Question

choose the right answer :

1- what is degradation of ' unwanted' proteins in eukaryotic cells

A- polyribosomes B- proteasomes C- editosome D- spliceosomes

2- addition or deletion of bases causes which kind of mutation

A- transition B- transcription C- transversion D- frameshift mutation

3- point mutation involve :

A- change in single base pair B- deletion C- duplication D- insertion

4- what is the complementary m-RNA sequence for the DNA sequence C-A-A-G-G-T

A- C-A-A-G-G-U B- G-U-U-C-C-A C- C-A-A-G-G-T D- G-T-T-C-C-A

5- in eukaryotic , the RNA polymerase recognition site on the template strand is

A- hogness box B- CAAT box C- TATA box D- prinbnows box

6- the initiation translation factor separate of 70S ribosome subunits to 50S and 30S subunits

A- TF IID B- TBP C- EF-Tu D- IF1

7- in prokaryotic , the first amino acid in the poly peptide chain is :

A- methionine B- all of these C- N- formly methionine D- N- methyl methionine

8- choose the INCORRECT statement about poly-A  

A- Help mRNA transport out of the nucleus B- increase the efficacy of the tranlation initial step C- provide stabillity to mRNA D- recognized by the transport protein

9- gene mutation occur at the time of :

A- RNA transcription B- cell division C- DNA replication D- DNA repair

10- the RNA polymerase that synthesizes tRNA as well as 5S rRNA is :

A- RNA polymerase IV B- RNA polymerase I C- RNA polymerase III D- RNA polymerase II

11- in prokaryotic , the ribosomal binding site on mRNA is called :

A- hogness box B- TATA box C- prinbnows box D- shine dalgarno sequences

12- what is the size of the prokaryotic ribosome :

A- 40S B- 60S C- 80S D- 70S

13- an operon define as :

A- Non- coding sequences between cistrones B- DNA sequences that interact with regulatory proteins C- A cluster of genes transcribed together into a single mRNA D- A section of a DNA or RNA molecules that codes for a specific protein

Answer 1

1.

Option A. Polyribosomes are a cluster of ribosomes linked together by mRNA and forms a site of protein synthesis. INCORRECT OPTION

Option B. Proteasomes are protein complexes which degrade unwanted proteins by proteolysis. The chemical reaction occurring here breaks peptide bonds and enzymes required are proteases. CORRECT OPTION

Option C. Editosomes are the multiprotein complex that catalyzes the editing of RNA. INCORRECT OPTION

Option D. Spliceosomes are the large and complex molecular machine found in the nucleus of eukaryotic cells. INCORRECT OPTION

2.

Option A. Point mutation involving substitution of one base pair for another by replacement of one purine by another purine and one pyrimidine by another pyrimidine. It is basically a substitution reaction. INCORRECT OPTION

Option B. Transcription is the first step in gene expression which involves copying DNA sequence to make an RNA molecule. INCORRECT OPTION

Option C. Transversion is a mutation in which a single purine is substituted for a pyrimidine or single pyrimindine is substituted by purine. INCORRECT OPTION

Option D. Frameshift mutation is caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read. CORRECT OPTION

3.

Point mutation involving substitution of one base pair for another by replacement of one purine by another purine and one pyrimidine by another pyrimidine. There is a change in single base pair.

Frameshift mutation is caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read.

CORRECT OPTION IS (A)

4. mRNA carries information from the synthesis of protein transcribed from a DNA template. In DNA, there are four bases namely, adenine (A), guanine (G), cytosine (C) and thymine (T). There are four nitrogenous bases that make up RNA namely, adenine (A), cytosine (C), guanine (G) and Uracil (U) replaces Thymine (T).

Hence, complementary m-RNA sequence for the DNA sequence C-A-A-G-G-T

G-U-U-C-C-A

CORRECT OPTION IS (B)