CPA #13 Questions

Question 1

define: recombinant DNA technology

Answer 1

aka genetic engineering; intentionally modifying the genomes of an organism

Question 2

what are the 3 main goals of recombinant DNA technology

Answer 2

1. eliminate undesirable phenotypic traits
2. combine beneficial traits of 2 or more organisms to create valuable new organism
3. create organisms that synthesize products that humans need

Question 3

define: reverse transcriptase

Answer 3

creates flow of genetic info in reverse order of conventional transcription; RNA template used to transcribe a molecule of DNA (cDNA); violating the central dogma

ex. viruses

Question 4

define: cDNA

Answer 4

DNA that is complementary to an RNA template

Question 5

explain synthetic nucleotides

Answer 5

molecules of DNA/RNA in a cell-free solution

Question 6

1. elucidating the genetic code;
2. creating genes for specific proteins
3. synthesizing DNA/RNA probes to locate specific sequences of nucleotides
4. synthesizing antisense nucleic acid molecules
5. synthesizing PCR primers

Answer 6

5 ways synthetic nucleic acids are used

Question 7

nucleic acid molecules with a specific nucleotide sequence that have been labeled radioactive/florescent chemicals so that their location can be detected; a given nucleotide sequence will preferentially bond to the complementary sequence

Answer 7

probes

Question 8

enzymes that cut DNA molecules at the restriction site; usually used as a bacterial protection mechanism to protect from phages by cutting phage DNA into nonfunctional pieces

Answer 8

restriction enzymes

Question 9

define: restriction site

Answer 9

specific nucleotide sequence; usually palindromes (same sequence forwards and backwards)

Question 10

define: blunt ends

Answer 10

both DNA strands are cut at the same point; non-specific because all of the hydrogen bonds are satisfied

Question 11

define: sticky ends

Answer 11

both strands of DNA are cut by staggered cuts that produce fragments that terminate in a mortise-like end; composed of 4 nucleotides that form hydrogen bonds with the complementary sticky end; specific, unsatisfied hydrogen bonds

Question 12

define: vector

Answer 12

nucleic acid molecules such as viral genomes, transposons, and plasmids that deliver a gene into a cell

Question 13

define: gene library

Answer 13

collection of bacterial or phage clones that are identical descendants; each one contains portion of genetic material

Question 14

why do we use gene libraries?

Answer 14

more time efficient because you do not have to isolate the genes every time, they are already readily available; use restriction enzymes to generate fragments of the DNA and then use ligase to synthesize recombinant vectors

Question 15

what are the 6 purposes of recombinant DNA?

Answer 15

1. multiply
2. identify
3. manipulate
4. isolate
5. map
6. sequence

Question 16

define: PCR

Answer 16

polymerase chain reaction; produce large number of identical molecules of a specific segment of DNA in vitro

Question 17

what are the ingredients of PCR?

Answer 17

excess DNA primers, Taq DNA polymerase, abundance of the 4 deoxyribonucleic acids (A,T,G,C)

Question 18

what are the three steps of PCR?

Answer 18

1. denaturation
2. priming
3. extension

Question 19

define: denaturation (PCR)

Answer 19

exposure to heat (94C) to separate two strands of the target DNA ; breaks hydrogen bonds, but leaves strands unaltered

Question 20

define: priming (PCR)

Answer 20

PCR mixture is added to target DNA; cool to 65C

Question 21

define: extension (PCR)

Answer 21

raise temp to 72C to increase the rate that DNA polymerase replicates each strand for more DNA

Question 22

define: gel electrophoresis

Answer 22

isolate fragments of DNA molecules that can be inserted into vectors, multiplied by PCR, or preserved in gene libraries

Question 23

what three characteristics are used to separate molecules of gel electrophoresis?

Answer 23

1. size
2. charge
3. shape

Question 24

define: southern blot

Answer 24

presence of DNA

Question 25

define: northern blot

Answer 25

presence of RNA

Question 26

what is the purpose of DNA microarray?

Answer 26

monitor gene expression, diagnose infection, identify organisms in an environmental sample

Question 27

what are the 3 artificial methods to introduce DNA to cells?

Answer 27

electroportation, protoplast fusion, injection

Question 28

define: electroporation

Answer 28

uses electrical current to puncture microscopic holes through cell membrane so that DNA can enter

Question 29

define: protoplast fusion

Answer 29

when protoplasts encounter one another, the cytoplasmic membranes may fuse to form a single cell containing 2 genomes; polyethylene glycol increases rate of fusion

Question 30

define: injection

Answer 30

1. gene gun
2. microinjection

used with larger eukaryotic cells

Question 31

define: genetic mapping

Answer 31

locating genes on nucleic acid molecule; provides scientists with information like: organisms metabolism and growth characteristics and potential relatedness to other microbes

Question 32

define: genomics

Answer 32

sequencing and analysis of the nucleotide bases of genomes of organisms, viruses, and eukaryotic mitochondria

Question 33

how can scientists use recombinant DNA for pharmaceutical/therapeutic applications?

Answer 33

1. synthesize medically impportant proteins
2. produce vaccines
3. screen for genetic diseases
4. diagnose diseases
5. aid in organ transplant
6. treat genetic illnesses
7. make animals respond more similarly to humans when treated with pathogens

Question 34

how can scientists use recombinant DNA for agricultural application?

Answer 34

1. herbicide resistance
2. tolerance to salty soil
3. resistance to freezing and pests
4. improvement in nutritional value