Answers:
a) carcinogenic
b) anti-carcinogenic
c) carcinogenic
d) carcinogenic
e) carcinogenic
f) anti-carcinogenic
g) anti-carcinogenic
h) anti-carcinogenic
Explanation:
Cyclins are proteins that regulate the progression through the cell cycle, i.e., the transition of G1 to S phase. It is well known that high cyclin expression may lead to cell proliferation states, which is closely associated with cancer progression. Moreover, the blockage of cyclins may have an anti-carcinogenic effect by inhibiting the progression through the cell cycle. MAP kinases are serine/threonine kinases that regulate the progression through the cell cycle by phosphorylating a variety of substrates during cell proliferation. In consequence, phosphatases that inactivate MAPK kinases (i.e., by dephosphorylation) may have an anticarcinogenic effect. The p53 is a tumor suppressor protein involved in diverse cellular processes including DNA repair, cycle arrest and programmed cell death. This protein (p53) is activated by phosphorylation at target residues and phosphatases inactivate it, thereby the blockage of its degradation may have an anticarcinogenic effect. Oncogene activation (i.e., the expression of oncogenes), may alter diverse cellular processes including DNA replication, and thereby may lead to cancer development. The G-protein α subunit is a GTPase that hydrolyses GTP and thus has a major role in controlling the kinetics of the G-protein signaling cascade. Platelet-derived growth factor receptors (PDGFR) are kinase receptors that play roles in regulating cellular differentiation, cell proliferation and cell growth. PDGFR receptors are present on the surface of normal cells, however, it has been shown that mutations of the PDGFR genes that lead to their high expression lead to uncontrolled cell growth and consequently cause cancer (i.e., by increasing PDGF signaling).
Answer:
A virus attaches to a specific receptor site on the host cell membrane through attachment proteins in the capsid or via glycoproteins embedded in the viral envelope. The specificity of this interaction determines the host—and the cells within the host—that can be infected by a particular virus.
The answer is D. This is referred to as reflex reaction. Reflex is the instantaneous and involuntary reactions to a stimuli. Reflex arc does not pass through the brain so the reaction time is shorter than normal. This is a adaptation to increase survival.
Neurons are the main cell of the nervous system which is responsible for communication of organs and control of many bodily functions. Neurons transmit electrochemical signals which are known as neurotransmitters and neuromodulators that act as messengers for sensory input and motor output.
Also, the nervous system is composed of two main branches which are the central nervous system and the peripheral nervous system. The central nervous system is composed of the brain and spinal cord whereas the peripheral nervous system is composed of the nerves around the body.
