Carotenoids MCQs With Answer

Carotenoids MCQs With Answer offer B. Pharm students a focused review of carotenoid chemistry, biosynthesis, pharmacology and clinical relevance. This set covers key terms — carotenoids, carotenes, xanthophylls, provitamin A, beta‑carotene, lutein, zeaxanthin, antioxidant activity, bioavailability, absorption, enzymatic cleavage (BCO1/BCO2), isoprenoid biosynthesis, stability and formulation. Questions integrate pharmacognosy, medicinal chemistry and pharmaceutics, addressing structure–activity relationships, HPLC analysis, delivery systems, metabolism, safety and therapeutic implications. Designed for exam preparation and practical application, the MCQs include dietary sources, interactions, toxicity and regulatory considerations. They are ideal for foundation and advanced exam revision. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which structural feature most reliably distinguishes xanthophylls from carotenes?

• Xanthophylls contain oxygen atoms while carotenes are hydrocarbons
• Xanthophylls have conjugated double bonds while carotenes do not
• Xanthophylls are shorter chain isoprenoids than carotenes

Correct Answer: Xanthophylls contain oxygen atoms while carotenes are hydrocarbons

Q2. Which carotenoid is the most important dietary provitamin A for humans?

• Beta‑carotene
• Lutein
• Zeaxanthin
• Astaxanthin

Correct Answer: Beta‑carotene

Q3. Which enzyme catalyses the central symmetric cleavage of beta‑carotene to yield retinal?

• BCO1 (beta‑carotene 15,15’‑dioxygenase)
• BCO2 (beta‑carotene 9’‑10’‑oxygenase)
• Retinal dehydrogenase
• Carotenoid synthase

Correct Answer: BCO1 (beta‑carotene 15,15’‑dioxygenase)

Q4. Immediately after intestinal absorption, carotenoids are primarily transported in which form?

• Incorporated into chylomicrons
• Bound to albumin
• Free in plasma
• Packaged into HDL only

Correct Answer: Incorporated into chylomicrons

Q5. Which pair of carotenoids constitutes the primary macular pigments in the human retina?

• Lutein and zeaxanthin
• Beta‑carotene and lycopene
• Astaxanthin and canthaxanthin
• Phytoene and phytofluene

Correct Answer: Lutein and zeaxanthin

Q6. The immediate isoprenoid precursor for carotenoid biosynthesis in plants is which compound?

• Geranylgeranyl pyrophosphate (GGPP)
• Acetyl‑CoA
• Mevalonic acid
• Isopentenyl phosphate

Correct Answer: Geranylgeranyl pyrophosphate (GGPP)

Q7. A principal antioxidant mechanism of carotenoids involves which action?

• Quenching singlet oxygen and scavenging free radicals
• Inhibiting cytochrome P450 enzymes
• Chelating transition metals
• Acting as proton donors to peroxidases

Correct Answer: Quenching singlet oxygen and scavenging free radicals

Q8. Under high partial pressures of oxygen or at very high concentrations, carotenoids may behave as what?

• Pro‑oxidants
• Strict antioxidants without exception
• Metal chelators
• Non‑reactive inert pigments

Correct Answer: Pro‑oxidants

Q9. Which geometric isomer of carotenoids is most abundant in fresh plant tissues?

• All‑trans isomers
• 9‑cis isomers
• 13‑cis isomers
• All‑cis isomers

Correct Answer: All‑trans isomers

Q10. Efficient intestinal absorption of carotenoids requires which of the following?

• Incorporation into mixed micelles with dietary lipids and bile salts
• Direct diffusion in aqueous chyme without bile
• Co‑administration with vitamin C only
• Presence of digestive proteases

Correct Answer: Incorporation into mixed micelles with dietary lipids and bile salts

Q11. Which enzyme is primarily associated with eccentric cleavage of carotenoids producing apocarotenoids?

• BCO2 (beta‑carotene oxygenase 2)
• BCO1
• Lipoxygenase
• Cytochrome P450 reductase

Correct Answer: BCO2 (beta‑carotene oxygenase 2)

Q12. Which analytical technique is most commonly used to separate and quantify individual carotenoids in biological samples?

• High‑performance liquid chromatography (HPLC) with UV/Vis detection
• Gas chromatography without derivatization
• Simple spectrophotometry at 280 nm
• Capillary electrophoresis without sample cleanup

Correct Answer: High‑performance liquid chromatography (HPLC) with UV/Vis detection

Q13. Carotenoid stability during storage and processing is most adversely affected by which factors?

• Oxygen, light and heat
• Low pH only
• High protein content
• Anaerobic refrigeration

Correct Answer: Oxygen, light and heat

Q14. Which formulation approach is commonly used to enhance oral bioavailability of lipophilic carotenoids?

• Lipid‑based formulations such as nanoemulsions or solid lipid nanoparticles
• Hydrophilic sugar capsules without oil
• Dry powder inhalation formulations
• Intramuscular aqueous injections

Correct Answer: Lipid‑based formulations such as nanoemulsions or solid lipid nanoparticles

Q15. A rich dietary source of beta‑carotene commonly recommended in nutrition is:

• Carrots (beta‑carotene rich)
• White rice
• Olive oil
• Egg white

Correct Answer: Carrots (beta‑carotene rich)

Q16. Which structural feature of a carotenoid confers provitamin A activity?

• Presence of at least one beta‑ionone ring
• Absence of conjugated double bonds
• Terminal hydroxyl groups on both ends
• A cleaved aldehyde group

Correct Answer: Presence of at least one beta‑ionone ring

Q17. Excessive dietary intake of carotenoids can cause which benign clinical condition?

• Carotenodermia (benign yellowing of the skin)
• Hypervitaminosis A with intracranial pressure
• Acute liver failure
• Neurotoxicity with seizures

Correct Answer: Carotenodermia (benign yellowing of the skin)

Q18. How does dietary fat influence carotenoid absorption?

• Dietary fat increases carotenoid absorption by promoting micelle formation
• Dietary fat inhibits carotenoid absorption by sequestering them
• Dietary fat has no effect on carotenoid absorption
• Dietary fat converts carotenoids into water‑soluble forms

Correct Answer: Dietary fat increases carotenoid absorption by promoting micelle formation

Q19. Macular carotenoids protect the retina primarily by which mechanism?

• Filtering high‑energy blue light and quenching reactive oxygen species
• Stimulating retinal cell proliferation
• Acting as neurotransmitters in the visual cortex
• Blocking vitamin A uptake

Correct Answer: Filtering high‑energy blue light and quenching reactive oxygen species

Q20. Clinical trials showed that high‑dose beta‑carotene supplementation in smokers was associated with which outcome?

• Increased lung cancer risk
• Reduced cardiovascular mortality
• Marked improvement in visual acuity
• Prevention of osteoporosis

Correct Answer: Increased lung cancer risk

Q21. In plant cells, carotenoid biosynthesis occurs in which subcellular compartment?

• Plastids (chloroplasts and chromoplasts)
• Mitochondria
• Cytosol freely
• Endoplasmic reticulum only

Correct Answer: Plastids (chloroplasts and chromoplasts)

Q22. Chemically, carotenes differ from xanthophylls primarily by which feature?

• Carotenes are pure hydrocarbons; xanthophylls contain oxygenated functional groups
• Carotenes are water‑soluble; xanthophylls are fat‑soluble
• Carotenes are monocyclic; xanthophylls are always acyclic
• Carotenes contain nitrogen while xanthophylls contain sulfur

Correct Answer: Carotenes are pure hydrocarbons; xanthophylls contain oxygenated functional groups

Q23. Which circulating lipoprotein carries the highest proportion of certain carotenoids to peripheral tissues?

• Low‑density lipoprotein (LDL)
• High‑density lipoprotein (HDL)
• Very low‑density lipoprotein (VLDL)
• Albumin

Correct Answer: Low‑density lipoprotein (LDL)

Q24. Which food handling practice commonly increases carotenoid bioavailability?

• Cooking vegetables with a small amount of oil
• Blanching in large volumes of water without oil
• Freezing raw and consuming frozen
• Consuming raw with cold water

Correct Answer: Cooking vegetables with a small amount of oil

Q25. Central oxidative cleavage of one molecule of beta‑carotene yields which immediate products?

• Two molecules of retinal (retinaldehyde)
• One molecule of retinol and one of retinoic acid
• Two molecules of lutein
• One molecule of lycopene and one of phytoene

Correct Answer: Two molecules of retinal (retinaldehyde)

Q26. Carotenoids typically show absorbance maxima in which region of the spectrum?

• Visible region around 400–500 nm (beta‑carotene peak ≈450 nm)
• Ultraviolet region around 260 nm
• Near infrared around 800–900 nm
• Far ultraviolet below 200 nm

Correct Answer: Visible region around 400–500 nm (beta‑carotene peak ≈450 nm)

Q27. Which pair of carotenoids are stereoisomers differing only in orientation of hydroxyl groups?

• Lutein and zeaxanthin
• Beta‑carotene and lycopene
• Astaxanthin and canthaxanthin
• Phytoene and phytofluene

Correct Answer: Lutein and zeaxanthin

Q28. Genetic polymorphisms in BCMO1 (BCO1) commonly result in what effect on vitamin A status?

• Reduced conversion of dietary provitamin A carotenoids to retinal and lower vitamin A availability
• Increased conversion leading to hypervitaminosis A
• No effect on carotenoid metabolism
• Complete inability to absorb carotenoids

Correct Answer: Reduced conversion of dietary provitamin A carotenoids to retinal and lower vitamin A availability

Q29. Which component of the food matrix typically decreases carotenoid bioavailability?

• Dietary fiber that entraps carotenoids in the matrix
• Dietary fat that promotes micelle formation
• Co‑consumed animal protein
• Presence of emulsifiers

Correct Answer: Dietary fiber that entraps carotenoids in the matrix

Q30. Which carotenoid is commonly recommended in supplements for support of age‑related macular degeneration?

• Lutein (often combined with zeaxanthin)
• Beta‑carotene alone
• Lycopene only
• Phytoene

Correct Answer: Lutein (often combined with zeaxanthin)

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.

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