331: The thermoregulatory centre of the man body is
(a) Pituitary
(b) Skin
(c) Hypothalamus
(d) Thyroid
332: Bile is secreted by:
(a) Liver
(b) Gall bladder
(c) Kidney
(d) Pancreas
333: With reference to the latest developments in stem cell research, consider the following statements:
1. The only source of human stem cells are the embryos at blastocyst stage
2. The stem cells can be derived a without causing destruction to blastocysts
3. The stem cells can regenerate themselves in vitro virtually forever
4. Indian research centres also created a few cell lines which can be developed into many types of tissues
Which of these statements are correct?
(a) 1, 2, 3 and 4
(b) 1, 2 and 3
(c) 1, 2 and 4
(d) 3 and 4
Explanation:
Stem cells are undifferentiated cells which are pluripotent in nature with a capacity to differentiate into different kinds of specialised cells. These re of 2 types : (1) Embryonic stem cell and (2) Adult/Somatic stem cell.
The embryonic stem cells are taken from blastocyst (<14 days old) which is an embryo, removed from the womb or brought from the fertility clinic which destroy the life of human being. The Adult/Somatic stem cells are derived from adult somatic/body tissues, ex. Bone marrow, umbilical chord etc.
334: Which of the following cell organelles play the most significant role in protein synthesis ?
(a) Lysosome and Centrosome
(b) Endoplasmic reticulum and Ribosome
(c) Golgi apparatus and Mitochondria
(d) Lysosome and Mitochondria
Explanation:
Endoplasmic reticulum and Ribosomes.
Ribosomes are the factories of protein synthesis. They are 70S type in prokaryotes and 80S type in Eukaryotes. When Ribosomes are attached to Endoplasmic reticulum (ER), it is called Rough ER which helps in protein synthesis.
335: "Lathyrism" is a crippling disease caused by:
(a) Tinned fish
(b) Chick pea and pulses
(c) Meat
(d) Adulterated oil