Question 8 and 9. It is one question just misnumbered Biochemistry1. In the inositol signaling pathway, both IP, and diacylglycerol (DAG) are hormonal secondmessengers. If certain protein kinases in cells are activated by binding, how do IP3 and DAG act in acomplementary fashion to elicit cellular responses inside cells?2. In some forms of diabetes, a mutation in the D subunit of the insulin receptor abolishes the enzymaticactivity of that subunit. How does the mutation affect the cell's response to insulin? Can additionalinsulin (e.g., from injections) overcome the defect?J. At pH 7, tryptophan crosses a lipid bilayer at about one-thousandth the rate of indole, a closely relatedcompound: Suggest an explanation for this observation,4. The removal of fatty acids from triacylglycerols leaves glycerol. Show how the actions of glycerolkinase and glycerol-3-phosphatedehydrogenase on glycerol produce an intermediate of glycolysis.5. Adipocytes store fat in phospholipid-coated droplets in the cytosol. The protein perilipin is alsoassociated with the surface of the lipid droplet. (a) Describe the likely structure of the perilipinprotein. (b) Explain how phosphorylation of perilipin could help expose the lipids in the droplet todigestion by lipases.6. A deficiency of a citric acid cycle enzyme in both mitochondria and the cytosol of some tissues (e.g.,blood lymphocytes) results in severe neurological abnormalities in newborns. The disease ischaracterized by excretion in the urine of abnormally large amounts of a-ketoglutarate, succinate, andfumarate. What enzyme deficiency would lead to these symptoms?EGO7. Name the three enzymes that form the pyruvate dehydrogenase complex.8. For each reaction listed below, indicate the appropriate enzyme(s) in the pyruvate dehydrogenasecomplex and the relevant cofactor(s), if applicable.9. ReactionEnzymeCofactor(a) Oxidative formation of an enzymatic disulfide bond(b) Transfer of hydroxyethyl group bound to TPP(c) Liberation of CO2(d) Oxidation of dihydrolipoamide(e) Formationof acetyl-CoA

Enzymes are biocatalyst that increases the rate of reaction without itself being changed or used in overall biochemical reaction. Enzymes may be simple or conjugate. Simple enzyme is made up of amino acid and conjugate enzyme(Holoenzyme) is made up of protein(Apoenzyme) as well as non-protein(Co-factor) part. Co-factor is essentially required for the biological activity of enzyme. S.N. Reactions Co-factor Enzymes a. Oxidative formation of an enzymatic disulfide bond NAD+, FAD Dihydrolipoyl dehydrogenase b. Transfer of hydroxyethyl group bound to TPP TPP Pyruvate dehydrogenase c. Liberation of CO2 TPP Pyruvate dehydrogenase d. Oxidation of dihydrolipoamide NAD+, FAD Dihydrolipoyl dehydrogenase e. Formation of acetyl-CoA Lipoic acid, CoA Dihydrolipoyl transacetylase