Lecture 17- DNA Technology

Question 1

Why is polymerase chain reaction (PCR) so useful?

Answer 1

Allows us to produce billions of copies of DNA in a short period of time, which allows us to study small DNA samples

Question 2

What is Taq polymerase?

Answer 2

DNA polymerase from Thermis aquaticus (a bacteria from hot springs in Yellowstone which tolerates high temperatures)

Question 3

True or false: The goal of PCR is to produce genetically unique DNA

Answer 3

False; PCR is used to synthesize identical DNA strands

Question 4

What type of material is gel electrophoresis conducted with?

Answer 4

Polyacrylamide gel (agarose polysaccharide)

Question 5

What are dNTPs?

Answer 5

Deoxyribonucleotides (A,T,C,G)

Question 6

What process can be used to figure out the order of the nucleotides of a DNA strand?

Answer 6

DNA sequencing

Question 7

What occurs during the denaturation step of PCR?

Answer 7

Hydrogen bonds between DNA strands break apart, separating the strands

Question 8

What is the difference between deoxyribonucleic acid and dideoxyribonucleic acid?

Answer 8

Oxygen is removed from the free 3’ OH on DNA -> becomes dideoxyribonucleic acid

Question 9

What can DNA sequencing be used for?

Answer 9

Determining common evolutionary ancestors of species (species diversity)

Question 10

What are the components required to conduct PCR?

Answer 10

dNTPs, primers, & Taq polymerase

Question 11

How does gel electrophoresis separate DNA fragments by size?

Answer 11

DNA fragments move from negative to positive. Small fragments move far and big fragments stay close

Question 12

True or false: RNA primers are required to conduct PCR

Answer 12

False; the primers used in PCR are DNA

Question 13

How does DNA elongate using dideoxyribonucleic acid?

Answer 13

It doesn’t. Dideoxyribonucleic acid terminates elongation

Question 14

What are the steps of PCR in order?

Answer 14

Denaturation-> Annealing-> Extension

Question 15

What is the function of Taq polymerase in PCR?

Answer 15

Replicates new strands in the 5’ to 3’ direction

Question 16

True or false: During the denaturation step of PCR, the phosphodiester bonds in DNA are broken, allowing DNA strands to separate

Answer 16

False; only the hydrogen bonds break. PCR does not reach high enough temperatures to break covalent bonds

Question 17

What occurs during the annealing step of PCR?

Answer 17

DNA primers anneal very specifically to the 3’ side of the DNA as the solution cools

Question 18

True or false: During PCR, Taq polymerase replicates the lagging DNA strand

Answer 18

False; there is no lagging DNA strand in PCR

Question 19

Which constituent of DNA gives it the properties necessary to be used in gel electrophoresis?

Answer 19

Phosphate group is negatively charged

Question 20

What is the dideoxy chain termination method?

Answer 20

Method of DNA sequencing by which dideoxyribonucleic acids inhibit elongation

Question 21

How do we know that dideoxyribonucleotides (ddNTPs) inhibit DNA elongation?

Answer 21

ddNTPs are labeled with fluorescent molecules