31. What is the enzyme that breaks down lactose?
[A] Lipase enzymes
[B] Pepsin
[C] Amylase
[D] Lactase
Show Answer
Correct Answer: D [Lactase]
Notes:
Lactase is the enzyme that breaks down lactose.
32. Mendel used which of the following one for his experiments.
[A] Pisum sativum
[B] Pisum album
[C] Oryza sativa
[D] Oryza Orientalis
Show Answer
Correct Answer: A [Pisum sativum]
Notes:
Mendel used Pisum sativum (peas)for his experiments because they saw many distinctive features in it and it could be easily grown and self-pollinated.
33. Which of the following is a free-living aerobic and non-photosynthetic nitrogen-fixing bacterium?
[A] Rhizobium
[B] Nostoc
[C] Azospirillum
[D] Azotobacter
Show Answer
Correct Answer: D [Azotobacter]
Notes:
Azotobacter is a free-living aerobic and non-photosynthetic nitrogen-fixing bacterium.
34. Which of the following is an important objective of biotechnology in the field of agriculture?
[A] to decrease seed number
[B] to produce pest-resistant varieties of plants
[C] to increase phosphorous, nitrogen production
[D] to reduce the number of plants
Show Answer
Correct Answer: B [to produce pest-resistant varieties of plants]
Notes:
An important objective of biotechnology in the field of agriculture is to produce pest-resistant varieties of plants.
35. Epidermal cells of which part of plant often secrete a waxy water resistant layer on their outer surface?
[A] Aerial parts only
[B] Roots only
[C] Both aerial parts and roots
[D] Neither aerial parts nor roots
Show Answer
Correct Answer: A [Aerial parts only]
Notes:
The major role of epidermis is to protect all the parts of the plant. Epidermal cells on the aerial parts of the plant often secrete a waxy, water-resistant layer on their outer surface. This aids in protection against loss of water, mechanical injury and invasion by parasitic fungi.
36. In which one of the following is swim bladder absent?
[A] Cartilaginous fish
[B] Silverfish
[C] Cuttlefish
[D] Bony fish
Show Answer
Correct Answer: A [Cartilaginous fish]
Notes:
The swim bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming. The cartilaginous fish (e.g. sharks and rays) split from the other fishes about 420 million years ago and lack both lungs and swim bladders, suggesting that these structures evolved after that split.
37. Azolla increases soil fertility for ____:
[A] Wheat cultivation
[B] Rice cultivation
[C] Maize cultivation
[D] Barley cultivation
Show Answer
Correct Answer: B [Rice cultivation]
Notes:
The nitrogen-fixing capability of Azolla an aquatic pteridophyte has led to it being widely used as a biofertiliser for increasing the productivity of rice fields. When rice paddies are flooded in the spring, they can be inoculated with Azolla, which then quickly multiplies to cover the water, suppressing weeds. The rotting plant material releases nitrogen to the rice plants, increasing the rice yield equivalent to that produced by 30-60 kg N/ha.
38. The cells of sclerenchyma tissue have their walls thickened due to which chemical substance?
[A] Cellulose
[B] Hemicellulose
[C] Lignin
[D] Pectin
Show Answer
Correct Answer: C [Lignin]
Notes:
Sclerenchyma cells are usually dead cells that have heavily thickened secondary walls containing lignin. The cells are rigid and non-stretchable and are usually found in non-growing regions of plant bodies, such as the bark or mature stems. Sclerenchyma is one of the three types of fundamental, tissue in plants; the other two types being Parenchyma and Collenchyma.
39. The plant from which cocoa and chocolate are obtained is a ___:
[A] Herb
[B] Shrub
[C] Small tree
[D] Very big tree
Show Answer
Correct Answer: C [Small tree]
Notes:
Chocolate production starts with harvesting cocoa in a forest. Cocoa comes from tropical evergreen Cocoa trees, such as Theobroma Cocoa which are small trees. These trees live in the understory of tropical forests and require other, taller trees to shelter them from wind and sun.
40. Glucose is a type of ____:
[A] Hexose sugar
[B] Pentose sugar
[C] Tetrose sugar
[D] Diose sugar
Show Answer
Correct Answer: A [Hexose sugar]
Notes:
Three common sugars (glucose, galactose and fructose) share the same molecular formula: C6H12O6. Because of their six carbon atoms, each is a hexose. They are “single” sugars or monosaccharides.
