Multiple choice questions

[_Luna_]

A ribozyme is:

a) a protein in 30S ribosome unit.

b) a RNA that hydrates proteins.

c) a protein that cleaves RNA

d) a RNA that splits oneself and then glues the pieces together in a new way.

 

mRNA binds oneself to the 30S ribosomal unit:

a) in a complex with GTP

b) and is then modified with a cap

c) together with elongating factors

d) first after it has been attached to initiating factors

e) none of the above.

 

Poly-a-tail:

a) Are in every eukaryote mRNA.

b) Are out on the end of every gene transcript

c) Exists if the transcript has a sequence which specify polyA on the 3’ end.

d) Exist in the end of every gene

e) Exists only in prokaryote mRNA

 

Stop codon:

a) Are recognized by equal terminating factors

b) Will always sit on the anti-codon bow.

c) Are recognize by own tRNA when these binds to the A seat

d) Are different in mitochondria’s and in cytoplasm.

e) Doesn’t exist in tRNA

 

Transcription factors binds to:

a) A intact DNA double helix, and promotes the binding of RNA Polymerase

b) RNA polymerase

c) Single stranded DNA

d) Special seats where DNA helix has been melted

e) Histones

 

 

The difference between sigma factor and transcription factor is that:

a) Sigmafactors are found in bacterias while transcription factors dominates in eukaryote

b) Sigma factors binds to DNA while transcriptionfactors bind to repressors.

c) They are included in respective eukaryote and prokaryote:

 

Does anyone of you have any comment? I am going on a lecture now, but I'll be back to comment some more.

[_Luna_]

Forget the first post!

 

mRNA binds oneself to the 30S ribosomal unit:

a) in a complex with GTP

a) first after it has been attached to initiating factors

 

Poly-a-tail:

a) Are in every eukaryote mRNA.

b) Exists if the transcript has a sequence which specify polyA on the 3’ end.

 

I didn't think it was in every single eykaryote mRNA, so I guess the b is correct

 

Stop codon:

Are recognized by equal terminating factors

Will always sit on the anti-codon bow.

Are recognize by own tRNA when these binds to the A seat

Are different in mitochondria’s and in cytoplasm.

Doesn’t exist in tRNA

 

Again I believe the answer is doesn't exist in rRNA, but I think I read somewhere that in mitochondrias one of the stopcodon actually codes for thryptofan?

 

Transcription factors binds to:

a. A intact DNA double helix, and promotes the binding of RNA Polymerase

b. Simple stranded DNA

c. Special seats where DNA helix has been melted

d. Histones

 

a or b?

 

A alfahelix is destabilized by:

a. Two Lys residues near amino terminus in alfa helix

b. Interactions between to hydrophobic Val residues in neighbouring positions.

c. Interactions between to Asp and Arg residues in neighbour positions.

 

Lys has a charge + while Val is 0, so I am thinking a

 

The advantage by measuring the initial reaction rate V0 at the beginning of the reaction is:

a. The [ES] is measured precisely

b. The changes in are insignificant and can be looked on as a constant

c. The changes in [Km] are insignificant and [Km] can be looked on as a constant.

 

Here I am a bit confused, maybe a or b.

 

E.coli DNA pol III:

a. Represents over 90% av DNA polymerase activity in E.coli?

b. Is the most important DNA polymerase in chromosomal DNA replication?

 

I think it's pol I that represents 90% and therefor I'll choose b

 

When a protein is completely hydrolyzed will the further analyse:

a. Only detect aminoacids in S conformation

b. Often detect other molecules besides aminoacids

c. Never detect more than 20 standard aminoacids

d. Never detect fewer than 20 standard aminoacids

e. Only detect the 20 standard aminoacids

 

This is a silly question because they don't mention what kind of protein where are looking on. Does anyone have some thoughts about this one?

 

Which of the following statements of E.coli RNA polymerase is wrong?

a. RNA made by this enzyme is complementary to the DNA template

b. The coreenzyme binds to the promoter, but will never initiate the synthesis without a sigma factor.

 

RNA will never be completyly complementary to the DNA because you change T with U.

[meena]

I went through the questions .I am meena preparing for varoius exams.could you please send few more MCQ along with their ans on life sciences.....