31. Which one of the following features is absent in a virus?
[A] Presence of cell wall
[B] Reproduce within host cell
[C] Fully parasitic in nature
[D] Presence of either DNA or RNA
Show Answer
Correct Answer: A [Presence of cell wall]
Notes:
A virus has a simple structure. It has no internal cellular structure, no cell wall or cell membrane, just the protein coat that holds the string of nucleic acid. It is made only of a nucleic acid + a protein coat. A cell wall is a layer located outside the cell membrane found in plants, fungi, bacteria, algae, and archaea.
32. When we touch leaves of “Touch me not plant”, they close, these movements are called ____:
[A] Seismonastic movements
[B] Photonastic movements
[C] Nyctinastic movements
[D] Chemonastic movements
Show Answer
Correct Answer: A [Seismonastic movements]
Notes:
These types of mechanism have been termed seismonastic movements. The movement occurs when specific regions of cells lose turgor pressure, which is the force that is applied onto the cell wall by water within the cell vacuoles and other cell contents.
33. Seed dormancy is regulated by ____:
[A] Abscisic acid
[B] Indole acetic acid
[C] Ethylene
[D] Gibberellic acid
Show Answer
Correct Answer: A [Abscisic acid]
Notes:
The transition from dormancy to germination in seeds is a key physiological process during the lifecycle of plants. Abscisic acid (ABA) is the sole plant hormone known to maintain seed dormancy. It acts through a gene expression network involving the transcription factor Abscisic Acid Insensitive 3 (ABI3).
34. Vitamin C is also known as _____:
[A] Tartaric acid
[B] Acetic acid
[C] Ascorbic acid
[D] Malic acid
Show Answer
Correct Answer: C [Ascorbic acid]
Notes:
Vitamin C is also known as ascorbic acid (C6H8O6). It is a water-soluble vitamin that occurs as a white or slightly yellow crystal or powder with a slight acidic taste. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone.
35. A molecule in plants comparable to haemoglobin in animals is ____:
[A] Carotene
[B] Chlorophyll
[C] Cellulose
[D] Cytochrome
Show Answer
Correct Answer: B [Chlorophyll]
Notes:
Haemoglobin is the iron-containing oxygen transporting metalloprotein in the red blood cells of all vertebrates. Similarly, Cytochromes are, in general, membrane-bound haemo-proteins containing heme groups and are primarily responsible for the generation of ATP via electron transport.
36. Which of the following processes are associated with plants during dark period?
[A] Respiration and transpiration
[B] Transpiration and conduction
[C] Photosynthesis and respiration
[D] Conduction and respiration
Show Answer
Correct Answer: D [Conduction and respiration]
Notes:
Conduction is the process by which vital nutrients are transported to the different parts of a plant. This process is independent of the light factor. Respiration process in plants is the intake of carbon-dioxide and exhales oxygen during the day as the plants gets energy through the photosynthesis process in which the carbon-dioxide is converted into sugars using the sun light energy, as this process uses carbon-dioxide and water, the resulting gas oxygen is given out as a waste product. During the night, as the photosynthesis process does not take place it exhales the carbon-dioxide itself.
37. Bio-magnification implies ____:
[A] Food is magnified
[B] Living beings are magnified
[C] Light is magnified
[D] Toxic matters are magnified
Show Answer
Correct Answer: D [Toxic matters are magnified]
Notes:
Biomagnification is the sequence of processes in an ecosystem by which higher concentrations of a particular chemical such as the pesticide DDT, are reached in organisms higher up the food chain. It’s principal cause is eutrophication of stagnant water leading to the increase in BOD level. The some biomagnifcation has led to the ban on the use of DDT as a pesticide.
38. The strongest muscle (based on its weight) of the body is the masseter muscle and is located in the ___:
[A] Hand
[B] Jaw
[C] Thigh
[D] Chest
Show Answer
Correct Answer: B [Jaw]
Notes:
The masseter is located in the jaw and is one of the muscles of mastication or chewing. ? The bite strength of an average man is between 117 to 265 pounds. ? This ability to exert a force on an external object is an example of absolute strength.
39. Which one of the following is known as the immovable property in the cell?
[A] Nucleic acid
[B] Fat
[C] Protein
[D] Carbohydrate
Show Answer
Correct Answer: A [Nucleic acid]
Notes:
Nucleic acids are large biological molecules essential for all known forms of life. They include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). They are merely transmitted from one generation to next.
40. Night blindness results from the deficiency of ___:
[A] Vitamin-E
[B] Vitamin-A
[C] Vitamin-B2
[D] Glucose
Show Answer
Correct Answer: B [Vitamin-A]
Notes:
Cause of night blindness is a deficiency of retinol, or vitamin A, found in fish oils, liver, dairy products, vegetable and fruits yellow in colour. Nyctalopia also called “Night Blindness” is a condition making it difficult or impossible to see in relatively dim light. To over come deficiency of vitamin-A, one needs to feed of food products rich in carotene which is used in synthesis of vitamin-A is liver.