B.Sc. II Biotechnology (Semester IV) (CBCS) Examination, 2018
Mechanisms in molecular biology
Day and Date Saturday, 8-12-2018 Total Marks 70
Time 10.30 a.m. to 1.00 p.m.
Instructions All questions are compulsory.
Figures to right indicate full marks.
Draw neat and labeled diagrams wherever necessary.
1. Rewrite the following sentences by using correct alternative. 14
are added to specific lysine residues on the core histones by a family of enzymes called histone acetyltransferases.
Acetyl groups Formyl groups
Ethyl groups Methyl groups
In lactose operon, β-Galactosidase enzyme is encoded by gene.
lac lac lac lac
In prokaryotes directly binds to site of ribosomes during initiation of translation process.
tRNAmet tRNAfmet
tRNApro tRNAval
enzymes required for charging of tRNA molecule.
Aminoacyl tRNA synthetase DNA glycosylase
Peptidyl di-sulphide isomerase Peptidyl transferase
T C loop of tRNA helpful for binding to
Amino acids Ribosomes
tRNA Aminoacyl tRNA synthetase
Formulated methionine amino acid specified by codon in
prokaryotes.
AGU AUG UAG GUG
are expressed from heat shock genes in response to elevated temperatures in E.coli.
Chaperons DNA methylases
Histone methylases Histone methyltransferases
In eukaryotes, 5S rRNA is transcribed by
RNA Polymerase α RNA polymerase II
RNA polymerase III RNA polymerase I
is required for termination of transcription process in prokaryotes.
Sigma factor Rho factor
Pol-α Core enzyme
10) During mRNA processing is required for capping of primary transcripts.
Poly polymerase snRNPs
RNA Polymerase III RNA polymerase I
11) Shine-Dalgarno sequences are
AGGAGGU TTAGGG CAAT TATA
12) Robert Holly proposed
Clover leaf model of tRNA Double helical structure of DNA
Hairpin loop model of tRNA Operon model
13) is responsible for proper recognition of splice site during slicing process.
SR proteins and U2AF Polyribosomes
Enhanceosome Replisome
14) Pan-editing starts with the base-pairing of the unedited primary transcript with a
mRNA snRNA miRNA gRNA
2. Answer the following (any 14
What is promoter sequence
ii) Write a note on regulatory gene in operon.
iii) What are split genes
iv) What are introns
What are translational repressors
vi) What is TBP
vii) What is exon shuffling
viii) Write a note on polyribosomes.
ix) What are General Transcription Factors
3. Answer the following (any 10
Explain RNA editing with suitable examples.
ii) Describe mechanism of intron splicing in eukaryotes.
iii) Describe regulation of translation in eukaryotes with suitable examples.
Describe structure, function and assembly of prokaryotic RNA
polymerase. 4
4. Answer any two of the following 14
Describe regulation of transcription in eukaryotes with any two suitable examples.
ii) Describe regulation of trp operon in bacteria.
iii) Explain post-translational modifications in proteins.
5. Answer any two of the following 14
Explain mechanism of translation in eukaryotes.
ii) Describe structure and regulation of lactose operon in bacteria.
iii) Describe mechanism of transcription in prokaryotes.