All Free Biology MCQs with Answers

• A. TAC
• B. UAC
• C. AUG
• D. CCA

Explanation: Anticodons are as follow:A = U( in case of RNA)A=T ( in case of DNA)C=G( same in both cases)

• A. Mg+ ions
• B. Na- ions
• C. Proteins
• D. Ribosomal RNA

Explanation: The attachment of two subunits of ribosomes on a single mRNA is controlled by Mg2+ ions.

• A. 2
• B. 3
• C. 5
• D. 4

Explanation: Building blocks of nucleic acids, i.e., DNA and RNA. A nucleotide consists of a sugar molecule attached to a phosphate group and a…

• A. TAC
• B. ATC
• C. UAC
• D. UTC

Explanation: AUG is the start codon that signals ribosomes to place in the amino acid methionine because the tRNA that has methionine attached to it…

• A. Transcription
• B. Replication
• C. Polymerization
• D. PCR

Explanation: The process by which DNA is copied to RNA is called transcription.

• A. AAUOCGT
• B. UUAACGA
• C. TTAACGA
• D. UUTTCGT

Explanation: RNA polymerase uses one of the DNA strands (the template strand) as a template to make a new, complementary RNA molecule.

• A. Poly genes
• B. Genome
• C. Promoter
• D. Pleiotropy

Explanation: The first step in transcription is initiation, when the RNA pol binds to the DNA upstream (5′) of the gene at a specialized sequence…

• A. 30S and 40S
• B. 70S and 10S
• C. 50S and 30S
• D. 60S and 40S

Explanation: Ribosomes are non-membrane-bounded organelles that are present in large numbers in all living cells and serve as the site of protein…

• A. Arginine
• B. Glutamine
• C. Tryptophan
• D. Valine

Explanation: A codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis.

• A. UAA,UAG,UGA
• B. UGC,UCG,AAA
• C. UUG,UCG,UCA
• D. UAA,UGC,UCA

Explanation: Stop codons are codons (triplets of nucleotides) in messenger RNA (mRNA) that signal the termination of protein synthesis.

• A. Phagosome
• B. Perosome
• C. Polysome
• D. Punosome

Explanation: When multiple ribosomes are attached to a single mRNA molecule, it forms a structure called a polysome.

• A. Arginine
• B. Tryptophan
• C. Methionine Stop Codon
• D. 1-butene.

Explanation: In mitochondrial DNA, the codon AGG indeed codes for the amino acid arginine.

• A. 4
• B. 8
• C. 16
• D. 20

Explanation: If a codon consisted of only two nucleotides, there would be 4 possible combinations for each position (since there are 4 different…

• A. Nuclear envelope
• B. Chromosome
• C. rRNA
• D. Cytoplasm

Explanation: The nucleolus is a region within the nucleus of eukaryotic cells where ribosome synthesis occurs.

• A. Bacteria
• B. Virus
• C. Parasite
• D. None of the above

Explanation: Gonorrhea is a sexually transmitted infection caused by the gram-negative bacterium Neisseria gonorrhoeae.

• A. 4 and 20 weeks
• B. 6 and 20 weeks
• C. 2-26 weeks
• D. 2-6 weeks

Explanation: The incubation period of the hepatitis B virus ranges from 30 to 180 days, which translates to approximately 4 to 20 weeks.

• A. Plasma
• B. Liver
• C. Inside various cells of body
• D. Outside the blood stream

Explanation: White blood cells are destroyed inside various cells of the body, where they encounter and destroy foreign substances through mechanisms…

• A. active immunity
• B. innate immunity
• C. passive immunity
• D. acquired immunity

Explanation: Passive immunity refers to the transfer of antibodies from one individual to another, providing immediate but temporary protection.

• A. active immunity
• B. inflammatory response
• C. c
• D. d

Explanation: Inflammation is a response triggered by damage to living tissues. The inflammatory response is a defence mechanism that evolved in higher…

• A. Children
• B. Adults
• C. Special populations
• D. All of the above

Explanation: The Bacillus Calmette-Guerin (BCG) vaccine is primarily given to children, especially in countries where tuberculosis (TB) is prevalent…