Chapter 13

Question 1

What was known in the 1920s?

Answer 1

It was know that chromosomes consisted of DNA and its proteins

Question 2

What are the three basic things that proved DNA was the genetic material?

Answer 2

It was in the right place
It varies among species
It was present in the right amounts

Question 3

What does it mean when it was in the right place?

Answer 3

DNA was confirmed to be part of the nucleus and the chromosomes.

Question 4

What does it mean to be varied among species?

Answer 4

Each had a specific amount of nuclear DNA.

Question 5

What does it mean by it was present in the right amount?

Answer 5

Amount in somatic cells was twice that found in the reproductive cells.

Question 6

What are chromosomes made up off?

Answer 6

DNA and proteins

Question 7

How many ammino acids are there?

Answer 7

20

Question 8

What is the genetic material?

Answer 8

DNA

Question 9

What is the polymer of DNA?

Answer 9

nucleotides

Question 10

What makes up a nucleotide?

Answer 10

A phosphate group, a nitrogenous base, and a ribose sugar.

Question 11

Purines

Answer 11

Adenine, and guanine

Question 12

Pyrimidine

Answer 12

Cytosine, thymine, uracil

Question 13

Chargaff’s rule in DNA

Answer 13

% adenine=% thymine
% cytosine= % guanine

Question 14

What is on the inside of the DNA strand?

Answer 14

Nitrogenous bases

Question 15

What is on the outside of the DNA strand?

Answer 15

Phosphate group

Question 16

How do the DNA strands run?

Answer 16

antiparallel

Question 17

Four key features of DNA?

Answer 17

It is double stranded
It is a right-handed helix
It has antiparallel strands
It has major and minor groves

Question 18

What are the strands held together by?

Answer 18

Hydrogen bonds between the bases, and covalent bonds connecting the nucleotides together.

Question 19

Which way do the strands wind?

Answer 19

they wind upwards.

Question 20

Genetic material stores an organisms genetic material

Answer 20

Average genes contain thousands of nucleotides
The base sequences store large amounts of genetic information
variations in DNA sequences account for species in individual differences

Question 21

Genetic information is susceptible to mutations in the information it encodes

Answer 21

Permanent changes can occur
changes can be positive and negative, the environment determines this

Question 22

Genetic information is precisely replicated in the cell division cycle

Answer 22

In the s phase of interphase

Question 23

Genetic material is expressed as a phenotype

Answer 23

Nucleotide sequences, copied into RNA , specify the sequences of amino acids in proteins which determines the phenotypes of the organism.

Question 24

What is semiconservative

Answer 24

The replication pattern

Question 25

What does semiconservative mean in relation to DNA replication

Answer 25

Each parent strand has a template, new molecules have one old and one new stand

Question 26

Initiation

Answer 26

Double helix is unwound, separating the two template strands and making them available for new base pairing

Question 27

Elongation

Answer 27

addition of nucleotides that form complementary base pairs with template DNA, incoming nucleotides are covalently linked by phosphodiester bonds.

Question 28

DNA helicase

Answer 28

unwinds the double helix and separates the two strands

Question 29

Single stranded binding proteins

Answer 29

bind to separated strands and prevent them from reforming the double helix

Question 30

DNA Primase

Answer 30

Creates an RNA primer

Question 31

DNA polymerase

Answer 31

links the new nucleotides to form the new DNA strands and removes the primers

Question 32

DNA Ligase

Answer 32

connects Okazaki fragments made by DNA polymerase to one another

Question 33

Telomeres

Answer 33

Repeated DNA sequences at the ends of eukaryotic chromosomes

Question 34

Continually dividing cells

Answer 34

Have telomerase, which catalyzes addition of lost telomeres.

Question 35

Proofreading

Answer 35

If an incorrect nucleotide is added, DNA polymerase recognizes the mismatched pairs and removes incorrectly paired bases.

Question 36

Mismatch repair

Answer 36

Newly replicated DNA is scanned for mismatched pairs in proofreading, enzymes detect bulges where wrong bases are inserted. When this occurs the DNA sequences are altered.

Question 37

Excision repair

Answer 37

DNA is scanned for damaged nucleotides, where they are replaced and removed for functional ones.