Nutritional requirements in plant tissue culture MCQs With Answer

Nutritional requirements in plant tissue culture MCQs With Answer

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Nutritional requirements in plant tissue culture MCQs With Answer

Understanding the nutritional requirements in plant tissue culture is essential for B. Pharm students studying plant biotechnology, pharmacognosy, and drug discovery. This introduction covers culture media composition, essential macronutrients (N, P, K, Ca, Mg, S), micronutrients (Fe, Mn, Zn, Cu, B, Mo), carbon sources, vitamins (thiamine, nicotinic acid, pyridoxine), chelators (EDTA), pH, osmoticum (sucrose), gelling agents (agar, gellan gum), and organic supplements. Grasping ionic balance, nutrient roles, media sterilization effects and medium modifications (MS, WPM, B5) helps optimize in vitro growth and secondary metabolite production. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which macronutrient is required in the largest quantity in standard MS medium for plant tissue culture?

  • Nitrogen
  • Phosphorus
  • Potassium
  • Calcium

Correct Answer: Nitrogen

Q2. Which carbon source is most commonly used in plant tissue culture media to supply energy and osmotic potential?

  • Glucose
  • Fructose
  • Sucrose (20–30 g/L)
  • Maltose

Correct Answer: Sucrose (20–30 g/L)

Q3. What is the primary role of agar in solid plant tissue culture media?

  • Provide nutrients
  • Act as a carbon source
  • Solidify the medium and support explants
  • Serve as a chelating agent

Correct Answer: Solidify the medium and support explants

Q4. What do the initials “MS” stand for in MS medium?

  • Medium for Shoots
  • Murashige and Skoog
  • Micro and Sucrose
  • Mineral Salts

Correct Answer: Murashige and Skoog

Q5. Which compound is commonly used as a chelating agent to keep iron soluble in culture media?

  • EDTA
  • SDS
  • Agar
  • Citric acid

Correct Answer: EDTA

Q6. Which vitamin is most commonly added to tissue culture media to support growth and metabolism?

  • Ascorbic acid (Vitamin C)
  • Thiamine (Vitamin B1)
  • Vitamin D
  • Vitamin K

Correct Answer: Thiamine (Vitamin B1)

Q7. Which element is the central atom in the chlorophyll molecule and is thus essential for photosynthetic capability in cultured tissues?

  • Iron (Fe)
  • Magnesium (Mg)
  • Calcium (Ca)
  • Potassium (K)

Correct Answer: Magnesium (Mg)

Q8. What is the commonly adjusted initial pH of culture media before autoclaving for most plant tissue cultures?

  • 7.0
  • 6.5
  • 5.8
  • 4.5

Correct Answer: 5.8

Q9. In MS medium, nitrogen is supplied mainly as which two ionic forms?

  • Ammonium (NH4+) and Nitrate (NO3-)
  • Nitrite (NO2-) and Amide
  • Urea and Amino acids
  • Nitrogen gas (N2) and Ammonia (NH3)

Correct Answer: Ammonium (NH4+) and Nitrate (NO3-)

Q10. Excess ammonium (NH4+) in the medium commonly leads to which immediate problem?

  • Increased pH and reduced nutrient uptake
  • pH drop (acidification) and ammonium toxicity
  • Excessive rooting only
  • Enhanced photosynthesis

Correct Answer: pH drop (acidification) and ammonium toxicity

Q11. Which gelling agent produces a clear, low-impurity medium and is often used as an alternative to agar?

  • Gelatin
  • Gellan gum (Phytagel)
  • Starch
  • Pectin

Correct Answer: Gellan gum (Phytagel)

Q12. Typical sucrose concentrations used in many plant tissue culture media fall within which range?

  • 0–5 g/L
  • 10–15 g/L
  • 20–30 g/L
  • 50–100 g/L

Correct Answer: 20–30 g/L

Q13. How is iron most commonly supplied in MS medium to prevent precipitation and ensure availability?

  • As ferric oxide powder
  • As Fe-EDTA complex
  • As elemental iron filings
  • As FeCl3 without chelator

Correct Answer: As Fe-EDTA complex

Q14. Which salt in MS medium is the primary source of sulfur?

  • KNO3
  • MgSO4
  • CaCl2
  • NH4H2PO4

Correct Answer: MgSO4

Q15. What is a commonly used agar concentration for solidifying MS medium for routine culture?

  • 1 g/L
  • 8 g/L
  • 50 g/L
  • 0.1 g/L

Correct Answer: 8 g/L

Q16. Which component is most prone to hydrolysis or degradation during autoclaving of the medium?

  • Inorganic phosphate
  • Sucrose (can hydrolyze to glucose and fructose)
  • Agar polymer chains
  • EDTA

Correct Answer: Sucrose (can hydrolyze to glucose and fructose)

Q17. Which micronutrient is essential as a cofactor for nitrate reductase activity in plants?

  • Boron (B)
  • Molybdenum (Mo)
  • Chlorine (Cl)
  • Sodium (Na)

Correct Answer: Molybdenum (Mo)

Q18. Boron deficiency in tissue culture typically causes which symptom related to cell structure?

  • Enhanced chlorophyll production
  • Poor cell wall formation and inhibited growth
  • Excessive root elongation only
  • Increased sugar uptake

Correct Answer: Poor cell wall formation and inhibited growth

Q19. Which micronutrient is most likely to cause toxicity if present in excess in culture medium?

  • Manganese at trace levels
  • Copper (Cu)
  • Potassium (K)
  • Calcium (Ca)

Correct Answer: Copper (Cu)

Q20. Which medium is specifically formulated as a low-salt option for woody plant species and explants?

  • MS medium
  • B5 medium
  • WPM (Woody Plant Medium)
  • LB medium

Correct Answer: WPM (Woody Plant Medium)

Q21. What is the primary physiological role of calcium in plant tissue culture?

  • Act as the main carbon source
  • Provide reducing power for respiration
  • Maintain cell wall stability and membrane integrity
  • Serve as a gelling agent

Correct Answer: Maintain cell wall stability and membrane integrity

Q22. Why are organic supplements such as casein hydrolysate or coconut water added to some culture media?

  • To increase agar strength
  • To provide amino acids, peptides and vitamins
  • To chelate heavy metals
  • To sterilize the medium

Correct Answer: To provide amino acids, peptides and vitamins

Q23. Which sugar alternative is often used to reduce browning or excessive hydrolysis compared to sucrose?

  • Fructose
  • Maltose
  • Glucose
  • Lactose

Correct Answer: Maltose

Q24. What is a typical photoperiod used for many in vitro cultures to support autotrophy and morphogenesis?

  • 24 hours light
  • 8 hours light / 16 hours dark
  • 16 hours light / 8 hours dark
  • Total darkness only

Correct Answer: 16 hours light / 8 hours dark

Q25. A high cytokinin-to-auxin ratio in culture medium generally promotes which response?

  • Root formation
  • Callus browning
  • Shoot proliferation and organogenesis
  • Somatic embryogenesis only

Correct Answer: Shoot proliferation and organogenesis

Q26. Which factor directly affects the ionic strength of a tissue culture medium?

  • Total dissolved salt concentration
  • Amount of agar
  • Type of explant

Correct Answer: Total dissolved salt concentration

Q27. Which of the following best describes “micronutrients” in the context of plant tissue culture?

  • Nutrients needed in the largest amounts
  • Nutrients required in trace or very small amounts (e.g., Fe, Zn, Cu)
  • Non-essential contaminants
  • Only organic vitamins

Correct Answer: Nutrients required in trace or very small amounts (e.g., Fe, Zn, Cu)

Q28. Which buffering agent is commonly added to stabilize pH in some plant tissue culture media formulations?

  • MES (2-(N-morpholino)ethanesulfonic acid)
  • Bovine serum albumin
  • EDTA as primary pH buffer
  • Chitosan

Correct Answer: MES (2-(N-morpholino)ethanesulfonic acid)

Q29. Which type of contamination is most commonly encountered during long-term plant tissue cultures from airborne sources?

  • Viral contamination only
  • Fungal contamination (molds)
  • Protozoan contamination
  • Parasitic plants

Correct Answer: Fungal contamination (molds)

Q30. Which combination of conditions commonly promotes somatic embryogenesis in many species?

  • Low sugar, high cytokinin
  • High auxin (e.g., 2,4‑D) and elevated sucrose
  • Absence of macronutrients
  • Only mineral salts without hormones

Correct Answer: High auxin (e.g., 2,4‑D) and elevated sucrose

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