Easy Biochemistry Notes

Change in the specific optical rotation with time is called mutarotation. When D-glucose is crystallized at room temperature, and the fresh solution is prepared, its specific rotation is +112˚, but after 12-18 hours, it changes to +52.5 ˚ If initial crystallization occurs at 98 ˚c temperature and then solubilized, the specific rotation is found to be +19 ˚ but also changes to +52.5 ˚. This change in rotation occurs because of the presence of anomeric carbon. The two forms of glucose, i.e., α D glucose exhibits optical rotation of +112 ˚, and β D glucose exhibits an optical rotation of +19 ˚, and both undergo mutarotation and at equilibrium 1/3 molecules are 77 α type, and 2/3 molecules are β type. The equilibrium mixture has an optical rotation of 52.5˚.  

ISOMERISM: § Compounds having the same molecular formula but different structures, i.e., different spatial arrangements, are called isomers/ Stereoisomers. § The ability to exist as isomers is called isomerism . § There are five types of isomerism : 1. Ketose-Aldose isomerism § Glucose & Fructose have the same molecular formula, C 6 H 12 O 6 , but they differ in their structure concerning their functional groups § Glucose is an aldose sugar with an aldehyde group at the first carbon § Fructose is a ketose sugar with a ketose group at the second carbon. 2. D and L isomerism § The spatial arrangement of –H & -OH groups is vital while writing monosaccharides' structure because of the asymmetric carbon atom. § D and L isomerism depend on the H and OH groups' orientation around the penultimate carbon atom. § E.g., in glucose at the C5 position, if the –OH group is present on the right side, it is called D-isomer. If it is present on the left side, it...

  Definition : • Aldehyde or Ketone compounds with multiple hydroxyl groups                                                               Or • The aldehyde or ketone derivatives of polyhydroxy alcohols. • The General molecular formula is Cn(H2O)n •   They are readily soluble in water because of the presence of multiple hydroxyl groups • They are sweet and hence called as sugars and are also called ‘’saccharides ’’(Greek, saccharin means sugar) Functions of Carbohydrates Serve as the primary source of energy, e.g., Glucose Serve as a storage form of energy, e.g., Glycogen in animal tissue and starch in plants Serve as a structural component of many organisms, e.g., Glycosaminoglycans in humans, cellulose in plants, and chitin in insects Serve as dietary fibers,e.g., Non-digestible carbohydrates like cellulose, ...

  Dyslipidemia - Laboratory Analysis is by Lipid Profile estimation Lipid profile  - consists of  Total Cholesterol Triglycerides HDL LDL VLDL HDL/LDL ratio Total Cholesterol/HDL ratio

 Thyroid disorders are analysed using the Thyroid function tests/Thyroid Profile 1. T3/T4 assay -  Total T3/T4 & Free T3 & T4 - analysed by radioimmunoassay(RIA) or ELISA or CLIA(chemiluminescence assay) or Fluorescent immunoassay(FIA) Normal Level  T3 - 1.8 - 3 nmol/L T4 - 65-150 nmol/L f T3 - 0.3% of total T3 f T4 - 0.03% of total T4 2.Plasma TSH Normal level - 0.5-5 mU/L TSH is produced by pituitary gland  its secretion is regulated by the feedback mechanism of fT3 & fT4 secretion 3.Thyroid Antibodies Thyroid stimulating immunoglobulin(TSIg) is the antibody generated against the TSH receptor Measurement of TSIg  help in the diagnosis of Graves disease. Antibodies to thyroid peroxidase - Measurement of Anti-TPO antibodies help in the diagnosis of Hashimoto's thyroiditis(autoimmune thyroiditis) 4.Radioactive Iodine uptake To study the thyroid structure & function Radioactive iodine is given and the radio scan of thyroid gland is done to check ...

Arterial Blood Gas Analysis (ABG) Helps in detecting acid base disorders like  Metabolic Acidosis & Alkalosis  Respiratory Acidosis & Alkalosis 1.Blood pH -  Normal pH - 7.35 - 7.45 helps in checking acidosis/alkalosis < 7.35 - acidosis >7.45 - alkalosis 2.HCO3- Normal value - 22-28 mmol/l 3.PCO2 Normal Value - 35-48 mmHg helps in checking CO2 retention Increase/Decrease seen in respiratory disorders 4.PO2 normal Value - 95-98% helps in checking blood oxygen saturation 5.Electrolytes  Electrolyte estimation tells about the anion gap Normal Level  Na+ - 135-145 meq/l K+ - 3.5-4.5 meq/l Cl- - 96-105  meq/l Ca++ - 9-11 mg/dl 6.Other investigations to know the cause RFT Blood Glucose Serum Lactate Urine & Plasma Ketones

Clinical Manifestations of Liver Dysfunction Jaundice Portal Hypertension Bleeding oesophageal varices Ascites Spontaneous bacterial peritonitis Hepatic encephalopathy Hepatorenal syndrome Disordered haemostasis in liver diseases- e.g.-dysfibrinogenemia, thrombocytopenia I.Serum Bilirubin   Serial measurement of bilirubin helps assess the severity of liver damage in several types of liver disease (e.g., alcoholic hepatitis, cirrhosis). In acute hepatitis, bilirubin peaks later than enzymes do, and serum bilirubin remains elevated for longer than urine bilirubin because of the presence of biliprotein (δ-bilirubin). In most liver diseases there is an increase in conjugated bilirubin whereas increases in unconjugated bilirubin mostly are due to causes other than liver diseases II.Serum Albumin Serum albumin measurements are useful in assessing the chronicity of the disease. The serum albumin concentration is decreased in 1.      Severe acute liver disease 2. ...

DEFINITION - Jaundice is the yellowish discoloration of the skin and mucous membrane due to hyperbilirubinemia and deposition of bile pigments. •It is clinically detectable when the plasma bilirubin exceeds >3 mg/dl. • Jaundice is the clinical term. • Icterus is the Greek term for jaundice •Normal plasma bilirubin level ranges from 0.2–0.8 mg/ dL. •The Unconjugated Bilirubin is about 0.2–0.6 mg/dL, while Conjugated Bilirubin is about 0–0.2 mg/dL. •If the plasma bilirubin level exceeds 1 mg/dL , the condition is called hyperbilirubinemia. •Levels between 1 and 2 mg/dL are indicative of latent jaundice.   CAUSES OF JAUNDICE SAMPLES USED FOR DIAGNOSIS OF JAUNDICE 1.      Blood 2.      Urine 3.      Stool 1.LAB DIAGNOSIS USING BLOOD SAMPLE Tests to assess serum bilirubin-  Vandenberg  Reaction Bilirubin reacts with diazo reagent (diazotized sulfanilic acid) to produce colored azo pigm...

Enzyme diagnosis is required for MI as : a) 25 to 30% of MI cases or not diagnosed antemortem. b) Clinical diagnosis and angiographic studies do not correlate in 25 to 30% of patients c) ECG findings may not be helpful if Prior left bundle branch block is present Presence of Old changes that may mask current ECG interpretation Intravascular infarction may not change ECG pattern Diaphragmatic infarction often missed on ECG

Inflammation of the pancreas is called pancreatitis. It can be Acute , i.e., a sudden inflammation of the pancreas. The causes for this condition can be many but most commonly due to gall stone obstruction and long term alcohol abuse Chronic , i.e., prolonged inflammation. The most common cause is long term alcohol abuse Lab diagnosis of pancreatitis is mainly made by measuring the enzyme levels like   serum lipase and serum amylase  I)Serum lipase levels – It is the preferred test It is the major lipolytic enzyme that hydrolyses glycerol esters of long-chain fatty acids. It is more specific than amylase as it is not elevated in salivary diseases. Acute pancreatitis - increases within 3–6 hours with a peak at 24 hours, usually returns to normal within 8–14 days. It remains elevated even after amylase returns to normal. Urinary lipase is not clinically useful Lipase: amylase ratio >3 (and especially >5) indicates alcoholic rather than non-alcoholic pancreatitis. In ch...

HbA 1 C or glycated hemoglobin is a derivative formed when adult hemoglobin(protein) reacts spontaneously with glucose(a reducing sugar) There are different types of glycated hemoglobin molecules, all are together called HbA 1  fraction In HbA 1 fraction - 80% molecules are HbA 1 C - glucose is attached to N-terminal valine of beta polypeptide of the hemoglobin molecule HbA 1 A 1 - fructose 1.6 bisphosphate is attached to valine HbA 1 A 2 - glucose 6 phosphates are attached to n terminal valine HbA 1 D - glucose is attached to the lysine residue of alpha or beta chain. Non-enzymatic addition of aldehyde of glucose to the N-terminal valine of beta polypeptide of hemoglobin molecule to form keto amine . In general, the concentration of hba1c in the blood is very low, contributing to 5% of total hemoglobin but when the blood glucose concentration is more as see in diabetes the hba1c concentration is more. The increased concentration of glucose increases the formation of HbA 1 C...