Physical and chemical properties of protein

-

  1. Most protein are colorless amorphous substance with no definite melting points or boiling points. On heating they undergo decomposition. 
  2. They forms important part of buffer system of body fluid as they are amphoteric in nature. This is due to large number of ionizable R-groups. 
  3. Isoelectric Point : This is because of presence on the protein chain of additional acidic or basic groups that are not involved in peptide linkages. Most proteins show minimum solubility and stability at their Isoelectric Point. 
  4. Precipitation / coagulation : proteins are easily precipitated by certain agents. Many of the normal function in body are essential precipitation reaction example clotting of blood. Precipitation of protein is an irreversible change and precipitated protein is said to be denatured. 
  5. Colloidal nature : These form colloidal dispersion in water. The inability of proteins to pass through a membrane is of great importance in body. Protein present in bloodstream can't pass through membranes and should remain in the blood stream.  
  6. Oxidation : They oxidised on burning and putrefaction . The product include nitrogen, amines, carbon dioxide and water.  The bad smell produced during putrefaction of dead animals is largely due to formation of amines and other nitrogen products by the bacterial oxidation of body proteins.
  7. Denaturation : loss of biological functioning and tertiary structure by extreme changes in temperature, pH, chemicals.
  8. Hydrolysis : Proteins can hydrolysed by Acid,alkalies,enzymes.The final product of hydrolysis is amino acid. 
  9. Reactivity : These react with a variety of inorganic ions, chemical groups and organic molecules due to presence of different reactive groups on side chains of amino acids of proteins. 


Comments

Post a Comment

Popular posts from this blog

Shell Coiling in snails 🐌

-
Image
 Maternal inheritance V/S Predetermination  Maternal inheritance : Inheritance of some traits of mother to the offspring through the cytoplasm of female gamete.  Predetermination : It is the effect of mother's genes on the characters of offspring through the cytoplasm of egg and embryo without involving plasmagenes of cytoplasm.  Shell coiling in snails 🐌  There are two types of coiling present in present in snails. 1.Dextral type 2. Sinistral type  The direction of coiling in shell is controlled by the orientation of mitotic spindle of the first cleavage of zygote. This all depends on the organization of egg before fertilisation. The spindle organisation is controlled by organisation of cytoplasm in the egg.  Dextral type : Shell is coiled clockwise (toward right when viewed from apex). It is shown by ( DD or Dd ) because D is dominant over d.  Sinistral type : Shell is coiled anticlockwise . It is shown by dd . 1.Cross between sinistral Female and Dextral male When eggs of Si
Read more

Nucleic Acid : DNA and RNA (PART -1)

-
Image
 Nucleic acid is biopolymer,essensial for all living beings. They were first reported by Friedrich Miescher (1871) in nuclei of pus cell. He named them nucleic. They can be found in both nucleus and cytoplasm . Altman renamed nuclein and called them Nucleic acid . Nucleoprotein  Nucleic acid along with basic proteins make nucleoprotein which is sub unit of chromosome.   In nucleoprotein, nucleic acid is prosthetic group and protein part consist of protamine and histone (basic nature).  They are very complex and high molecular proteins.  Composition  Basic structure of nucleic acid consist of Sugar, nitrogenous base *(adenine,guanine,thymine,cytosine,uracil) and phosphorus. This combined structure of sugar, phosphorus and nitrogenous base is known as nucleotide.   DNA is made up of deoxyribonucleotides  which is further made up of Deoxyribose sugar, phosphorus, and nitrogenenous bases (adenine,thymine guanine, cytosine) RNA is made up of ribonucleotides which is further composed of Ri
Read more

DNA :Structue and Functions

-
Image
  Deoxyribose nucleotide acid is polymer of deoxyribonucleotide . Each deoxyribonucleotide is made up of Ribose sugar , phosphate , and Nitrigenous base .  Sugar: DNA consist deoxyribose* sugar . Nitrigenous Base : It is of two types.  Purines : Adenine (A), Guanine (G) are purines,9_membraned double ring structure having N at 1,3,7,9 position  Add caption Pyrimidines : Thymime (T) ,Cytosine (C)  are Pyrimidines, 6_memberaned single ring structure having N at 1,3 position.  Bonding in DNA  There are two types of binding present in DNA i .e. Hydrogen bonding and covalent bonding.  Hydrogen bonding is present between nitrogenous bases. Adenine joined by  double bond with Thymime . Guanine joined with cytosine by Triple bond.  Covalent bonding :  Phosphodiester bond is formed between 5'phoshphate group of one  nucleotide with 3'OH of another nucleotide.  Bond between nitrogenous base and sugar is known as glycosidic bonds .  X-ray diffraction method    Maurice Wilkins,  R
Read more