restriction enzymes?

They protect bacterial cells from invasion by foreign DNA.

Which of the following statements about genomic libraries and cDNA libraries is TRUE?

A cDNA library is derived from mRNA and is made using reverse transcriptase.

Restriction enzymes are invaluable tools in gene cloning because

they cut at specific sites within the DNA and produce sticky ends allowing DNA from different sources to be joined together.

A DNA library is

a collection of recombinant vectors containing DNA fragments of a given organism.

Which stretch of double-stranded DNA is most likely to be recognized as a restriction enzyme cutting site?

5' - TCCGGA -31 3' - AGGCCT -5'.

You insert a fragment of sheep DNA into a plasmid containing an Amp gene. You transform bacteria with the recombinant plasmid, and plate the cells on growth media containing the antibiotic ampicillin. Each colony on the plate arose from ________ that _______ to ampicillin.

a single bacterium; is resistant

Select the only technique that is associated with functional genomics rather than traditional genomics.

DNA microarray

In a DNA microarray ______ are attached to the slide and _______ are fluorescently labelled

the samples; the cDNAs

You are working in a cancer lab and are interested in identifying some genes that are important in the onset of lung cancer. You have several genes you think may be involved, so you "print" spots of the DNA sequences of interest on a microarray slide. After doing this, you isolate mRNA from both normal lung cells and cancerous lung cells. Before you use these mRNAs to probe the microarray slide, you need to

add reverse transcriptase and fluorescent nucleotides to the mRNA to make cDNA

You are performing a DNA sequencing reaction and add dideoxy cytosine to one tube. What can you conclude about the products of the reaction?

They will be of different sizes, all ending in a C.

The output from an automated sequencing reaction is shown here. What is the sequence of the DNA template strand?

3' - GGACTATCTCAGAGGGA - 5°

By what mechanism can CRISPR-Cas technology introduce a point mutation into a gene?

A double crossover replaces DNA cut by Cas9 with a donor DNA.

Which of the following is TRUE regarding plasmids?

Plasmids are small, usually a few thousand to ten thousand base pairs

Researchers are interested in the genomes of prokaryotic species for all of the following reasons EXCEPT that

bacteria are more highly advanced than humans.

What is required if a researcher wants to analyze homologous genes in different species?

Relatively long DNA sequences.

Homologous genes in different species are called

orthologs.

Homologous chromosomes pair with each other during meiosis, but are misaligned. What is the likely outcome if crossing over occurs?

One daughter chromosome contains a gene duplication, one contains a gene deletion, and the remaining two are normal.

Functionally important gene sequences such as those encoding ribosomal RNA are

moderately repetitive sequences.

Which of the following statements is TRUE of highly repetitive sequences?

They can be found millions of times in a eukaryotic genome.

chapter 21

Madeline Joslyn · 46回閲覧 · 25問 · 1年前

chapter 21