Bio Molecules in Cells

8/3/2019 Bio Molecules in Cells

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BIOMOLECULES IN CELLS

-Major biomolecules in cells-Function of biomoleculesCarbohydrate, lipid, protein, DNA,RNA-Cell isolation technique-Homogenization and centrifugation


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Introduction to Biochemistry

Biochemistry is the study of chemistry of lifeprocess

Great unity of all living things at biochemicallevel

Single-celled organisms present with greatdiversity in soil, water or with other living

organisms eg: protozoa, yeast and bacteria Large organisms are built from single cells

At biochemical level all organisms have manycommon features


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Basing on the biochemical characteristics theorganisms are classified into 2 fundamentalgroups

1) Prokaryotes

2) Eukaryotes

Organisms with out nucleus Prokaryotes

Prokaryotes are again differentiated intoseparate domains basing on biochemical

characteristics 1) bacteria 2)archaea

Well differentiated nucleus - Eukaryotes

bacteria

Archaea (red color)

Eukaryotes
http://www.google.co.in/imgres?imgurl=http://www.lestout.com/modules/article/images/lestout/article-what-is-a-eukaryotic-cell.jpg&imgrefurl=http://www.lestout.com/article/news-society/science-nature/what-is-a-eukaryotic-cell.html&usg=__52bG7UZGlnWY7bncYqyZOaaPqI4=&h=410&w=628&sz=29&hl=en&start=46&zoom=0&um=1&itbs=1&tbnid=lG6hW1RSY-kDjM:&tbnh=89&tbnw=137&prev=/images%3Fq%3Dphoto%2Bof%2BEukaryotic%26start%3D40%26um%3D1%26hl%3Den%26sa%3DN%26ndsp%3D20%26tbs%3Disch:1


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Biochemical Molecules of Cell

Two different classes

1) high molecular weight eg: nucleic acids (DNA,RNA) & proteins

2) low molecular weight eg: carbohydrates,lipids (metabolites)


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high molecular weight molecules

DNA Stores genetic information in all cellularorganisms

RNA key for synthesis of proteins and also DNA

Proteins all proteins are made of 20 amino acids(the building blocks of protein)

Proteins function is similar in different organisms often similar 3D structure

eg: Insulin
http://itech.dickinson.edu/chemistry/wp-content/uploads/2008/04/insulinmonomer1.jpg


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Composition of DNA

DNA is double stranded and composed of

1)pentose sugar back bone (deoxy ribose),

2)phospho diester bonds

3) Nitrogen basesPurines (Adenine, Guanine), Pyrimidines (Cytosine, Thymine)


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Composition RNA & Proteins

RNA is single stranded and composed of

1) pentose sugar back bone (ribose),

2) phospho diester bonds3) purines (Adenine, Guanine) and pyramidines (Cytosine,

Uracil) mRNA, tRNA & rRNA

All Proteins (monomers and dimers) are made of 20 amino

acids linked by peptide bonds


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Functions of DNA, RNA & Proteins

DNA - hereditary material which transfers information onegeneration to other

RNA helps in formation of proteins (transcription)

Different types of RNA basing on functionmRNA (messenger RNA) directs proteins to ribosomedirects

tRNA (transfer RNA) directs amino acids to ribosomes,rRNA (ribosomal RNA) links amino acids to form proteins

PROTEINS will function as directed by the genomeeg: Immunoglobulins, Albumin, Ferritin, Insulin etc.


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Low molecular weight molecules

Key metabolic process is common in all cells (metabolites)

Eg: Carbohydrates and lipids

The set of chemical transformations that converts glucose& oxygen into CO2 and H2O is SAME for single cellorganism and human beings

These observations suggests that human beings evolvedfrom microorganisms


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Composition of carbohydrates and

lipids

Carbohydrates Sugars

Eg: glucose, fructose, galactose, lactose,maltose, sucrose

Lipids basic form is glycerolEg: palmitic acid,Cholestrol,Triacylglycerols,


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Function

The main function of carbohydrates andlipids is production of energy by oxidative

process.

Carbohydrate 1 gm 4 calories

Lipids 1 gm 9 calories

Proteins 1 gm 4 calories


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Cell isolation techniques

Centrifugation

Chromatography

Electrophoresis


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Centrifugation

Macromolecules are insensitive to gravitational settingrandom bombardment of molecules in the solution out

weighs the gravitational force.

Centrifugation - increasing the gravitational potentialenergy of macromolecules by enclosing in the vessel

rotating at high speed.


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Components of centrifuges

Basic components of centrifuge

1) Metal rotor with holes toaccommodate vessel of liquid

2) A motor for spinning the rotor atselected speed
http://en.wikipedia.org/wiki/File:Tabletop_centrifuge.jpg


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Applications

isolation and determination the biological properties andfunctions of subcellular organelles and large molecules.

Determination of properties of cells - surface tension,relative viscosity of the cytoplasm, and the spatial and

functional interrelationship of cell organelles.


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Different types of centrifuges

1) Desktop centrifuge (3000 rpm) RBC, yeast cells

2) High speed centrifuge (25,000 rpm) cell debris, cells,large molecular organelles, immunoproteins

3) Ultra centrifuge(75,000) proteins, DNA, RNA


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Homogenization

It is a process in which a mixture is made uniform

throughout.

This procedure involves reducing the size of theparticles of one component of the mixture and

dispersing them evenly throughout the othercomponent.


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Homogenizer

homogenizer blades are lowered into abeaker of the solution and ran at very

high speeds.

The solution is drawn up into the bladeand shot out a very small in hole in theshaft of the blade assembly.

Particle reduction is very quick at thesehigh speeds.


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Applications

most familiar example of a homogenized product is

commercially sold milk.

It makes milk smoother mouthfeel and flavor.


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Dreams

Thank You

Documents

Bio Molecules in Cells