the following pertain to ribosomes during protein synthesis except

Question 1


Question 2


Question 3

All of the following statements pertain to ribosomes during protein synthesis EXCEPT:

a. It binds to 5′ end of mRNA with their small subunit.

b. It reads mRNA codons in 3′ to 5′ direction.

c. It is found in cytoplasm.

d. It consists of an A site, P site and E site.



Answer to question 1

1 a

Ribosomes does all the functions in the given options except carrying amino acids which is done by tRNA.

2 C

DNA is made up of deoxyribonucleotides units which contain sugar,  nitrogenous base and phosphate. 

3c

DNA synthesis from DNA molecule is called DNA replication. 

4 c

DNA polymerase enzyme has the ability for proof reading as well as polymerase activity. 

5 c

Leading strand is the newly replicated strand which is continuous in 5′ to 3′ direction. 


Answer to question 2

Ribosomes are the sites where protein synthesis takes place with in the cells. These ribosones are seen in the cytoplasm of the cells.

The process by which genetic information is transferred from nucleus to ribosomes is called the Transcription.

Transcription takes place in the nucleus.

During transcription RNA is synthesized which is called mRNA that is complimentary to the portion of DNA that directed it.

RNA polymerase is the enzyme which controls the transcription process.

Ribosomes do participate in the process of translation which involves catalyzing the reactions that joins the amino acids to make a protein chain.

Ribosomes are composed of rRNA and Protein.

During the protein synthesis the Ribosomes move along the mRNA which results in vacating the initiation site for additional protein synthesis.

AUG is the most common codon which is usually the START codon during the protein synthesis. Ribosomes usually scan the mRNA for this start codon AUG and it is the tRNA which recognises the AUG codon.

so the incorrect one is Ribosomes are not involved in the transcription process since it takes place in nucleus.


Answer to question 3

Answer and Explanation: All of the statements provided above about ribosomes during protein synthesis are correct except for: b. It reads mRNA codons in 3′ to 5′ direction. This is simply an incorrect statement. Ribosomes read all mRNA strands in the 5′ to 3′ direction. The ribosomes move along the mRNA reading codons three bases at a time, and this information results in single amino acids at a time being added to the growing polypeptide chain.

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