Transcript Chemical Aspects of Life

Introduction
Atoms: the smallest units of matter that can
not be broken down further. There are 94
different types of atoms, from 94 elements.
Examples:
carbon (C)
oxygen (O)
nitrogen (N)
hydrogen (H)
copper (Cu)
Molecules: a combination of atoms, usually of
different types. There are an infinite number
of different molecules.
• Chemistry deals with the combination of
atoms to form molecules.
• Organic chemistry deals with molecules
containing carbon atoms. Carbon can form 4
stable bonds with other atoms.
▬C▬
Macromolecules (large organic molecules)
• Carbohydrates = sugars = saccharides
• Lipids = fats
• Proteins
• nucleic acids
Carbohydrates, proteins and nucleic acids are
formed from smaller subunits, which are
monomers. The combinations are polymers.
Polymers in which the order of monomers
provides information: proteins and nucleic
acids.
• Carbohydrate monomers = Monosaccharides
= simple sugars
• 5 or 6 carbon atoms. Also contain hydrogen
and oxygen.
• Examples: glucose, fructose, ribose
Oligosaccharides: short chain of monomers
Polysaccharides: many sugar monomers
• Starch: plant sugar formed from many glucose
monomers, for energy storage
• Cellulose: plant sugar formed from many
glucose monomers, makes the cell wall
• Glycogen: animal sugar formed from many
glucose monomers, for energy storage
• Chitin: animal sugar, which build the external
skeleton of crabs, insects, ticks, etc.
Polysaccharides:
FUNCTION OF CARBOHYDRATES:
• transportable energy
• energy storage
• structural material
Benedict’s reaction
Cu+2 (blue) + sugar  Cu+1
2Cu+1 + H2O  Cu2O (precipitate)
Note: Cu = copper
PROTEINS:
• Polymers of amino acids (monomers)
• 20 different amino acids
• All have an amino group and an acid group
Structure of proteins
Amino acids join one after the other by
PEPTIDE BONDS
Primary structure
Secondary structure
Polypeptide chain coils or twists because
of noncovalent interactions between
amino acids
Types of proteins and their function
• Materials for spider web, feathers, bones,
hair, muscles, eggs, plant seeds
• Enzymes-speed reactions
• Antibodies- defend against pathogens
LIPIDS
• Includes fats, oils, cholesterol.
• do not dissolve much in water.
• Most lipids have 2 types of subunits
1. Fatty acids
2. Glycerol or a related molecules
• Lipid subunits do not form long
polymer chains as in proteins,
polysaccharides and nucleic acids
Structural Formula of a Fatty Acid
(saturated)
Unsaturated Fatty Acid
Functions of lipids:
•Main component of cell membranes
•Source of energy
•Insulation
•Padding
•Protect surfaces: hair and skin, bird
feathers, plant surfaces
Lipids as parts of cell membranes
Hydrophilic
part
Hydrophobic
part
The plasma membrane. [Just know the basic structure of lipids in the membrane]
Copyright © 2009 Pearson Education, Inc.
pH test for lipids
• Triglycerides are lipids which are neutral with
regard to pH (a measure of the hydrogen ion
concentration) because their fatty acids are
bound to other molecules.
• When triglycerides is broken down, fatty acids
are released which then release hydrogen ion
concentration, causing a lower pH.
• Pancreatin contains an enzyme that breaks
triglyceride molecule.
Nucleic Acids
Ribose or
deoxyribose
phosphate
nucleotide
DNA (deoxyribonucleic acid)
• Sugar is deoxiribose
• 4 types of bases
• A-adenine
• G-guanine
• T-thymine
• C-cytosine
• 2 nucleotide chains are twisted together in a
double helix
• The bases fit together in specific ways
A-T
G-C
Double Helix of DNA
DNA [Just know the basic structure]