54417.Which type of selection is industrial melanism observed in moth, Biston betularia
Stabilising
Directional
Disruptive
Artificial
Explanation:
The industrial melanism is a type of directional selection observed in moth. Under this,individuals at one end of the frequency distribution do well light and so more individuals of that type will be present in next generation.The other options are incorrect because in stabilising selection, average sized individuals are favoured, e.g., weight of new -born babies and in disruptive selection both extremes are favoured,
while intermediate varieties are elemmated. e.g., black bellied seed cracker, Pyrenestes ostrinus.In artificial selection, the individuals with desirable characteristics are deliberately selected to produce a progeny with all those characteristics.
The industrial melanism is a type of directional selection observed in moth. Under this,individuals at one end of the frequency distribution do well light and so more individuals of that type will be present in next generation.The other options are incorrect because in stabilising selection, average sized individuals are favoured, e.g., weight of new -born babies and in disruptive selection both extremes are favoured,
while intermediate varieties are elemmated. e.g., black bellied seed cracker, Pyrenestes ostrinus.In artificial selection, the individuals with desirable characteristics are deliberately selected to produce a progeny with all those characteristics.
54418.The RNA polymerase holoenzyme transcribes
the promoter, structural gene and the terminator region
the promoter and the terminator region
the structural gene and the terminator regions
the structural gene only
Explanation:
transcription begins with the binding of the RNA polymerase complex (or holoenzyme) to a special DNA sequence at the beginning of the gene known as the promoter. Activation of the RNA polymerase complex enables transcription initiation, and this is followed by elongation of the transcript. Once the RNA polymerase reaches the termination region of DNA, the RNA polymerase is separated from DNA-RNA hybrid, as a result nascent RNA separates. This process is called termination.
transcription begins with the binding of the RNA polymerase complex (or holoenzyme) to a special DNA sequence at the beginning of the gene known as the promoter. Activation of the RNA polymerase complex enables transcription initiation, and this is followed by elongation of the transcript. Once the RNA polymerase reaches the termination region of DNA, the RNA polymerase is separated from DNA-RNA hybrid, as a result nascent RNA separates. This process is called termination.
54419.If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is 5 –A T G A A T G-3 , the sequence of bases in its RNA transcript would be
5-A U G A A U G -3
5 -U A C U U A C -3
5-C A U U C A U-3
5-G U A A G U A -3
Explanation:
5 -A T G A A T G -3 (coding strand) -> 5 -T A C T T A C -3 (complementary strand)->5 -A U G A A U G -3 (RNA)
5 -A T G A A T G -3 (coding strand) -> 5 -T A C T T A C -3 (complementary strand)->5 -A U G A A U G -3 (RNA)
54420.Animal husbandry and plant breeding programmes are the examples of
reverse evolution
artificial selection
mutation
natural selection
Explanation:
These are examples of artificial selection Artificial selection is a process of breeding of plants and animals to produce desirable traits.The other three options are incorrect as mutation is a sudden change in DNA sequence due to mutagenic agents such as cherncals and radiations.Natural selection is a gradual process by which biological traits become either more or less common in a population as a function of the effect of the changing environment.Reverse evolution or devolution is a notion that species can change into more primitive forms over time.
These are examples of artificial selection Artificial selection is a process of breeding of plants and animals to produce desirable traits.The other three options are incorrect as mutation is a sudden change in DNA sequence due to mutagenic agents such as cherncals and radiations.Natural selection is a gradual process by which biological traits become either more or less common in a population as a function of the effect of the changing environment.Reverse evolution or devolution is a notion that species can change into more primitive forms over time.
54421.Appearance of antibiotic-resistant bacteria is an example of
adaptive radiation
transduction
pre-existing variation in the population
divergent evolution
Explanation:
Appearance of antibiotic-resistant bacteria is an example of pre-existing variation in the population. When a bacterial population encounters a particular antibiotic, those sensitive to it die.But some bacteria having mutations become resistant to the antibiotic. Soon, the resistance providing genes beco
me widespread and the entire population becomes resistant.Adaptive radiation is development of different functional structures from a common ancestral form which is also known as divergent evolution.
Transduction is a process whereby, foreign DNA is introduced into another cell via a viral vector.
Divergent evolution gives rise to homologous organs.
Appearance of antibiotic-resistant bacteria is an example of pre-existing variation in the population. When a bacterial population encounters a particular antibiotic, those sensitive to it die.But some bacteria having mutations become resistant to the antibiotic. Soon, the resistance providing genes beco
me widespread and the entire population becomes resistant.Adaptive radiation is development of different functional structures from a common ancestral form which is also known as divergent evolution.
Transduction is a process whereby, foreign DNA is introduced into another cell via a viral vector.
Divergent evolution gives rise to homologous organs.
54422.The bones of forelimbs of whale, bat, cheetah and man are similar in structure, because
one organism has given rise to another
they share a common ancestor
they perform the same function
they have biochemical similarities
Explanation:
The bones of forelimbs of whale, bat, cheetah and man are similar in structure, because they
have a common ancestor.These are homologous organs which have different functions across diverse forms, but are developed along same pattern. These organs arise due to divergent evolution.
The bones of forelimbs of whale, bat, cheetah and man are similar in structure, because they
have a common ancestor.These are homologous organs which have different functions across diverse forms, but are developed along same pattern. These organs arise due to divergent evolution.
54423.The amino acid attaches to the tRNA at its
5-end
3-end
Anticodon site
DHU loop
Explanation:
AA-binding site (amino acid binding site) lies at the 3 end opposite the anticodon and has CCA-OH group. It
is the site where amino acid attaches to the tRNA.
AA-binding site (amino acid binding site) lies at the 3 end opposite the anticodon and has CCA-OH group. It
is the site where amino acid attaches to the tRNA.
54424.Which of the following is used as an-atmospheric pollution indicator?
Lepidoptera
Lichens
Lycopersicon
Lycopodium
Explanation:
Lichens can be used as an atmospheric pollution indicator. They do not grow in areas that are
polluted, as they are sensitive (especially phycobiont) to oxides of nitrogen and sulphur, hence
unable to synthesise organic food and do not grow well.
Lichens can be used as an atmospheric pollution indicator. They do not grow in areas that are
polluted, as they are sensitive (especially phycobiont) to oxides of nitrogen and sulphur, hence
unable to synthesise organic food and do not grow well.
54425.Fossils are generally found in
sedimentary rocks
igneous rocks
metamorphic rocks
any type of rock
Explanation:
Fossils are generally found in sedimentary rocks,-which are formed by the gradual deposition of silt, sand or calcium carbonate over millions of years in regions such as lakes or sea during their formation, the dead animals flow down into the sea or large lake, sink down and get burried in the rocks. The animals, thus preserved in the rocks, are converted into fossils.Igneous rocks are formed from lava and hence no fossil can be found in them.
Metamorphic rocks can be made from igneous or sedimentary rocks.
Fossils are generally found in sedimentary rocks,-which are formed by the gradual deposition of silt, sand or calcium carbonate over millions of years in regions such as lakes or sea during their formation, the dead animals flow down into the sea or large lake, sink down and get burried in the rocks. The animals, thus preserved in the rocks, are converted into fossils.Igneous rocks are formed from lava and hence no fossil can be found in them.
Metamorphic rocks can be made from igneous or sedimentary rocks.
54426.If the base sequence of a codon in mRNA is 5 -AUG-3 , the sequence of tRNA pairing with it must be
5-UAC -3
5–CAU –3
5-AUG –3
5 –GUA –3
Explanation:
5 -A U G -3 (codon in mRNA) ||| 5 -U A C -3 (RNA)
5 -A U G -3 (codon in mRNA) ||| 5 -U A C -3 (RNA)
54427.Analogous organs arise due to
divergent evolution
artificial selection
genetic drift
convergent evolution
Explanation:
Analogous organs arise due to convergent evolution. These are the organs which have similar
functions, but are different in their structural details and origin, e.g., wings of insect and bird.
The other three options are incorrect, because divergent evolution gives rise to homologous
organs, genetic drift can contribute to speciation and artificial selection is used to produce
improved varieties of animals and plants.
Analogous organs arise due to convergent evolution. These are the organs which have similar
functions, but are different in their structural details and origin, e.g., wings of insect and bird.
The other three options are incorrect, because divergent evolution gives rise to homologous
organs, genetic drift can contribute to speciation and artificial selection is used to produce
improved varieties of animals and plants.
54428.(p + q)2= p2+ 2pq+ p2=1, represents an equation used in
population genetics
Mendelian genetics
biometrics
molecular genetics
Explanation:
(p + q)2= p2+ 2pq + q2= 1 represents an equation used in population genetics.It is a mathematical representation of Hardy-Weinberg principle . This principle says that allele frequencies in a population are stable and are constant from generation to generation,i.e.,the gene pool remains constant.
(p + q)2= p2+ 2pq + q2= 1 represents an equation used in population genetics.It is a mathematical representation of Hardy-Weinberg principle . This principle says that allele frequencies in a population are stable and are constant from generation to generation,i.e.,the gene pool remains constant.
54429.To initiate translation, the mRNA first binds to
the smaller ribosomal sub-unit
the larger ribosomal sub-unit
the whole ribosome
No such specificity exists
Explanation:
The ribosome consists of structural RNAs and about 80 different proteins. In its inactive state, it exist as two subunits, a large subunit and a small subunit. When the smaller subunit encounters the mRNA, the process of translation of the mRNA to protein begins .
The ribosome consists of structural RNAs and about 80 different proteins. In its inactive state, it exist as two subunits, a large subunit and a small subunit. When the smaller subunit encounters the mRNA, the process of translation of the mRNA to protein begins .
54430.Evolution of Life shows that Life forms had a trend of moving from
land to water
dryland to wet land
freshwater to sea water
water to land
Explanation:
Evolution of life shows that life forms had a trend of moving from water to land. The early
vertebrates were fishes (which lived in only water). Some fishes gradually changed into
amphibians (can live both on land and in water).Certain amphibians then transformed into the reptiles (live on land) some of the latter finally evolved into birds (can fly) and then mammals. Thus, showing life forms moved from water to land.
Evolution of life shows that life forms had a trend of moving from water to land. The early
vertebrates were fishes (which lived in only water). Some fishes gradually changed into
amphibians (can live both on land and in water).Certain amphibians then transformed into the reptiles (live on land) some of the latter finally evolved into birds (can fly) and then mammals. Thus, showing life forms moved from water to land.
54431.In E. coli, the lac operon gets switched on when
inds to RNA polymerase
inds to RNA polymerase
lactose is present and it binds to the repressor
repressor binds to operator
RNA polymerase binds to the operator
lactose is present and it b
Explanation:
Incaseof lactose presence
(i) Lactose acts as an inducer which binds to the repressor and forms an inactive repressor.
(ii) The repressor fails to bind to the operator region.
(iii) The RNA polymerase binds to the operator and transcript lac mRNA.
(iv)lac mRNA is polycistronic, i.e., produces all three enzymes, (β-galactosidase, permease and transacetylase.
(v) The lac operon is switched on
Incaseof lactose presence
(i) Lactose acts as an inducer which binds to the repressor and forms an inactive repressor.
(ii) The repressor fails to bind to the operator region.
(iii) The RNA polymerase binds to the operator and transcript lac mRNA.
(iv)lac mRNA is polycistronic, i.e., produces all three enzymes, (β-galactosidase, permease and transacetylase.
(v) The lac operon is switched on
54432.The theory of spontaneous generation stated that
life arose from living forms only
life can arise from both living and non-living
life can arise from non-living things only
life arises spontaneously, neither from living norfrom the non-living.
Explanation:
The theory of spontaneous generation stated that an obsolete theory that states that living organisms can originate from inanimate (non-living) objects. It is also known as abiogenesis.
The theory of spontaneous generation stated that an obsolete theory that states that living organisms can originate from inanimate (non-living) objects. It is also known as abiogenesis.
54433.If Meselson and Stahl s experiment is continued for four generations in bacteria,the ratio of 15N/ 15N: 15N/ 14N:14N/ 14N containing DNA in the fourth generation would be
1:1:0
1:4:0
0:1:3
0:1:7
Explanation:
The ratio of 15N/ 15N remains zero in subsequent generation. The second generation of bacteria after 40 minutes, contained two types of DNA, 50% light (N14 N14) and 50% intermediate (N15 N14).The third generation of bacteria after 60 minutes contained two types of DNA, 25% intermediate (N15N14) and 75% light (N14N14) in 1:3 ratio. The fourth generation after 80 minutes contained 12.5% N15 N14 and 87.5% N14N14 DNA in 1:7 ratio.
The ratio of 15N/ 15N remains zero in subsequent generation. The second generation of bacteria after 40 minutes, contained two types of DNA, 50% light (N14 N14) and 50% intermediate (N15 N14).The third generation of bacteria after 60 minutes contained two types of DNA, 25% intermediate (N15N14) and 75% light (N14N14) in 1:3 ratio. The fourth generation after 80 minutes contained 12.5% N15 N14 and 87.5% N14N14 DNA in 1:7 ratio.
54434.Palaeontological evidences for evolution refer to the
development of embryo
homologous organs
fossils
analogous organs
Explanation:
Palaeontological evidences for evolution refer to the evidences from fossils. Fossils are the preserved remains or traces of organisms from the distant past. The study of fossils is called
Palaeontology. The other options are not correct because the development patterns of embryo
refer to embryological evidences for evolution.Homologous and analogous organs provide evidences for comparative anatomy and morphology.
Palaeontological evidences for evolution refer to the evidences from fossils. Fossils are the preserved remains or traces of organisms from the distant past. The study of fossils is called
Palaeontology. The other options are not correct because the development patterns of embryo
refer to embryological evidences for evolution.Homologous and analogous organs provide evidences for comparative anatomy and morphology.
54435.Viviparity is considered to be more evolved because
the young ones are left on their own
the young Ones are protected by a thicks shell
the young ones are protected inside the mothers body and are looked after they are born leading to more chances of survival
the embryo takes a long time to develop
Explanation:
Viviparity is considered to be more evolved because the young’s ones are protected inside the mother s body and are looked after once they are born, leading to more chances of survival,e.g., mammals.However, in oviparity, the female lays fertilised/unfertilised eggs covered by a hard calcareous shell in a safe place in the environment. The chances of survival are less as the young ones are left on their own.
Viviparity is considered to be more evolved because the young’s ones are protected inside the mother s body and are looked after once they are born, leading to more chances of survival,e.g., mammals.However, in oviparity, the female lays fertilised/unfertilised eggs covered by a hard calcareous shell in a safe place in the environment. The chances of survival are less as the young ones are left on their own.
54436.In some viruses, DNA is synthesised by using RNA as template. Such a DNA is called
A-DNA
B-DNA
cDNA
rDNA
Explanation:
In some viruses, like retroviruses (e.g., HIV), an enzyme called reverse transcriptase is used to
generate complementary DNA (cDNA) from an RNA template. This process is termed reverse transcription.
In some viruses, like retroviruses (e.g., HIV), an enzyme called reverse transcriptase is used to
generate complementary DNA (cDNA) from an RNA template. This process is termed reverse transcription.