Molecular biochemistry w1 redo

Question 1

What do most DNA exist as

Answer 1

• dsDNA

Question 2

What is the primary structure

Answer 2

sequence of nucleotides

Question 3

What is the secondary sturcture

Answer 3

Refres the alpha helix and beta pleated sheet

Question 4

In eukaryotes where is DNA+ what is it asscoiated with

Answer 4

Nucles, associated with proteins

Question 5

In prolaryotes where is DNA

Answer 5

• nucleoid

Question 6

What is at the 5’ end of DNA

Answer 6

• Phosphate group

Question 7

What is at the 3 end

Answer 7

• hudroxyl group

Question 8

What direction are DNA sequences written

Answer 8

• 5’ to 3’ direction

Question 9

What enzmye is used to hydrolyze phosphodiester bonds in DNA

Answer 9

Deoxyribonucleases

Question 10

What enzmye is used to hydrolyze phosphodiester bonds in RNA

Answer 10

• Ribonucleases

Question 11

DO Alkaline conditions cleave RNA or DNA

Answer 11

rna

Question 12

What does the double hekix structure create

Answer 12

• major and minor grooves where regulatory proteins bind

Question 13

How many h bonds between A - T + C-g

Answer 13

A-T = 2 hydrogen bonds
C-G= 3 hydrogen bonds

Question 14

What does Chargaffs rule state?

Answer 14

• DNA contains equal amounts of A&T + C&G

Question 15

What stabilizes the DNA helix

Answer 15

• Hydrogen bonds + hydrophobic stacking

Question 16

What happens in denaturation

Answer 16

• The H bonds between the bases are disturpted by :
  -heat and pH changes
  -The covalent bonds remain intact

Question 17

What is the melting temperature+ when it is higher

Answer 17

• The temperature where half the DNA becomes single-stranded
• DNA with guanine and cytosine

Question 18

What does denaturation increase

Answer 18

Absorbance

Question 19

What is the overall purpose of renaturation

Answer 19

• Cooling and restoring neutral pH

Question 20

Name the 3 structural forms of DNA

Answer 20

• B-DNA
  -A-DNA
  Z-DNA

Question 21

wHAT IS The most common type of DNA

Answer 21

• b-dna

Question 22

What is the structure of B-DNA+ the structure of the base pairs

Answer 22

Right handed helix
- Base pairs are perpendicular

Question 23

Explain the structure of A-DNA+ base pairs+ Wher is it found

Answer 23

• Right handed
  -Base pairs tilted
• Found in DNA-rna HYBRIDS

Question 24

What type of condtins is A-DNA formed under

Answer 24

• dehydrating conditions

Question 25

What is the structure of Z-DNA+ what does it play a role in+ structure of backbone

Answer 25

- left handed helix -Plays a role in gene regulation -Has zigzag backbone

Question 26

What does a nucleotide contain

Answer 26

- phosphoric acid(phosphat group) - Pentose sugar Nitogenous base

Question 27

What does a nucleoside contain

Answer 27

- Pentose sugar - Nitrogenous base

Question 28

Name purines

Answer 28

Adenine + guanine

Question 29

Name pyrimidines

Answer 29

cytosine and thymine

Question 30

Explain the structure of Eukaryotic DNA

Answer 30

- long linear double-stranded DNA

Question 31

In eukaryotic DNA, what is DNA packed with+ what this formed

Answer 31

- Packed wth histones and nonhistone proteins, forming chromatin

Question 31

What type of DNA does mitochondria contain

Answer 31

- circular dsDNA

Question 31

Explain the strcure of prokaryotic DNA

Answer 31

single circular DNA

Question 32

In prokaryotes what is DNA compacted with

Answer 32

- Nonhistone proteins into a structure called nucleoid

Question 33

What is the function of plasmids

Answer 33

- carry genetic information

Question 34

Wht is plasmids(structure)

Answer 34

small circular extrachromosomal DNA molecules

Question 35

What is used as vectores in recombinant DNA technonolgy

Answer 35

Plasmids

Question 36

In deamination reactions what does these produces: -Cytosine -Adenine -Guanine 5-methylcytosine

Answer 36

cytosine- uracil adenine- hypoxanthine guanine- xanthine 5 msthylcytosine- thymine

Question 37

What does the methylation of uracil make

Answer 37

thymine