30 MCQs: Cutin, Waxes, Suberin (Plant Surface Protection)

⭐

Cutin, Suberin और Waxes जैसे टॉपिक को बार-बार PDF पढ़कर revise करने की बजाय 30 अच्छे MCQs solve किए जाएँ, तो आपका base clear हो जाएगा और exam memory भी strong हो जाएगी।

मैंने आपके लिए 30 Part B type MCQs (memory + concept clarity + exam pattern based) तैयार किए हैं। ये पूरे टॉपिक के हर angle (composition, structure, location, function, comparison) को cover करते हैं।

30 MCQs: Cutin, Waxes, Suberin (Plant Surface Protection)

Q1. Cutin, suberin, and waxes belong to which class of compounds?

A. Hydrophilic polysaccharides

B. Hydrophobic lipid-based compounds

C. Structural proteins

D. Phenolic alkaloids

---

Q2. Cutin is primarily found in:

A. Underground roots only

B. Aboveground plant parts

C. Xylem vessels

D. Phloem tissues

---

Q3. Suberin is deposited in:

A. Leaf cuticle only

B. Root endodermis, woody stems, and wound sites

C. Guard cells exclusively

D. Palisade mesophyll

---

Q4. Waxes are associated with:

A. Cutin only

B. Suberin only

C. Both cutin and suberin

D. Neither cutin nor suberin

---

Q5. Cutin is a:

A. Simple lipid

B. Polymer of long-chain fatty acids linked by ester bonds

C. Polysaccharide

D. Aromatic alkaloid

---

Q6. The fatty acids forming cutin typically include:

A. 10:0 and 12:0 fatty acids

B. 16:0 and 18:1 fatty acids

C. 6:0 and 8:0 fatty acids

D. 20:4 and 22:6 fatty acids

---

Q7. Which type of linkages stabilize the rigid network of cutin?

A. Glycosidic linkages

B. Ester linkages

C. Peptide bonds

D. Phosphodiester bonds

---

Q8. Waxes differ from cutin because they are:

A. Polymers

B. Complex mixtures of long-chain acyl lipids

C. Proteins

D. Polysaccharides

---

Q9. The most common wax components are:

A. Steroids and terpenes

B. Straight-chain alkanes and alcohols (C25–C35)

C. Pentose sugars

D. Polypeptides

---

Q10. Which of the following is NOT a wax component?

A. Aldehydes

B. Ketones

C. Esters

D. Nucleotides

---

Q11. Wax synthesis occurs in:

A. Mesophyll cells

B. Epidermal cells

C. Guard cells

D. Xylem cells

---

Q12. Suberin is structurally distinct from cutin because it contains:

A. Dicarboxylic acids and phenolic compounds

B. Only saturated fatty acids

C. Only carbohydrates

D. Only proteins

---

Q13. Suberin is considered poorly understood structurally, but is known to involve:

A. Phenolics + long-chain fatty acids + dicarboxylic acids

B. Amino acids + sugars

C. Sterols only

D. Hemicelluloses

---

Q14. Which compound helps in reducing transpiration in plants?

A. Cutin

B. Suberin

C. Waxes

D. All of the above

---

Q15. Which compound provides surface barrier against pathogen invasion?

A. Cutin

B. Suberin

C. Waxes

D. All of the above

---

Q16. Suberin deposition in root endodermis forms:

A. Casparian strip

B. Plasmodesmata

C. Middle lamella

D. Cuticle

---

Q17. The phenolic component in suberin provides:

A. Flexibility

B. Antimicrobial properties

C. Energy storage

D. Photosynthetic function

---

Q18. Cutin polymer is mainly formed from fatty acids with functional groups like:

A. Amino groups

B. Hydroxyl or epoxide groups

C. Sulfhydryl groups

D. Carbonyl groups only

---

Q19. Which is more rigid: cutin or wax?

A. Cutin (3D polymer network)

B. Wax (simple acyl mixture)

C. Both equal

D. Depends on plant type

---

Q20. Wound healing and cork formation in plants is related to:

A. Cutin deposition

B. Suberin deposition

C. Wax deposition

D. Callose deposition

---

Q21. Which lipid barrier is most associated with drought resistance?

A. Cutin

B. Suberin

C. Waxes

D. Both A and C

---

Q22. Epidermal waxes provide:

A. UV protection

B. Mechanical strength

C. Prevention of non-stomatal water loss

D. All of the above

---

Q23. Cutin differs from suberin mainly in:

A. Location and presence of phenolics/dicarboxylic acids

B. Presence of proteins

C. Type of glycosidic bonds

D. Cellular localization only

---

Q24. Which protective layer is synthesized primarily by epidermal cells?

A. Cutin

B. Waxes

C. Both A and B

D. Suberin

---

Q25. Which compound is part of periderm/cork tissue?

A. Cutin

B. Wax

C. Suberin

D. Callose

---

Q26. Cutin and waxes together form:

A. Middle lamella

B. Cuticle

C. Casparian strip

D. Lignin layer

---

Q27. Suberin layers in roots help regulate:

A. Apoplastic water movement

B. CO₂ uptake

C. Light penetration

D. Transpiration in leaves

---

Q28. Long-chain acyl lipids in waxes make them:

A. Hydrophilic

B. Amphipathic

C. Extremely hydrophobic

D. Neutral polysaccharides

---

Q29. Which of the following combinations is correct?

A. Cutin – Aboveground organs – Fatty acid polymer

B. Suberin – Wounds and cork – Phenolic-rich polymer

C. Waxes – Hydrophobic acyl lipids – Epidermal origin

D. All of the above

---

Q30. The collective function of cutin, suberin, and waxes is:

A. Water retention and pathogen resistance

B. Carbohydrate transport

C. Energy storage

D. Nitrogen assimilation

---

✅ Answer Key

1. B

2. B

3. B

4. C

5. B

6. B

7. B

8. B

9. B

10. D

11. B

12. A

13. A

14. D

15. D

16. A

17. B

18. B

19. A

20. B

21. D

22. D

23. A

24. C

25. C

26. B

27. A

28. C

29. D

30. A

बार-बार practice से आपका base + memory दोनों strong होंगे और exam में चाहे question twist हो, आप confidently attempt कर पाओगे।

Cutin, Suberin, Waxes के ऊपर 30 Advanced–Medium/High CSIR-NET (Part B style) MCQs तैयार किए हैं।

ये सवाल स्मृति-आधारित और कॉन्सेप्चुअल दोनों तरह के हैं — बारीक बिंदुओं, बायोकेमिस्ट्री, बायोसिंथेसिस, लोकेशन, फंक्शन और प्रयोगात्मक पहचान तक कवर करते हैं। हर प्रश्न के बाद विकल्प (A–D) हैं; सभी के सही उत्तर मैंने अंत में एक साथ दिए हैं ताकि आप पहले खुद हल करकर चेक कर सकें।

30 MCQs — Cutin, Suberin & Waxes (advanced, Part-B style)

Q1. Cutin is mainly polymerized from which types of monomers?

A. Very-long-chain alkanes (C25–C35)

B. C16 and C18 fatty acids bearing mid-chain hydroxyl or epoxide groups

C. Short-chain fatty acids (C6–C10)

D. Aromatic amino acids

Q2. Which statement about epicuticular waxes is CORRECT?

A. They are macromolecular polyesters like cutin

B. They are complex mixtures of long-chain acyl lipids (straight alkanes, alcohols, esters) typically C25–C35

C. They are water-soluble and diffuse freely in apoplast

D. They are synthesized in the vacuole

Q3. Suberin differs from cutin primarily because it:

A. Is only composed of monosaccharides

B. Contains α,ω-dicarboxylic acids and a significant phenolic domain in addition to ω-hydroxy fatty acids

C. Is hydrophilic and aids water uptake

D. Is only present on leaf epidermis

Q4. Which of the following locations is MOST TYPICAL for suberin deposition?

A. Leaf epidermal cuticle

B. Root endodermis (Casparian strip), periderm/cork and wound-healed tissues

C. Chloroplast thylakoid membranes

D. Phloem sieve elements

Q5. The Casparian strip in root endodermis is best described as:

A. A suberized/lignified band that blocks apoplastic flow into the stele

B. A waxy coating on leaf surface

C. An intracellular vacuolar inclusion

D. A proteinaceous channel for water

Q6. Which enzyme family is primarily responsible for ω-hydroxylation of fatty acids (formation of ω-hydroxy fatty acids) used in cutin/suberin biosynthesis?

A. Glycosyltransferases

B. Cytochrome P450 monooxygenases (e.g., CYP86 family)

C. Proteases

D. Kinases

Q7. Cutin polymerization in some species is catalyzed by which identified enzyme?

A. Cutin synthase (a GDSL-lipase family member, e.g., CUS1)

B. Cellulase

C. Rubisco

D. Peroxidase only

Q8. Waxes are synthesized primarily in which subcellular compartment before export to the epidermal surface?

A. Mitochondria

B. Endoplasmic reticulum (ER)

C. Golgi lumen only

D. Chloroplast stroma

Q9. Which transporter class is implicated in exporting cutin/wax/suberin monomers across the plasma membrane of epidermal/endodermal cells?

A. Aquaporins

B. ABCG (ATP-binding cassette G) transporters and lipid transfer proteins (LTPs) assist movement

C. Na⁺/K⁺ ATPase

D. Ribosomes

Q10. Primary alcohols in plant waxes are formed by which enzyme activity?

A. Fatty acyl-CoA reductase (FAR) converting acyl-CoA → primary alcohol

B. Lipoxygenase

C. Dehydratase acting on glycerol

D. Decarboxylase converting fatty acids to alcohols directly

Q11. Straight-chain alkanes in epicuticular waxes are produced by:

A. Oxidative cleavage of polysaccharides

B. Decarbonylation of aldehydes derived from fatty acyl-CoAs (CER1/CER3 pathway in Arabidopsis)

C. Direct polymerization of isoprene units on the surface

D. Peroxisomal β-oxidation exclusively

Q12. Which dye/technique is commonly used to visualize suberin in plant tissues?

A. Lugol’s iodine

B. Fluorol Yellow 088 or Sudan dyes that stain hydrophobic polyesters

C. Alcian blue specific for pectin

D. DAPI for DNA

Q13. Which statement about cuticle permeability is TRUE?

A. Waxes mainly influence non-stomatal transpiration and surface reflectance; cutin provides the polymeric scaffold that embeds waxes.

B. Cutin alone determines stomatal conductance.

C. Suberin controls leaf gas exchange directly.

D. Cuticle has no role in UV protection.

Q14. The phenolic domain of suberin (e.g., ferulic acid derivatives) contributes primarily to:

A. Hydrophobicity only

B. Antimicrobial/physical cross-linking properties and rigidity (via oxidative coupling)

C. Sugar storage

D. Chlorophyll synthesis

Q15. Which gene/product is often required for formation of suberin aliphatic domain in Arabidopsis roots?

A. GPAT5 (glycerol-3-phosphate acyltransferase 5) involved in suberin assembly

B. RUBISCO small subunit

C. Photosystem II D1 protein

D. Cellulose synthase CESA1

Q16. In wound-healing and periderm (cork) formation, which polymer predominates and why?

A. Cutin predominates to allow gas exchange

B. Suberin predominates to form an impermeable protective barrier and prevent water loss/pathogen entry

C. Waxes only are deposited for mechanical strength

D. Pectin is the major wall layer deposited

Q17. Which statement about the developmental origin of cutin vs. waxes is CORRECT?

A. Cutin and waxes are synthesized in the same cell type (epidermal cells), but waxes are low-molecular mixtures exported from the ER while cutin is a cell-wall polymer assembled in the apoplast.

B. Waxes are synthesized in xylem only.

C. Cutin is synthesized in vascular cambium.

D. Waxes are synthesized in stomatal guard cells exclusively.

Q18. Suberin lamellae in endodermis influence radial transport by:

A. Enhancing apoplastic flow across endodermis

B. Blocking apoplastic flow and forcing solutes/water through symplastic/transport routes (membrane transporters)

C. Increasing transpiration through roots

D. Acting as ion channels

Q19. Which of the following monomers is LEAST likely to be a major constituent of cutin?

A. ω-hydroxy C16 fatty acids

B. Mid-chain epoxy C18 fatty acids

C. α,ω-dicarboxylic long-chain acids (major in suberin)

D. Glycerol backbone units (involved in suberin)

Q20. Experimental mutation/knockout of a plant ABCG transporter involved in wax export would most likely cause:

A. Increased epicuticular wax load on leaf surface

B. Defective wax export → glossy or reduced-wax phenotype, increased cuticle permeability and water loss

C. Increased suberin deposition in roots only

D. No observable phenotype since waxes are not essential

Q21. Which analytical technique is commonly used to determine chain-length distribution of cuticular wax components?

A. Gas chromatography–mass spectrometry (GC-MS) after solvent extraction and derivatization

B. Light microscopy only

C. SDS-PAGE electrophoresis

D. PCR amplification

Q22. The rigid 3-D network of cutin is stabilized mainly by:

A. Peptide crosslinks

B. Ester bonds between hydroxy fatty acid monomers (and some oxidative phenolic crosslinks in suberin)

C. Ionic interactions of sugars

D. Hydrogen bonds only

Q23. Which of the following is TRUE about wax function beyond water barrier?

A. Waxes have no role except preventing evaporation

B. Epicuticular wax crystals can reduce surface wetting and influence insect attachment and reflect UV light

C. Waxes act as enzymes for cutin polymerization

D. Waxes store nitrogen for the plant

Q24. In species adapted to very arid climates, typical modifications include:

A. Reduced wax amounts to increase transpiration

B. Increased wax load, thicker cuticle, and altered wax composition (longer chains / denser crystallinity) to reduce water loss

C. Replacement of cutin by cellulose on epidermis

D. Elimination of stomata only

Q25. Which enzyme activity is most directly associated with polymerization of phenolic suberin domain?

A. Laccases and peroxidases that catalyze oxidative coupling of phenolics

B. Lipoxygenases that form hydroperoxides only

C. Kinases phosphorylating fatty acids

D. Isomerases converting alkanes to alcohols

Q26. Glycerol is an important component in suberin structure because:

A. It forms part of the aliphatic polyester backbone linking fatty acyl monomers (glycerol-based esters)

B. It is the monomer of cutin

C. It is the major wax component on leaf surface

D. It is only present in cellulose

Q27. Which of the following statements is FALSE?

A. Cuticle (cutin + wax) is mainly produced by epidermal cells and protects aboveground organs.

B. Suberin forms an effective barrier in roots and periderm and often contains phenolic and aliphatic domains.

C. Waxes are macromolecular polyesters similar to cutin.

D. Transport of monomers to the apoplast involves specific transporters and lipid transfer proteins.

Q28. Which plant example is classically known for a thick suberin-rich cork layer used commercially?

A. Arabidopsis thaliana leaves

B. Quercus suber (cork oak) bark

C. Rice paddy roots

D. Spinacia oleracea (spinach) leaves

Q29. Which genetic manipulation would most likely decrease cutin polymer amount in fruit epidermis?

A. Overexpressing CUS1 (cutin synthase)

B. Knockout of CYP86A ω-hydroxylase family members that produce ω-hydroxy fatty acid monomers

C. Overexpressing ABCG exporters

D. Increasing FAR activity for wax alcohols

Q30. A researcher stains a root cross-section and observes strong Sudan dye fluorescence in the endodermis and periderm. This indicates presence of:

A. Hydrophilic pectins

B. Hydrophobic polyesters and waxes (suberin/wax)

C. DNA and RNA

D. Lignified xylem only

---

Answer Key — सभी सही विकल्प (एक साथ)

1 → B

2 → B

3 → B

4 → B

5 → A

6 → B

7 → A

8 → B

9 → B

10 → A

11 → B

12 → B

13 → A

14 → B

15 → A

16 → B

17 → A

18 → B

19 → C

20 → B

21 → A

22 → B

23 → B

24 → B

25 → A

26 → A

27 → C (False statement is C)

28 → B

29 → B

30 → B

Must remember Qs 12, 15, 19, 25, 28,