In: Biology
a)Phospholipase C can be activated by a G protein, which in turn leads to the formation of Sn-diacylglycerol and inositol-1,4,5 triphosphate. True/False?
b)Oncogenes are mutated protooncogenes through the intermediacy of viral infection. True/False?
c)Paracrine growth factors differ from hormones in their long-range of action. True/False?
d)Prostanoids are extremely metabolic labile and therefore have a short lifetime. True/False?
e)Carbohydrate consumption is necessary for the synthesis of triacylglycerols in adipose cells. True/Falsew?
f)Thymidylate synthase: The inhibition of dihydrofolate reductase can suppress the proliferation of cancer cells because dTMP is required for DNA synthesis. True/False?
a) Answer- True.
Phospholipase C can be activated by a G protein. It is a truely remarkably signalling moiety and only enzyme that can modulate three distinct signal directly, known as inositol 1,4,5-triphosphate (IP3) DAG (Diacylglycerol) and PIP2 (Phosphatidylinositol 4,5-biphosphate).
Sn-diacylglycerol is a stereochemical form (can exist in three form Sn-1,2- diacylglycerol or Sn- 2,3- diacylglycerol or Sn-1,3- diacylglycerol) of Diacylglycerol (DAG) or diglycerides.
b) Answer- False.
RNA and Dna virus both participate in the development of cancer in human. For example, Epstein-Barr virus, Human pipilloma virus etc. The path from viral infection to tumerogenesis is inefficient and slow. only a minority of infected people grow cancer, sometimes years and decades after primary infection. Viral infection has no significant role in cancer development mainly.
c) Answer- True.
Paracrine growth factors includes GM-CSF, IGF-l, NGF, VEGF PDGF, EGF, TGF-beta, and IL-1. These factors can modulate microinvironment to the benifit of tumor growth and invesion.
d) Answer- True.
Prostanoids are extreamly metabolic liable compounds and thus the quantation of their inactive metabolite is used to determine their synthesis rate rather than the active compounds.
Prostanoids do not circulate due to their short half-life and do not directly impact the systemic vascular tone. However at the site of their formation, they can modulate local vascular tone and affect systemic blood pressure through the kidney.
e) Answer- True.
Excess engestion of carbohydrates stored in the form of glycogen and then it is used in the synthesis of triacylglycerol in yhe adepose tissue.
f) Answer- True.
Folate cycle inhibition inhibits dTMP supply, prevents DNA synthesis and ultimately cell proliferation. Thymidylate synthase, an enzyme that catalysase the conversion of dUMP (deoxyuridine monophosphate) to dTMP (deoxythymidine monophosphate) and Thymidine is a component of DNA.