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Explore the elements, atoms, compounds, and organic compounds that form the basis of biochemistry and the chemistry of life. Learn about carbohydrates, lipids, proteins, and nucleic acids and their importance in living organisms.
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CHEMISTRY OF LIFE • Elements: simplest form of a substance - cannot be broken down any further without changing what it is • Ex. C, H, O, N, Fe • Atom: the actual basic unit - composed of protons, neutrons, and electrons
THE ATOM • Just like cells are the basic unit of life, the ATOM is the basic unit of matter. • They are very small. If placed side by side one million would stretch a distance of 1cm. • The atom is made up of 3 particles.
Electrons are not present within the atom, instead THEY REVOLVE AROUND THE NUCELUS OF THE ATOM & FORM THE ELECTRON CLOUD PROTONS NEUTRONS + + ATOMIC # = 2 (PROTONS) ATOMIC MASS = 4 (PROTONS & NEUTRONS) - - ELECTRONS
ISOTOPES • atoms of the same element that HAVE A DIFFERENT NUMBER OF NEUTRONS • Some isotopes are radioactive. This means that their nuclei is unstable and will break down at a CONSTANT RATE over time. • There are several practical uses for radioactive isotopes: • CARBON DATING • TRACERS • KILL BACTERIA / CANCER CELLS
COMPOUNDS • a substance formed by the chemical combination of 2 or more elements in definite proportions • Ex: water, salt, glucose, carbon dioxide H20 CO2 NaCl
Elements and Life • The cell is a COMPLEX CHEMICAL FACTORY containing some of the same elements found in the nonliving environment. • carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) are present in the greatest percentages
TWO TYPES OF COMPOUNDS • Organic - Contain C&H in some ratio (usually referred to as chemicals of life) • Carbohydrates, Proteins, Lipids, Nucleic Acids • Inorganic - usually "support" life - no specific ratio of C&H • Water (H2O), Carbon Dioxide (CO2)
CHEMICAL BONDS • Chemical bonds hold the atoms in a molecule together. • There are 2 types of chemical bonds IONIC and COVALENT
IONIC BONDS • Occur when 1 or more electrons are TRANSFERRED from one atom to another. • When an atom loses an electron it is a POSITIVE charge. • When an atom gains an electron it is a NEGATIVE charge • IONS: Charged particles formed when electrons are lost or gained • Example: Na+
COVALENT BONDS • Occur when electrons are SHARED by atoms. • ** In general, the more chemical bonds a molecule has the more energy it contains SHARING IS CARING!
FORMULA • The chemical symbols and numbers that compose a compound ("recipe") • Structural Formula – Line drawings of the compound that shows the elements in proportion and how they are bonded • Molecular Formula – the ACTUAL formula for a compound C2H6O
ORGANIC COMPOUNDS LIPIDS PROTEINS NUCLEIC ACIDS CARBOHYDRATES
CARBOHYDRATES • Why are carbohydrates important? • Living things use carbohydrates as a key source of ENERGY! • Plants use carbohydrates for structure (CELLULOSE) • include sugars and complex carbohydrates (starches) • contain the elements carbon, hydrogen, and oxygen in a 1:2:1 ratio
Monosaccharides (simple sugars) • all have the formula C6 H12 O6 • all have a single ring structure • (glucose is an example)
Disaccharides (double sugars) • Sucrose (table sugar) is an example
Polysaccharides • Formed of three or more simple sugar units • Glycogen - animal starch stored in liver & muscles • Cellulose - indigestible in humans - forms cell walls • Starches - used as energy storage
Dehydration Synthesis • Combining simple molecules to form a more complex one with the removal of water • ex. monosaccharide + monosaccharide ----> disaccharide + water • (C6H12O6 + C6H12O6 ----> C12H22O11 + H2O • Polysaccharides are formed from repeated dehydration syntheses of water • They are the stored extra sugars known as starch
Hydrolysis • Addition of WATER to a compound to SPLIT it into smaller subunits • ex. disaccharide + H2O ---> monosaccharide + monosaccharide C12 H22 O11 + H2 O ---> C6 H12 O6 + C6 H12 O6
Lipids (Fats) • Why are lipids important? • Chiefly function in energy storage, protection, and insulation • Contain carbon, hydrogen, and oxygen but the H:O is not in a 2:1 ratio • Tend to be large molecules – that are insoluble in water
Lipids • Lipids are formed from the union of one glycerol molecule and 3 fatty acids • 3 fatty acids + glycerol ----> (lipid) • Lipids along with proteins are key components of cell membranes
PROTEINS • contain the elements carbon, hydrogen, oxygen, and nitrogen • composed of MANY amino acid subunits • The basic amino acid form has a carboxyl groupon one end, a methyl groupthat only has one hydrogen in the middle, and a amino groupon the other end. • Attached to the methyl group is a Rgroup.
*R-Groups vary producing different amino acids *20 amino acids exist in living things
Why are Proteins important? • Growth and repair • Energy • Carrying out chemical reactions(enzymes)
Polypeptide (protein) • composed of three or more amino acids linked by synthesis reactions • Examples of proteins include insulin, hemoglobin, and enzymes. • ** There are an extremely large number of different proteins. • The bases for variability include differences in the number, kinds and sequences of amino acids in the proteins
NUCLEIC ACIDS • in all cells • composed of NUCLEOTIDES • store & transmit heredity/genetic information • Nucleotides consist of 3 parts: • 1. 5-Carbon Sugar • 2. Phosphate Group • 3. Nitrogenous Base
DNA (deoxyribonucleic acid) • contains the genetic code of instructions that direct a cell's behavior through the synthesis of proteins • found in the chromosomes of the nucleus
RNA (ribonucleic acid) • directs cellular protein synthesis • found in ribosomes & nucleoli