Free Biological Molecules MCQs with Answers
1,790 Biological Molecules MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The chapter covers water's polarity and biological roles, carbohydrates, lipids, proteins and nucleic acids, including their monomers, bonds, structures and functions. It also distinguishes RNA from DNA and explains conjugated molecules such as glycoproteins, glycolipids and nucleoproteins, which combine organic molecules with a non-protein component.
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- A. Number of polypeptide chains involved
- B. Bending of polypeptide chains
- C. Amino acid sequence
- D. Coiling of polypeptide chains
Explanation: The primary structure of a protein is the exact linear sequence of its amino acids, joined by peptide bonds.
Correct answer: Amino acid sequence- A. NH2 group
- B. COOH group
- C. R group
- D. All of these
Explanation: All standard amino acids have an amino group and a carboxyl group, but their variable R groups differ and produce their chemical variety.
Correct answer: R group- A. 170
- B. 20
- C. 25
- D. 15
Explanation: In the basic genetic code, there are mainly 20 functional types of tRNA, each associated with one of the 20 standard amino acids.
Correct answer: 20- A. 3-4 %
- B. 10-20%
- C. 80%
- D. 90%
Explanation: Ribosomal RNA makes up about 80% of the total RNA in a typical cell because ribosomes contain a large amount of rRNA and cells have many…
Correct answer: 80%325. The sequence of 3 bases on tRNA which is complementary to condon of mRNA is called____________?
- A. Gene
- B. Anticodon
- C. Code
- D. Codon
Explanation: The anticodon is a three-base sequence on tRNA that pairs complementarily with a codon on mRNA during translation.
Correct answer: Anticodon- A. It produces another DNA molecule
- B. It produces mRNA
- C. It is a semi conservation process
- D. It occurs at surface of ribosomes
Explanation: Transcription uses one DNA strand as a template to synthesize a complementary RNA molecule, commonly mRNA for a protein-coding gene.
Correct answer: It produces mRNA- A. 3
- B. 4
- C. 5
- D. 2Health
Explanation: A furanose ring is a five-membered ring containing four carbon atoms and one oxygen atom, so ribofuranose has 4 ring carbons.
Correct answer: 4- A. The pentose sugar in it is Ribose.
- B. It contains Adenine Guanine Thymine and Cytosine
- C. It is present in the nucleoli
- D. It may be folded back on itself to give double helical characteristics.
Explanation: RNA contains ribose sugar and the bases adenine, guanine, cytosine and uracil, not thymine.
Correct answer: It contains Adenine Guanine Thymine and Cytosine- A. Polymer
- B. Polypeptide
- C. Polysomes
- D. Monomer
Explanation: A polysome, or polyribosome, is a group of ribosomes simultaneously attached to one mRNA molecule, allowing several copies of a…
Correct answer: Polysomes- A. Transcription
- B. Secretion
- C. Translation
- D. Division
Explanation: A polysome, or polyribosome, forms when several ribosomes simultaneously translate one mRNA molecule, allowing many copies of a protein to…
Correct answer: Translation- A. Molecular biologists
- B. Microbiologists
- C. Freshwater biologists
- D. Social biologist
Explanation: Molecular biologists study DNA, genes, chromosomes, and mutations at the molecular level to determine how inherited diseases arise.
Correct answer: Molecular biologists- A. Nucleus
- B. Genes
- C. Chromosomes
- D. Nucleolus
Explanation: A gene is a specific segment of DNA that carries information for a functional product, such as a protein or functional RNA, making it the…
Correct answer: Genes- A. Amino acids
- B. RNA
- C. Nucleotides
- D. Polypeptides
Explanation: Nucleic acids carry genetic information and are long chains formed by joining nucleotides, each containing a sugar, phosphate group, and…
Correct answer: Nucleotides- A. A portion of RNA
- B. A linkage group
- C. A portions of DNA
- D. A sequence of Amino
Explanation: A gene is a specific sequence of DNA that contains information for a functional product, such as a protein or functional RNA.
Correct answer: A portions of DNA- A. Histones
- B. Lipoproteins
- C. Polynucleotides
- D. Hydrocarbons
Explanation: Genes are made of polynucleotides because DNA is a polymer consisting of many nucleotide units joined in long chains, and genes are…
Correct answer: Polynucleotides- A. 10A
- B. 20A
- C. 30A
- D. 40A
Explanation: Wilkins's X-ray diffraction data supported a DNA helix diameter of about 20 Å, which is 2 nm because 10 Å = 1 nm and 20 Å ÷ 10 = 2 nm.
Correct answer: 20A- A. Louis Pasture
- B. William Harvey
- C. Charles Darwin
- D. Watson and Crick
Explanation: Watson and Crick proposed the double-helical model of DNA in 1953, using evidence including Chargaff's rules and X-ray diffraction data…
Correct answer: Watson and Crick- A. Appearance of an individual
- B. Genetic basis of few characters
- C. Full set of genes of an individual
- D. All of these
Explanation: A genome is the complete genetic material of an organism, including its full set of genes and associated DNA sequences.
Correct answer: Full set of genes of an individual- A. 5
- B. 10
- C. 20
- D. 25
Explanation: In the common B-form of DNA, one complete turn of the double helix contains about 10 base pairs.
Correct answer: 10- A. F.Miescher
- B. Chargaff
- C. Watson & Crick
- D. Harshay & Chase
Explanation: Chargaff showed that DNA contains approximately equal amounts of purines and pyrimidines because adenine pairs with thymine and guanine…
Correct answer: Chargaff