The answer is; A
The active site of the enzyme is bound by a substrate and probably the enzyme catalyzes a hydrolysis reaction. The poison mimics the substrate and competes with the substrate for the active site of the enzyme. The poison may bind permanently to the enzyme rendering the enzyme unavailable for other substrates. This could make a particular biochemical reaction, in which the enzyme is involved, to reduce drastically hence threatening life.
Answer:
Constitutive activation is the alteration of a protein or signaling pathway such that it is functional or engaged even in the absence of an upstream activating event. For example, RasD is constitutively active because it cannot bind GAP and therefore remains in the GTP-bound, active state even when cells are not stimulated by growth factor to activate a receptor tyrosine kinase.
Constitutively active Ras is cancer promoting because cells will proliferate in the absence of growth factors, and thus normal regulatory mechanisms for cell proliferation are bypassed.
(a) A mutation that resulted in Smad3 binding Smad4, entering the nucleus, and activating transcription independent of phosphorylation by the TGFβ receptor would render Smad3 constitutively active.
(b) A mutation that made MAPK active as a kinase and able to enter the nucleus without being phosphorylated by MEK would render MAPK constitutively active.
(c) A mutation that prevented NF-KB from binding to IK-B or that allowed NF-KB to enter the nucleus and regulate transcription even when bound to IK-B would render NF-KB constitutively active.
Answer: Option A
The primary function of DNA polymerase is to add nucleotides to the growing daughter strands.
Explanation:
DNA polymerase is an enzyme that synthesis DNA and its main function is to make DNA from nucleotides which is the building block of DNA. It is essential for DNA replication and work in pairs by creating identical DNA strands from the original DNA molecule. DNA copies are created by pairing the nucleotides to each bases present in the DNA molecule.The bases are thymine, cytostine,guanine, and adenine, the pairing occur with any of the above combinations forming two pairs respectively.
