11. Typhoid fever is caused by which of the following?
[A] Allergy
[B] Fungus
[C] Bacteria
[D] Virus
Show Answer
Correct Answer: C [Bacteria]
Notes:
Typhoid fever is a systemic infection caused by bacteria Salmonella typhi, usually through ingestion of contaminated food or water. The acute illness is characterized by prolonged fever, headache, nausea, loss of appetite, and constipation or sometimes diarrhoea.
12. Which among the following has segmented body?
[A] Phylum Mollusca
[B] Phylum Arthopoda
[C] Phylum Annelida
[D] Phylum Coelenterata
Show Answer
Correct Answer: C [Phylum Annelida]
Notes:
Annelids contain largely segmented bodies with each segment containing elements of the different body systems essential for life, such as the nervous system. Earthworms, ringed worms and leeches all fall into the annelida category.
13. Bile is secreted by which of the following organs? (UPSC Prelims 1985)
[A] Liver
[B] Gall bladder
[C] Kidney
[D] Pancreas
Show Answer
Correct Answer: A [Liver]
Notes:
Bile or gall is a dark green to yellowish brown fluid, produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver and stored and concentrated in the gallbladder.
14. Oxygen transportation in a human body takes place through
I. Blood
II. Lungs
III. Tissue
The correct sequence of transportation is (UPSC Prelims 1997)
[A] I, II, III
[B] III, I, II
[C] II, I, III
[D] I, III, II
Show Answer
Correct Answer: C [II, I, III]
Notes:
The lungs serve to exchange the two gases in the blood. Oxygen enters the blood from the lungs and carbon dioxide is expelled out of the blood into the lungs. The blood serves to transport both gases. Oxygen is carried to the cells and tissues.
15. Which blood group is referred to as universal recipient?
[A] AB +ve
[B] AB -ve
[C] O +ve
[D] O -ve
Show Answer
Correct Answer: A [AB +ve]
Notes:
Persons with AB +ve blood group are called as universal recipients as they can get blood from persons with any of the blood groups. AB -ve cannot be regarded as universal donor as it cannot accept blood from persons with Rh factor.
16. Cell theory was formulated by __?
[A] Charles Darwin
[B] Theodor Schwann
[C] Robert Hooke
[D] Robert Koch
Show Answer
Correct Answer: B [Theodor Schwann]
Notes:
The classical cell theory was proposed by Theodor Schwann in 1839. There are three parts to this theory. In the first part explains that all organisms are made up of cells. The second part explains that cells are the basic units of life. The third part, explains that cells come from preexisting cells that have multiplied. It was described by Rudolf Virchow in 1858.
17. A segment of DNA consists of 120 adenine and 120 cytosine bases. What is the total number of nucleotides present in the segment?
[A] 120
[B] 240
[C] 345
[D] 480
Show Answer
Correct Answer: D [480]
Notes:
According to Chargaff’s laws, the amount of adenine is always equal to that of thymine, and the amount of guanine is always equal to that of cytosine, i.e. A = T(120) and G = C (120), hence, the total no. The number of nucleotides would be 120 x 4 = 480.
18. Which bacteria are used in production of biogas/gobar gas plants?
[A] Methanogens
[B] Ethanogens
[C] Propanogens
[D] N-butane
Show Answer
Correct Answer: A [Methanogens]
Notes:
Methanogens belong to the Euryarchaeota of the Archaebacteria. They convert inorganic organic compounds into methane and carbon dioxide.
19. How many ribosomes are there in eukaryotic cells?
[A] 70S
[B] 60S
[C] 80S
[D] Not specific
Show Answer
Correct Answer: C [80S]
Notes:
All prokaryotes have 70S (S = Svedberg units) ribosomes whereas eukaryotes have large 80S ribosomes in their cytosol.
20. Bryophytes are dependent on water because__?
[A] Archegonium has to remain filled with water for fertilization
[B] Water is essential for fertilization for their homosporous nature
[C] Water is essential for their vegetative propagation
[D] The sperms can easily reach up to egg in the archegonium
Show Answer
Correct Answer: D [The sperms can easily reach up to egg in the archegonium]
Notes:
Bryophytes are dependent on water because the sperms can easily reach up to eggs in the archegonium.
