1. Which part of the Central Nervous System controls “reflex Actions” ?
[A] Mesencephalon
[B] Rhombencephalon
[C] Medulla oblongata
[D] Spinal Chord
Show Answer
Correct Answer: D [Spinal Chord]
Notes:
The nervous system is made of two parts viz. Central Nervous System (CNS) and the Peripheral Nervous System (PNS). CNS is made of Brain [cerebrum, brainstem and cerebellum] and spinal cord. The PNS is made of nerves and neural ganglia. Further, the meninges (three membranes that envelop the brain and spinal cord) are also a part of the nervous system
2. How many pairs of ribs are there in a human body?
[A] 10 pairs
[B] 12 pairs
[C] 14 pairs
[D] 16 pairs
Show Answer
Correct Answer: B [12 pairs]
Notes:
There are total 24 ribs (12 pairs), out of which 14 (7 pairs) are true ribs
3. Chickpeas when soaked in water can swell up to three times their volume. The phenomenon involved in this is called _?
[A] Imbibition
[B] Osmosis
[C] Reverse Osmosis
[D] Diffusion
Show Answer
Correct Answer: A [ Imbibition]
Notes:
The movement of water through semipermeable membrane from region of higher concentration to region of lower concentration is called Osmosis. The uptake or absorbtion of water by solid substance without forming solution is called Imbibition.
4. ‘Dendrochronology’ is the study of the age of which of the following?
[A] Woody Plants
[B] Shrubs
[C] Fungi
[D] All of the above
Show Answer
Correct Answer: A [Woody Plants]
Notes:
Dendrochronology is the branch of biology which studies and estimates the age of woody plants.
5. Which of the following is not a feature of organisms in the class Mammalia ?
[A] milk producing mammary glands
[B] cells with a membrane-bounded nucleus
[C] dorsal hollow nerve chord
[D] chitin in the cell membrane
Show Answer
Correct Answer: D [ chitin in the cell membrane ]
Notes:
Organisms in the class Mammalia all have milk producing mammary glands; cells with a membrane-bounded nucleus and a dorsal hollow nerve cord. Chitin in Cell Walls is the feature of Kingdom fungi.
6. What is that gene called which have two or more than two characters?
[A] Duplicate gene
[B] Pleiotropic gene
[C] Polymeric gene
[D] Su-HW gene
Show Answer
Correct Answer: B [Pleiotropic gene]
Notes:
A single gene may have two or more phenotypic expressions or characters. The multiple phenotypic effect of a single gene is called pleiotropism. Hence the gene associated with this phenomenon is called Pleiotropic gene.
7. Which of the following is the reason behind when one enters a dark room; he is not able to see anything but after some time his vision improves? (UPSC Prelims 1983)
[A] The retina of the eye comes forward
[B] The retina of the eye moves backward
[C] The pupil of the eye contracts
[D] The pupil of the eye dilates
Show Answer
Correct Answer: D [The pupil of the eye dilates]
Notes:
Our eyes cannot see everything clearly when we enter a dark room from a bright light. This is due to the reason that in dark room the pupil is large so when we come out in bright light, a large amount of light enters our eyes and we feel glare.
8. Which one of the following statements regarding starch and cellulose is not correct? (UPSC Prelims 1998)
[A] Both of them are of plant origin
[B] Both of them are polymers
[C] Both of them give colour with iodine
[D] Both of them are made up of glucose molecules
Show Answer
Correct Answer: C [Both of them give colour with iodine]
Notes:
Starch and cellulose both are plant origin. Starch deposits in plant cells, whereas cellulose is most important constituent of plant cell wall. Both starch and cellulose are polymers. Starch is branched polymer of α – D – glucose unit linked by α – 1, 4 glycosidic bond. Cellulose is a linear polymer of β – D – glucose unit. Glucose molecules are present in both starch and cellulose. Amylose in starch is responsible for the formation of deep blue colour in the presence of iodine but cellulose does not give any colour at the treatment with iodine, because amylose is absent in cellulose.
9. Which of the following is the name given to the cellular and molecular control of programmed cell death? (UPSC Prelims 2001)
[A] Apoptosis
[B] Ageing
[C] Degeneration
[D] Necrosis
Show Answer
Correct Answer: A [Apoptosis]
Notes:
• Apoptosis is the process of programmed cell death in multicellular organisms. Apoptosis occurs during normal cell turnover, development and in immune system.
• Ageing is the accumulation of changes.
• Degeneration is the deterioration of a tissue or an organ in which its function is diminished or its structure impaired.
• Necrosis is the disorganized break down of flesh in some part of the body of multicellular organism.
10. How many bones are present in healthy adult human being?
[A] 205
[B] 207
[C] 206
[D] 208
Show Answer
Correct Answer: C [206]
Notes:
An adult human skeleton comprises of 206 bones which is greater than the number of bones present at birth. This is due to the fusing of bones as one grows up. The bone density in the human body reaches maximum at the age of 21.
