31. Which of the following contains notochord in the embryonic stage?
[A] Non-chordates
[B] Vertebrates
[C] All chordates
[D] Some of the chordates
Show Answer
Correct Answer: C [All chordates]
Notes:
All chordates contain notochord in the embryonic stage. This midline serves as the source of the signal. It patterns the surrounding tissue and serves as a major skeletal element of the developing embryo.
32. Which of the following is / are correct features of amphibians?
[A] unable to regulate body temperature
[B] able to regulate body temperature
[C] heart is three chambered.
[D] All of the above
Show Answer
Correct Answer: A [unable to regulate body temperature]
Notes:
Amphibians are unable to regulate body temperature, skin types limit distribution to warm, moist climates, and fertilization may be internal or external.
33. Melatonin is a hormone secreted by __
[A] Pituitary gland
[B] Gonads
[C] Pineal gland
[D] Adrenal glands
Show Answer
Correct Answer: C [Pineal gland]
Notes:
Melatonin is a hormone secreted by the Pineal gland. It is a peptide hormone.
34. What cannot sperm do in the absence of acrosome?
[A] Cannot penetrate the egg
[B] Cannot get energy
[C] Cannot get food
[D] Cannot swim
Show Answer
Correct Answer: A [Cannot penetrate the egg]
Notes:
The acrosome contains digestive enzymes. Digestive enzymes break down the outer membrane of the ovum. In the absence of acrosome, sperm cannot enter the egg.
35. Which of these are the primary sex organs of the female reproductive system?
[A] fallopian tubes
[B] ovaries
[C] uterus
[D] cervix
Show Answer
Correct Answer: B [ovaries]
Notes:
Ovaries are the primary sex organs of the female reproductive system. They produce the female gamete (ovum) and several steroid hormones.
36. Bacteria protect themselves from viruses by fragmenting viral DNA?
[A] Ligase
[B] Endonuclease
[C] Exonuclease
[D] Gyrase
Show Answer
Correct Answer: C [Exonuclease]
Notes:
Bacteria protect themselves from viruses by fragmenting viral DNA with Exonuclease. Enzymes that work by cleaving one nucleotide at a time from the end (Exo) of the polynucleotide chain are called exonucleases.
37. Who among the following did the mapping of the human genome?
[A] Oswald Avery
[B] James Watson
[C] Linda Buck Born
[D] Rachel Carson
Show Answer
Correct Answer: B [James Watson]
Notes:
James Watson did the mapping of the human genome. The complete set of nucleic acid sequences for humans encoded as DNA within 23 chromosome pairs in the cell nucleus and a small DNA molecule found within individual mitochondria is called the human genome.
38. Grey hair is caused due to
____:
[A] Aging of epidermal cells
[B] Death of dermal cells
[C] Loss of sebum in epidermal cells
[D] Loss of melanin in epidermal cells
Show Answer
Correct Answer: D [Loss of melanin in epidermal cells]
Notes:
The hair follicles have pigment cells that make melanin, a chemical that gives the hair its color. As one ages, these cells start to die. Without pigment, new hair strands grow in lighter and take on various shades of gray, silver, and eventually white.
39. Which of the following brings back deoxygenated blood from different parts of human body to heart?
[A] Veins
[B] Arteries
[C] Nerves
[D] Lungs
Show Answer
Correct Answer: A [Veins]
Notes:
Veins carry the deoxygenated blood from different parts of the body to the heart. There are two main veins that carry out this job. The superior vena cava carries deoxygenated blood from head, neck, thorax and hands to the right atrium of our heart. The inferior vena cava carries deoxygenated blood from legs, pelvic region and abdominal organs to the right atrium of our heart. Among the veins, only pulmonary vein carries oxygenated blood.
40. The basic structural and functional unit of living organisms is ____:
[A] Systems
[B] Cell
[C] Tissue
[D] Organ
Show Answer
Correct Answer: B [Cell]
Notes:
Robert Hooke (1665) observed a section of cork under his microscope and found its structure resembling a ‘honey comb’. He gave the name ‘cell’ to each of the compartments of the honey comb like structure. Two German biologists, M Schleiden and T Schwann, later proposed the famous cell theory in 1938-39.
