Ch 7 DNA

Question 1

What are the purine bases?

Answer 1

Adenine

Guanine

Question 2

What are the pyrimidine bases?

Answer 2

Thymine
Cytosine
Uracil

Question 3

What is Streptococcus pneumonia?

Answer 3

Pathogen that can cause benign infections

Question 4

What do smooth strains of streptococcus pneumonia produce? (S) cells

Answer 4

Capsule called Virulent which are deadly

Question 5

What are rough strains of streptococcus pneumonia called? (R) cells

Answer 5

Avirulent which are benign

Question 6

What is the capsule of the smooth strain?

Answer 6

Extracellular polysaccharides that are sticky

Question 7

Is the capsule deadly or harmless?

Answer 7

(S) cells containing capsule are deadly

Question 8

What happens to the mice injected with (R) strain? (Avirulent)

Answer 8

They live; it’s harmless

No capsule renders it benign

Question 9

What happens if mice are injected with live (S) strain cells (Virulent)?

Answer 9

It dies; (S) cells are virulent

Overwhelm immune system

Question 10

What happens to mice injected with (S) cells that have been heated to kill the cells?

Answer 10

They live; Virus is dead

Question 11

What happens to mice injected with live harmless (R) cells and heat killed (S) cells?

Answer 11

They die; The heat killed (S) cells broke open and transformed (R) cells.
(R) cells absorbed (S) cell DNA making them deadly

Question 12

What did Griffith’s transforming principle conclude?

Answer 12

Something in (S) cell DNA, RNA and Proteins transformed (R) cells. Assumption was proteins were inherited

Question 13

What are Degradative enzymes?

What do they destroy?

Answer 13

RNase - RNA only
Protease - Proteins only
DNase - DNA only
You can identify which degradative enzyme by which it destroys

Question 14

What happened when DNase was added to heat-killed (S) cells?

Answer 14

DNase killed the DNA preventing capsule from growing

Question 15

Was the transforming principle experiment a paradigm shift? Was the finding of DNA being the molecule of inheritance important?

Answer 15

Yes it was a paradigm shift
Won a Nobel prize
Discovered horizontal gene transfer

Question 16

What is the 3 Dimensional structure of DNA?

Answer 16

Double Helix
RIght handed twist every 3.4 nm
Diameter of 2.0 nm

Question 17

What did streptococcus do?

Answer 17

(R) strains absorbed DNA from the (S) strains and made the capsule

Question 18

What is horizontal gene transfer?

Answer 18

Acquiring DNA from environment to make part of their chromosome

Question 19

Does the number of pyrimidines always equal the number of purines?

Answer 19

Yes

Question 20

How did Rosalind Franklin capture a photo of DNA

Answer 20

X-Ray Crystallography

2D image

Question 21

Who determined the double helix shape of DNA?

Answer 21

Francis Crick and James Watson without any of their own experiments and won Nobel prizes

Question 22

Who won the Nobel prize for discovering the structure of DNA?

Answer 22

Watson
Crick
Maurice Wilkins (Helix shape/Right-hand twist)

Question 23

What is DNA composed of

Answer 23

Phosphate
Sugar
Base

Question 24

How are A and T and G and C paired?

Answer 24

Hydrogen bonds

Question 25

How many hydrogen bonds do A and T always have?

Answer 25

2

Question 26

How many hydrogens bonds do G and C always have?

Answer 26

3

Question 27

How are the strands of DNA held together?

Answer 27

Hydrogen bonds

Question 28

DNA is anti-parallel T/F

Answer 28

True

Question 29

In what direction is DNA copied?

Answer 29

5 Prime to 3 Prime

Question 30

DNA is made to engage proteins T/F

Answer 30

True

Question 31

What was the advantage of X-ray crystallography to measure DNA?

Answer 31

Scattering of X-RAYS produced a diagnostic pattern

Question 32

What was the breakthrough Watson and Crick made building DNA models?

Answer 32

Pairing of Py and Pu were consistent with 2nm diameter | Determined DNA was a double helix

Question 33

What did the Hershey and Chase experiment conclude?

Answer 33

DNA and NOT protein is in genetic bacteriophages; Singled out that DNA was responsible for inheritance

Question 34

Why is DNA held together by hydrogen bonds?

Answer 34

Hydrogen bonds are easy to break

Question 35

DNA is half old and new strands T/F

Answer 35

True

Question 36

Is DNA replication semi-conservative?

Answer 36

Yes

Question 37

What did Meselson and Stahl find int their experiment?

Answer 37

DNA replication is semiconservative

Question 38

How do N14 and N15 differ?

Answer 38

One neutron

Question 39

What does DNA polymerase do?

Answer 39

- Enzymes that put in complementary base - Proofreads - 1 in every billion nucleotides it makes a mistake

Question 40

What happens to DNA before it is replicated?

Answer 40

It is pulled apart by replisome

Question 41

What is a replisome?

Answer 41

Protein that carries out replication and unwinds DNA for it to be copied

Question 42

What do DNA polymerase Dimers do?

Answer 42

Ensure DNA is simultaneously copied but only in 5 prime to 3 prime direction

Question 43

Why is it important for bio students to ID the 5' and 3' prime carbons in Deoxyribose?

Answer 43

Knowledge of DNA structure is important for understanding biological processes

Question 44

Avery, Macleod, and McCarty followed up Griffith's transforming principle by treating heat killed (S) cells then added (R) cells. What did it conclude?

Answer 44

Only solutions with intact (S) cell DNA resulted in transformation

Question 45

Hydrogen and Oxygen are highly electronegative? T/F

Answer 45

True

Question 46

What is complimentary base pairing?

Answer 46

Bases like PY and PU pairing together

Question 47

When the (S) cell was heat killed and broke open, What did the benign (R) cells absorb to make them deadly?

Answer 47

(S) cell DNA | (R) cells acquired the genes that formed capsule

Question 48

What did Griffth's experiment find?

Answer 48

How genetics and inheritance work

Question 49

What is the molecule of inheritance?

Answer 49

DNA

Question 50

What is the portion "Deoxyribose" made up of?

Answer 50

Phosphate and sugar backbone

Question 51

What was Chragaff's findings?

Answer 51

Purines always equaled Pyrimidines