Ch.12 DNA

Question 1

Frederick Griffiths experiment

Answer 1

Injected R pneumonia into mice that didnt die
But S pneumonia did make them die
Dead S did not kill them BUT
Dead S mixed with live R killed them! And found LIVE S DNA in it

Question 2

Conclusions of Griffiths experiment

Answer 2

There was some transforming substance that turned R pneumonia into S pneumonia!

Question 3

Transformation

Answer 3

Process in which one strain of bacteria so changed by a gene from another strand of bacteria

Question 4

S pneumonia

Answer 4

pneumonia with a sugar coat that makes it too slippery for cells to kill so it reproduces (rampid) and eventually kills the host. Pathogenic

Question 5

McCarthy, Avery, and Mac Leod

Answer 5

Mixed different enzymes to dead S pneumonia and R and then if a mouse survived that means the specific enzyme killed the transforming substance! The mouse with a DNA destroying enzyme survived because DNA was destroyed which means the R never transformed into S!

Question 6

Bacteriophages

Answer 6

A kind of virus that infects bacteria

• enters a bacteria, attaches to the surface and injects its DNA into it
• the bacteria then starts to use this DNA and produces more pages until the bacteria explodes releasing them to go infect more bacteria

Question 7

Hershey and Chase experiment

Answer 7

Added radioactive sulphur to the protein coat of pages and radioactive phosphorus in the DNA of the phage
When the pages were spun off there was radioactive phosphorus in the bacteria proving that DNA was the substance being injected into the phage, not proteins

Question 8

What are the restrictions of bases in the sequence of DNA

Answer 8

Every Adenine must be bonded to a thymine and every guanine to a cytosine but no restriction on the order of the bases

Question 9

Who discovered the shape of DNA

Answer 9

Watson and Crick

Question 10

Shy is DNA a polymer

Answer 10

It is a long chain of nucleotides which are monomers and by definition the DNA must be a polymer.
Called a polynucleotide

Question 11

Phosphate group

Answer 11

A phosphate with a halo of oxygen

-negative charge

Question 12

Deoxyribose sugar

Answer 12

A 5 carbon ribose sugar without one oxygen

Question 13

Nitrogen base

Answer 13

4 kinds

Single or double ring

Question 14

Components of a nucleotide

Answer 14

Phosphate group—> deoxyribose sugar—> base

Question 15

What part of the nucleotide do the bases bond to?

Answer 15

The deoxyribose sugar

Question 16

Which base bonds to which base?

Answer 16

Adenine to thymine

Guanine to cytosine

Question 17

Purines

Answer 17

Double ringed bases

Adenine and guanine

Question 18

Pyrimidines

Answer 18

Single ringed bases

Thymine and cytosine

Question 19

What is the “backbone” of the DNA?

Answer 19

Alternating phosphate groups and sugar

Question 20

What are the “uprights”

Answer 20

Nitrogen bases

Question 21

What holds the double helix together

Answer 21

The nitrogen bonds between the bases

Question 22

Roslyn Franklin and Maurice Wilkins

Answer 22

Used X-ray crystallography to figure out DNA was a double helix

Question 23

Chargaff

Answer 23

Found the number of C always = G and A = T

Question 24

Where does DNA replication happen

Answer 24

In the nucleus in sites called “origins of replication”

Question 25

When does DNA replication happen

Answer 25

During interphase, S period S stands for DNA synthesis

Question 26

Helicase

Answer 26

An enzyme that untwists and separates the 2 strands of DNA

-breaks the hydrogen bonds between the bases

Question 27

DNA polymerase

Answer 27

Adds new free floating nucleotides to the old strands