Glycosides – Bitter Almond MCQs With Answer

Glycosides – Bitter Almond MCQs With Answer

Glycosides are important phytoconstituents comprising a sugar (glycone) bonded to a non‑sugar moiety (aglycone). Bitter almond is a classical source of the cyanogenic glycoside amygdalin, relevant to pharmacognosy, toxicology and B.Pharm studies. Understanding classification (cyanogenic vs cardiac glycosides), enzymatic hydrolysis by β‑glucosidases (emulsin), release of hydrogen cyanide (prussic acid), analytical detection (HPLC, IR, sodium‑picrate test) and safety/antidotes (hydroxocobalamin, rhodanese pathway) is essential for pharmacy students. This set emphasizes structure, mechanism, extraction, identification and clinical implications. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which cyanogenic glycoside is the principal constituent of bitter almonds?

• Amygdalin
• Prunasin
• Linamarin
• Glycyrrhizin

Correct Answer: Amygdalin

Q2. Enzymatic hydrolysis of amygdalin primarily yields which toxic product along with benzaldehyde?

• Hydrogen cyanide (HCN)
• Carbon monoxide (CO)
• Nitric oxide (NO)
• Sulfur dioxide (SO2)

Correct Answer: Hydrogen cyanide (HCN)

Q3. In glycosides, which term describes the sugar component attached to the aglycone?

• Glycone
• Aglycone
• Glyceride
• Lipid

Correct Answer: Glycone

Q4. Which enzyme class catalyzes the hydrolysis of cyanogenic glycosides like amygdalin in plant tissue?

• β‑Glucosidase
• Esterase
• Amylase
• Protease

Correct Answer: β‑Glucosidase

Q5. Bitter almond poisoning symptoms are primarily caused by inhibition of which physiological process?

• Cellular respiration via cytochrome c oxidase inhibition
• Sodium channel blockade in nerves
• Excessive cholinergic stimulation
• Inhibition of acetylcholinesterase

Correct Answer: Cellular respiration via cytochrome c oxidase inhibition

Q6. Amygdalin is classified pharmacognostically as which type of glycoside?

• Cyanogenic glycoside
• Cardiac glycoside
• Saponin glycoside

Correct Answer: Cyanogenic glycoside

Q7. The aglycone produced from amygdalin on enzymatic breakdown is best described as which compound?

• Mandelonitrile (a benzaldehyde cyanohydrin)
• Quinone methide
• Stearic acid
• Coumarin

Correct Answer: Mandelonitrile (a benzaldehyde cyanohydrin)

Q8. Which simple qualitative test paper is commonly used to screen plant material for cyanogenic glycosides?

• Sodium‑picrate paper test
• Fehling’s reagent test
• Kedde’s test
• Keller‑Kiliani test

Correct Answer: Sodium‑picrate paper test

Q9. Bitter almond trees used for pharmacognostic samples belong to which botanical species name (commonly cited)?

• Prunus dulcis var. amara
• Prunus cerasus
• Prunus domestica
• Prunus serotina

Correct Answer: Prunus dulcis var. amara

Q10. Which solvent system is typically most efficient for extracting amygdalin from bitter almond kernels for analytical work?

• Polar solvents such as methanol or aqueous ethanol
• Pure hexane
• Diethyl ether
• Chloroform

Correct Answer: Polar solvents such as methanol or aqueous ethanol

Q11. Amygdalin is structurally a diglycoside. Which statement best describes its sugar portion?

• Contains two glucose units (a disaccharide glycone)
• Contains a single fructose unit
• Contains a galactose‑rhamnose disaccharide
• Contains an N‑acetylglucosamine residue

Correct Answer: Contains two glucose units (a disaccharide glycone)

Q12. Which functional group in cyanogenic glycosides is directly responsible for HCN release upon cleavage?

• Cyanohydrin moiety
• Sulfhydryl group
• Carboxylate group
• Phenolic hydroxyl

Correct Answer: Cyanohydrin moiety

Q13. For accurate quantification of amygdalin in extracts, which analytical technique is preferred in modern pharmaceutical analysis?

• High‑performance liquid chromatography (HPLC)
• Paper chromatography
• Colorimetric spot test only
• Simple gravimetric assay

Correct Answer: High‑performance liquid chromatography (HPLC)

Q14. Cyanide toxicity primarily impairs which mitochondrial enzyme complex?

• Cytochrome c oxidase (Complex IV)
• ATP synthase (Complex V)
• Succinate dehydrogenase (Complex II)
• NADH dehydrogenase (Complex I)

Correct Answer: Cytochrome c oxidase (Complex IV)

Q15. Which of the following is an accepted antidote for acute cyanide poisoning in clinical settings?

• Hydroxocobalamin
• Pyridoxine alone
• Naloxone
• Atropine

Correct Answer: Hydroxocobalamin

Q16. Laetrile is best described as which of the following in relation to amygdalin?

• A semisynthetic derivative/related compound historically promoted as an anticancer agent
• An unrelated antibiotic compound
• A cardiac glycoside analogue
• A fermentation byproduct of amygdalin

Correct Answer: A semisynthetic derivative/related compound historically promoted as an anticancer agent

Q17. A characteristic sensory clue indicating benzaldehyde formation from bitter almond breakdown is:

• A characteristic bitter‑almond odor (benzaldehyde scent)
• A garlic‑like odor
• A fruity citrus scent
• An odorless emission only detectable by instruments

Correct Answer: A characteristic bitter‑almond odor (benzaldehyde scent)

Q18. The glycosidic linkage between sugar and aglycone in amygdalin is primarily which bond type?

• O‑glycosidic bond
• N‑glycosidic bond
• C‑glycosidic bond
• S‑glycosidic bond

Correct Answer: O‑glycosidic bond

Q19. To minimize enzymatic hydrolysis of amygdalin during storage of plant samples, the best practice is:

• Store dry, cool and airtight to limit moisture and enzyme activity
• Keep samples warm and humid
• Expose samples to sunlight to denature enzymes
• Soak samples in water for long‑term storage

Correct Answer: Store dry, cool and airtight to limit moisture and enzyme activity

Q20. Chemical hydrolysis of glycosides in the laboratory is commonly achieved by which method?

• Acidic hydrolysis (dilute HCl with heat)
• Base hydrolysis at cold temperature only
• Neutral buffer incubation
• Oxidative photolysis without acid

Correct Answer: Acidic hydrolysis (dilute HCl with heat)

Q21. Which IR absorption band is indicative of a nitrile (C≡N) group in cyanogenic compounds?

• A sharp band around 2250 cm⁻¹
• A broad band around 3400 cm⁻¹
• A strong band near 1700 cm⁻¹
• A medium band around 1450 cm⁻¹

Correct Answer: A sharp band around 2250 cm⁻¹

Q22. Current evidence regarding amygdalin/laetrile as an anticancer therapy indicates which of the following?

• No proven anticancer efficacy and potential for cyanide toxicity
• Clearly proven curative effects with no toxicity
• Effective only when administered by inhalation
• Safe and effective in all patients as an adjunct

Correct Answer: No proven anticancer efficacy and potential for cyanide toxicity

Q23. In bitter almonds, the highest concentration of amygdalin is found in which part of the plant?

• Seed kernels (the bitter seeds)
• Leaf surface wax
• Bark phloem only
• Root xylem sap

Correct Answer: Seed kernels (the bitter seeds)

Q24. The plant β‑glucosidase specifically associated with hydrolysis of cyanogenic glycosides is commonly called what?

• Emulsin
• Invertase
• Cellulase
• Protease

Correct Answer: Emulsin

Q25. The disaccharide glycone present in amygdalin is commonly identified as:

• Gentiobiose (a disaccharide of glucose)
• Sucrose
• Raffinose
• Lactose

Correct Answer: Gentiobiose (a disaccharide of glucose)

Q26. Which human enzymatic pathway converts cyanide to the less toxic thiocyanate for excretion?

• The rhodanese (sulfurtransferase) pathway using thiosulfate
• Cytochrome P450 hydroxylation
• Glutathione peroxidase pathway
• Monoamine oxidase oxidation

Correct Answer: The rhodanese (sulfurtransferase) pathway using thiosulfate

Q27. β‑Glucosidase enzymes that hydrolyze amygdalin typically show optimal activity at which pH range?

• Acidic pH around pH 4–6
• Strongly alkaline pH >10
• Neutral pH 7.5–8.5 only
• pH has no effect on enzyme activity

Correct Answer: Acidic pH around pH 4–6

Q28. The approximate molecular weight (molar mass) of amygdalin is closest to:

• 457 g·mol⁻¹
• 300 g·mol⁻¹
• 1000 g·mol⁻¹
• 58 g·mol⁻¹

Correct Answer: 457 g·mol⁻¹

Q29. To differentiate and confirm amygdalin versus prunasin in a sample, which analytical approach provides the most definitive separation and identification?

• HPLC coupled with mass spectrometry (HPLC‑MS)
• Simple paper chromatography alone
• Phytochemical color spot tests only
• Microscopy of powdered drug

Correct Answer: HPLC coupled with mass spectrometry (HPLC‑MS)

Q30. Cold‑pressed bitter almond oil typically contains which two characteristic compounds formed from glycoside breakdown or present as volatiles?

• Benzaldehyde and traces of cyanide (HCN)
• Acetic acid and ethanol
• Menthol and camphor
• Coumarin and glycyrrhetinic acid

Correct Answer: Benzaldehyde and traces of cyanide (HCN)

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com