Ch 6 Quiz Review

Question 1

diploid

Answer 1

the presence of two complete sets of chromosomes in an organism’s cells, with each parent contributing a chromosome to each pair

Question 2

histone

Answer 2

a special protein molecule that is the core around which the DNA strand wraps

Question 3

nucleosome

Answer 3

a unit of DNA storage, consisting of 8 histones with DNA strands wrapped around them

Question 4

gene

Answer 4

a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring

Question 5

plasmid

Answer 5

a small circular section of DNA found in the cytosol of bacteria; replicates independently of the chromosomal DNA

Question 6

nucleotide base pair

Answer 6

Two nitrogen-containing bases (or nucleotides) that pair together to form the structure of DNA.

The four bases in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T).

These bases form specific pairs (A with T, and G with C)

Question 7

semiconservative replication

Answer 7

a mechanism of DNA replication in which each of the two strands of parent DNA is incorporated into a new double-stranded DNA molecule

Question 8

DNA helicase

Answer 8

a replication enzyme that separates and unwinds the DNA strands

Question 9

topoisomerase

Answer 9

a class of enzymes that relieve tensions caused by the unwinding of parent DNA; they cleave one or two of the DNA strand(s), allow the strands to untwist, and then rejoin the strand(s)

Question 10

single-strand binding protein (SSBP)

Answer 10

a replication enzyme that prevents parent DNA strands from annealing to each other once they have been separated by helicase

Question 11

replication bubble

Answer 11

the separating of DNA in both directions during replication

Question 12

DNA polymerase l

Answer 12

a prokaryotic replication enzyme that fills in gaps in the lagging strand between Okazaki fragments; also proofreads the final strands

Question 13

DNA polymerase ll

Answer 13

a prokaryotic replication enzyme that repairs damage to DNA, including damage that occurs between replication events

Question 14

DNA polymerase lll

Answer 14

a prokaryotic replication enzyme that builds new DNA strands from nucleotides

Question 15

okazaki fragment

Answer 15

the piece of new DNA on the lagging strand

Question 16

leading strand

Answer 16

the DNA strand that is copied in the direction toward the replication fork

Question 17

lagging strand

Answer 17

the DNA strand that is copied in the direction away from the replication fork

Question 18

RNA primase

Answer 18

a replication enzyme that produces RNA primers

Question 19

RNA primer

Answer 19

a replication molecule that acts as a starting point for replication

Question 20

DNA ligase

Answer 20

an enzyme that catalyzes the formation of a phosphodiester bond between 2 DNA strands, as well as between okazaki fragments

Question 21

telomere

Answer 21

a repeating sequence of DNA at the end of a chromosome that protects coding regions from being lost during replication

Question 22

telomerase

Answer 22

an enzyme that adds new telomere sequences to the ends of chromosomes

Question 23

Hayflick limit

Answer 23

the total number of times that a normal cell can divide

Question 24

Gregor Mendel

Answer 24

hypothesized the existence of a hereditary molecule that passes genetic info through generations

Question 25

Frederick Meischer

Answer 25

Studied the composition of the nucleus
-collected pus from bandages and extracted an unknown substance that was acidic and contained phosphorus
-named it “nuclein”

Question 26

Frederick Griffith

Answer 26

studied pneumonia bacteria
-used 2 diff strains of the pneumonia bacterium
-showed some sort of hereditary transmission
–> transformation

Question 27

Avery, McLeod and McCarty

Answer 27

based on Griffith’s findings, they carried out similar studies in 1944 using streptococcus
-results showed that DNA was the hereditary substance

Question 28

Hershey and Chase

Answer 28

In 1952, they attempted to verify if DNA or protein was the genetic material
-found radioactivity only inside cell’s DNA

Question 29

Edward Chargaff

Answer 29

disagreed with thinking that there was an equal concentration of A,T,C and G
-discovered that the bases occur in definite ratios (A=T and C=G)

Question 30

Rosalind Franklin and Wilkins

Answer 30

Used x-ray crystallography to study shape of DNA molecule
-x-ray suggested double helix rotating clockwise, with sugar-phosphate backbone on the outside

Question 31

Watson and Crick

Answer 31

in 1952, they were building a variety of models of DNA to determine structure
-discovered it has a double helix shape