molecular basis of inheritance Flashcards
number of nucleotides in phix174
5386
number of bp in bacteriophage lambda
48502
number of bp in e coli
4.6x10^6
adenosine, guanosine,cytidine and uridine are
nucleosides
the additional OH grp of RNA is at
2’ position of ribose
dna as an acidic substance was first identified by federick meischer in
1869
double helix model proposed in
1953
pitch of the helix of dna
3.4 nm
how many base pairs in each turn of dna
10
distance between a bp in the helix of dna
0.34 nm
ventral dogma of biology proposed by
francis crick
dimension of typical nucleus
app. 10^-6
length of ecoli dna
1.36 mm
number of bp in a nucleosome
2000
year range of work of ostwald avery, collin macleod and maclynmccarty was
1933-1944
harshey and chase experiment in which year
1952
three steps in harshey and chase experiment
infection
blending
centrifugation
two eg for viruses that use rna as genetic material
qb bacteriophage
tobacco mosaic virus
stability as one of the properties of genetic material was evident in whose experiment
griffith experiment
what makes rna labileand easily degradable
extra oh at 2’
semiconservative replication was first shown in
ecoli
experiment on semiconservatic replication was done on which year
1958
e coli divides in how many minutes
20 min
similar experiment for semiconservative replication was done by taylor and colleagues using radioactive thymidine on vicia faba(faba beans) in which yesr
1958
rate of polymerisation in e coli
2000 bp / s
who provides energy for replication of dna
deoxyribonucleoside triphosphate
the two terminal phosphates in deoxyribonucleoside triphosphate are ____ phosphates, same as in the case of ___
high-energy
ATP
direction of polymerisation of dna dependent dna polymerase
5’ to 3’
three regions of transcription unit
promotor
structural gene
terminator
promotor is located at
5’ end of structural gene
functional unit of inheritance
gene
the dna sequence coding for ___ and ___ molecule also define a gene
tRNA and rRNA
monocistronic mostly in
eukaryotes
defining a cistron as a
segment of dna coding for a polypeptide
the __ complicates the definition of a gene in terms of dna segment
split gene arrangement
symbol of initiation factor
sigma
symbol of termination factor
rho
there are atleast __ RNA polymerases in the nucleus other than those found in the organelles
three
RNA polymerase I transcribes
rRNA (28s,18s,5.8s)
rRNA (28s,18s,5.8s) is transcribed by
RNA polymerase I
RNA polymerase II transcribes
hnRNA
RNA polymerase III transcribes (3)
tRNA, 5srRNA, snRNA
tRNA, 5srRNA, snRNA are transcribed by
RNA polymerase III
hnRNA is transcribed by
RNA polymerase II
capping of hnRNA is done at __ by adding
5’
methyl guanosine triphosphate
adenylate residues are addded to hnRNA during tailing, in a ___ ___ manner
template independent
the chemical method developed by ____ was instrumental in synthesising RNA molecules with defined combination of bases (homopolymers and copolymers)
Har Gobind Khorana
cell free system ofor protein synthesis is given by
Marshell Neirenberg
severo ochoa enzyme is a
polynucleotide phosphate
UUU codes for
phenylalanine
the code is universal. exception to this rule is found in ___ and ___
mitochondrial codons
some protozoans
deletion mutations are also called
frameshift mutations
tRNA wa searlier called
sRNA
the ribosomes consist of
RNAs and Proteins
how many different types of proteins can be seen in ribosome
80
which rna in bacteria is ribozyme
23S rRNA
during translation, amino acida are added one by one, translated into polypeptide sequences dictated by ___ and represented by ___
DNA
mRNA
at the end of translation, a ___ binds to the stop codon, terminating translation and releasing the complete polypeptide from the ribosome
release factor
which are the four levels at which regulation of gene expression could be exerted in eukaryotes
transcriptional level (formation of primary transcript)
processing level (regulation of splicing)
transport of mrna from nucleus to cytoplasm
translational level
the operator regions is adjacent to the ___ elements in most operons
promoter
in most cases the sequences of the operon bind a ___ protein
repressor
elucidation of lac operon done by
Francois Jacob (geneticist) and Jacque Monad (biochemist)
in lac operon, a ___ ____ ____ is regulated by common promoter and regulatory genes
polycistronic structural gene
in lac operon, a polycistronic structural gene is regulated by common promoter and regulatory genes. such arrangement is very common in __
bacteria
the i in i gene is derived from the word
inhibitor
three structural genes of lac operon
z, y and a
z gene of lac operon codes for
beta-galactosidase
in lac operon, beta-galactosidase is coded by which gene
z gene
in lac operon, y gene codes for
permease
permease increases
permeability of the cell to beta galactosidase
permease is coded by which structural gene
y gene
in lac operon, a gene codes for
transacetylase
transacetylase is coded by
gene a
lactose is the substrate for which enzyme
beta galactosidase
the repressor protein binds to the ___ region of the operon
operator region
regulation of lac operon by repressor is referred to as
negative regulation
It is the sequence of ___ in DNA that determines the genetic information of a given organism
Bases
A very ambitious project of sequencing human genome was launched in the year ___
1990
Human genome project was called a
Mega project
Human genome is said to have approximately ___ bp
3x10^9
The total estimated cost of HGP was approximately __ with __ dollars per bp
9 billion US dollars
3 dollars per bp
How many books with how many words and pages would be required to store the information of DNA
3300 books with 1000 pages and each page having 1000 letters
HGP was closely associated with the rapid development of a new area in biology called
Bioinformatics
Appr. How many genes are there in human DNA
20,000-25,000
How many bp make up human DNA
3 billion
Full form of ELSI
Ethical, legal and social issues
For how long did the HGP last
13 year
HGP was coordinated by which two companies
U.S department of energy
National institute of health
During the early years of HGP, the ___ became a major partner
The Wellcome Trust (U.K)
Countries that contributed to HGP
Japan, France , Germany, China and othes
The HGP was completed in
2003
Which two plants were the non human model that were sequenced
Rice
Arabidopsis
Which insect was the non human model that were sequenced
Drosophila
Eg for a free living non pathogenic nematode
Caenorhabditis elegans
Give 5 eg for non human models that were sequenced
Bacteria Yeast Caenorhabditis elegans Plants (2) Drosophila
EST full form
Expressed sequence tags
What are EST
All the genes that are expressed as RNA
Tge commonly used hosts for cloning were (2)
Bacteria and yeast
The commonly used vectors used for cloning were
BAC
YAC
The fragments were sequenced using automated DNA sequencers that worked in the principle of a method developed by
Frederick Sanger
Who was credited for developing method for determination of amino acid sequences in proteins
Frederick Sanger
The sequence of chromosome 1 was completed in
May 2006
From the result of HGP, the human genome contains ___ bp
3164.7 million bp
From the result of HGP, The avg gene consists of __ bases
3000
Largest human gene is? How many bases does it have
Dystrophin
2.4 million bases
From the result of HGP, the total number of genes is estimated at ___ -much lower that previous estimates of ___ to ___ genes
30,000
80,000 to 1,40,000
Almost ____% of nucleotide bases are exactly the same in all people
99.9%
The functions are unknown for over __% of tge discovered genes
50%
Less than __% of the genome codes for proteins
2%
___ sequence make up very large portion of human genome
Repeated sequence
Repetative sequences are stretches of DNA sequences that are repeated many times, sometimes ___ to __ times
Hundred to thousand times
Repeetitive sequences have no direct __ functions but they shed light on __, __ and __
Coding
Chromosome structure, dynamics and evolution
Which chromosome has most genes. How many?
Chromosome 1
2968
Which chromosome has least genes. How many
Y chromosome
231
Scientists have identified about how many locations where single base DNA differences occure in humans
1.4 million
Full form of SNP
Single nucleotide polymorphism
SNPs are also called
Snips
In how many base sequences of DNA would theere be differences
3x10^6
Repetitive DNA are separated from the bulk DNA as different peaks during density gradient centrifugation. The ___ forms a major peak and tge other small peaks are referred to as __
Bulk DNA
satellite DNA
What is the basis of DNA fingerprinting
Variable Number of Tandem Repeat (VNTR) polymorphism
Allelic sequence variation is decribed as a DNA polymorphism if more than __ variant(allele) at a locus occurs in human population with a frequency greater than__
0.01
What is DNA Polymorphism
If an Inheritable mutation is observed in a population at high frequency, it is reffered to as DNA polymorphism
The probability of inheritable variations to be observed in non-coding DNA sewuence would be lower/higher as mutation in these sequences may/may not have any impact in an individual’s reproductive ability
Higher
May not
Dna fingerprinting was developed by who
Alec Jeffreys
Alec jaffrey used __ as probe that shows ___
Satellite DNA
very high degree of polymorphism
What is VNTR
Satellite dna that shows very high degree of polymorphism
Southern blot hybridisation using __ as probe
Radiolabelled VNTR
Detection of hybridised Dna fragments was done by what method
Autoradiography
The VNTR belongs to a class of ___ DNA referred to as ___
Satellite dna
Mini-satellite
The suze of VNTR varies in size from __ to __
0.1 to 20kb
After hybridisations, the bands give a characteristic pattern for an individual DNA. It differs from individual to individual in a population except in the case of
Monozygotic (identical) twins
The sensitivity of dna fingerprinting was increased by use of
PCR
The tRNA binds to specific amino acids at one end and pairs through __ bonding
H-bonding
Which is the primary step for regulation of transcription
Regulation of transcription
Genetic material of T2 bacteriophage
DNA
When was Wilkins, Watson and Crick awarded nobel prize
1962
Which component of dna gives it the negative charge
Phosphate
Chargaff’s rule is applied only to ___ and not applicable to __ and __
dsDNA
ssDNA and RNA
What was the two chargaff’s rules
A+G = T+C
A+T/G+C = constant for species
Nature of dna of phix174
ssDNA
Nature of DNA in lambda phage
dsDNA
Nature of dna in ecoli
dsDNA
Nature of DNA in prokaryotic cell
dsDNA, circular and naked(without histones)
Histones have high/low molecular weight
Low
Types of histones in nucleosome (4)
H2A, H2B, H3 and H4
H1 hostone is ____ part of nucleosome and H1 is present in ___ or __ DNA
Not the part of
Linker or spacer DNA
In each nucleosome tge DNA is wrapped for about ____ turns
1 3/4
What is chromatosome
Nucleosome and H1 histone in liner or spacer DNA is called chromatosome
The heavy isotope of N is
Non radioisotopic
Who unwinds the strands of DNA
DNA helicase/ unwindase/ unzipping enzyme
Due to unwing of DNA strands, tension or strain is created in the distal ends of dna, which is relieved by__. It has __ and __ activity
DNA Gyrase/ Topoisomerase
Cut and seal
To prevent rewinding and recoiling of the opened dna, ___ attaches to tamplate strands
Single strand binding proteins (ssb)
Using rna primer, ___ adds nucleotides to the replicating dna
DNA polymerase III
After adding nucleotides, ___ degrade rna primer and replace it with dna
DNA polymerase I
Cistron is equivalent to
Structural gene
