Molecular Basis Of Inheritence Flashcards
What does genetic code determines?
Sequence of amino acids in proteins
The length of DNA is usually defined as?
Number of nucleotides (or a pair of nucleotides) present in it.
Place in asceding order of no of nucleotides or base pairs. Bacteriophage phi*174 ,bacteriphage lamba,e coli, haploid content of human.
Bacteriphage phi174(5386) < bacteriphage lambda(48502) < e coli(4.610^6) < human haploid(3.3*10^9)
Linkage between sugar and base
N -glycosidic linkage
Linkage between two nucleotides
Phosphodiester linkage
What does 5’ end of chain has
Phosphate moiety
What does 3’ end of chain has
OH group at 3’ carbon of sugar
Pyrimidines are how many ring compund?give example
Single ring
Thymine,cytosine,uracil
In purines how many rings are seen?give example
Two
Adenine guanine
Thymine is also called
5 methyl uracil
Make structure if adenine and uracil
.
Diff between deoxyribose and ribose
In ribose there is OH group at 2’ carbon
What is pitch in DNA.
Distance (line) parallel to the helix that corresponds to one turn.
34 angstrom
3.4nm
How many base pairs are there in one pitch/one turn
10
Lenth of one base pair
0.34nm
What is B Dna
Dna with structural characteristics of 3.4nm pitch
The two chains are coiled in which fashion?
Right handed
What was the hallmark proposition of double helical model of DNA? Watson and Crick stole that idea from whom?
Base pairing between the two strands of nucleotide chains.
This was based on the proposition made by Erwin Chargaff that the ration of adenine and thymine and guanine and cytosine is one.
Who was the first to detect DNA as the acidic substance present in nucleus?when?
Friedrich Meischer in 1869
When and who proposed double helix model of DNA structure?
James Watson and Francis Crick
In 1953
Double helical modelwas based on x ray diffraction data produced by?
Maurice Wilkins and Rosalind Franklin
Who proposed central dogma?
Francis Crick
What is the typical dimension of nucleus?
10^-6
What is the length of Dna in human
2.2m
Is DNA scattered in whole cell of prokaryotes as they don’t have nucleus?if not how it is organised?
Itdna is negatively charged and held together by positively charged proteins in region termed as nucleoid.this dna is organised in large loops held by proteins.
Why histones can bind Dna?
Because they are positively charged and basic as dna is negatively charged and acidic.
So they attract each other
Histones are rich in which type of amino acids?what type of chrage their residues carry?
Lysine and arginine.
Positive
Dna plus histone octamer?how does ot look lik
Nucleosome.beads on string
How many base pair of dna is wrapped around in one nucleosome?
200
How many beads can be seen in one cell?
3.3*10^7
The beads on string structure is packaged to form?
Chromatin fibres
Chromatin fibres are further coiled to form?
Chromosome
Where are non histone proteins used?
For packaging of chromatic fibres at higher level.
What is euchromatin?
The region of chromatin in typical nucleus that is loosely packed and lightly stained.
What is hetrochromatin?
Region of chromatin that densely packed and stains dark.
It is inactive .
