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. Primary structure
- B. Secondary structure
- C. Tertiary structure
- D. Quaternary structure
Explanation: More than one molecules of tertiary proteins are bonded to acquire a stable aggregated configuration called quaternary configuration e.g.
Correct answer: Quaternary structure- A. Insulin
- B. α-helix
- C. Alpha chain of hemoglobin
- D. Hemoglobin molecule
Explanation: The correct answer is the Hemoglobin molecule. Hemoglobin is a complex protein consisting of four polypeptide chains, each having its…
Correct answer: Hemoglobin molecule- A. Number of individuals
- B. Number of chromosomes
- C. Number of cells
- D. Number of genes
Explanation: The correct answer is the number of chromosomes. In a given species, the amount of DNA is determined by its chromosome number, which…
Correct answer: Number of chromosomes- A. Somatic cells, Germ cells
- B. Gametocytes, Somatic cells
- C. Germ cells, Somatic cells
- D. Somatic cells, Gametocytes
Explanation: Germ cells (sperms and ova) are meiotic products, thus contain haploid number of chromosomes, whereas rest of the body cells are mitotic…
Correct answer: Germ cells, Somatic cells- A. 4,639,221
- B. 4,639,222
- C. 4,629,221
- D. 4,638,221
Explanation: The E. coli genome consists of exactly 4,639,221 base pairs. This number is significant because it provides the genetic blueprint for the…
Correct answer: 4,639,221- A. ATP
- B. NAD
- C. FAD
- D. RNA
Explanation: The correct answer is RNA. RNA, or ribonucleic acid, is a polymer composed of ribonucleotides, just as DNA is a polymer of…
Correct answer: RNA- A. 3 to 4
- B. 5 to 6
- C. 80
- D. 10 to 20
Explanation: It is intermediate in quantity among three types of RNAs.
Correct answer: 10 to 20- A. A French chemist
- B. A German chemist
- C. A Swiss chemist
- D. A Spanish chemist
Explanation: The molecule now known as DNA was first identified by Johann Friedrich Miescher, a Swiss chemist, in the 1860s.
Correct answer: A Swiss chemist869. Who discovered DNA?
- A. Frederick Miescher
- B. Frederick Sanger
- C. Frederick Griffith
- D. Frederick Aldrich
Explanation: Frederick Miescher, a Swiss chemist, is credited with the discovery of DNA in 1869 when he isolated a substance he named 'nuclein' from…
Correct answer: Frederick Miescher- A. Their isolation from nuclei
- B. Their isolation from pus cells
- C. Their acidic nature
- D. Their isolation from nucleus and acidic nature
Explanation: The term 'nucleic acids' originates from their initial isolation from cell nuclei ('nucleic') and their acidic nature ('acids').
Correct answer: Their isolation from nucleus and acidic nature- A. RNA
- B. Proteins
- C. Nucleic acids
- D. DNA
Explanation: DNA is the primary genetic material located in the nucleus of eukaryotic cells, where it forms chromosomes and genes.
Correct answer: DNA- A. DNA
- B. RNA
- C. Proteins
- D. Nucleic acids
Explanation: RNA being associated with protein synthesis mostly occurs in cytoplasmhowever it is synthesized inside the nucleus from DNA that is why it…
Correct answer: RNA- A. Amino acids
- B. Nucleosides
- C. Fatty acids
- D. Nucleic acids
Explanation: Nucleic acids are polymers made up of monomeric units called nucleotides.
Correct answer: Nucleic acids- A. One subunit
- B. Two subunits
- C. Three subunits
- D. Four subunits
Explanation: A nucleotide is the basic building block of nucleic acids, such as DNA and RNA.
Correct answer: Three subunits- A. Ribose
- B. Ribulose
- C. Deoxyribulose
- D. Deoxyribose
Explanation: The correct answer is Deoxyribose. Deoxyribose is a five-carbon sugar and a key component of DNA, making it a deoxyribonucleotide.
Correct answer: Deoxyribose- A. Ribose
- B. Ribulose
- C. Deoxyribulose
- D. Deoxyribose
Explanation: The correct answer is Ribose. RNA, or ribonucleic acid, contains ribose as its pentose sugar.
Correct answer: Ribose- A. Purine
- B. Pyrimidines
- C. Adenine
- D. Guanine
Explanation: The correct answer is pyrimidines. Pyrimidines are one of the two types of nitrogenous bases found in nucleic acids and are distinguished…
Correct answer: Pyrimidines- A. Purines
- B. Adenine
- C. Cytosine
- D. Guanine
Explanation: The correct answer is Cytosine. Pyrimidines, such as cytosine, thymine, and uracil, have a single-ring structure, making them smaller…
Correct answer: Cytosine879. Purines include:
- A. Adenine and cytosine
- B. Adenine and thymine
- C. Adenine and guanine
- D. Adenine and uracil
Explanation: The correct answer is Adenine and guanine. Both adenine and guanine are purines, which are characterized by a two-ring structure.
Correct answer: Adenine and guanine- A. Cytosine and Thymine
- B. Cytosine and Uracil
- C. Cytosine and Adenine
- D. Cytosine and Guanine
Explanation: RNA contains the pyrimidine bases cytosine and uracil. In RNA, uracil replaces thymine, which is found in DNA.
Correct answer: Cytosine and Uracil