Answer:
A mutation in Ras protein which will cause hyperactivity will eventually lead to cancer.
Explanation:
Ras protein was first discovered in Rous sarcoma virus (RSV) and it is a proto-oncogene product. In normal conditions, it plays an important role in cellular signalling but in case of gain of function/hyperactivity it gets converted into cellular oncogene. In several types of cancers a point mutation has been reported in Ras protein.
Just like G protein, it is also a GTPase switch protein but unlike G protein which is trimeric, it is monomeric. In the plasma membrane, it is attached with the help of lipids like prenyl or palmitoyl groups. During signal transduction pathway when it gets activated, it downstream activates MAPK pathway and causes gene expression but when it gets hyperactivated it causes over expression of genes leading to cancer.
Answer:
C. Prolactin
Prolactin is a
hormone that controls milk production together with oxytocin. The anterior lobe of the
pituitary gland secretes prolactin and the posterior lobe secretes oxytocin when
a baby suckles at the breast. The level of prolactin in the blood slowly
increases during pregnancy, and stimulates the growth and development of the
mammary tissue, in preparation for the production of milk after delivery.
Moreover, Prolactin
is in the highest level in about 30 minutes after the beginning of the feed,
which is most important for producing milk for the next feed.
Mitocondria, the power house of a cell.
Answer:
Neurons in the parasympathetic division release neurotransmitters that act on receptors that slow heart rate
Stimulating the organs of digestion is a parasympathetic response
Parasympathetic nerves are associated with the cranial and sacral regions of the spinal cord, whereas sympathetic nerves are associated with the thoracic and lumbar regions
The sympathetic division of the PNS prepares the body for physical exertion in stressful situations.
Explanation:
The autonomic nervous system also called the vegetative nervous system is part of the peripheral nervous system which inervates smooth muscle and glands. Thus, it directly affects the function of internal organs and regulates functions such as the heart rate, digestion, respiratory rate, urination etc. This nervous system control is unconscious.
The autonomic nervous system is divided into: the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system.
Parasympathetic nervous system works when organism is at rest so it is known as system responsible for "rest and digest functions". On the other hand, sympathetic nervous system works at active and stressful situations and it is known as "fight and flight" system.
