Molecular Basis Of Inheritance Flashcards
(455 cards)
1
Q
_____acts as a genetic material in some viruses .
A
RNA
2
Q
RNA mostly functions as a __.
A
Messenger
3
Q
The determination of complete nucleotide sequence of human genome during last decade has set in a new era of _____.
A
Genomics
4
Q
DNA is a long polymer of ___.
A
Deoxyribonucleotides
5
Q
The length of DNA is usually defined as _____ present in it .
A
Number of nucleotides (or base pairs present )
6
Q
A pair of nucleotides are referred to as ____.
A
Base pairs
7
Q
A bacteriophage - phi * 174 has ____nucleotides .
A
5386
8
Q
Bacteriophage -lambda hs ____ base pairs
A
48502
9
Q
E.coli has _____BASE pairs .
A
4.6 * 10_6 ( 4600000)
10
Q
Haploid content of human DNA has __base pairs .
A
3.3 * 10_9
11
Q
Which bacteriophage has 5386 base pairs ?
A
Phi*174
12
Q
A __has 3 components -a N base , a PENTOSE sugar and a phosphate grp .
A
Nucleotide
13
Q
Name the N bases that are purines .
A
Adenine
Guanine
14
Q
Name the N bases that are pyrimidine .
A
Cytosine
Uracil
Thymine
15
Q
In case of pyrimidines , __is common in both DNA and RNA .
A
Cytosine
16
Q
In case of pyrimidines , __is present in RNA ,in place of ____ .
A
Uracil
Thymine
17
Q
A N base is linked to the __of __C pentose sugar through a __linkage to form a ___ .
A
OH
1’ C
N glycosidic linkage
Nucleoside
18
Q
Name a nucleoside which is exclusively present in DNA and in RNA ?
A
DNA- deoxythymidine
RNA - uridine
19
Q
Adenosine and deoxyadenosine are __.
A
Nucleosides
20
Q
When a phosphate grp is linked to ____ of ____C of a ____through ____linkage , a corresponding nucleotide is formed .
A
OH
5’C
Nucleoside
PHOSPHOESTER linkage
21
Q
2 nucleotides are lined through __ to form a _____ .
A
3’-5’ phosphodiester linkage
Dinucleotide
22
Q
A polynucleotide is formed has at one end a __ at 5 ‘ end of sugar , which is referred to as 5’ -end of polynucleotide chain .
A
Phosphate moiety
23
Q
At The other end of polynucleotide chain , the sugar has a ____ of 3 C grp which is referred to as 3’ end of the polynucleotide chain .
A
Free OH
24
Q
The back bone of a polynucleotide chain is formed due to __and ____ . The ____project from the backbone .
A
Sugar
Phosphates
N bases
25
In RNA ,every nucleotide residue has an additional ____ present at ____ position in the RIBOSE .
-OH grp
| 2’position
26
Other name of thymine -
5-methyl uracil
27
DNA as an acidic substance present in the nucleus was first identified by ____in ___ .
Friedrich meischer
| 1869
28
Name given by friedrich meischer to DNA .
Nuclein
29
It was only in ____that ___and ____ based on ____ proposed a very simple but famous double helix model for the structure of DNA .
1953
James Watson
Francis crick
X-diffraction data
30
X-ray diffraction data was produced by _and _.
Maurice Wilkins
| Rosalind franklin
31
One of the hallmarks of the proposition given by Francis and rick was -
Base pairing btw 2 strands of polynucleotide chains
32
The proposition given by Francis and crick was based on the observation of _____
Erwin chargaff
33
Observation of chargaff -
For double stranded DNA ,
| Ratios btw ADENINE and THYMINE and GUANINE and CYTOSINE are constant and equals 1 .
34
The salient features of double helix structure of DNA -
Made of 2 polynucleotide , where backbone is sugar-phosphate and bases project INSIDE .
Chains have anti-parallel polarity
Bases are paired through H-bonds
2 chains are coiled in a right-handed fashion . Pitch of helix is 3.4nm .
The plane of one base pair stacks over the other in double helix .
35
Adenine forms ____ H-bonds with thymine and cytosine forms ____ H-bonds with guanine .
2
| 3
36
Always a purine comes ____To pyrimidine .
Opposite
37
The pitch of the helix is ____ , and there are __ bp in each turn .
3.4nm
| 10
38
The distance btw a bp in a helix is ______ .
0.34nm
39
Which 2 features confer stability of the helical structure .
1) H-bonding
| 2) plane of one base pair stacks over the other in double helix
40
____ proposed the Central Dogma in molecular biology .
Francis crick
41
What does the central dogma state ?
Genetic info flows from DNA —> RNA —>protein
42
In some ____ , the flow of info is in the reverse direction , ie from RNA to DNA .
Viruses
43
Length of DNA double helix -
2.2 m ( 6.6* 10_9 bp. * 0.34 *10_-9 m/bp)
44
No of base pairs in humanDNA .
6.6 * 10_9 bp
45
Length of E.coli DNA -
1.36 mm
46
How is the DNA arranged in a prokaryotic cell such as E. Coli ?
The DNA is not scattered throughout the cell . DNA being negatively charged is held with some proteins (+ve charged ) in a region termed as NUCLEOID .
47
The DNA in _____ is organised in large loops held by proteins in prokaryotes .
Nucleoid
48
The type of DNA organisation in eukaryotes -
Complex
There is a set of +ve charged , basic proteins called HISTONES .histones are organised to form a unit of 8 molecules called HISTONE OCTAMER .the -ve charged DNA is wrapped around the +ve histone octamer to form a nucleosome .
49
The proteins ( which constitute the histone octamer ) acquire charge depending upon the _____
Abundance of amino acids residues with charged side chains .
50
Histones are rich in ___amino acid residues __and ____ .
Basic
Lysine
Arginine
51
Amino acid residues , arginine and lysine carry _____charge in their ____.
+ve
| Side chains
52
Histones are arranged to form a unit of ______ molecules .
8
53
The -ve dna is wrapped around + histone octamer to form a structure called _____.
Nucleosome
54
A typical nucleosome contains ______ bp of DNA helix .
200
55
Nucleosomes constitute the repeating unit of a structure in nucleus called ________ .
Chromatin (thread -like coloured bodies seen in nucleus )
56
The _____ are seen as BEADS ON STRING when viewed under electron microscope .
Nucleosomes ( in chromatin )
57
The beads on string. Structure(of nucleosome) in chromatin is packaged to form ______ that are further coiled and condensed at _____ of cell division to form _______.
Chromatin fibres
Metaphase
Chromosomes
58
The packaging of chromatin at higher level req additional set of proteins that collectively are referred to as _______ .
Non-histone chromosomal proteins ( NHC )
59
In a typical nucleus , some region of chromatin are loosely packed and stains light . They are called _______ .
Euchromatin
60
The chromatin that is more densely packed and stain dark are called ____.
Heterochromatin
61
_____is said to be transcriptionally active chromatin , whereas _____is inactive .
Euchromatin
| Heterochromatin
62
Discovery of nuclein By meischer and principles of inheritance by Mendel were almost at the same time but ____ took long to be discovered and proven .
DNA acts as the genetic material
63
By ____ , the quest to determine the mechanism for genetic inheritance had reached the molecular level .
1926
64
In ____ , ______ gave the transforming principle .
1928
| Fredrick Griffith
65
Fredrick Griffith in a series of experiments with _____witnessed a miraculous transformation in. The bacteria .
Streptococcus pneumoniae ( bacteria responsible for causing pneumonia )
66
During the course of Griffith’s experiment , bacteria had changed in ____form .
Physical
67
When streptococcus pneumoniae are grown in a culture plate , some produce ______ while others produce ______ .
Rough colonies
| Smooth shiny colonies
68
Smooth shiny colonies were produced because the S-strain bacteria have ______while R-strain does not .
Mucous polysaccharide coat
69
Effect of injecting S -strain , R- strain , S-strain heat killed , S-strain heat killed + R-strain .
S—— mice die
R——mice live
S-heat killed —— mice live
S-heat killed + R-strain ——mice die
70
Griffith recovered _____from the dead mice .
LIVING S-bacteria ( though he injected heat killed S -strain + Liv R strain )
71
What did Griffith conclude ?
R-strain bacteria had somehow been transformed by the heat -killed S-strain
72
According to Griffith , some transforming principle transferred from heat killed S strain , had enabled ____ to _____ and become virulent .
R-strain
| Synthesise a smooth polysaccharide coat
73
__was not defined from Griffith’s experiments .
Biochemical nature of genetic material
74
Prior to the work of __, ____and ____ , the genetic material was thought to be a protein .
Oswald Avery
Colin Macleod
Maclyn McCarty
75
Avery , Macleod and McCarty worked to determine the ____.
Biochemical nature of ‘transforming principle “ in Griffith’s experiment .
76
Avery , Macleod and McCarty worked in the year ___.
1933- 1944 ( after Griffith - 1928)
77
What did Avery , macleod and McCarty do ?
They purified biochemicals (proteins ,DNA and RNA ) from heat-killed S-cells to see which ones could transform live R cells into S- cells .
78
Avery , Macleod and McCarty discovered that DNA alone from ____ caused ____ to become _____ .
S-bacteria
R-bacteria
Transformed
79
Avery , Mac and Mac also discovered that ___and ____ did not affect transformation .
Protease (protein -digesting enzyme )
| RNase ( RNA digesting enzyme )
80
Digestion with ______ did inhibit transformation .
DNase
81
The unequivocal proof that DNA is the genetic material came from __ in the year ____ .
Hershey and chase
| 1952
82
Alfred Hershey and Martha chase worked on _____ .
Bacteriophage ( viruses that infect bacteria )
83
Hershey and chase worked to discover whether it was __or ___ from ___ that __.
Protein
DNA
Viruses
Entered the bacteria
84
In Hershey’s experiment , the ___attaches to the bacteria and its genetic material enters _____ , which treats the viral genetic material as if ______ and subsequently manufactures more viruses .
Bacteriophage
Bacterial cell
It was its own
85
Hershey and chase grew some viruses on a medium that contained _____ and some others on medium containing ___>
Radioactive phosphorus
| Radioactive sulphur
86
Viruses grown in presence of radioactive phosphorus contained ___but not __ becoz ____ . And viruses grown on radioactive sulphur Contained _________ but not ___.
```
Radioactive DNA
Radioactive proteins
DNA contains P but protein does not .
Radioactive Protein
Rad DNA
```
87
After radioactive labeling of DNA and proteins in chase’s exp , the next step was -
Infection
| Radioactive phages were allowed to attach to E.coli bacteria
88
What were the 3 steps in Hershey and chase’s exp ?
1) infection - radioactive phages were allowed to attach to E.coli
2) blending - the viral coats were removed from the bacteria by agitating them in a blender .
3) centrifugation - the virus particles were separated from bacteria by spinning in a centrifuge
89
______ indicated that DNA was the genetic material that passed from virus to bacteria in Hershey and chase’s exp .
Bacteria which was infected with virus that had radioactive DNA were radioactive .
90
In chase and Hershey’s exp , bacteria that were infected with viruses that had radioactive protein were _____.
Not radioactive
91
In _____, RNA is the genetic material .
SOME viruses
92
Give a few examples of viruses where RNA is the genetic material .
TMV
| QB bacteriophage
93
A molecule that can act as a genetic material must fulfill the following criteria -
1) able to generate its own replica ( replication )
2) stable chemically and structurally
3) must provide the scope for slow changes (mutation) that are req for evolution .
4) able to express itself in the form of Mendelian chars
94
__ has the ability to direct its duplication (1st criteria of genetic material ) . __fail to fulfill this criteria .
Both DNA and RNA
| Proteins
95
_____as one of the properties of genetic material was very evident in Griffith’s transformation principle ‘ itself that ______ .
Stability
| Heat which killed the bacteria did not destroy some of the properties of genetic material
96
The 2 strands of DNA being complementary if separated by heating come together when appropriate conditions are provided . T/F
T
97
____grp present at every nucleotide in RNA is a reactive grp and makes RNA LABILE and EASILY DEGRADABLE .
2’-OH
98
RNA is also known to be ____ , hence reactive .
Catalytic
99
DNA as compared to RNA is chemically __and structurally _____ .
Less reactive
| More stable
100
______confers additional stability to DNA .
Presence of thymine at the place of uracil
101
__is able to mutate .
Both DNA and RNA
102
__DNA /RNA mutates at a faster rate .WHY ?
RNA
| Being unstable
103
Viruses having __and ____ mutate and evolve faster .
RNA genome
| Shorter lifespan
104
____can directly code for the synthesis of PROTEINS ., hence can easily express the characters .
RNA
105
_is dependent on ____for synthesis of proteins .
DNA
| RNA
106
_has evolved around RNA .
Protein synthesizing machinery
107
DNA being ____ is preferred for ____ . For ____ RNA is better .
More stable
Storage of genetic info
Transmission of genetic info
108
___Was the first genetic material . __evolved around it
RNA
| Essential life processes ( metabolism , translation , splicing )
109
RNA being ___ was unstable . Therefore DNA has evolved from RNA with chemical modifications that make it more stable .
Catalytic
110
DNA being _____ further resists changes by evolving a process of repair .
Double stranded and having complementary strand
111
“ it has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material “ . This statement was given by ____ in the year ___ .
Watson and crick
| 1953
112
It is now roved that DNA replicates ____.
Semiconservatively
113
Semiconservative nature of DNA replication was shown in ___ and subsequently in ____ , such as ____ and ______ .
E. Coli
Higher organisms
Plants
Human cells
114
_____and _____ performed the exp to prove semiconservative nature of DNA replication n the year ____ .
Mathew messelson
Franklin. Stahl
1958
115
Meselson and stahl grew E.COLI in a medium containing ___ as the only __source for many generations . The result was ____ .
15-NH4Cl ( 15-N is the heavy isotope of N)
N2
15-N was incorporated into newly synthesised DNA (as well as other N containing compounds )
116
The heavy DNA molecule in meselson and Stahl’s exp could be distinguished from the normal DNA by ____ in ____ .
Centrifugation
| CsCl ( cesium chloride ) density gradient
117
N-15can be separated from N-14 only based on _____ . Why ?
Only based on densities .
| Becoz it is not a radioactive isotope
118
The 2nd step in meselson’s exp -
Transferred the cells into a medium with normal 14-NH4Cl and took samples at various definite time intervals as the cells multiplied and extracted the DNA that remained as double-stranded helices .
The various samples were separated independently on CsCl gradients to measure the densities of DNA .
119
In meselson’s exp , DNA that was extracted from the culture one generation after the transfer from 15N to 14N medium (ie,. After 20 mins ) had a _density .
Hybrid or Intermediate
120
DNA extracted from the culture after another generation , after 40 mins was composed of _____ .
Equal amts of hybrid DNA and of ‘light’ DNA
121
Exp similar to meselson and stahl’s were performed by ______ in ____ .
Taylor and colleagues
| 1958
122
Exp similar to meselson’s involving use of ____ to detect distribution of newly synthesised DNA in the chromosomes was performed on ____ by TAYLOR .
```
Radioactive thymidine
Vicia faba ( faba beans )
```
123
In living cells , such as E. Coli , the process of replication requires a set of ____ .
Catalysts ( enzymes )
124
The main enzyme used for replication is called -
DNA dependent DNA polymerase
125
Why is the main enzyme of replication called - DNA dependent DNA polymerase ?
Since it uses a DNA template to catalyse the polymerisation of deoxynucleotides
126
DNA dependent DNA polymerase is a __enzyme as it has to catalyse polymerisation of a large number of nucleotides in a very short time .
Highly efficient
127
E .coli that has only _____ bp completes the process of replication within ____ minutes . Which means avg rate of polymerisation has to be approx __.
4.6*10_6
18 mins
2000bp/s
128
These polymerase have to be highly ___ becoz any mistake during replication would result into ____.
Accurate
| Mutations
129
Energetically ,replication is a __process .
Very expensive
130
___serves dual purpose in replication .
Deoxyribonucleoside triphosphate
131
Which 2 purposes does depxyribonucleoside triphosphate serve in replication ?
1) acts as the substrate
2) provide energy for polymerisation rxn ( the 2 terminal phosphates in a deoxynucleoside triphosphates are high energy phosphates , same as case of ATP )
132
In addition to DNA dependent DNA polymerase , many additional enzymes are also req to complete replication . T/F
T
133
For __DNA molecules , since the 2 strands of DNA cannot be separated in its entire length due t ___ , the replication occurs within a small opening of the DNA helix , referred to as _____ .
Long
Very high energy requirement
Replication fork
134
The DNA dependent -DNA polymerase catalyse polymerisation in _directions . Which ?
Only in 1 direction
| 5’—-> 3’
135
____creates an additional complication at the replication fork . What is its consequence ?
1 direction polymerisation by DNA dependent DNA polymerase ( 5’—>3’)
On one strand , the replication is continuous and on the other it is discontinuous .
136
Replication is continuous on template strand with polarity ____ and discontinuous on template strand with polarity ___.
3’—>5’
| 5’—>3’
137
The discontinuously synthesised fragments are later joined by the enzyme _____.
DNA ligase
138
The ___on their own cannot initiate the process of replication .
DNA polymerases
139
The replication initiates randomly at any place in DNA . T/F
F
140
The definite region in E.coli DNA where the replication originates are -
Origin of replication
141
It is because of the req of ori that a piece of DNA if needed to be propagated during recombinant DNA procedures , req a ____ .
Vector
142
The vectors provide _____ .
Ori
143
In eukaryotes , the replication of DNA takes place at ___ of the cell cycle .
S-phase
144
A failure in cell division after DNA replication results into ___ . Therefore _and ____ must be highly cocordinated .
Polyploidy ( a chromosomal anomaly )
| DNA replication and cell division cycle
145
The process of ___ from one strand of __into ___ is termed as TRANSCRIPTION .
Copying info
DNA
RNA
146
The principle of ____ governs the process of transcription . Exception to this is ___ .
Complementarity
| Adenosine complements now forms base pair with uracil instead of thymine .
147
Major Difference btw replication and transcription -
Replication -total DNA gets duplicated
| Transcription-only a segment of DNA and only one of the strands is copied into RNA .
148
Defining the boundaries is necessary to demarcate the region and the strand of DNA in transcription/replication .
Transcription
149
Similarity btw transcription and replication .
Complementarity governs both processes
| But in transcription , adenosine forms bp with uracil
150
Why both the strands are not copied during transcription -
1) if both strands act as template , they would code for RNA molecule with diff sequences , and in turn if they code for proteins , the sequence of amino acids in the proteins would be diff .
Hence, one segment of DNA would be coding for 2 diff proteins , complicating the genetic info .
2) the 2 RNA molecules if produced simultaneously would be complementary to each other , hence would form a DOUBLE STRANDED RNA . This would prevent RNA from being translated into proteins and the exercise of transcription would become futile .
151
What would happen if the 2 RNA’s are produced simultaneously ?
They would be complementary to each other , hence forming double stranded RNA . This would prevent RNA from being translated into proteins , thus the whole process of transcription would become futile .
152
A transcription unit in DNA is defined primarily by the 3 regions in the DNA :
A promoter
The structural gene
A terminator
153
The strand that has polarity __Acts as the template , and is also referred to as template strand .
3’—>5’
154
The strand which has polarity ___ coding strand .
5’—>3’
155
Why is there a convection in defining the 2 strands of DNA ?
Since the 2 strands have opposite polarity and the DNA -dependent RNA polymerase also catalyses polymerisation in only one direction , ie. 5’—> 3’ , one strand acts as template and the one with opposite polarity acts as coding .
156
The DNA dependent RNA polymerase catalyses polymerisation in ___ direction .
Only 1
| 5’—>3’
157
Which strand has the sequence same as RNA (except thymine at the place of uracil ) ?
Coding
158
Which strand is displaced during transcription ?
Coding
159
The strand which does not code for anything is called -
Coding strand
160
All the reference point while defining a transcription unit is made with ___ .
Coding strand
161
The ____and____flank the structural gene in a transcription unit .
Promoter
| Terminator
162
The promoter is said to be located towards the __End of the ___gene . ( wrt coding strand )
5’ - upstream
| Structural gene
163
It is the ___that provides binding site for RNA polymerase and it is the presence of a ____ in a transcription unit that also defines the template and coding strands .
DNA sequence
| Promoter
164
By switching the position of ____with ____ , the definition of coding and template strands could be reversed .
Promoter
| Terminator
165
The terminator is located towards the __end of the coding strand and it usually defines the ____ of the process of transcription .
3’ end -downstream
| End
166
The ____ is located upstream and____downstream of the coding strand .
Promoter
| Terminator
167
There are additional regulatory that may be present further upstream and downstream to the _____.
Promoter
168
A ___is defined as the functional unit of inheritance .
Gene
169
The DNA sequence coding for ____or ____also define a gene .
tRNA
| rRNA
170
By defining a cistron as a segment of DNA coding for polypeptide , the structural gene in a transcription unit could be said as ___ or ____.
Monocistronic
| Polycistronic
171
Monocistronic gene is found mostly in __and polycistronic gene is found mostly in _____ .
Eukaryotes
| Prokaryotes or bacteria
172
In eukaryotes ,the monocistronic structural genes have ____ coding sequence - the genes in EUKARYOTES are ______ .
Interrupted
| Split
173
The coding sequences or EXPRESSED sequences are defined as _____.
Exons
174
Exons are said to be those sequences that appear in _____.
Mature or processed RNA
175
The exons are interrupted by _____.
Introns
176
___do not appear in mature or processed RNA .
Introns
177
The ___arrangement further complicates the definition of a gene in terms of a DNA segment .
Split gene
178
Inheritance of a char are also affected by _____and ____sequnces of a structural gene .
Promoter
| Regulatory
179
Sometimes the regulatory sequnces are loosely defined as ____ though they do not code for any RNA or proteins .
Regulatory genes
180
In bacteria , there are _major types of RNA .
3
M-RNA
T-RNA
R-RNA
181
All the 3 RNAs are needed to synthesise a ___ in a cell .
Protein
182
The ___provides the template , __brings amino acids and reads the genetic code , ___ play structural and catalaytic role during translation .
mRNA
tRNA
rRNA
183
There is a single ____ that catalyses transcription of all types of RNA in bacteria.
DNA dependent RNA polymerase
184
RNA polymerase binds to ___ and initiates transcription . This process is called ____.
Promoter
| Initiation
185
RNA polymerase uses ___ as substrate and polymerises in a ____ fashion following the rule of ____ .
Nucleosides triphosphates
Template dependent
Complementarity
186
___ somehow also facilitates opening of helix and continues ELONGATION during transcription .
RNA polymerase
187
Once the RNA polymerase reaches the ____end , the ____ falls off .
Terminator end
| Nascent RNA
188
What results in the termination of transcription ?
When the RNA polymerase reaches the terminator region , the nascent RNA falls off , so also the RNA polymerase . This results in termination .
189
_____ remains bound to the enzyme RNA polymerase during elongation in transcription .
Only a short stretch of RNA
190
How is the RNA polymerase able to catalyse all the 3 steps of transcription : initiation , elongation , termination ?
It is only capable of catalysing elongation .
| It associates transiently with initiation factor and termination factor to initiate and terminate .
191
The RNA polymerase is only capable of catalysing ___during transcription .
Elongation
192
RNA polymerase associates transiently with ____ and ____ .
```
Initiation factor (sigma )
Termination ( rho )
```
193
Association with sigma and rho factors alters _____ to either initiate or terminate .
The specificity of the RNA polymerase
194
transcription and translation can be coupled in __.
Bacteria
195
In bacteria , translation an sometimes begin before ___ .
The RNA is fully transcribed
196
Why is trancscription and translation coupled in bacteria ?
1) mRNA does not require any processing to become active .
2) since transcription and translation take place in the same compartment ( there is no separation of cytosol and nucleus in bacteria )
197
What are the complexities found in eukaryotes during transcription ?
1) at least 3 RNA polymerases in the nucleus ( in addition to the RNA polymerase found in cell organelles ). There is a clear cut division of labour btw the 3 RNA polymerases .
2) primary transcript contain both exons and introns and are non-functional .hence they are subjected to splicing .
198
How many RNA polymerases are found in eukaryotes .
At least 3 in the nucleus
| 1 in the cell organnelles
199
The RNA polymerase 1 transcribes ____ .
rRNAs - 28S , 18S , 5.8S
200
RNA polymerase 3 is responsible for -
Transcription of tRNA , 5 srRNA , snRNAs (small nuclear RNAs)
201
The RNA polymerase 2 transcribes ____.
Precursor of mRNA - hnRNA ( heterogenous nuclear )
202
Introns are removed and exons are joined in a defined order by -
Splicing
203
____undergoes additional processes called capping and tailing ( in addition to splicing ).
hnRNA
204
In CAPPING , ___is added to _____end of hnRNA .
Methyl guanosine triphosphate - unusual NUCLEOTIDE
| 5’ end of hnRNA
205
In tailing , ____ are added to __end of hnRNA , in a ____ manner .
Adenylate residues - 200-300
3’end
Template INDEPENDENT manner
206
It is the ______ RNA that is transported out of the NUCLEUS for TRANSLATION .
Fully processes hnRNA - now called mRNA
| After capping and tailing
207
In ____, an unusual nucleotide is added .
Capping of hnRNA
| Addition of methyl guanosine triphosphate
208
How many adenylate residues are added in tailing ? In what manner .
200-300
| Template -independent
209
The process of splicing represents _____.
Dominance of RNA world
210
During ____and ______ , a nucleic acid was copied to form another nucleic acid .
Replication
| Transcription
211
The process of translation req transfer of genetic info from a ____to form a ______ .
Polymer of nucleotides
| Polymer of amino acids
212
Complementarity exists btw nucleotides and amino acids . T/F
F
No complementarity btw nucleotides and amino acids .
This differentiates translation form transcription .
213
It was ____ , a ____ 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 3 nucleotides .
George Gamow
| Physicist
214
The chemical methods developed by ____ instrumental in synthesizing RNA molecules with defined combinations of bases ( homopolymer s and copolymers ).
Har Gobind Khorana
215
______ ‘s cell free system for protein synthesis finally helped the code to be deciphered .
Marshall nirenberg’s
216
__enzyme was also helpful in polymer is int RNA with defined sequnces in a template independent manner .
Severo Ochoa - polynucleotide phosphorylase
217
Finally a ___for genetic code was prepared .
Checker board
218
Severo Ochoa was helpful in polymer is int RNA with defined sequnces in a __manner .
Template independent - ENZYMATIC SYNHESIS OF RNA
219
Gorge Gamow , a physicist argued that since there are only __bases and if they have to code for ____ , the code should be made up of ____ .
4
20 amino acids
3 nucleotides
220
Proof that the codon was triplet was given by -
Khorana
221
_____finally helped the code to be deciphered .
Marshall nirenberg’s cell free system
222
Salient features of genetic code -
1) codon is triplet
2) code is DEGENERATE
3) codon in mRNA is read in a CONTAGIOUS fashion
4) code is nearly universal
5) AUG has dual functions. initiator codon and codes for methionine
6) UAA, UAG, UGA - terminator codons
223
____codons code for amino acids . ____ codons do not code for amino acids , hence the function as _____ .
61
3
Stop codons
224
Why is the code called DEGENERATE ?
Some amino acids are coded by more than one codon
225
Codon in mRNA is read in a contagious fashion . Meaning -
No punctuations
226
From bacteria to humans , UUU would code for ___.
Phenylalanine (Phe)
227
The codon is NEARLY universal . Exceptions to this -
Found in mitochondrial codons and in some protozoans
228
Dual function of AUG -
Codes for methionine
| Acts as initiator codon
229
Terminator codons -
UAA
UAG
UGA
230
Insertion or deletion of 1 or 2 bases changes the reading frame from the point of ____ . Such mutations are called -
Insertion or deletion
| frameshift insertion or deletion mutations
231
Insertion or deletion of ____ inserts or deletes in 1 or multiple codons , hence the reading frame remains unaltered from that point onwards .
3 or its multiple bases
232
In living cells , such as E. Coli , the process of replication requires a set of ____ .
Catalysts ( enzymes )
233
The main enzyme used for replication is called -
DNA dependent DNA polymerase
234
Why is the main enzyme of replication called - DNA dependent DNA polymerase ?
Since it uses a DNA template to catalyse the polymerisation of deoxynucleotides
235
DNA dependent DNA polymerase is a __enzyme as it has to catalyse polymerisation of a large number of nucleotides in a very short time .
Highly efficient
236
E .coli that has only _____ bp completes the process of replication within ____ minutes . Which means avg rate of polymerisation has to be approx __.
4.6*10_6
18 mins
2000bp/s
237
These polymerase have to be highly ___ becoz any mistake during replication would result into ____.
Accurate
| Mutations
238
Energetically ,replication is a __process .
Very expensive
239
___serves dual purpose in replication .
Deoxyribonucleoside triphosphate
240
Which 2 purposes does depxyribonucleoside triphosphate serve in replication ?
1) acts as the substrate
2) provide energy for polymerisation rxn ( the 2 terminal phosphates in a deoxynucleoside triphosphates are high energy phosphates , same as case of ATP )
241
In addition to DNA dependent DNA polymerase , many additional enzymes are also req to complete replication . T/F
T
242
For __DNA molecules , since the 2 strands of DNA cannot be separated in its entire length due t ___ , the replication occurs within a small opening of the DNA helix , referred to as _____ .
Long
Very high energy requirement
Replication fork
243
The DNA dependent -DNA polymerase catalyse polymerisation in _directions . Which ?
Only in 1 direction
| 5’—-> 3’
244
____creates an additional complication at the replication fork . What is its consequence ?
1 direction polymerisation by DNA dependent DNA polymerase ( 5’—>3’)
On one strand , the replication is continuous and on the other it is discontinuous .
245
Replication is continuous on template strand with polarity ____ and discontinuous on template strand with polarity ___.
3’—>5’
| 5’—>3’
246
The discontinuously synthesised fragments are later joined by the enzyme _____.
DNA ligase
247
The ___on their own cannot initiate the process of replication .
DNA polymerases
248
The replication initiates randomly at any place in DNA . T/F
F
249
The definite region in E.coli DNA where the replication originates are -
Origin of replication
250
It is because of the req of ori that a piece of DNA if needed to be propagated during recombinant DNA procedures , req a ____ .
Vector
251
The vectors provide _____ .
Ori
252
In eukaryotes , the replication of DNA takes place at ___ of the cell cycle .
S-phase
253
A failure in cell division after DNA replication results into ___ . Therefore _and ____ must be highly cocordinated .
Polyploidy ( a chromosomal anomaly )
| DNA replication and cell division cycle
254
The process of ___ from one strand of __into ___ is termed as TRANSCRIPTION .
Copying info
DNA
RNA
255
The principle of ____ governs the process of transcription . Exception to this is ___ .
Complementarity
| Adenosine complements now forms base pair with uracil instead of thymine .
256
Major Difference btw replication and transcription -
Replication -total DNA gets duplicated
| Transcription-only a segment of DNA and only one of the strands is copied into RNA .
257
Defining the boundaries is necessary to demarcate the region and the strand of DNA in transcription/replication .
Transcription
258
Similarity btw transcription and replication .
Complementarity governs both processes
| But in transcription , adenosine forms bp with uracil
259
Why both the strands are not copied during transcription -
1) if both strands act as template , they would code for RNA molecule with diff sequences , and in turn if they code for proteins , the sequence of amino acids in the proteins would be diff .
Hence, one segment of DNA would be coding for 2 diff proteins , complicating the genetic info .
2) the 2 RNA molecules if produced simultaneously would be complementary to each other , hence would form a DOUBLE STRANDED RNA . This would prevent RNA from being translated into proteins and the exercise of transcription would become futile .
260
What would happen if the 2 RNA’s are produced simultaneously ?
They would be complementary to each other , hence forming double stranded RNA . This would prevent RNA from being translated into proteins , thus the whole process of transcription would become futile .
261
A transcription unit in DNA is defined primarily by the 3 regions in the DNA :
A promoter
The structural gene
A terminator
262
The strand that has polarity __Acts as the template , and is also referred to as template strand .
3’—>5’
263
The strand which has polarity ___ coding strand .
5’—>3’
264
Why is there a convection in defining the 2 strands of DNA ?
Since the 2 strands have opposite polarity and the DNA -dependent RNA polymerase also catalyses polymerisation in only one direction , ie. 5’—> 3’ , one strand acts as template and the one with opposite polarity acts as coding .
265
The DNA dependent RNA polymerase catalyses polymerisation in ___ direction .
Only 1
| 5’—>3’
266
Which strand has the sequence same as RNA (except thymine at the place of uracil ) ?
Coding
267
Which strand is displaced during transcription ?
Coding
268
The strand which does not code for anything is called -
Coding strand
269
All the reference point while defining a transcription unit is made with ___ .
Coding strand
270
The ____and____flank the structural gene in a transcription unit .
Promoter
| Terminator
271
The promoter is said to be located towards the __End of the ___gene . ( wrt coding strand )
5’ - upstream
| Structural gene
272
It is the ___that provides binding site for RNA polymerase and it is the presence of a ____ in a transcription unit that also defines the template and coding strands .
DNA sequence
| Promoter
273
By switching the position of ____with ____ , the definition of coding and template strands could be reversed .
Promoter
| Terminator
274
The terminator is located towards the __end of the coding strand and it usually defines the ____ of the process of transcription .
3’ end -downstream
| End
275
The ____ is located upstream and____downstream of the coding strand .
Promoter
| Terminator
276
There are additional regulatory that may be present further upstream and downstream to the _____.
Promoter
277
In living cells , such as E. Coli , the process of replication requires a set of ____ .
Catalysts ( enzymes )
278
The main enzyme used for replication is called -
DNA dependent DNA polymerase
279
Why is the main enzyme of replication called - DNA dependent DNA polymerase ?
Since it uses a DNA template to catalyse the polymerisation of deoxynucleotides
280
DNA dependent DNA polymerase is a __enzyme as it has to catalyse polymerisation of a large number of nucleotides in a very short time .
Highly efficient
281
E .coli that has only _____ bp completes the process of replication within ____ minutes . Which means avg rate of polymerisation has to be approx __.
4.6*10_6
18 mins
2000bp/s
282
These polymerase have to be highly ___ becoz any mistake during replication would result into ____.
Accurate
| Mutations
283
Energetically ,replication is a __process .
Very expensive
284
___serves dual purpose in replication .
Deoxyribonucleoside triphosphate
285
Which 2 purposes does depxyribonucleoside triphosphate serve in replication ?
1) acts as the substrate
2) provide energy for polymerisation rxn ( the 2 terminal phosphates in a deoxynucleoside triphosphates are high energy phosphates , same as case of ATP )
286
In addition to DNA dependent DNA polymerase , many additional enzymes are also req to complete replication . T/F
T
287
For __DNA molecules , since the 2 strands of DNA cannot be separated in its entire length due t ___ , the replication occurs within a small opening of the DNA helix , referred to as _____ .
Long
Very high energy requirement
Replication fork
288
The DNA dependent -DNA polymerase catalyse polymerisation in _directions . Which ?
Only in 1 direction
| 5’—-> 3’
289
____creates an additional complication at the replication fork . What is its consequence ?
1 direction polymerisation by DNA dependent DNA polymerase ( 5’—>3’)
On one strand , the replication is continuous and on the other it is discontinuous .
290
Replication is continuous on template strand with polarity ____ and discontinuous on template strand with polarity ___.
3’—>5’
| 5’—>3’
291
The discontinuously synthesised fragments are later joined by the enzyme _____.
DNA ligase
292
The ___on their own cannot initiate the process of replication .
DNA polymerases
293
The replication initiates randomly at any place in DNA . T/F
F
294
The definite region in E.coli DNA where the replication originates are -
Origin of replication
295
It is because of the req of ori that a piece of DNA if needed to be propagated during recombinant DNA procedures , req a ____ .
Vector
296
The vectors provide _____ .
Ori
297
In eukaryotes , the replication of DNA takes place at ___ of the cell cycle .
S-phase
298
A failure in cell division after DNA replication results into ___ . Therefore _and ____ must be highly cocordinated .
Polyploidy ( a chromosomal anomaly )
| DNA replication and cell division cycle
299
The process of ___ from one strand of __into ___ is termed as TRANSCRIPTION .
Copying info
DNA
RNA
300
The principle of ____ governs the process of transcription . Exception to this is ___ .
Complementarity
| Adenosine complements now forms base pair with uracil instead of thymine .
301
Major Difference btw replication and transcription -
Replication -total DNA gets duplicated
| Transcription-only a segment of DNA and only one of the strands is copied into RNA .
302
Defining the boundaries is necessary to demarcate the region and the strand of DNA in transcription/replication .
Transcription
303
Similarity btw transcription and replication .
Complementarity governs both processes
| But in transcription , adenosine forms bp with uracil
304
Why both the strands are not copied during transcription -
1) if both strands act as template , they would code for RNA molecule with diff sequences , and in turn if they code for proteins , the sequence of amino acids in the proteins would be diff .
Hence, one segment of DNA would be coding for 2 diff proteins , complicating the genetic info .
2) the 2 RNA molecules if produced simultaneously would be complementary to each other , hence would form a DOUBLE STRANDED RNA . This would prevent RNA from being translated into proteins and the exercise of transcription would become futile .
305
What would happen if the 2 RNA’s are produced simultaneously ?
They would be complementary to each other , hence forming double stranded RNA . This would prevent RNA from being translated into proteins , thus the whole process of transcription would become futile .
306
A transcription unit in DNA is defined primarily by the 3 regions in the DNA :
A promoter
The structural gene
A terminator
307
The strand that has polarity __Acts as the template , and is also referred to as template strand .
3’—>5’
308
The strand which has polarity ___ coding strand .
5’—>3’
309
Why is there a convection in defining the 2 strands of DNA ?
Since the 2 strands have opposite polarity and the DNA -dependent RNA polymerase also catalyses polymerisation in only one direction , ie. 5’—> 3’ , one strand acts as template and the one with opposite polarity acts as coding .
310
The DNA dependent RNA polymerase catalyses polymerisation in ___ direction .
Only 1
| 5’—>3’
311
Which strand has the sequence same as RNA (except thymine at the place of uracil ) ?
Coding
312
Which strand is displaced during transcription ?
Coding
313
The strand which does not code for anything is called -
Coding strand
314
All the reference point while defining a transcription unit is made with ___ .
Coding strand
315
The ____and____flank the structural gene in a transcription unit .
Promoter
| Terminator
316
The promoter is said to be located towards the __End of the ___gene . ( wrt coding strand )
5’ - upstream
| Structural gene
317
It is the ___that provides binding site for RNA polymerase and it is the presence of a ____ in a transcription unit that also defines the template and coding strands .
DNA sequence
| Promoter
318
By switching the position of ____with ____ , the definition of coding and template strands could be reversed .
Promoter
| Terminator
319
The terminator is located towards the __end of the coding strand and it usually defines the ____ of the process of transcription .
3’ end -downstream
| End
320
The ____ is located upstream and____downstream of the coding strand .
Promoter
| Terminator
321
There are additional regulatory that may be present further upstream and downstream to the _____.
Promoter
322
____postulated the presence of an adapter molecule that would on one hand read the code and on the other hand would bind to specific amino acids .
Francis crick
323
The _____ was known before the genetic code was postulated .
TRNA ( sRNA - soluble RNA)
324
TRNA was known much before the genetic code was postulated but its role as an _____ was assigned much later .
Adapter molecule
325
TRNA has an _____ that has bases complementary to the code .
Anticodon loop
326
TRNA also has an _____ to which it binds to amino acids .
Amino acid acceptor end
327
TRNAs are __for each amino acid .
Specific
328
For initiation , there is another specific tRNA known as ____ .
Initiator tRNA
329
There are no tRNAs for _____ .
Stop codons
330
The secondary structure of tRNA looks like __
Clover leaf model
331
In actual structure , tRNA is a compact molecule and looks like ___.
Inverted L
332
Parts of tRNA -
Anticodon loop
| Amino acid acceptor end
333
Translation refers to the process of ___of amino acids to form a ____ .
Polymerisation
| Polypeptide
334
The order and sequence of amino acids are defined by the ____ .
Sequence of bases in the mRNA
335
The amino acids are joined by __bond .
Peptide
336
Process of peptide bond formation req ___.
Energy
337
What happens in the 1st phase of translation ?
Charging of tRNA /aminoacylation of tRNA
338
What is charging / AMINOACYLATION of tRNA ?
The activation of amino acids in the presence of ATP and linking to their cognate tRNA .
339
If 2 __are brought close enough , the formation of peptide bond btw them would be favoured ENERGETICALLY .
Charged tRNAs
340
The presence of ____would enhance the rate of peptide bond formation .
Catalyst
341
Th cellular factory responsible for synthesizing proteins is the -
Ribosome
342
The ribosome consists of ___ and ____ .
Structural RNAs
| 80 diff proteins
343
The ribosome consists of __ proteins .
80 diff types
344
In its __state , Ribosome exists as 2 subunits.
Inactive
345
When the __ encounters __ , the process of translation begins .
Small subunit of ribosome
| An m-RNA
346
When the _____ subunit encounters an mRNA ,the process of translation begins .
Small
347
There are ___ sites in the ___ subunit ( of ribosome )for subsequent amino acids to bind to and thus be close enough to each other for the formation of peptide bond.
2
348
The ______ also acts as a catalyst for the formation of peptide bond .
Ribosome
349
_____ in BACTERIA is the enzyme - ______ for the formation of peptide bond .
23S rRNA
| Ribozyme
350
A translation unit in mRNA is the sequence of ___ that is flanked by the ___ and ____ and codes for a polypeptide .
RNA
Start codon -AUG
Stop codon
351
An mRNA also has some additional sequences that are not translated and are referred as ______.
Untranslated regions (UTRs)
352
UTRs are additional sequences in the ____.
MRNA
353
The UTRs are present at ____ end .
Both ends of mRNA
5’end-before start codon
3’end-after stop codon
354
____are required fo efficient translation process .
UTRs
355
For initiation , the ribosome binds to the mRNA at the ____codon that is recognised only by the ______ .
Start codon
| Initiator tRNA
356
when the ribosome proceeds to the elongation phase of protein synthesis , what happens ?
Complexes composed of an amino acid linked to tRNA , sequentially bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNA anticodon .
357
The ____move from codon to codon along mRNA during translation .
Ribosome
358
At the end of translation , ____binds to _____ , terminating translation and releasing the complete polypeptide form the ribosome .
A release factor
| Stop codon
359
Gene expression can be regulated at ____levels .
Several
360
In eukaryotes , the regulation could be exerted at -
1) transcriptional level ( formation of prim transcript )
2) processing level ( regulation of splicing )
3) transport of mRNA from nucleus to the cytoplasm
4) translational level
361
The ___ in a cell are expressed to perform a particular function or a set of functions .
Genes
362
If an enzyme called __ is synthesised by E.coli , it is used to catalyse _____ .
Hydrolysis of a disaccharide -lactose into galactose and glucose
363
The bacteria use _____as a source of energy .
Lactose
364
It is the _____,____or ____ conditions that regulate the expression of genes .
Metabolic
Physiological
Environmental
365
In a transcription unit , the activity of ____ at a given promoter is in turn regulated by interaction with ____ .
RNA polymerase
| Accessory pigments
366
The regulatory proteins can act both ______and ______ .
Positively (activators )
| Negatively ( repressors )
367
The accessibility of promoter regions of prokaryotic DNA is in many cases regulated by the ____ termed _____ .
Interaction of proteins with sequences
| Operators
368
The operator region is adjacent to the ___ in most operons and in most cases , the sequences of the ___ bind a ___ .
Promoter
Operator
Repressor protein
369
Each operon has its specific ____and ____ .
Operator
| Repressor
370
___ is present only in lac operon and it interacts specifically with ____ only
Lac operator
| Lac repressor
371
The elucidation of the lac operon was also a result of a close association btw a ___ - _____ and ____ - ______.
Geneticist - Francois jacob
| Biochemist -Jacques monad
372
Jacob and monad were the first to elucidate a _______ system .
Transcriptionally regulated
373
In lac operon , lac refers to ____.
Lactose
374
In lac operon , a _____ gene is regulated by a COMMON promoter and regulator genes .
Polycistronic structural
375
Lac operon is very common in __.
Bacteria
376
Name a few operons -
```
Lac operon
Trp operon
Ara operon
His operon
Val operon
```
377
The lac operon consists of -
1 regulatory gene - i gene
| 3 structural genes
378
The i gene in lac refers to -
Inhibitor ( not inducer )
379
The 3 structural genes are -
Z
Y
A
380
The i gene codes for the ___ .
Repressor of lac operon
381
The z gene codes for _____ , which is primarily responsible for _____ .
Beta -galactosidase ( beta-gal )
| Hydrolysis of the disaccharide - lactose into its monomeric units -galactose and glucose
382
The y-gene codes for _____ .
Permease
383
Function of permease -
Inc permeability of the cell to beta -galactosidase
384
The a-gene codes for ____ .
Transacetylase
385
All the 3 gene products in lac are req for the metabolism of ____ .
Lactose
386
Lactose is the substrate for the enzyme ____ .
Beta -galactosidase
387
__regulates switching on and off of the operon .
Lactose
388
Lactose is termed as the _____ in lac operon .
Inducer
389
Preferred carbon source for lac operon -
Glucose
390
How is lactose transported into the cells in the absence of the preffered C source -
In the absence of C , if lactose is provided in the growth medium of the bacteria , the lactose is transported to the cels through the action of permease .
391
A very low level of expression of ___ has to be present in the cell all the time , otherwise lactose cannot enter the cells .
Lac operon
392
The __of the operon is synthesised all the time -constitutively from the __gene .
Repressor
| i-gene
393
The ___protein binds to the operator region of the operon and prevents ____ from transcribing the operon .
Repressor
| RNA polymerase
394
In the presence of _______ , such as ____and ____ , the repressor is inactivated by interaction with the inducer .
Inducer
Lactose
Allolactose
395
In the presence of an inducer , RNA polymerase has access to the ___ and transcription proceeds .
Promoter
396
____or ____cannot act as inducers for lac operon .
Glucose
| Galactose
397
Regulation of lac operon by ____ is referred to as negative regulation .
Repressors
398
Human genome project was launched in the year ____ .
1990
399
HGP was called a _____ .
Mega project
400
HGP was closely associated with the rapid development of a new area in biology called ______ .
Bioinformatics
401
Human Genome is said to have ____bp and if the cost of sequencing req is ___ per bp, the total estimated cost would be approx ____ US dollars .
3*10_9 bp
US $ 3 per bp
9 billion US dollars
402
One of the goals of HGP is to identify all the approx _____ genes in human DNA .
20,000 -25,000 genes
403
Imp goal of HGP is to determine the sequence of ____ chemical bp that make up human DNA .
3 billion
404
Imp goals of HGP are to -
1) identify all the approx 20,000 -25,000 genes in human DNA .
2) determine the sequence of the 3 billion bp hat make up human DNA
3) store this info in databases .
4) improve tools for data analysis
5) transfer related technologies to other sectors such as industries .
6) address the ETHICAL , LEGAL and SOCIAL issues ( ELSI ) that may arise from the project .
405
The HGP was a _____ year project coordinated by the ____ .
13 year
| U.S Department of Energy And the National Institute of Health
406
During the early years of HGP , the ____ became a major partner . Additional contributions came from ____, _____ ,____ and _____ .
```
Welcome Trust ( UK )
Japan
France
Germany
China
```
407
HGP was completed in _____ .
2003
408
Name some non-human model organisms , that have been sequenced -
```
Bacteria
Yeast
Caenorhabditis elegans
Drosophila (fruit fly )
Plants ( rice and Arabidopsis )
```
409
Caenorhabditis elegans is a _____ nematode that has been sequenced .
Free-living NON - PATHOGENIC nematode
410
Name 2 plants that have been sequenced?
Rice
| Arabidopsis
411
What are the 2 major approaches in the method of HGP ?
1) identifying all the genes that are expressed as RNA ( referred to as ESTs - Expressed Sequence Tags )
2) blind approach of simply sequencing the whole set of genome that contained all the coding and non-coding sequence , and later assigning diff regions in the sequence with functions - referred to as SEQUENCE ANNOTATION )
412
The commonly used hosts for cloning in HGP -
Bacteria and yeast
413
The vectors used for cloning -
BAC -bacterial artificial chromosome
| YAC -yeast artificial chromosome
414
The fragments were sequenced using automated DNA sequencers that worked on the principle of a method developed by -
Fredrick Sanger
415
Sanger is credited for which 2 things -
1) sequencing DNA fragments
| 2) developing method for the determination amino acid sequence in proteins .
416
The sequenced DNA fragments were arranged based on some ______ present in them .
Overlapping regions
417
Specialized computer based programmers were developed for -
Alignment of the sequences of DNA
418
the sequence of ________ was completed only in may 2006 .
Chromosome 1
419
___was the last of the 24 human chromosomes - 22 autosomes and X and Y to be sequnced .
Chromosome 1
420
Genetic and physical maps were assigned on the genome using info on ____and some ____ .
Polymorphism of restriction endonuclease recognition sites
| Repetitive DNA sequences known as MICROSATELLITES .
421
REPETITIVE DNA sequences were known as ______ .
MICROSATELLITES
422
Some of the salient observations drawn from HGP are -
1) human genome contains 3164.7 million bp .
2) the avg gene consists of 3000 bp but sizes vary greatly
3) the total number of genes is estimated at 30,000 -much over the previous estimates of 80,000 to 1,40,000 genes .
4) the functions are unknown for over 50% of the discovered genes
5) less than 2% of the genome codes for protein .
6) repeated sequnces make up very large portion of the human genome .
7) chromosome 1 has most genes- 2968 and Y has the fewest -231
8) scientists have identified about 1.4 million locations where single base differences ( SNPs ) occur in humans .
423
The human genome contains ___ bp.
3164.7 million bp
424
The average gene consists of ___bases , but sizes vary greatly , with the largest gene being ___.
3000 bases
| Dystrophin
425
Dystrophin gene-largest has ___ bases .
2.4 million bases
426
The total number of genes is estimated at ___ - much lower than previous estimates of ___ to ____ genes .
30,000
| 80,000-1,40,000
427
Almost ___ nucleotide bases are exactly the same in all people.
All ( 99.9%)
428
The functions are know for over ___ of the discovered genes .
50%
429
_____ % of the genome codes for proteins .
Less than 2 %
430
___make up a very large portion of the human genome .
Repeated sequnces
431
__are stretches of DNA sequences that are repeated many times ,sometimes hundred to thousand times .
Repetitive sequences
432
Function of repetitive sequences -
No direct coding functions , but they shed light on CHROMOSOME STRUCTURE , DYNAMICS and EVOLUTION .
433
___has most genes . How many ?
Chromosome 1
| 2968
434
___has the fewest genes . How many ?
Y chromosome
| 231
435
Scientists have identified about ___ locations where single base DNA diff occur in humans .
1.4 million
436
Full form of SNPs
Single nucleotide polymorphism
| Occur at 1.4 million locations
437
DNA fingerprinting involves identifying diff in some specific regions in DNA sequence called as ____ . Why ?
Repetitive DNA ( becoz in these , a small stretch of DNA is repeated many times )
438
The repetitive DNA are separated from bulk genomic DNA as diff peaks during density gradient config . The ___forms the major peak and the other small peaks are referred to as ____ .
Bulk DNA
| Satellite DNA
439
Depending on _____ , ____ and ____ , the satellite DNA is classified into many categories ,such as MICRO-SATELLITES and MINI-SATELLITES .
Base composition ( A:T rich or G:C rich )
Length of segment
Number of repetitive units
440
Repetitive DNA sequences show ___ and form the basis of __ .
High degree of polymorphism
| DNA fingerprinting
441
Polymorphism ( variation at __level) arises due to ____ .
Genetic level
| Mutations
442
_____ variation has traditionally been described as a DNA polymorphism if more than one variant (allele ) at a locus occurs in human population with a freq greater than ___ .
Allele sequence
| 0.01
443
If an ___is observed in a population at HIGH FREQ ,it is referred to as DNA polymorphism .
Inheritable mutation
444
The probability of allele sequence variation ( inheritable mutation ) is observed in ____ sequence would be HIGHER as mutations in these sequences may not have an immediate effect / impact in an individual’s REPRODUCTIVE CAPABILITY .
Non-coding DNA sequence
445
The technique of DNA fingerprinting was initially developed by _____ .
Alec jefferys
446
Alec Jefferys used a____as probe that shows very HIGH DEGREE OF POLYMORPHISM .
Satellite DNA
447
The satellite DNA was called as _____ .
VNTR (variable number of tandem repeats )
448
DNA fingerprinting involves ____ hybridization using ___ as probe .
Southern blotting
| Radiolablled VNTR
449
The process of DNA fingerprinting is -
1) isolation of DNA
2) digestion of DNA by restriction endonucleases
3) separation of DNA fragments by electrophoresis
4) transferring ( blotting ) of separated DNA fragments to synthetic membranes ,such as NITROCELLULOSE or NYLON
5) hybridization using labeled VNTR probes
6) detection of hybridised DNA fragments by AUTORADIOGRAPH .
450
A VNTR belongs to a class of satellite DNA called ____
Mini-satellites
451
What does mini satellites mean -
A small DNA sequence is arranged tandemly in many copy numbers .the copy numbers vary from chromosome to chromosome in an indivisual .
452
The number of repeats show very high degree of polymorphism . As a result the size of VNTR varies in size from __ to ____ kB .
0.1. To 20 kB
453
After hybridization with VNTR probe , the ___ gives many bands of differing sizes
Autoradiogram
454
Pattern of DNA differs from individual to individual in a population except in the case of __.
Monozygotic twins 👯♀️
455
The sensitivity of DNA fingerprinting has been increased by use of _____.
PCR
