Chapter 4: DNA, RNA and the flow of genetic material Flashcards
Hvilke N-atomer danner glykosid bindinger i pyrimidiner og purines
N-1 ,
N-9
What is the glycosidic bond in nucleotides
N-B-glycosidic linkage
nucleosides
adenosine, guanosine, thymidine and cytidine
In DNA, nucleoside monophosphates are called
deoxyadenylate, deoxyguanylate, deoxycytidylate, thymidylate
how many chromosomes
22 autosomal + x and y
The double helical structure facilitates
replication
The rotation per base in a DNA-helix
36
Bases per helical turn
10,4
vertical separation between bases in a DNA-helix
3,4
the length of a helical turn
34
Stacking forces arise fro
Van der Waals interactions between vertical bases
Under physiological conditions, which form of DNA is present?
B
Difference between A and B forms
A is shorter, wider, bases are tilted with regards to the helical axis
Dehydration favours which form of DNA
A-form it binds fewer H2O than B-form
why differences between A, B arise
Because of puckering of ribose units
C2- in B is out of plane. C2-endo
C3- in A is out of plane
Z-form is because
Backbone is zigzagged
The negative charge of backbone repels which ions and reduce the hydrolytic attacks on phosphate groups
Hydroxide ions (alkaline compounds)
why is supercoiling of DNA-important?
1- more compact than the relaxed DNA
2- hinder or favor the capacity to binde other molecules
Single stranded nucleic acids can be stabilised by metal ions such as
Mg2+
Syn and anti orientations of glycosidic linkages
pyramidines and purins orientations?
base above the deoxyribose unit,away from deoxyribose unit,
pyrimidines can only be in anti
purines can be in both
what is the conservativity of DNA-replication
Semiconservative model, one strand is from the parent and other strand is newly synthesised
hypochromism
When stacking basepairs absorb less ultraviolet lighgt at 260 nm than when they are not in helical structure
Genes in all cellular organismer are made of .,,, nucleic acids
DNA-nucleic acids
Reverse transcriptase functions as …. and a ….
polymerase and an RNase
what is eccDNA
Extrachromosomal circular DNA
which types of RNA are most abundant
1 -ribosomal
2- transfer
3-mRNA
Differences between DNA and RNA polymerases
RNA does not require a primer and is more prone to error
at which ends are the cap and poly A-tail is added?
5’ (5’-5’ linkage)
3’ adenylates
synonyms
codons encoding the same aminoacids
Why is there a degeneracy in the genetic code?
Because there would be 44 codons stopping the translation og only 22 coding aminoacids. Therefore minimises the effects of mutations
codon bias
A prefered set of synonymous codons in an organism and it is not random
what mechanism is used to release antibodies and make them soluble?
alternative splicing of the primary transcript
