Question

Within a cell, the amount of protein made using a given mRNA molecule depends partly on

(A) the degree of DNA methylation.

(B) the rate at which the mRNA is degraded.

(C) the number of introns present in the mRNA.

(D) the types of ribosomes present in the cytoplasm.

Short answer

(A) The option “the degree of DNA methylation” is false.

(B) The option “the rate at which the mRNA is degraded” is true.

(C) The option “the number of introns present in the mRNA” is false.

(D) The option “the types of ribosomes present in the cytoplasm” is false.

Step-by-step solution

Protein

Protein is the sequence of amino acids attached via peptide bonds. The proteins have defined functions in metabolic reactions. The amino acids present in the protein sequences are formed by the sequences present in the mRNA.

Explanation of option “(A)”

DNA methylation is the process that regulates gene expression. It is the mechanism that adds a methyl group to the cytosine ends.

Proteins are the component created from amino acids. DNA methylation does not control the amount of protein because it involves adding a methyl group to the DNA sequence.

Therefore, the given option is false.

Explanation of option “(B)”

mRNA is the component that codes for the protein. The degradation of mRNA may result in a reduced number of proteins produced. The amount of protein produced is directly proportional to the mRNA degradation rate.

The protein quantity is partly dependent on the mRNA degradation rate.

Therefore, the given option is true.

Explanation of option “(C)”

The introns are non-coding regions present in the pre mRNA that is created from the transcription. It is not necessary for the protein-coding. The proteins are produced from the coding region of the mRNA.

Thus, the number of introns does not influence the amount of protein since the introns are removed via splicing from the mRNA before it enters into the translation process.

Therefore, the given option is false.

Explanation of option “(D)”

There are two types of ribosomes: free and fixed ribosomes, such that the fixed ribosomes are found attached to the endoplasmic reticulum. The free ribosome moves along the cytosol.

The ribosomes are the site of the protein synthesis that does not influence the amount of protein that is formed. It is dependent on the mRNA that codes for the protein component.

Therefore, the given option is false.