Which of the following is NOT a rate limiting enzyme –
Correct Answer: Malonate dehydrogarase
Description: (D) (Malonate dehydrogenase) (256- U. Satyannarayan 4th)ReactionsRate limiting enzymesGlycolysisPhosphofructokinaseGlycogen synthesisGlycogen phosphorylaseGlycogenolysisGlycogen phosphorylaseTCA cycleIsocitrate dehydrogenaseFatty acid synthesisAcetyl CoA carboxylaseCholesterol synthesisHMG CoA reductaseKetone body synthesisHMG CoA synthaseBite acid synthesis7-a -hydroxylaseCatecholamine synthesisTyrosine hydroxylaseUrea synthesisCarbamonyl transferasePyrimidine synthesisAspartate transcarbamylaseHeme synthesisALA synthasePOINTS TO REMEMBER* Substrate level phoshorylation is catalysed by succinate thiokinase.* Methionine can enter the TCA cycle at Succinyl-CoA- level.* In glycolysis, inorganic phosphate is used reaction catalyzed by Glyceraldehyde-3-p-dehydrogenase.* In first step of Heme synthesis, Succinyl-CoA and Glycine is required.* In beta oxidation of fatty acids, carnitine is required for transport of long chain fatty acid to mitochondrial inner layer.* First acetyl group donor in FA synthesis is Acetyl CoA.* Rate controlling enzyme of FA synthesis is Acetyl CoA carboxylase.* NADPH, ATP, Mn++, biotin and HCO3- is required for FA synthesis.* HMG-CoA in liver mitochondria is inhibited by Insulin.* Resiratory burst is due to NADH oxidase.* Glucose 6-phoshate is involved in glycogenolysis, glycolysis and gluconeogenesis.* Chemiosmotic coupling of oxidation phosphorylation is related to ATP generation of pumping of protein.* Mehionine, Isoleucine, valine enters the TCA cycle at succinyl-CoA.* Citrate is intermediate between gluconeogenesis and FA synthesis.* Rate limiting step in TCA cycle - a-ketoglutarate - succinyl CoA.* Rate limiting step in Gluconeogenesis is catalysed by Pyruvate carboxylase.High Yield Points1.Endonucleases (Restriction) enzymes that cut ds DNA at specific DNA sequences within the molecule (as opposed to exonucleases, which digest from the ends of DNA molecules) are a key tool in recombinant2.DNA research.3.Primase initiates synthesizing small RNA fragments during transcription.RNA enzyme or Ribozymes arei) The peptidyl transferase that catalyzes peptide bond formation on the ribosomeii) Ribozymes involved in the RNA splicing4. Human mitochondira contain 2 to 10 copies of a small circular double-stranded DNA molecules, High mutation rate (5 to 10 times that of nuclear DNA)5i. Xanthoproteic reaction - The aromatic aminoacids such as phenylalanine, tyrosine and tryptophan present in the protein give yellow precipitate when heated with concentrated HNO3 (Nitric acid)ii. Ninhydrin test - All a-amino acidsiii. Millon's test (Millon - Nasse reaction); Tyrosine (phenol group of tyrosine) Therefore millon's test is positive in tyrosinosisiv. Diazo reaction (Pauli's): Histidine ortyrosinev. Aldehyde test: Tryptophan (indole ring)6Dietary fibers: consists of unabsorbable cell wall and other constituents of vegetable food like cellulose, lignin, hemicelluloses, gums, pectins, aliginates and other polysaccharides.* Dietary fibre has caloric value of 2cal/gm (8.36 joules/gm)* The presence of fibre shortens the transit time and increases the stool bulk.7Carnosine is present in muscle tissue (Homocamosine is present in large quantities in brain)8PC R is a method of enzymatic amplification of a target sequence of ds DNA.The DNA to be amplified is replicated by DNA polymerase of Thermus aquaticus (Taq). Taq polymerase is used because it is thermostable.9Telomers are RNA dependent DNA polymerase (Reverse transcriptase)Telomers are short repeated sequences of DNA present at the end of eukaryotic chromosomes present at the end of eukaryotic chromosomesTelomerase provide longetivity to the cellsTelomerase is absent from most of the somatic cells and hence they suffer progressive loss of telomers and they exit the cell cycle.10Strongest bond - Covalent; Weakest bond - Vander Walls forces11i. Rothera's, Gerhardt's test - Ketone bodies in urineii. Benedict's, Fehling's test - Reducing sugars in urineiii. Ehrlich's aldehyde test - Porphobilinogen and Urobilinogen in urineiv. Fouchet's, Gmelin's, vander Bergh test - Bile pigment: bilirubin12Frame shift mutation - occur due to insertion or deletion of one or two bases which causes change in the reading frame distal to the mutation.13Nucleosomes are DNA + HistoneHistones are basic proteins rich in Lysine and Arginine14Shine dalgarno sequence in prokaryotes and Kozak consensus sequences in eukaryotes helps in initiation of protein synthesis (Translation)15Glucose is virtually the sole fuel for the brain, except in prolonged starving when ketone bodies are the major source.
Category:
Biochemistry
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