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DNA polymerase:
A. Is the main enzyme for RNA synthesis
B. Is DNA dependent DNA polymerizing enzyme
C. Is highly efficient enzyme
D. Is catalyses reaction with high degree of accuracy
RNA polymerase is the main enzyme for RNA synthesis in transcription.
The difference(s) between mRNA and tRNA is / are that:
A. mRNA has more elaborated 3-dimensional structure due to extensive base-pairing.
B. tRNA has more elaborated 3-dimensional structure due to extensive pairing.
C. tRNA is usually smaller than mRNA.
D. mRNA bears anticodon but tRNA has codons.
The key differences between mRNA and tRNA are: B) tRNA has a more elaborated 3D structure due to extensive base pairing, and C) tRNA is smaller than mRNA. mRNA does not bear an anticodon, and tRNA has anticodons, not codons. Therefore, the correct option is o3.
In eukaryotes the gene expression is regulated at:
A. Transcriptional level
B. Processing level
C. Transport of mRNA from nucleus to the cytoplasm
D. Translational level
Gene expression results in the formation of a polypeptide which in eukaryotes is regulated at following levels:
(i) transcriptional level (formation of primary transcript)
(ii) processing level (regulation of splicing)
(iii) transport of mRNA from nucleus to the cytoplasm
(iv) translational level.
(page-115)
In prokaryotes, gene regulation occurs at the level of:
In prokaryotes, control of the rate of transcriptional initiation is the predominant site for control of gene expression.
In a transcription unit, the activity of RNA polymerase at a given promoter is in turn regulated by interaction with accessory proteins.
(page-116)
Which one(s) is / are correct?
A. In prokaryotes single type of RNA polymerase can transcribe mRNA, tRNA and rRNA.
B. In eukaryotes RNA polymerase I transcribes rRNA (28s, 18s and 5.8s) whereas RNA pol III is responsible for transcription of tRNA, 5s rRNA and RNAs.
C. RNA pol II transcribes HnRNA in eukaryotes.
D. Ribosomal large subunit has p and A-sites.
All of the above mentioned statements are correct.
A. Transcription in prokaryotes is catalysed by RNA Polymerase only.
B. In eukaryotes,
RNA polymerase I : transcribes rRNAs (28S, 18S, and 5.8S)
RNA polymerase III : transcription of tRNA, 5srRNA, and snRNAs
C. RNA polymerase II : precursor of mRNA, the heterogeneous nuclear RNA (hnRNA).
D. Large subunit of Ribosome has three sites- E, P and A site
The fact that the genetic code is almost universal in living organisms is considered to be evidence that all organisms:
Genetic code is universal in living organisms and this proves that all organisms are evolutionarily related as all contains amino acids composed of 61 universal code.
(page-112)
Choose the correct statements:
I. Binding of mRNA to the ribosome is loose and reversible.
II. The ribosome, which is composed of tRNA and proteins, consists of a small and large subunit.
III. Each of the 20 amino acids has a minimum of one specific tRNA molecule.
IV. tRNAMET binds to the first codon (AUG) - this is called the START codon.
V. The second tRNA binds to the second codon so that their attached monosaccharides are next to each other
VI. The newly formed polypeptide may undergo post-transcriptional modification.
All the statements are correct except:-
II. The ribosome consists of structural RNAs and 80 different proteins.In its inactive state, it exists as two subunits; a large subunit and a small subunit.
V. Complexes composed of an amino acid linked to tRNA bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNA anticodon. The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one, translated into Polypeptide sequences.
VI. The newly formed polypeptide undergoes post-translational modifications.
(page-115)
The length of DNA has 45000 base pairs. How many complete turns will the DNA molecule take?
According to Watson and Crick model of DNA, DNA exists as a double helix.
The two chains are coiled in a right-handed fashion. There are roughly 10
Base pairs in each turn so length of DNA with 45000 bp will take 4500
turns in a DNA molecule.
(page-98)
The full form of ELSI is:
One of goals of HGP is to address the ethical, legal, and social issues (ELSI) that may arise from the project.
(page-118)
DNA fingerprinting works because:
DNA-fingerprinting is a technique of determining nucleotide sequences of areas of DNA which are unique to each individual. Each person has a unique DNA fingerprint. Only 0.1% of base pairs provide individuality to each person.
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