DNA Stucture

Question 1

What is a monomeric unit of dna made of

Answer 1

The sugar, phosphate attached to it and the base attached to it

Question 2

What is dna

Answer 2

Form of linear information where the sequence of based characterizes the nucleic acid

Question 3

What is the sugar of the monomeric unit

Answer 3

It’s an aldopentose in furanose form (5 membered ring

Question 4

What diff in ribonucleic acid (RNA) compared to deoxy (DNA)

Answer 4

RNA has 2 prime oh on the sugar

DNA has 2’ H

Question 5

Where does the phosphate group link in dna/rna

Answer 5

The 3’ oh of one and the 5 oh of the other

Question 6

What is the diretionality of dna

Answer 6

Read from the 5 prime to the 3’ end

3’ is where the oh group is

Question 7

Which is more stable DNA or RNA and why

Answer 7

DNA because the 2’ Oh in rna can act as a nucleophile

This means it can hydrolyze its phosphodiester bond/backbone and is prone to degredation

Question 8

What are the purines

Answer 8

Adenine and guanine

Question 9

What are the pyrimidine

Answer 9

Cytosine thymine (in rna thymine is replace with uracil)

Question 10

Which nitrogen’s of the Purine and pyramids form the glycosidic bond with the sugar of the backbone

Answer 10

N9 of the purine

N1 of the pyrimidine

Question 11

Structures of bases memorize

Answer 11

Okay

Question 12

What is a nucleotide

Answer 12

The monomeric unit of dna/RNA

the base, the Pentose sugar, and 1 or more phosphate groups

Question 13

What type of bond it is between the sugar and the phosphate in a nucleotide

Answer 13

An ester linkage

Question 14

What is a nucleoside

Answer 14

Only the base and the Pentose sugars (no phosphates)

Question 15

If a nucleoside has one phosphate group it’s called:

Answer 15

Nucleoside monophophate

If the base attached is adenine this would be AMP

Question 16

If an rna nucleoside has adenine as a base what is it named

Answer 16

Adenosine

All types of adenosines (atp, amp, adp) are called adenylates

Question 17

If a DNA nucleoside has adenine as a base what is it named

Answer 17

Deoxyadenosine

All types of theses (datp,damp,dadp) are called deoxyadenylates

Question 18

What is the distance between stacked bases in the double helix

Answer 18

3.4A

Question 19

How many A in one full turn

How many bases per turn

Of the double helix

Answer 19

34A

10.4

Question 20

What is the width of the double helix

Answer 20

20A

Question 21

What degreee rotation is it in the double helix between each base

Answer 21

36 degrees

Question 22

What is the direction of the double helix

Answer 22

Right handed,

Opposites directionality on each strand (one is 5-3 other is 3-5)

Question 23

Bases are nearly _____ to the axis of the helix

Answer 23

Perpendicular

Question 24

How many h bond between GC

AT

Answer 24

3

2

Question 25

Why do purine pair with pyrimidines

Answer 25

To keep a uniform diameter of the helix

Question 26

What are the four types of base pairin

Answer 26

Watson crick Reverse Watson crick Wobble base pairs Hoogsteen

Question 27

Why does reverse Watson crick happen

Answer 27

Because of the 180 degree rotation of a base in rna or dna ends

Question 28

Why does wobble base pairing happen

Answer 28

Tautomerization (makes it pair with something else)

Question 29

Why does hoogsteen happen

Answer 29

Rotation around the c1 of the sugar to N of the base glycosidic bond This rotates the base This make it anti and syn In Watson crick the bases are anti anti

Question 30

Why are bases inside the helix

Answer 30

The hydrophobic effect where the hydrophobic interactions of the base move them away from water The more polar part of dna are on the outside This add stability to the helix

Question 31

Why are bases stacked

Answer 31

They attract each other by vander wall This gives stability of the helix through non covalent interactions

Question 32

What is the energy per vanderwall interaction of stacked bases

Answer 32

2.4kj/mol

Question 33

What is the major and minor groove of dna

Answer 33

The glycosidic bond to the backbone between opposite bases (base pairs) arent completely across from each other The major groove (12A) is where the distance between glycosidic bond it larger Minor (6A) is where the distance is shorter

Question 34

What are the major and minor grooves lined by

Answer 34

H bond donors and accpetors the are unique to each base pair They allow the base pair to be accessed by other protiens

Question 35

What are the three forms of dna

Answer 35

B A Z

Question 36

What are the B and a forms of dna

Answer 36

B is where the bases are perpendicular to the back bond A is where they are not, this is normally seen in dna rna hybrids. Caused by the rna 2’ oh causing hindrance Both still right handed helix

Question 37

What is the z form of DNA

Answer 37

It’s left handed and specific protiens bind only to this form This means it’s biologically significant

Question 38

If circular dna is unwound what forms can it take

Answer 38

Negative superhelix (unwound by three right hand turns) Unwound circle (unwound two times)

Question 39

Is supercoiled dna larger or smaller than telexed circular dna What does this mean

Answer 39

Smaller Travels further in gel

Question 40

What are nucleosome

Answer 40

Histone octamers with +200bp of dna wrapped around them

Question 41

How much dna is packaged into how many chromosome What is the diameter of the nucleus they’re packed in

Answer 41

3.6m 46 5 micrometers

Question 42

What are histones made of

Answer 42

Argenine and lysine (basic) residues

Question 43

What are nucleosomes compacted into By what factor

Answer 43

Chromatin Form left handed helical structures By a factor of 7

Question 44

What is the diameter of a histon octamer

Answer 44

100A

Question 45

How does rna fold Why is this Important

Answer 45

Into complex structure, It can create stem loops Its structures let it act as a catalyst. Ex. Ribozymes where AGC are all linked together