molecular basis of inheritance

a bacteriophage known as φ ×174 has

5386 nucleotide

Bacteriophage lambda has

48502 bp

Escherichia coli has

4.6 × 10⁶ bp

haploid content of human DNA

3.3 × 10⁹ bp

adenine

purine

cytosine

pyrimidine

guanine

purine

thymine

pyrimidine

uracil

pyrimidine

A nitrogenous base is linked to the OH of ____ pentose sugar

1’C

phosphate group is linked to OH of 5' C of a nucleoside through_____

phosphoester linkage

The backbone of a polynucleotide chain is formed due to

sugar and phosphate

isolation of DNA was done by

Friedrich Meischer

The pitch of the helix of DNA is

3.4nm

the distance between a bp in a helix is approximately

0.34nm

which scientist gave the central dogma

Francis Crick

The negatively charged DNA is wrapped around the positively charged histone octamer to form a structure called

nucleosome

typically nucleosome contains ___bp

200

typically 2 nucleosome can have_____bp

400

The packaging of chromatin at higher level requires additional set of proteins that collectively are referred to as

non histone chromosomal protein

nucleosome = DNA+___

histone octamer

densely stained part of chromatin

heterochromatin

transcriptionally inactive

heterochromatin

light stained chromatin part

euchromatin

transcriptionally active

euchromatin

in 1928 which scientist indirectly proved that the genetic material is sort of heat stable

Frederick Griffith

in the experiment of transforming principle which organism was used

Streptococcus pneumoniae

Frederick Griffith is associated with

transforming principle

Oswald Avery, Colin MacLeod and Maclyn McCarty were associated with

biochemical nature of transforming principle

alfred hershey and martha chase were associated with

unequivocal proof

when the bacteriophage is grown in radioactive suplhur then on centrifugation the suphur is retained in

supernatant

when the bacteriophage is grown in radioactive phosphorus then on centrifugation the phosphorus is retained in

bacteria

generally bacteriophages have dsDNA exception to this is

QB bacteriophage

ex of RNA viruses

QB bacteriophage and Tobacco Mosaic virus

better for storage of genetic material

DNA

better for transmission of genetic information

RNA

who gave the initial idea of DNA replication

Watson and Crick

Matthew Meselson and Franklin stahl are associated with

experimental proof of DNA replication

organism used in the proof of semiconservative DNA replication

E.coli

compound used as density gradient in the experiment to prove semiconservative DNA replication

Caseium chloride (CsCl)

who used radioactive thymidine to prove the semiconservative DNA replication

Taylor and collegues

the radioactive thymidine to detect new chromosome was performed on which plant

Vicia faba

enzyme responsible for DNA replication

DNA-dependent DNA polymerase

E.coli can replicate within

18 minutes

E.coli can divide within

20 minutes

during replication ______ in addition to acting as substrate also provide energy for polymerisation

deoxyribonucleoside triphosphate

in replication _____ serves dual function

deoxyribonucleoside triphosphate

replication of template strand from 3’-5’ is

continuous

replication of template strand from 5’-3’ is

discontinuous

the discontinuously formed fragments are joined by

DNA ligase

A failure in cell division after DNA replication results into

polyploidy

the process of transcription requires an enzyme

DNA dependent RNA polymerase

during transcription 3’-5’ strand acts as

template strand

during transcription 5’-3’ strand acts as

coding strand

All the reference point while defining a transcription unit is made with

coding strand

The promoter is said to be located towards_____ of structural gene

5’(upstream)

The terminator is said to be located towards_____ of structural gene

3’(downstream)

the DNA sequence coding for tRNA or rRNA molecule is called

gene

sequences which appears in mature RNA

exons

sequences do not appear in mature or processed RNA

introns

regulatory genes

do not code for RNA or proteins

which type of RNA provides template

mRNA

which type of RNA brings amino acid

tRNA

which type of RNA reads the genetic code

tRNA

which type of RNA plays structural role

rRNA

which type of RNA plays catalytic role

rRNA

RNA polymerase uses_____ as substrate

nucleoside triphosphate

RNA polymerase is only capable of catalysing the process of

elongation

transcribes rRNA

RNA polymerase I

transcribes 28S, 18S, 5.8S

RNA polymerase I

transcribes precursor of mRNA

RNA polymerase II

transcribes tRNA

RNA polymerase III

transcribes 5srRNA

RNA polymerase III

transcribes snRNA

RNA polymerase III

unusual nucleotide (methyl guanosine triphosphate) this is

capping

capping is done on which end

5’

adenylate residues (200-300) added this is

tailing

tailling is done on which end

3’

The process of _______ requires transfer of genetic information from a polymer of nucleotides to synthesise a polymer of amino acid

translation

who argued that since there are only 4 bases and if they have to code for
20 amino acids, the code should be made up of three nucleotides
a permutation combination of 4³ (4 × 4 × 4) would generate 64 codon

George Gamow

who was instrumental in synthesising RNA molecules with defined combinations
of bases (homopolymers and copolymers)

Har Gobind Khorana

who’s cell-free system for protein synthesis finally helped the code to be deciphered

Marshal Nirenberg

_______ was helpful in polymerising RNA with defined sequences in a template independent manner

Severo Ochoa enzyme

Severo Ochoa enzyme aka

polynucleotide phosphorylase

Some amino acids are coded by more than one codon, hence the code is

degenerate

UUU

phenylalanine

AUG

methionine

CCC

proline

AAA

lysine

GGG

glycine

From the very beginning of the proposition of code, it was clear to _______ that there has to be a mechanism to read the code and also to link it to the amino acids, because amino acids have no structural specialities to read the code uniquely.

Francis Crick

which scientist postulated the presence of tRNA

Francis Crick

type of RNA which initiates the process of translation

initiator tRNA

2^o structure of tRNA

clover leaf

actual structure of tRNA

inverted L

1st step of translation is

aminoacylation of tRNA

The ribosome consists of structural RNAs and about _____different proteins

eighty

when the _____ subunit of ribosome encounters the mRNA the process of translation begins

smaller

the _____ subunit of ribosome continues the elongation of the amino acid chain

larger

tRNA aka

solubleRNA