1. What are viroids?
A) Proteinaceous infectious agents
B) Covalently closed circular RNA molecules
C) Linear DNA molecules
D) Non-infectious proteins
Answer: B) Covalently closed circular RNA molecules
2. Which was the first viroid reported?
A) Potato spindle tuber viroid
B) Citrus exocortis viroid
C) Hop stunt viroid
D) Grapevein viroid
Answer: A) Potato spindle tuber viroid
3. What is the size range of viroids?
A) 50–100 nucleotides
B) 246–388 nucleotides
C) 500–800 nucleotides
D) 1000–2000 nucleotides
Answer: B) 246–388 nucleotides
4. Viroids are known to be the smallest infectious agents that lack a:
A) DNA genome
B) Protein coat
C) Circular structure
D) Phloem movement
Answer: B) Protein coat
5. Which of the following viruses is a viroid responsible for a disease in potatoes?
A) Tomato apical stunt viroid
B) Potato spindle tuber viroid
C) Avocado sunblotch viroid
D) Hop stunt viroid
Answer: B) Potato spindle tuber viroid
6. Which plant is affected by the Citrus exocortis viroid?
A) Potatoes
B) Citrus trees
C) Grapevines
D) Avocados
Answer: B) Citrus trees
7. What is the primary symptom of Potato Spindle Tuber Viroid (PSTV) infection in potatoes?
A) Yellow spots on leaves
B) Spindle-shaped tubers
C) Fruit distortion
D) Flower wilting
Answer: B) Spindle-shaped tubers
8. What is the vector for Potato spindle tuber viroid (PSTV)?
A) Aphids
B) Whiteflies
C) Mites
D) Leafhoppers
Answer: A) Aphids
9. What is the typical mode of spread of viroids?
A) Airborne transmission
B) Mechanical transmission
C) Waterborne transmission
D) Insect transmission
Answer: B) Mechanical transmission
10. Viroid replication occurs in which part of the plant cell?
A) Mitochondria
B) Nucleus or chloroplast
C) Cytoplasm
D) Vacuole
Answer: B) Nucleus or chloroplast
11. Which of the following viroids causes stunting and bark scaling in citrus trees?
A) Hop stunt viroid
B) Potato spindle tuber viroid
C) Citrus exocortis viroid
D) Grapevein viroid
Answer: C) Citrus exocortis viroid
12. What is the main symptom of Tomato Planta Macho Viroid infection?
A) Leaf curling
B) Stunting and growth retardation
C) Fruit discoloration
D) Root rot
Answer: B) Stunting and growth retardation
13. Which viroid causes the disease known as Cadang Cadang in coconuts?
A) Coconut cadang cadang viroid
B) Coconut tinangaja viroid
C) Avocado sunblotch viroid
D) Grapevein viroid
Answer: A) Coconut cadang cadang viroid
14. How are viroids generally spread between plants?
A) Through soil contamination
B) By wind-borne spores
C) By mechanical means through tools, hands, or contact
D) By root-to-root contact
Answer: C) By mechanical means through tools, hands, or contact
15. Which of the following viroids is associated with grapevine diseases?
A) Hop stunt viroid
B) Grapevine yellow speckle viroid
C) Potato spindle tuber viroid
D) Apple scar skin viroid
Answer: B) Grapevine yellow speckle viroid
16. What kind of RNA structure do viroids have?
A) Double-stranded RNA
B) Single-stranded RNA with a linear structure
C) Circular RNA
D) Double-stranded DNA
Answer: C) Circular RNA
17. Which plant is primarily affected by Hop Stunt Viroid?
A) Potatoes
B) Grapevines
C) Hops
D) Tomatoes
Answer: C) Hops
18. What is the main mechanism of viroid pathogenesis in plants?
A) Through the production of proteins
B) By disrupting the host’s immune response
C) Through the replication and movement of RNA using the host’s enzymes
D) By causing cell division defects
Answer: C) Through the replication and movement of RNA using the host’s enzymes
19. Which of the following viroids causes stunting and growth retardation in chrysanthemums?
A) Chrysanthemum stunt viroid
B) Avocado sunblotch viroid
C) Potato spindle tuber viroid
D) Hop stunt viroid
Answer: A) Chrysanthemum stunt viroid
20. Which viroid causes “sunblotch” symptoms in avocado plants?
A) Tomato apical stunt viroid
B) Avocado sunblotch viroid
C) Coconut tinangaja viroid
D) Chrysanthemum chlorotic mottle viroid
Answer: B) Avocado sunblotch viroid
21. Which of the following is a characteristic of viroid RNA?
A) It encodes for several proteins
B) It is a circular RNA molecule
C) It is a single-stranded DNA molecule
D) It contains a protein coat
Answer: B) It is a circular RNA molecule
22. Viroids do not code for any:
A) RNA molecules
B) Proteins
C) Lipids
D) Carbohydrates
Answer: B) Proteins
23. Which viroid is commonly associated with avocado trees?
A) Avocado sunblotch viroid
B) Tomato planta macho viroid
C) Grapevine yellow speckle viroid
D) Coconut cadang cadang viroid
Answer: A) Avocado sunblotch viroid
24. What is the primary symptom of viroid infection in tomatoes?
A) Yellowing of leaves
B) Stunting of plant growth
C) Root decay
D) Fruit cracking
Answer: B) Stunting of plant growth
25. Viroids replicate in the host cell’s:
A) Mitochondria
B) Nucleus or chloroplast
C) Cytoplasm
D) Plasma membrane
Answer: B) Nucleus or chloroplast
26. Viroids are most commonly transmitted by:
A) Insects
B) Airborne spores
C) Mechanical means through contaminated tools and equipment
D) Water
Answer: C) Mechanical means through contaminated tools and equipment
27. Which viroid causes “stiff and upright growth habit” in infected potatoes?
A) Hop stunt viroid
B) Potato spindle tuber viroid
C) Chrysanthemum chlorotic mottle viroid
D) Tomato apical stunt viroid
Answer: B) Potato spindle tuber viroid
28. Which of the following viroids is responsible for grapevine diseases?
A) Hop stunt viroid
B) Grapevine yellow speckle viroid
C) Tomato planta macho viroid
D) Potato spindle tuber viroid
Answer: B) Grapevine yellow speckle viroid
29. What is a common symptom of viroid infection in cucumbers?
A) Yellowing of leaves
B) Pale fruits
C) Root rot
D) Leaf curl
Answer: B) Pale fruits
30. What type of molecules are virusoids?
A) Proteins
B) DNA molecules
C) Viroid-like satellite RNA
D) Ribosomal RNA
Answer: C) Viroid-like satellite RNA