Lecture 1 & 2

Question 1

Genetic Info is ____

Answer 1

transmissible

Question 2

What provided the first proof that DNA is genetic material? And how?

Answer 2

Bacterial transformation because it showed that DNA extracted from one bacterial strain can change properties on second strain

Question 3

How did phage infection prove that DNA is genetic material of viruses?

Answer 3

When DNA and protein components of bacterial viruses were labeled with radioactive isotopes, only the DNA is transmitted to the phages produced within infected bacteria

Question 4

What are the components of DNA/RNA?

Answer 4

5 carbon sugar (pentose), phosphate group, nitrogenous base (purine or pyrimidine)

Question 5

What is the structure of a deoxyribose sugar? Draw it as well

Answer 5

5 carbon with hydroxyl group on 3’ carbon and no hydroxyl group on 2’

Question 6

What is structure of ribose sugar? Draw it as well

Answer 6

5 carbon with hydroxyl group on 2’ carbon

Question 7

How many carbons in a pyrimidine?

Answer 7

6

Question 8

Where do you start counting atoms for prymidines?

Answer 8

Start at the nitrogen (go towards the singular carbon)

Question 9

What are the prymidines?

Answer 9

Cytosine, Thymine, Uracil

Question 10

What is the structure of a cytosine? Draw it

Answer 10

Double bond oxygen on C2, amino group (NH2) on C4

Question 11

What is the structure of thymine? Draw it

Answer 11

Double bond oxygen on C2, double bond oxygen on C4, methyl (CH3) on C5

Question 12

What is the structure of Uracil? Draw it

Answer 12

Double bound oxygen on C2, double bond oxygen on C4, H off of N3 (remove the amino group from C4 in cytosine)

Question 13

How many atoms in purines?

Answer 13

9

Question 14

How do you count atoms in purines?

Answer 14

Start at N, go to singular C, then to the N and around the rest of the circle (like you do for pyrimidines), then start at N on the opposite side of C5 and go around

Question 15

What are the purines?

Answer 15

Adenine and guanine

Question 16

What is the structure of adenine? Draw it

Answer 16

Amino group off of C6

Question 17

What is the structure of guanine? Draw it

Answer 17

Amino group off of C2, double bond oxygen off of C6

Question 18

What is the bond between sugar and base called? What atoms does it go between?

Answer 18

N-gylcosidic bond
Pyrimidine: bond between 1’ and N1
Purine: bond between 1’ and N9

Question 19

What is the difference in phosphate between DNA and RNA?

Answer 19

the number of phosphate groups

Question 20

Where is the bond between the sugar and phosphate group?

Answer 20

Between the 5’ carbon and oxygen off of phosphate group

Question 21

What is the bond between nucleotides called?

Answer 21

3’ to 5’ phosphodiester linkage

Question 22

Is DNA parallel or antiparallel?

Answer 22

Antiparallel

Question 23

What bases pair up?

Answer 23

A-T (DNA), A-U (RNA), C-G

Question 24

Is it easier to break A-T or C-G and why?

Answer 24

A-T because there are only 2 h-bonds to break instead of 3

Question 25

What is the major groove? What is the minor groove? Which is easier to access DNA in? (For b DNA)

Answer 25

The major groove is the wider of the two grooves in DNA. It is easier to access minor groove DNA

Question 26

What are the different types of DNA? Are they right handed or left handed?

Answer 26

A - right hand, B - right hand, Z - left handed

Question 27

What is the diameter of B DNA? How long does it take to complete a turn?

Answer 27

2nm diameter, 10 bp per turn so 3.4 nm

Question 28

How is DNA packaged in bacterias? What proteins help with this?

Answer 28

Packaged into nucleoids by proteins that include H-NS (histone-like nucleoid structuring protein) and Fis (factor for inversion stimulation)

Question 29

How is DNA packaged in eurkaryotes?

Answer 29

Packaged by wrapping around nucleosomes and poorly-defined higher order structures