chemistry of cell

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Chemistry of cell

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The Chemistry of the Cell
Biology is the study of chemistry systems that happen to be alive!
Five topics:
• The importance of carbon
• The importance of water
• The importance of selectively permeable membrances
•The importance of synthesis by polymerization of small molecules
•The importance of self-assembly

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Importance of carbon
Carbon-containing compounds
domain of organic chemistry
most important atom in biological molecules
diversity & stability of carbon-containing compounds are due to nature of interactions of C
atoms with one another
1.1fundamental property = valence (4)
Carbon atoms form covalent bond with one another or with atoms of oxygen (O), hydrogen (H),
Nitrogen (N) and Sulfur (S)

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The diversity of carbon-containing molecules
•Hydrocarbons are the major component
of fuels (gasoline). However,
with limited function in
biological systems -- the
phospholipid tail of
membranes;
•Functional groups

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Stereoisomers of biological molecules
•A tetrahedral structure of carbon
atoms have geometric symmetry – An asymmetric carbon

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2. Importance of Water
 Universal backbone of biologically important
molecule
 Universal solvent in biological system
 75-85% of cell by weight
 Polar (asymmetric charge distribution)
 H2O are cohesive (HYDROGEN BOND)
 H2O has high temperature stabilizing

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The importance of selectively permeable membranes
 Membranes are physical barriers of cells and
subcellular compartments controlling material
exchange between the internal environment and the
extracellular environment
Polar head
Nonpolar tail
 A membrane is essentially a hydrophobic
permeability barrier consisting of
phospholipids, glycolipids, and membrane
proteins
 Membranes contain amphipathic
molecules such as phosphatidyl
ethanolamine, an example of
phosphoglycerides, the major class of
membrane phospholipids in most cells.

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A membrane is a lipid bilayer with proteins
embedded in it. Each layer is about 3-4 nm thick,
with the hydrophobic tails facing each other in the
middle.

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Functions of the associated proteins: transport proteins; enzymes, receptors,
electron transport intermediates (mitochondria), or chlorophyll-binding proteins
(chloroplast) •Membranes are selectively permeable.
Freely diffusing molecules: H2O, CO2 or MW < Dalton
However, ions like Na + and K+ are effectively excluded (10 8 times less efficient).

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Importance of Synthesis of polymerization

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Importance of self assembly
Asserts the information required to specify the folding of
macromolecules and their interactions to form more complicated
structures with specific biological functions.
Chemical substances in an organism

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