MDCAT MCQs with Answers | Free Practice Tests

Test your Biology preparation with this MDCAT 2026 Biological Molecules Quiz for MDCAT, featuring 27 important MCQs on carbohydrates, lipids, fatty acids, amino acids, proteins, enzymes, coenzymes, enzyme inhibition, nucleic acids, and biological catalysts. Practice these MDCAT Biology MCQs to strengthen your concepts and prepare effectively for the MDCAT 2026 entrance test. Let us start with the online Biological Molecules Quiz for MDCAT 2026 now:

Online Biological Molecules Quiz for MDCAT 2026

1. Sara is a chemistry student who is experimenting with an alcohol and acetic acid in the laboratory. The product formed at the end of the experiment will be
2. Lipids contain double amount of energy as compared to the same amount of carbohydrates due to the presence of
3. Which of the following is an unsaturated fatty acid?
4. Which lipid is totally hydrophobic or insoluble?
5. —————– inhibitors have structural similarity with substrate
6. Enzyme B requires $Zn^{2+}$ in order to catalyze the conversion of substrate x. The zinc is best identified as a(n)
7. What about enzymes is wrong?
8. Which will cause the breakdown of the substrate?
9. One which help enzyme and is organic and non-protein
10. Which of the following is a coenzyme?
11. At a temperature below the freezing point of an enzyme is
12. The most important property of an enzyme is its
13. Enzyme inhibition caused by a substrate analog is
14. An amino acid consists of which of the following elements
15. The position of the double bond in oleic acid is
16. The highest percentage of RNA in the cell is of
17. What about pyrimidines is not correct?
18. One of the following is not true about biological catalysts
19. Which structure of an enzyme is essential for the special shape of its active site?
20. What is common in both competitive and non-competitive inhibition?
21. The type of energy reduced by the enzymes for biological reactions to occur is
22. Carbohydrates in cells combine with, and the resulting compounds are called glycoproteins and glycolipids, respectively.
23. Which of the following is a peptide bond?
24. An amino acid in which the R-group is hydrogen is
25. Myosin is a ————— type of protein
26. Secondary structure of protein is found in
27. Fatty acids are the organic compounds containing hydrogen, oxygen, and one of the following

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Prepare for the MDCAT Biology test with this Biological Molecules MCQs Quiz covering key concepts in enzymes, proteins, amino acids, carbohydrates, disaccharides, glycosidic bonds, protein structure, ribozymes, and enzyme activity. These practice questions are designed to help MDCAT aspirants assess their understanding and prepare effectively for the medical entrance test. Let us start with the online Biological Molecules MCQs for MDCAT Preparation:

Online Biological Molecules MCQs for MDCAT with Answers

• What term is used to describe the process by which proteins are synthesized from a genetic code?
• Poisons like cyanide, antibiotics, and some drugs are examples of
• Which step causes activation of the catalytic site of an enzyme?
• A certain enzyme will hydrolyze egg white but not starch. Which statement best explains this observation?
• Which statement about enzymes is not true?
• The proteinaceous part of a holoenzyme is
• Why do drastic changes in the temperature or pH of a system alter enzyme activity?
• Why do drastic changes in the temperature or pH of a system alter enzyme activity?
• Which of the following statements about enzymes is true?
• The rate of any enzyme-controlled reaction increases rapidly if the amount of enzyme is doubled in the presence of an unlimited substrate concentration. This is due to
• A ribozyme is —————– with a well-defined tertiary structure that enables it to catalyze a chemical reaction
• Starch is present in tubers, fruits and grains but absent in animal cells; instead, animals have a substance stored in liver and muscles known as
• Which is an example of a disaccharide?
• The covalent bond or bridge between two monosaccharides to form a disaccharide is called a
• Glycosidic bond is formed by the
• Most proteins are made up of
• In glycine, R is ——————–?
• The structure of a fibrous protein comprises polypeptide chains in the form of
• Which of the following holds the alpha helix of protein in its place?
• The number and sequence of amino acids along a polypeptide chain is called —————- structure of a protein

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Test your MDCAT Biology preparation with this MDCAT Biological Molecules Quiz featuring 20 important MCQs. The quiz covers proteins, carbohydrates, lipids, DNA, RNA, enzymes, amino acids, nucleic acids, tRNA, translation, enzyme inhibition, and other important concepts in biological molecules. Practice these MDCAT Biology MCQs to strengthen your concepts, improve accuracy, and prepare effectively for the MDCAT entrance test.

Online MDCAT Biological Molecules Quiz with Answers

• Which one of the following graphs shows how the rate of reaction of pepsin is affected by pH?
• Secondary structure of protein is found in
• Phosphoric acid can form with the OH group of pentose sugar
• NAD is an important
• A common carbohydrate composed of glucose and fructose joined by a linkage between C-1 of glucose and C-2 of fructose is
• The DNA of an elephant and the DNA of a cherry tree will probably differ in all of the following respects except the
• The sugar component of the DNA molecule has an empirical formula
• All proteins contain
• ———————— Arises only when a protein consists of two or more polypeptide chains
• The two-dimensional shape of tRNA is
• In beta glucose, the hydroxyl group at the anomeric carbon is present at —————
• The end products of translation are
• Backbone of DNA and RNA
• Inhibition of succinic dehydrogenase by malonate is an example of
• A dipeptides have
• Number of carbon atoms in monosaccharides called heptoses are
• During the course of analyzing an unknown chemical, a chemist determines that the chemical is composed of carbon, hydrogen, and oxygen in the proportion of 1 carbon to 2 hydrogen to 1 oxygen. The chemical is probably
• An amino acid has a minimum of —————- carbon atoms and —————- nitrogen atoms
• Distance between base units of DNA is
• On which of the following molecules would you find codons?

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Test your MDCAT Biology preparation with this comprehensive Biological Molecules Quiz covering fats, oils, fatty acids, enzymes, coenzymes, cofactors, enzyme inhibition, active sites, pH, and enzyme models. This 20-question MDCAT Biology MCQ quiz is designed to help students practice key concepts in biological molecules and enzymes, which are frequently tested in medical entrance examinations. Challenge yourself, check your understanding, identify weak areas, and improve your MDCAT Biology score through focused practice. Let us start with the Online Biological Molecules Quiz now

Online Biological Molecules Quiz with Answers

1. Fats containing fatty acids are usually liquid at room temperature and are said to be oils
2. Fats containing ————- fatty acids are solid at room temperature
3. Fats containing unsaturated fatty acids are usually represented by
4. —————- fats are solid at room temperature
5. Fats and oils are
6. The specific gravity of fats and oils is
7. The inhibitors that bind tightly and permanently to enzymes and destroy their globular structure and catalytic activity are
8. Enzyme succinate dehydrogenase converts succinate into
9. If the detachable co-factor is an inorganic ion, then it is designated as
10. The view that the active site of an enzyme is flexible and when a substrate combines with it, causes changes in enzyme structure is known as
11. All coenzymes are derived from
12. The optimum pH value for the working of pancreatic lipase is
13. The competitive inhibitors have structural similarity with
14. Which molecular structure of an enzyme is essential for its activity?
15. Some enzymes require a helper, which is a non-protein part, for their efficient functioning; that is called
16. Pepsin, a protein-digesting enzyme, acts best at pH
17. Which one of the following is an example of a competitive inhibitor?
18. An enzyme requires Mg++ to catalyze the substrate. The Mg+ is best identified as
19. The figure represents ————— inhibitor
20. According to ——————– model the active site of the enzyme is modified as the substrate interacts with the enzyme

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Test your MDCAT Biology preparation with this Biological Molecules MDCAT Quiz containing 20 important multiple-choice questions (MCQs). The quiz covers essential concepts related to carbohydrates, lipids, fatty acids, nucleic acids, DNA and RNA, enzymes, enzyme inhibition, phosphodiester bonds, and the structure and properties of biological molecules.

This online Biology quiz is designed for MDCAT students to practice important concepts, identify weak areas, and improve their preparation for the Biology section of the MDCAT exam. Questions include chemical energy in glucose, fatty acids, waxes, nucleotides, purine and pyrimidine bases, DNA structure, enzyme active sites, cofactors, enzyme inhibition, and melting points of fatty acids.

Online Biological Molecules MDCAT Quiz with Answers

1. The chemical energy stored in 10 grams of glucose is
2. These are comparatively less sweet in taste and less soluble in water
3. Waxes are formed by the combination of fatty acids with
4. The combination of a pentose sugar with a base results in a compound known as
5. One of the pyrimidine bases is absent in DNA
6. Which of the follwing combination of base pairs is absent in DNA?
7. Which of the following is a purine?
8. Number of base pairs in one turn of DNA is
9. A phosphodiester bond is
10. An enzyme and substrate react through a special feature or site present in the enzyme known as
11. The non-protein part of an enzyme, which is covalently and permanently bonded, is called
12. Enzymes increase the rate of reaction by
13. The type of inhibition in which the inhibitor has no structural similarity to the substrate and combines with the enzyme at a site other than the active site is called
14. Solubility of fatty acids in organic solvents and their melting points increase with an increase in the
15. —————- is much more soluble in organic solvent than
16. Melting point of palmitic acid is
17. Melting point of butyric acid is
18. The smallest fatty acid is
19. A saturated fatty acid with four carbon atoms is
20. A saturated fatty acid with sixteen carbon atoms is

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