DNA Replication

Question 1

gregor mendel

Answer 1

worked with peas to develop preliminary ideas about genetics and inheritance

Question 2

genotype

Answer 2

what the genes say (Rr, rr, RR)

Question 3

phenotype

Answer 3

what the genes show (blue eyes, tall, etc.)

Question 4

erwin & chagoff

Answer 4

demonstrated that DNA had equal masses of A/T and C/G, helping watson and crick with their theory

Question 5

purines

Answer 5

A/G, because they have two C rings

Question 6

pyrimidines

Answer 6

C/U/T, one ring

Question 7

structure of DNA

Answer 7

phosphate-sugar-base-base-sugar-phosphate

Question 8

antiparallel

Answer 8

dna strands go in opposite directions, on is 3’-5’, the other is 5’-3’

Question 9

polymerase

Answer 9

enzymes that replicate DNA, works only in the 5’-3’ direction

Question 10

leading strand

Answer 10

5’-3’ strand, synthesized continuously

Question 11

lagging strand

Answer 11

3’-5’ strand, synthesized in chunks

Question 12

polymerase 1

Answer 12

reads bases and corrects mistakes

Question 13

polymerase 3

Answer 13

adds bases

Question 14

single-strand binding proteins (SSBP)

Answer 14

stabilizes the DNA when it has been forked

Question 15

helicase

Answer 15

splits H-bonds and creates a DNA fork

Question 16

RNA primase

Answer 16

starts the new strand by adding a chunk of RNA to the old strand

Question 17

ligase

Answer 17

connects the Okazaki fragments

Question 18

Okazaki fragments

Answer 18

parts of the DNA that have been copied in the opposite direction of the replication direction (3’-5’ strand copied) but not connected to form a longer DNA strand

Question 19

Messelson & Stahl (M&S)

Answer 19

theorized the process of DNA replication through an experiment in which they used a radioactive marker to mark the original DNA strand. after several rounds of replication, they tested to see what the DNA looked like, finding that there was a small amount of marked DNA settled at the bottom of the test tube, showing that DNA is replicated in a semiconservative model.

Question 20

conservative model

Answer 20

original strand is kept intact and essentially copy/pasted to create the new one. the two strands at the end are one new, one old. the tube in M&S would show such a small amount of the original DNA that it wouldn’t even be observable.

Question 21

dispersive model

Answer 21

original strand replicated such that the two new strands have the old strand equally distributed throughout. the test tube in M&S would show the marker dispersed within it.

Question 22

semiconservative model

Answer 22

original strand is split in two and the daughter strands have one old side and one new side. M&S tube shows a small amount of marked DNA at the bottom, enough to be observable. (this is what they saw)

Question 23

deletion (chromosomal mutation)

Answer 23

section of chromosome is removed (ABCDE -> ADE)

Question 24

duplication (chromosomal mutation)

Answer 24

section of a chromosome is repeated (ABCDE -> ABCBCDE)

Question 25

inversion (chromosomal mutation)

Answer 25

reverses a sequence within a chromosome (ABCDE -> ADCBE)

Question 26

reciprocal translation (chromosomal mutation)

Answer 26

two different chromosomes cross over and trade (not 13/13, but 13/10; creates chromosome sections that code for genes not addressed on that chromosome)

Question 27

Rosalind Franklin

Answer 27

showed through an X-ray graph that DNA was a double helix

Question 28

Hershey & Chase

Answer 28

marked viral DNA and viral proteins to see which conveyed genetic information. results showed that it was DNA

Question 29

point mutation

Answer 29

a change made to a single base during DNA replication

Question 30

silent mutation (point mutations)

Answer 30

change in a single base that has no effect on the protein that is coded for

Question 31

nonsense mutation (point mutation)

Answer 31

change in a single base resulting in a strand that doesn’t code for anything

Question 32

conservative missense mutation (point mutation)

Answer 32

change in a single base that codes for a new protein with similar properties to the original, resulting in little change to the trait

Question 33

non-conservative missense mutation (point mutation)

Answer 33

change in a single base that codes for a new protein entirely, resulting in observable change to the trait

Question 34

frameshift mutation

Answer 34

changes the codons through insertion or deletion of bases

Question 35

deoxyribose (DNA) vs dideoxyribose (dDNA)

Answer 35

DNA has an OH group on the 3’ carbon, which means the sequence can continue. dDNA has simply an H on the 3’ carbon, so the sequence stops replicating.

Question 36

sanger sequencing steps

Answer 36

1. split the DNA into four tubes, adding dDNA bases for one base in each tube (one has A, one has T, once has C, and one has G)
2. let the DNA replicate in the tubes, creating strands of different lengths
3. run this through a gel and sequence the genes (longest on top, so the last base would be the top mark)
4. [optional] if the DNa was color-dyed, you can use a computer to sequence the DNA