biology chapter 20 Flashcards
How does a bacterial cell protect its own DNA from restriction enzymes?
A) by adding methyl groups to adenines and cytosines
B) by using DNA ligase to seal the bacterial DNA into a closed circle
C) by adding histones to protect the double-stranded DNA
D) by forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching
Which of the following best describes the complete sequence of steps occurring during every cycle of PCR? MAKE IT SIMPLER
1. The primers hybridize to the target DNA.
2. The mixture is heated to a high temperature to denature the double-stranded target DNA.
3. Fresh DNA polymerase is added.
4. DNA polymerase extends the primers to make a copy of the target DNA.
A) 2, 1, 4
B) 1, 3, 2, 4
C) 3, 4, 1, 2
D) 3, 4, 2
) Which of the following Enzymes is used to make complementary DNA (cDNA) from RNA?
A) Restriction enzymes
B) DNA polymerase
C) DNA ligase
D) Reverse transcriptase
Why is it so important to be able to amplify DNA fragments when studying genes?
A) DNA fragments are too small to use individually.
B) A gene may represent only a millionth of the cell's DNA.
C) Restriction enzymes cut DNA into fragments that are too small.
D) A clone requires multiple copies of each gene per clone.
The reason for using Taq polymerase for PCR is that
A) it is heat stable and can withstand the temperature changes of the cycler.
B) only minute amounts are needed for each cycle of PCR.
C) it binds more readily than other polymerases to primer.
D) it has regions that are complementary to primers.
) Why might a laboratory be using dideoxy nucleotides?
A) to separate DNA fragments
B) to clone the breakpoints of cut DNA
C) to produce cDNA from mRNA
D) to sequence a DNA fragment
Which of the following describes the transfer of DNA fragments from the gel after gel electrophoresis to a membrane for carrying out Restriction Fragment Analysis?
A) Southern blotting
B) Northern blotting
C) Western blotting
D) Eastern blotting
) Use this Figure to answer the following question.
Which enzyme was used to produce the molecule in Figure shown above?
C) a restriction enzyme
D) DNA polymerase
Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?
In recombinant DNA methods, the term vector can refer to
A) the enzyme that cuts DNA into restriction fragments.
B) the sticky end of a DNA fragment.
C) a SNP marker.
D) a plasmid used to transfer DNA into a living cell.
Which of the following tools of recombinant DNA technology is incorrectly paired with its use? What is the WRONG PAIRING?
A) restriction enzyme / analysis of RFLPs
B) DNA ligase / cutting DNA, creating sticky ends of restriction fragments
C) DNA polymerase / polymerase chain reaction to amplify sections of DNA
D) electrophoresis / separation of DNA fragments
DNA fragments from a gel are transferred to a nitrocellulose paper during the procedure called Southern blotting. What is the purpose of transferring the DNA from a gel to a nitrocellulose paper?
A) to attach the DNA fragments to a permanent substrate
B) to separate the two complementary DNA strands
C) to transfer only the DNA that is of interest
D) to prepare the DNA for digestion with restriction enzymes