Easy Biochemistry Notes

Vitamin D is a fat soluble vitamin  Vitamin D is also known as Cholecalciferol & anti- rachitic factor. STURCTURE OF VITAMIN D there are two forms of vitamin D Cholecalciferol -   also called as Vitamin D2 naturally occurring  obtained from animal sources by the action of UV rays of sunlight on 7 dehydrocholesterol Ergocalciferol -   also called as Vitamin D3 artificially occurring  obtained from plant sources by the action of UV rays on ergosterol

-- Normal catabolism of sphingolipids is by series of lysosomal hydrolases enzymes like 1.α and β glucosidase,  2.Galactosidase,  3.Neuraminidase,  4.Hexosaminidase & 5.Arylsulfatase --Deficiency of a single enzyme results in failure of breakdown of sphingolipids thus causing these lipid storage disorders. --Affected children are severely mentally retarded (MR) --Pre-natal diagnosis of these disorders is by amniocentesis and by culture of amniotic fluids. COMMON FEATURES OF ALL DISORDERS: --Accumulation of only one type of sphingolipid --Normal rate of synthesis of lipid but abnormal degradation of lipids -- same extent of enzyme defect in all tissues TYPES OF LIPID STORAGE DISORDERS 1.Niemann Pick's Disease -AR(autosomal recessive) -Enzyme Defect - Sphingomyelinase - Lipid accumulated - Sphingomyelin - Clinical Features - Severe CNS damage, hepatosplenomegaly, cherry rod spot in the macula Death by 2 years of age 2.Gaucher's Disease AR(autosomal recessive) -E...

 Definition -  Specialized group of proteins having antibody activity are called as  Immnuoglobulins. Functional term is immunoglobulin & Physical term is gamma globulin abbreviated as Ig. STRUCTURE OF IMMUNOGLOBULINS Y-shaped tetramer  made of Two identical Heavy chains (H) &  Two identical Light chains (L) held together by interchain disulfide linkages and noncovalent interactions.  Each heavy chain has 450 amino acids Each light chain has 20 amino acids Each chain of Ig  has variable amino acid sequence at amino end called as the variable region (VL & VH) has constant amino acid sequence at carboxy end called as the constant region (CL & CH) The variable region ( both heavy & light chain )of the immunoglobulin is concerned with binding with the antigen Two types of light chains in all classes of Ig -- kappa (K) and lambda (λ) CLASSES OF IMMUNOGLOBULINS & FUNCTIONS depending on the type of heavy chain Immunoglobulins...

DEFINITION -To become water soluble lipids get complexed with proteins to form lipoproteins -the protein part of lipoproteins is called as apolipoproteins. CLASSIFICATION depending on density of ultracentrifugation or depending on the electrophoretic mobility the lipoproteins are classified into five types 1.Chylomicrons - contain apo B-48 2.Very Low density Lipoproteins(VLDL) - contains apo-B 100 3.Intermediate density  lipoprotein 4.Low-Density Lipoprotein(LDL) -  contains apo B-100 5.High density lipoprotein(HDL) -  contain apo A STRUCTURE OF LIPOPREOTEIN -lipoproteins are made up of  --Polar Periphery - made of proteins --Polar Head - made of phospholipid & free cholesterol --Inner Core - made of hydrophobic triglycerides & tail of phospholipids FUNCTIONS OF LIPOPROTEIN Functions of Chylomicrons -Transport of dietary triglycerides from the intestine into adipose tissue from storage -Transport of dietary triglycerides form intestine ...

 --Change in the base sequence of DNA due to faulty replication or faulty repair of DNA is called as Mutations. --mutations affects somatic cells and so are carried to successive generations. --due to horizontal transmission of mutations ,they  also results in many diseases. --Mutations can be     --Gross that involves large areas of a chromosome (or)     --Subtle that involves only few nucleotides. CAUSES OF MUTATIONS: 1.Errors in DNA repair Mechanisms 2.Spontaneous Change in DNA  3.External/Environmental factors     Physical Agents - Ultraviolet rays/Nuclear rays     Chemical Agents - Deaminating/Alkylating agents --Substance capable of causing mutations are called MUTAGENS. TYPES OF MUTATIONS 1.POINT MUTATIONS/SUBSTITUTION: --Replacement of one base by another base. -- 2 types of point mutations -  a) Transition - replacement of purine by purine and pyrimidine by pyrimidine respectively b)Transversion - Replacement o...

  The Linear arrangements of genes required for metabolism is called as OPERON. The genes involved in making the enzymes necessary for metabolism of lactose is called as LAC OPERON or LACTOSE OPERON. --In 96, Jacob & Monad described the concept of lac operon in E.Coli. STRUCTURE OF LAC OPERON --it is a region of DNA in E.Coli. -- it contains four elements  1.Regulatory Gene(i) - produces repressor protein 2.Promoter site (P) - contains two sites  a) catabolic activator protein binding site(CAP) site b)RNA polymerase entry site to which RNA polymerase gets bound. 3.Operator Site(O) - lac repressor protein produced in the (i) region binds to this site and blocks the transcription initiation 4.Three structural genes (Z,Y,A) coding for  β-galactosidase,galactoside permease & transacetylase respectively required for lactose metabolism REGULATION OF LAC OPERON -E.coli mainly depends on glucose for energy and in the absence of gluco...

used to understand the molecular basis of many diseases  like sickle cell disease, cystic fibrosis, etc. used to diagnose existing diseases used for production of many proteins that are used in research, therapy and diagnosis e.g -growth hormone, erythropoietin, interleukins, etc. used for production of vaccines used for gene therapy i.e. in diseases like sickle cell disease, thalassemia's etc.  - normal genes are introduced into patients having defective genes as treatment protocol used in genetic counselling as a part of screening investigations where the passage of defective genes to the offspring are detected and prevented used in special techniques like DNA fingerprinting in crime detection commercially -  used in the production of enzymes that are used in preparation of detergents, sugar and cheese  used in production of plants that are resistant to diseases, insects, drought and temperatures.

 DEFINITION - Mutations in the gene coding for globin chains affecting the formation and functioning of hemoglobin results in formation of abnormal hemoglobin's.

 Anion Gap: --Na+ & K+ together accounts for 95% of cations and Cl- ,HCO3- accounts for 86% of anions. --commonly only these electrolytes are measured but there is always a difference between measured cations & measured anions -- the unmeasured anions like sulfates, phosphates, organic acids contribute to the anion gap. -- Calculation of anion gap - Difference between (Na+ + K+) & (HCO3- + Cl-) --Normal anion gap is about 12mmol/l 2 types of anion gap  1.High Anion Gap Metabolic acidosis(HAGMA) -- acidosis along with increased anion gap is called as high anion gap metabolic acidosis -- Causes of HAGMA are Lactic Acidosis , Diabetic Keto acidosis  2.Normal Anion Gap Metabolic Acidosis(NAGMA) --when there loss of both anions & cations the anion gap is normal but acidosis may be present and it is called as normal anion gap metabolic acidosis - -Causes of NAGMA are - Diarrhea, Renal Tubular Acidosis

-- Hemoglobin is spherical or globular in shape -- It is  present inside RBC -- It is a conjugated tetrameric protein made of     Protein component -  Globin chain &    Prosthetic or non protein component -  Heme -- Molecular weight of hemoglobin is 67000 Daltons. STRUCTURE OF HEME  -- Heme is the non-protein part of hemoglobin --It is a derivative of porphyrin. -- Porphyrin is a cyclic compound formed by the fusion of four pyrrole rings and so it is a tetrapyrrole structure -- The pyrrole rings are joined together by methenyl (=CH-) bridges -- Iron is present in the center of proto- porphyrin molecule and it is held by forming coordinated bonds with four Nitrogen's (N) of the four porphyrin rings. --  Heme is also called as ferroprotoporphyrin as iron is present in the center of the porphyrin ring. -- The four pyrrole rings present in heme are numbered as I,II,III,IV and the methenyl bridges are named as alpha, beta, gamma ...

•   Sucrose is also called invert sugar because its rotation changes from +66.5 to -19.8 (from dextrorotatory to levorotatory) on hydrolysis. REASON FOR CHANGE IN ROTATION OF SUCROSE Sucrose on hydrolysis liberates glucose and fructose and fructose is more levorotatory than dextrorotatory and this leads to inversion of rotation from dextro to levo.

GAG’s are degraded by enzymes called lysosomal hydrolases. • Deficiency of these enzymes leads to accumulation of GAG’s and a group hereditary diseases called as Mucopolysaccharidoses. • The diseases are rare and inherited as autosomal recessive trait. • The GAG’s are accumulated in liver, spleen, skin, bones and CNS. • The cause of the enzyme deficiency is mutation of the enzyme gene. • These diseases are progressive in nature. • Children are normal at birth and gradually show changes in appearance and deteriorate. • Severely affected children die at early childhood. • Out of all Hurlers Syndrome and Hunters syndrome are common. Clinical features • T ypical Facial Appearance • Flat Nasal Bridge And Thick Lips • Short Torso • Organomegaly – Enlargement of Liver, Spleen And Heart. • Multiple Organs Are Affected • Skeletal Abnormalities Are Seen With Abnormal Bone Size • Mental Retardation • Hearing Loss And Visual Impairment Diagnosis • Assay of suspected enzyme • Identification of accu...

-Contain two / more different monosaccharides -Heteropolysaccharides containing uronic acid (acidic unit) and amino sugar are called mucopolysacharrides or glycosaminoglycans. -Because of charged groups, i.e., uronic acid and amino sugars, they attract water molecules producing viscous solutions. -When these mucopolysaccharides are combined with proteins are called  proteoglycans.

Made of two molecules of monosaccharides The two monosaccharides are joined together by O – glycosidic linkage. The O- glycosidic linkage is formed when –OH group of monosaccharide reacts with anomeric carbon of other. Sub classified on the basis of the presence or absence of free reducing (aldehyde or ketone) group 1. Reducing disaccharides with free aldehyde or keto group, e.g. maltose, lactose 2.Non-reducing disaccharides with no free aldehyde or keto group, e.g. sucrose.   1. Maltose - Reducing Disaccharide -- Made of two glucose units joined together by  α  1, 4 -glycosidic linkage formed between the anomeric carbon of one glucose unit and fourth carbon of other glucose unit. --the first carbon of one glucose unit is free and so maltose is a reducing disaccharide --Maltose is produced from starch by amylase. Isomaltose: --Made of two glucose units joined together by  α  1,6 glycosidic linkage --By product formed during digestion of starch along with glucose...

-- Dietary Fibre is the polysaccharide fraction of plant cell wall. -- It is a form of starch that is resistant to hydrolysis --Dietary fibre is important in animals for maintaining normal healthy intestinal tissues. -- In humans it is not digested due to the absence of the enzyme cellobiase. --Cellobiase is an enzyme that can split cellulose at beta 1-4 glycosidic linkage --Dietary Fibre as such does not have any nutritional value but it promotes peristalsis in intestines and prevents constipation. TYPES OF DIETARY FIBRE Advantages: --hypolipidemic effect --hypoglycemic effect' --keeps intestinal tract healthy --prevents constipation Disadvantages - -Excessive Fibre may cause irritation to intestinal mucosa causing diarrhoea,abdominal discomfort,bloating & constipation. --Excessive Fibre binds to zinc,calcium,magnesium and decreases their absorption.