ap bio test 6: DNA MB's

During which step in the PCR cycle do primers form bonds with a single-stranded template?

annealing

How many DNA molecules would there be after four rounds of PCR if the initial reaction mixture contained two molecules?

32

Why is it so important to be able to amplify DNA fragments when studying genes? DNA fragments are too small to use individually. A clone requires multiple copies of each gene per clone. A gene may represent only a millionth of the cell's DNA. Restriction enzymes cut DNA into fragments that are too small. It is important to have multiple copies of DNA in the case of laboratory error.

A gene may represent only a millionth of the cell's DNA

polymerase chain reaction (PCR)

A method to amplify a fragment of DNA

What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? Extract plasmid DNA from bacterial cells. Cut the plasmid DNA using restriction enzymes. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Use ligase to seal plasmid DNA to nonplasmid DNA. Transform bacteria with a recombinant DNA molecule. Transform bacteria with a recombinant DNA molecule. Cut the plasmid DNA using restriction enzymes. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Extract plasmid DNA from bacterial cells. Use ligase to seal plasmid DNA to nonplasmid DNA. Extract plasmid DNA from bacterial cells. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Use ligase to seal plasmid DNA to nonplasmid DNA. Transform bacteria with a recombinant DNA molecule. Cut the plasmid DNA using restriction enzymes. Cut the plasmid DNA using restriction enzymes. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Use ligase to seal plasmid DNA to nonplasmid DNA. Extract plasmid DNA from bacterial cells. Transform bacteria with a recombinant DNA molecule.

Extract plasmid DNA from bacterial cells. Cut the plasmid DNA using restriction enzymes. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. Use ligase to seal plasmid DNA to nonplasmid DNA. Transform bacteria with a recombinant DNA molecule.

Which of the following statements accurately describes why Taq polymerase is used in PCR? It binds more readily than other polymerases to the primers. It has regions that are complementary to the primers. Only minute amounts are needed for each cycle of PCR. It is heat stable, and it binds more readily than other polymerases to the primers. It is heat stable and can withstand the heating step of PCR.

It is heat stable and can withstand the heating step of PCR.

Archaeologists unearthed a human skull with a small dried fragment of the scalp still attached. They extracted a tiny amount of DNA from the scalp tissue. How could they obtain sufficient DNA for an analysis of the ancient human's genes? Use a nucleic acid probe. Subject the specimen to amniocentesis. Subject the DNA to electrophoresis. Use the polymerase chain reaction. Subject the DNA to restriction enzymes.

Use the polymerase chain reaction.

What information can not be obtained from the sequence of a gene? Whether the gene is methylated. Amino acid sequence of the protein. Relationship between two species. Effects of mutation on gene function.

Whether the gene is methylated.

In recombinant DNA experiments, what is used to cut pieces of DNA and what joins the resulting fragments to form recombinant DNA? a transposon ... a plasmid a plasmid ... DNA ligase a restriction enzyme ... DNA ligase a transposon ... a restriction enzyme DNA ligase ... a restriction enzyme

a restriction enzyme ... DNA ligase

How does a bacterial cell protect its own DNA from restriction enzymes? by adding histones to protect the double-stranded DNA by forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching by using DNA ligase to seal the bacterial DNA into a closed circle by adding methyl groups to adenines and cytosines

by adding methyl groups to adenines and cytosines

Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X. cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme. cut the plasmid with restriction enzyme X and insert the fragments cut with restriction enzyme Y into the plasmid. insert the fragments cut with restriction enzyme X directly into the plasmid without cutting the plasmid. cut the plasmid with restriction enzyme X and then insert the gene into the plasmid.

cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme.

Which of the following functions in the regulation of gene expression? plasmids telomeres euchromatin nucleoids nucleases

euchromatin

During which step in the PCR cycle are nucleotides used?

extension

euchromatin

form of eukaryotic chromatin that is available for transcription

methylated

genes can be passed to offspring cells

Which of the following modifications is most likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? altering the nucleotide sequence of the DNA fragment without adding or removing nucleotides increasing the length of the DNA fragment leaving the length of the DNA fragment the same radioactively labeling the cytosine bases within the DNA fragment

increasing the length of the DNA fragment

Which of the following is an example of "recombinant DNA technology"? cloning genes from homologous pairs of chromosomes alternate alleles assorting independently introducing a human gene into a bacterial plasmid manipulating a meiotic crossing-over event combining alternate alleles of a gene in a single cell

introducing a human gene into a bacterial plasmid

Gel electrophoresis separates DNA fragments on the basis of what characteristic?

length

The unpaired nucleotides produced by the action of restriction enzymes are referred to as _____. sticky ends base sequences single strands restriction fragments ligases

sticky ends

Please use the following information to answer the question(s) below. A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest. Why might they be conducting such an experiment? to collect population data that can be used to assess natural selection to prepare to isolate the chromosome on which the gene of interest is found to find the location of this gene in the human genome to find which of the students has which alleles

to find which of the students has which alleles