Chapter 16: The Molecular Bais of Inheritance

Question 1

T H Morgan

Answer 1

Found that genes are located on chromosomes

Question 2

Fredrick Griffith

Answer 2

Discovery of the genetic role of DNA, and the phenomenon called transformation

Question 3

Transformation

Answer 3

A change in genotype and phenotype due assimilation of foreign DNA

Question 4

Avery, McCarty, MacLeod

Answer 4

The transforming substance was DNA

Question 5

Bacteriophages

Answer 5

Viruses that infect bacteria

Question 6

Virus

Answer 6

DNA enclosed by a protective coat, often simply protein

Question 7

Hershey and Chase

Answer 7

DNA is the genetic material of a phage

Question 8

Chargaff

Answer 8

DNA composition varies from one species to the next

Question 9

Wilkins and Franklin

Answer 9

X-ray crystallography to study molecular structure

Question 10

Pauling

Answer 10

Proposed the triple helix model

Question 11

Crick and Watson

Answer 11

Deduced that DNA is helical, made of two strands, forming a double helix

Question 12

Antiparallel

Answer 12

Two helices move in opposite directions

Question 13

DNA composition

Answer 13

Double helix, antiparallel, sugar-phosphate backbone, complementary nitrogenous bases

Question 14

DNA replication

Answer 14

The copying of DNA

Question 15

Meselson and Stahl

Answer 15

Devised the experiment to differentiate among the three proposed DNA replication mechanisms

Question 16

DNA replication mechanisms

Answer 16

Conservative, semiconservative, dispersive

Question 17

Origins of replication

Answer 17

Particular sites where the replication of DNA begins

Question 18

Replication fork

Answer 18

Y shaped region where parental strands of DNA are being unwound

Question 19

Helicase

Answer 19

Enzyme that “unzips” the double helix at the replication fork

Question 20

Single-strand binding proteins

Answer 20

Bind to and stabilize single-stranded DNA

Question 21

Topoisomerase

Answer 21

Corrects “overwinding” ahead of replication forks by breaking, swiveling, and rejoining DNA strands

Question 22

Primer

Answer 22

Short initial nucleotide

Question 23

Primase

Answer 23

Makes RNA primer

Question 24

DNA polymerase

Answer 24

Catalyzes the synthesis of new DNA at replication fork

Question 25

Okazaki fragments

Answer 25

Series of segments that are synthesized as the lagging strand

Question 26

DNA ligase

Answer 26

Joins together Okazaki fragments

Question 27

Leading strand

Answer 27

Synthesized as one molecule, primase makes a single RNA primer

Question 28

Lagging strand

Answer 28

Okazaki fragments consist of RNA primers plus DNA

Question 29

Mutations

Answer 29

Changes that are the source of genetic variation upon which natural selection operates

Question 30

Telomeres

Answer 30

Special nucleotides sequences at the end of eukaryotic chromosomal DNA fragments

Question 31

Telomerase

Answer 31

Catalyzes the lengthening of telomeres in gamete cells (inactive in somatic cells)

Question 32

Chromatin

Answer 32

Complex in which DNA is precisely combined with proteins

Question 33

Histones

Answer 33

Proteins responsible for the main level of DNA packing

Question 34

Nucleosome

Answer 34

Beads on the unfolded chromatin string, composed of DNA wound twice around a core of histones

Question 35

Euchromatin

Answer 35

Loosely packed chromatin

Question 36

Heterochromatin

Answer 36

Highly condensed centromeres and telomeres