Chapter 4: DNA, RNA and the flow of genetic material

Question 1

Hvilke N-atomer danner glykosid bindinger i pyrimidiner og purines

Answer 1

N-1 ,

N-9

Question 2

What is the glycosidic bond in nucleotides

Answer 2

N-B-glycosidic linkage

Question 3

nucleosides

Answer 3

adenosine, guanosine, thymidine and cytidine

Question 4

In DNA, nucleoside monophosphates are called

Answer 4

deoxyadenylate, deoxyguanylate, deoxycytidylate, thymidylate

Question 5

how many chromosomes

Answer 5

22 autosomal + x and y

Question 6

The double helical structure facilitates

Answer 6

replication

Question 7

The rotation per base in a DNA-helix

Answer 7

36

Question 8

Bases per helical turn

Answer 8

10,4

Question 9

vertical separation between bases in a DNA-helix

Answer 9

3,4

Question 10

the length of a helical turn

Answer 10

34

Question 11

Stacking forces arise fro

Answer 11

Van der Waals interactions between vertical bases

Question 12

Under physiological conditions, which form of DNA is present?

Answer 12

B

Question 13

Difference between A and B forms

Answer 13

A is shorter, wider, bases are tilted with regards to the helical axis

Question 14

Dehydration favours which form of DNA

Answer 14

A-form it binds fewer H2O than B-form

Question 15

why differences between A, B arise

Answer 15

Because of puckering of ribose units
C2- in B is out of plane. C2-endo
C3- in A is out of plane

Question 16

Z-form is because

Answer 16

Backbone is zigzagged

Question 17

The negative charge of backbone repels which ions and reduce the hydrolytic attacks on phosphate groups

Answer 17

Hydroxide ions (alkaline compounds)

Question 18

why is supercoiling of DNA-important?

Answer 18

1- more compact than the relaxed DNA

2- hinder or favor the capacity to binde other molecules

Question 19

Single stranded nucleic acids can be stabilised by metal ions such as

Answer 19

Mg2+

Question 20

Syn and anti orientations of glycosidic linkages

pyramidines and purins orientations?

Answer 20

base above the deoxyribose unit,away from deoxyribose unit,
pyrimidines can only be in anti
purines can be in both

Question 21

what is the conservativity of DNA-replication

Answer 21

Semiconservative model, one strand is from the parent and other strand is newly synthesised

Question 22

hypochromism

Answer 22

When stacking basepairs absorb less ultraviolet lighgt at 260 nm than when they are not in helical structure

Question 23

Genes in all cellular organismer are made of .,,, nucleic acids

Answer 23

DNA-nucleic acids

Question 24

Reverse transcriptase functions as …. and a ….

Answer 24

polymerase and an RNase

Question 25

what is eccDNA

Answer 25

Extrachromosomal circular DNA

Question 26

which types of RNA are most abundant

Answer 26

1 -ribosomal
2- transfer
3-mRNA

Question 27

Differences between DNA and RNA polymerases

Answer 27

RNA does not require a primer and is more prone to error

Question 28

at which ends are the cap and poly A-tail is added?

Answer 28

5’ (5’-5’ linkage)

3’ adenylates

Question 29

synonyms

Answer 29

codons encoding the same aminoacids

Question 30

Why is there a degeneracy in the genetic code?

Answer 30

Because there would be 44 codons stopping the translation og only 22 coding aminoacids. Therefore minimises the effects of mutations

Question 31

codon bias

Answer 31

A prefered set of synonymous codons in an organism and it is not random

Question 32

what mechanism is used to release antibodies and make them soluble?

Answer 32

alternative splicing of the primary transcript