Nucleotides/DNA Structure

Question 0

Purines

Answer 0

Adenine

Guanine

Question 1

Nucleic Acids - components

Answer 1

Bases, sugars, phosphate groups

Question 2

Prymidines

Answer 2

Cytosine
Thymine
Uracil

Question 3

Nuclosides

Answer 3

Purine and Prymidine bases and pentose (ribose or deoxyribose)

Question 4

Nulceotides

Answer 4

Phosphorylated nucleosides

Question 5

Oligonuclotides

Answer 5

Short polymers of nucleotides

Question 6

Ionic forces & DNA

Answer 6

Ionic forces also affect the stability and confirmation of double helix

Question 7

DNA ligase - fxn

Answer 7

Forms phosphodiester bonds between free 5’ and 3’ ends of DNA

Question 8

Active site of enzyme

Answer 8

contains substrate bindind site and the catalytic site

Question 9

Nucleases - fxn

Answer 9

Hydrolyze phosphodiester bonds

Question 10

Exonucleases - action

Answer 10

cleave the last nucleotide residue a either of the two terminals.

Question 11

Endonucleases - action

Answer 11

cleave phosphodiester bonds in the interior

Question 12

DNA confirmations

Answer 12

B, Z, A

Question 13

Common cell DNA confrimation

Answer 13

B

Question 14

Z -DNA

Answer 14

occurs within DNA sequences that control gene transcription

Question 15

A-DNA

Answer 15

form taken by DNA-RNA hybrid during transcription

Question 16

Topoisomerases - fxn

Answer 16

specific enzymes that regulate superhelices

Question 17

Topoisomerases - types

Answer 17

Type I
Type II
Gyrases

Question 18

Type I Topoisomerases

Answer 18

break only one DNA strand and alllow it to rotate about the other to relive the super coil. Also reseal the break that was created after supercoild relieved

Question 19

Type II Topoisomerases

Answer 19

beak both DNA strands, relax the supercoil and then reseal the DNA.
REUIRES ATP

Question 20

Gyrases

Answer 20

Topoisomerases that relive supercoiling generated by the unwinding of DNA

Question 21

Topoisomerases - clinical function

Answer 21

Used as targets for antimicrobial and antineoplastic agents. They convert Topoisomerases into DNA-breaking agents by specifically interfering with DNA ligase activity of the topoisomerase.

Question 22

Alternative DNA Confirmations

Answer 22

DNA Bending
Cruciforms
Triplex DNA
Quadruplex DNA

Question 23

Cruciforms - def., fxn

Answer 23

regions of DNA in which interchain hydrogen bonds are disrupted and interchain bonds form
fxn in control of replication and transcription

Question 24

Hoogsten pairing

Answer 24

pairing of bases occurs in different faces of bases than do Watson and crick pairing

Question 25

Triplex DNA

Answer 25

Occurs in DNA w string of purine bases
Fxn in transcription control, initiation and termination of replication, exchanging telomeres stability
Third strand pairs with Hoogsten pairing

Question 26

triple stranded DNA - clinical

Answer 26

associated with hereditary persistence f fetal hemoglobin

Question 27

Quaduplex DNA

Answer 27

forms in immunoglobulin genes that undergo recombination

also occurs in teleomeres

Question 28

Histones

Answer 28

Basic proteins in eukaryotic DNA

NOT in prokaryotic DNA, instead HU protiens

Question 29

Chromatin

Answer 29

DNA with its associated proteins

During cell division, becomes condensed to chromosones

Question 30

Chormosones - components

Answer 30

Condensed chromatin
Centromere
Telomere

Question 31

Centromere

Answer 31

site of attachment of the chromosome to the mitotic spindle

Question 32

Telomere

Answer 32

ends of chromosomes

Question 33

Structural genes

Answer 33

DNA coding sequences that code for protein