BIOMOLECULES

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Difference between living and nonliving things.(in terms of elements)

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ANALYSIS OF ELEMENTS AND COMPOUNDS

I. Analysis of organic constituents of cells

• Organic compounds – Containing carbon.

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HOW TO ANALYSE CHEMICAL COMPOSITION(organic)?

• Take any living tissue (a vegetable or a piece of liver, etc.)

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• Grind it in trichloroaceticacid (Cl3CCOOH) using a mortar and a pestle.

• Obtain a thick slurry.

• Strain the slurry through a cheesecloth or cotton.

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• Obtain two fractions

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HOW TO ANALYSE CHEMICAL COMPOSITION?

• 2. retentate or the acid-insoluble fraction.

• 1. filtrate or more technically, the acid-soluble pool,

• Smaller or biomolecules are present in the acid-soluble pool.

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HOW TO ANALYSE CHEMICAL COMPOSITION?

• The acid-insoluble fraction(macromolecular fraction) contains biomacromolecules

• (Proteins, Nucleic acids Lipids? etc.)

The acid insoluble fraction, has only four types of organic compounds i.e.,

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proteins,

nucleic acids,

polysaccharides

lipids.

and

molecular weights in the range of ten thousand daltons and above.

Lipids are not macromolecules.

• WHY lipids are present in acid insoluble pool?

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Lipids are not strictly macromolecules.

Lipids are present not only as such but also arranged into structures like cell membrane and other membranes.

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When we grind a tissue, cell membrane and other membranes are broken into pieces, and form vesicles which are not water soluble.

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Therefore, these vesicles get separated along with the acid insoluble pool and hence in the macromolecular fraction.

Biomolecules (organic) are of two types.

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2. Macromolecules or biomacromolecules: Those which are found in the acid insoluble fraction.

1. Micromolecules(metabolites) or simply biomolecules: Those which have molecular weights less than one thousand dalton.

- Present in acid soluble pool

Acid soluble pool

The acid soluble pool represents roughly the smaller molecules present in cytoplasm(cytoplasmic composition - smaller).

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the macromolecules from cytoplasm and organelles become the acid insoluble fraction

But,

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cell composition(ORGANIC)

Acid insoluble pool Acid soluble pool

proteins,

nucleic acids,

polysaccharides

(>10,000 dalton

biomacromolecules.)

and

lipids.

(< one thousand(18-800) daltonmicromolecules or biomicromolecules).

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BIOMICROMOLECULES (METABOLITES)present in ACID SOLUBLE POOL

SECONDARY METABOLITES(plants)

PRIMARY METABOLITES(Plants& animals)

monosaccharides, amino acids,

glycerol, triglycerides, cholesterol,

nitrogenous base -adenine, guanine, nucleoside, nucleotide

alkaloids, flavonoids, rubber, essential oils, antibiotics, coloured pigments, scents, gums, spices.

Biomicromolecules - (metabolites)

2 TYPES

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1. Primary metabolites - present In animal and plant tissues -

eg: monosaccharides,

amino acids,

glycerol, triglycerides, cholesterol,

nitrogenous base - adenine, guanine, cytosine, uracil, thymine

nucleoside- Adenosine, guanosine, cytidine

nucleotide - ATP, GTP, CTP UTP

They have identifiable functions

Biomolecules (metabolites)

2. Secondary metabolites - present in plants, fungal and microbial cells.

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e.g. alkaloids, flavonoids,

rubber, essential oils,

antibiotics,

coloured pigments,

scents, gums, spices.

we do not at the moment, understand the role or functions of these in those cells.

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secondary metabolites

Which chemical is most abundant in cells?

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water is the most abundant chemical in living organisms

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Average Composition of Cells

II.Analysis of inorganic constituents of cells

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ANALYSIS OF INORGANICELEMENTS AND COMPOUNDS

• Weigh a small amount of a living tissue (say a leaf or liver and this is called wet weight) and dry it.

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• All the water, evaporates. The remaining material gives dry weight.

ANALYSIS OF INORGANICELEMENTS AND COMPOUNDS

• Burn it.

• During the burning of dried tissue , all the carbon compounds are oxidised to gaseous form (CO2, water vapour) and are removed.

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• The remaining is called ‘ash’.

• This ash contains inorganic elements like calcium, magnesium etc.

• Inorganic compounds like sulphate, phosphate, etc.,

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cell composition

Acid insoluble pool Acid soluble pool

proteins, nucleic acids,

polysaccharides

(>10,000 dalton

biomacromolecules.)

and lipids(800 dalton).

(< 1000 (18-800) dalton micromolecules or biomolecules).

ORGANICINORGANIC

Primarymetabolite

Secondarymetabolite

water, Na, K, Ca

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BIOMICROMOLECULES (METABOLITES)present in ACID SOLUBLE POOL

SECONDARY METABOLITES(plants)

PRIMARY METABOLITES(Plants& animals)

monosaccharides, amino acids,

glycerol, triglycerides, cholesterol,

nitrogenous base -adenine, guanine, nucleoside, nucleotide

alkaloids, flavonoids, rubber, essential oils, antibiotics, coloured pigments, scents, gums, spices.