11. The mosquito fern or Azolla is used as a biofertiliser because it__:
[A] Multiplies very fast to produce massive biomass
[B] Has association of nitrogen-fixing Rhizobium bacteria
[C] Has association of nitrogen fixing bluegreen algae
[D] Has association of mycorrhiza
Show Answer
Correct Answer: C [ Has association of nitrogen fixing bluegreen algae]
Notes:
Azolla, also known as mosquito fern, is used as a biofertilizer because it has a symbiotic relationship with nitrogen-fixing cyanobacteria. The cyanobacteria, Anabaena azollae, lives on the leaves of Azolla and can fix atmospheric nitrogen. This nitrogen-fixing ability increases the fertility of the soil and enhances crop yields.
Azolla is a small aquatic fern that grows on the surface of water or moist soil. It is used as a biofertilizer for rice in Asia. Azolla can be grown as a green manure before transplanting rice or as an intercrop with the rice. Both practices are reported to increase the growth and yield of rice.
Azolla is also used as animal feed, human food, medicine, and water purifier.
12. What is the number of mitochondria present in a bacterial cell?
[A] Zero
[B] One
[C] Two
[D] Four
Show Answer
Correct Answer: A [Zero]
Notes:
Bacterium contain no membrane bound nucleus and rarely contain membrane bound organelles. Simply, most don’t have any large organelles with their own membranes; this means no nucleus, no mitochondria and no chloroplast. Even if a bacteria wanted to have mitochondria , it is couldn’t.
13. Which part of the plant is used in making saffron spice?
[A] Stigma
[B] Sepal
[C] Petal
[D] Leaf
Show Answer
Correct Answer: A [Stigma]
Notes:
Stigma of the plant is used in making the saffron spices. In making the saffron spice, stigma of the plant is used. Stigma is the top of the centre part of a flower. It receives the pollen that allows it to form new seeds.
14. Exobiology refers to the study of which of the following?
[A] Organism
[B] Endodermis
[C] Life in the air
[D] Life on the other planets
Show Answer
Correct Answer: D [Life on the other planets]
Notes:
Exobiology is the study of the origin, evolution and distribution of life in the context of cosmic evolution.
15. The sporophytic generation is represented only by the zygote__?
[A] Funaria
[B] Chlamydomonas
[C] Pinus
[D] Pinus
Show Answer
Correct Answer: B [Chlamydomonas]
Notes:
Important Features of Chlamydomonas: The plant body is unicellular, pear-shaped, and biflagellate, Each cell typically contains a cup-shaped chloroplast, an eye sac, and two contractile vacuoles, Pamela-stage appearance, Asexual reproduction occurs through biflagellate zoospore formation.
16. Which of the following is the proof of the aquatic origin of bryophytes?
[A] Ciliated sperms
[B] Green colour
[C] Protonema thread
[D] Some are still aquatic
Show Answer
Correct Answer: A [Ciliated sperms]
Notes:
Ciliated sperms are proof of the aquatic origin of bryophytes.
17. Fruits are not found in gymnosperm plants because__?
[A] They are seedless plants
[B] They are not pollinated
[C] They have no ovary
[D] Process of fertilization does not take place in them
Show Answer
Correct Answer: C [They have no ovary]
Notes:
Fruits are not found in gymnosperm plants because they have no ovaries. Gymnosperms belong to the Kingdom Plantae and the sub-kingdom Embryophyta.
18. Which of the following is a compound leaf having an axis on either side of the midrib?
[A] Imparipinnate
[B] Unipinnate
[C] Bipinnate
[D] Pinnate
Show Answer
Correct Answer: D [Pinnate]
Notes:
Pinnate is a compound leaf having an axis on either side of the midrib.
19. Which of the following also play a role in protecting plants against bacterial and fungal infections?
[A] Jasmonates
[B] Oligosaccharins
[C] Strigolactones
[D] Brassinosteroids
Show Answer
Correct Answer: B [Oligosaccharins]
Notes:
Oligosaccharides also play a role in protecting plants against bacterial and fungal infections. They act locally at the site of injury. They can also be carried to other tissues.
20. Which of the following is rat-fish?
[A] Salmons
[B] Lamprey
[C] Sharks
[D] Chimeras
Show Answer
Correct Answer: D [Chimeras]
Notes:
Chimeras are cartilaginous fish in the order Chimaeriformes. They are known informally as ghost sharks, ratfish, spookfish, or rabbitfish.
