ch 15 and 16

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15.1 Explain how a typical restriction enzyme cuts DNA molecules and give examples of the ways in which these enzymes are used in recombinant DNA technology.

Recombinant DNA technology isolates and amplifies specific sequences of DNA by incorporating them into vector DNA molecules.

Researchers then clone—propagate and amplify—the resulting recombinant DNA in organisms such as E. coli.

DNA + vector= recombinant DNA

Researchers use restriction enzymes to cut genomic DNA into specific fragments. (Alternatively, researchers will amplify a specific region of genomic DNA using PCR.) Each type of restriction enzyme recognizes and cuts DNA at a highly specific base sequence.

Geneticists often construct recombinant DNA molecules by allowing the ends of a DNA fragment and a vector, both cut with the same restriction enzyme, to associate by complementary base pairing. Then DNA ligase covalently links the DNA strands to form a stable recombinant molecule.

*Many restriction enzymes cleave DNA sequences to produce complementary, single-stranded sticky ends.

Why does DNA migrate to the positive pole? because the backbone of DNA is negatively charged

Backbone is phosphate + ribose

Small DNA migrates faster than big DNA

15.2 Explain how gel electrophoresis is used to characterize cloned DNA fragments.

Gel electrophoresis is a method for separating charged macromolecules in a porous gel medium, such as agarose or polyacrylamide.

DNA library : useful when trying to figure out what proteins do certain activities

Each cycle of PCR gives you multiple copies of DNA

PCR used for: forensics, genetic testing, medicine HIV testing

RNA interference (post-transcriptional control) interference: controls how much translation occurs

Small-interfering RNAs: help control damage from viral infections and regulate gene expression of protein-coding genes

Micro RNAs (miRNAS) inhibit expression of MRNA molecules with sequences complementary to the miRNA

Next generation sequencing: allows genomes to be easily sequenced leading to "personalized medicine"

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A plasmid

Answer

can be used as a DNA vector

is a type of bacteriophage

is a type of cDNA

is a retrovirus

b and c

DNA molecules with complementary sticky ends associate by

Answer

covalent bonds

hydrogen bonds

ionic bonds

disulfide bonds

phosphodiester linkages

Human DNA and a particular plasmid both have sites that are cut by the restriction enzymes HindIII and EcoRI. To make recombinant DNA, the scientist should

Answer

cut the plasmid with EcoRI and the human DNA with HindIII

use EcoRI to cut both the plasmid and the human DNA

use HindIII to cut both the plasmid and the human DNA

a or b

b or c

Which technique rapidly replicates specific DNA fragments without cloning in cells?

Answer

gel electrophoresis

cDNA libraries

DNA probe

restriction fragment length polymorphism

polymerase chain reaction

The PCR technique uses

Answer

heat-resistant DNA polymerase

reverse transcriptase

DNA ligase

restriction enzymes

b and c

A cDNA clone contains

Answer

introns

exons

anticodons

a and b

b and c

The dideoxynucleosides ddATP, ddTTP, ddGTP, and ddCTP were important in DNA sequencing because they

Answer

cause premature termination of a growing DNA strand

are used as primers

cause the DNA fragments that contain them to migrate more slowly through a sequencing gel

are not affected by high temperatures

have more energy than deoxynucleotides

Gel electrophoresis separates nucleic acids on the basis of differences in

Answer

length (molecular weight)

charge

nucleotide sequence

relative proportions of adenine and guanine

relative proportions of thymine and cytosine

A CRISPR locus in a bacterium contains

Answer

short repeated sequences

short DNA sequences homologous to bacteriophages

genes that encode guide RNAs and one or more proteins

a, b, and c

none of the preceding

Tissue growth factor-β

Answer

is a DNA probe for recombinant plasmids

is a product of DNA technology used in tissue engineering

is necessary to make cDNA library

cannot be synthesized without a heat-resistant DNA polymerase

is isolated by the Southern blot technique

These highly polymorphic molecular markers are useful in DNA fingerprinting:

Answer

plasmid vectors

cloned DNA sequences

palindromic DNA sequences

short tandem repeats

complementary DNAs