Chapter 16

Question 1

In Fredrick griffiths experiment why did the mice injected with both heat killed s cells and living r cells die, when neither one alone was fatal?

Answer 1

The r bacteria was transformed into an s bacteria by an unknown heritable substance

Question 2

A change in genotype and phenotype due to the assimilation of external dna by a cell

Answer 2

Transformation

Question 3

Viruses that infect bacteria

Answer 3

Bacteriophages

Question 4

Hershey and chase created phages with radioactive protein and phages with radioactive DNA. Which one resulted in radioactive bacteria? Why?

Answer 4

DNA

it functions as the genetic material of phage t2

Question 5

What year did Watson crick publish their structure for DNA

Answer 5

1953

Question 6

Chargoffs rule

Answer 6

A=t

C=g

Question 7

Two strands of DNA w double helix and sugar-phosphate backbone

Answer 7

See chapter notes

Question 8

Nucleotide pairs

Answer 8

C & G

A & T

Question 9

DNA is replicated by base pairing to a template strand. If you missed class and copied your friends notes, who’s notes are acting as a template?

Answer 9

The friends

Question 10

In a new DNA molecule ___ of the new double helix is made up of nucleotides from the previously existing molecule

Answer 10

Half

Question 11

DNA replication can only begin at particular called

Answer 11

Origins of replication

Question 12

Diagram of replication fork

Answer 12

See chapter notes

Question 13

Unwinds and pulls apart the 2 DNA strands

Answer 13

Helicase

Question 14

Prevents over winding

Answer 14

Topi isomerism

Question 15

Builds primer (short RNA sequence to begin new strand)

Answer 15

Promise

Question 16

Adds DNA nucleotides to 3’ end of growing strand

Answer 16

DNA polymerase

Question 17

DNA polymerase can only add nucleotides to an existing chain, so in order to initiate replication it requires a short chain of RNA called

Answer 17

Primer

Question 18

Bc of the antiparallel structure of DNA, each single strand has a 3’ end a

Answer 18

5’ end

Question 19

DNA polymerase can only add nucleotides to the ___ end of the growing new strand

Answer 19

3’

Question 20

Elongation occurs in the direction away from the ___ end of the template strand and towards the ____ end of the template strand

Answer 20

5’

3’

Question 21

The lagging strand cannot be but in one continuous piece, and must be pieces together as a series of segments called

Answer 21

Okazaki fragments

Question 22

Each of these segments begins with a ____ made of RNA

Answer 22

Primer

Question 23

A primer is eventually replaced with DNA by the enzyme ____

Answer 23

DNA polymerase

Question 24

The segments are joined together into a continuous strand by the enzyme

Answer 24

DNA ligase

Question 25

Mechanisms for minimizing errors in DNA replication

Answer 25

Proofreading by the enzyme DNA polymerase during replication
Removal and replacement of incorrect nucleotides during replication, in a process know as mismatch repair
Removal of a damaged DNA strand after replication is complete by the enzyme nuclease

Question 26

The 5’ end of the lagging strand consists of a primer made of

Answer 26

RNA

Question 27

This primer cannot be replaced because DNA polymerase ____ add nucleotides to the 5’ end of the strands

Answer 27

Cannot

Question 28

With each replication, a linear chromosome becomes

Answer 28

Shorter

Question 29

The end of each of our chromosomes consists of a chunk of nonsense DNA known as

Answer 29

Telomeres

Question 30

In germ cells (cells that produce egg and sperm) this nonsense DNA is lengthened by the enzyme

Answer 30

Telomerase

Question 31

What would happen if you had no telomerase in your germ cells?

Answer 31

Babies would be born w no telomeres - would be born already old

Question 32

What would happen if you had telomeres in all of your cells?

Answer 32

More susceptible to cancer