Free Chromosomes MCQs with Answers

• A. Primary structure is conserved
• B. Secondary structure is conserved
• C. Primary structure is changed
• D. Primary structure is disrupted

Explanation: In the process of semi-conservative replication, the primary structure is conserved.

• A. Be disrupted
• B. Remain intact
• C. Be opened
• D. Remain partially intact

Explanation: According to conservative replication, the entire parental DNA duplex is conserved, and a completely new duplex is formed.

• A. Conservative
• B. Semi conservative
• C. Dispersive
• D. Semi-dispersive

Explanation: The model of DNA replication in which parental DNA would become completely dispersed, and each strand of all the daughter molecules would…

• A. Rapid cell division
• B. Lack of nutrition
• C. Fast mutation
• D. Lack of oxygen

Explanation: Cancerous cells are the cells that undergo rapid cell division. These cells are destroyed by X-ray radiation.

• A. RNA virus converts its RNA to DNA
• B. There are no host cells present
• C. Nutrients are scarce
• D. Spikes are forming in the new virus

Explanation: Reverse transcriptase is an enzyme that allows the conversion of RNA into DNA.

• A. Vinca rosea
• B. Vicia faba
• C. Drosophila melanogaster
• D. E. coli

Explanation: Taylor conducted his experiment on treated root tip cells of Vicia faba and treated them with radioactive thymidine (3H) to label the…

• A. The lagging strand towards the replication fork
• B. The leading strand away from replication fork
• C. The lagging strand away from the replication fork
• D. The leading strand towards the replication fork

Explanation: A lagging strand is a replicated strand of DNA that is formed in short segments called Okazaki fragments. Its growth is discontinuous.

• A. tRNA
• B. mRNA
• C. miRNA
• D. rRNA

Explanation: The most abundant RNA molecule in a cell is typically ribosomal RNA (rRNA).

• A. Muton
• B. Cistron
• C. Operon
• D. Recon

Explanation: Cistron (or gene) is a length of DNA that contains the information for coding a specific polypeptide chain or a functional RNA molecule…

• A. 5S rRNA
• B. 18S rRNA
• C. 23S rRNA
• D. 5.8S rRNA

Explanation: The 23s rRNA is a structural RNA present in the ribosomes and a ribozyme that catalyses the formation of peptide bonds during translation…

• A. Heterocyclic nitrogenous bases
• B. Chargaff's rule
• C. Complementary base pairing
• D. 5' phosphoryl and 3' hydroxyl ends

Explanation: Chargaff's rules are applicable only to double-stranded DNA molecules. These are not applicable to single-stranded DNA or RNA molecules.

• A. Negative and repressible because repressor protein prevents transcription
• B. Feedback inhibition because excess of b-galactosidase can switch off transcription
• C. Positive and inducible because it can be induced by lactose
• D. Negative and inducible because repressor protein prevents transcription

Explanation: The control of expression of the lac operon is negative (as it is turned off normally) and inducible.

• A. A-Transcription, B-Translation, C-Francis Crick
• B. A­-Translation, B-Extension, C ­-Rosalind Franklin
• C. A­-Transcription, B-­Replication, C-James Watson
• D. A­-Translation, B­-Transcription, C­-Ervin Chargaff

Explanation: The expression of the genetic material occurs normally through the production of proteins. This involves two consecutive steps.

• A. Transacetylase
• B. Lactose permease and transacetylase
• C. β-galactosidase
• D. Lactose permease

Explanation: A nonsense mutation is the one that stops polypeptide synthesis due to the formation of a termination or non­sense codon.

• A. A-­Maurice Wilkins, B-­Transcription, C­-Translation
• B. A-­James Watson, B­-Replication, C­-Extension
• C. A­-Erwin Chargaff, B­-Translation, C-­Replication
• D. A-­Francis Crick, B­-Translation, C­-Transcription

Explanation: The expression of the genetic material occurs normally through the production of proteins. This involves two consecutive steps.

• A. Viroids
• B. Prions
• C. Bacteriophages
• D. Plant viruses

Explanation: Plant viruses often contain parasites of their own, referred to as satellites.

• A. tRNA
• B. hnRNA
• C. mRNA
• D. rRNA

Explanation: In eukaryotes, RNA polymerase enzymes (Type I, II, III) catalyze the synthesis of RNA using as a template either an existing DNA strand or…

• A. (ii) and (iii)
• B. (i) and (iii)
• C. (ii) and (iv)
• D. (i) and (ii)

Explanation: The two French scientists, Jacob and Monod proposed the lac operon of E.coli.

• A. One DNA strand with the other DNA strand
• B. One nucleoside with another nucleoside
• C. One nucleotide with another nucleotide
• D. One nitrogenous base with a pentose sugar

Explanation: The phosphodiester bonds are formed between the phosphate group, which is connected to carbon 5' of the sugar residue of one nucleotide…

• A. The centromere is found in animal cells, which produces an aster during cell division
• B. The gene for producing insulin is present in every body cell
• C. The nucleosome is formed from nucleotides
• D. DNA consists of a core of eight histones

Explanation: The Insulin gene is found in every body cell but is not expressed in all cells. A nucleosome consists of a core of eight histones.