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2-Chemical-Basis-of-Life

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Compound – two or more diff. types of atoms that are
chemically combined
CHEMICAL BASIS
OF LIFE
Basic Chemistry
Chemistry – concerned with atomic composition and
structure of substances and the reactions they undergo
Matter, Mass, and Weight
Matter – anything that occupies space and has mass
Mass – amount of matter in an object; kilogram
Dissociation
§ Separation of ions in an ionic compound by
polar water molecules
Electrolytes – dissociated ions
Chemical Rxns
§ Substances interact either to form or to break
chemical bonds
Weight – gravitational force acting on an object
Reactants – substances that enter into a chemical
reaction
Elements and Atoms
Element – simplest type of matter having unique
properties
Products – substances that result from the chemical rxn
Atom – smallest particle of an element
Atomic Structure
Neutrons – no electrical charge
Anabolism – synthesis rxns that occur in the body
Protons – positive charges
Catabolism – decomposition rxns that occur in the body
Electrons – negative charges
Metabolism – anabolic + catabolic rxns in the body
Nucleus – formed by protons and neutrons
Electron cloud – where electrons are most likely to be
found
Atomic number – no of protons in each atom
Mass number – no. of protons + no. of neutrons
Electrons and Chemical Bonding
Chemical Bonding – electrons are transferred or shared
between atoms
Ionic Bond – electrons are transferred
Covalent Bond – electrons are shared
Polar covalent bond – unequal, asymmetrical sharing of
electrons
Polar molecules
electrical charge
–
molecules
Classification of Chemical Rxns
1. Synthesis – combination of reactants
2. Decomposition – breakdown of larger reactants
3. Exchange – decomposition + synthesis
with
asymmetrical
Nonpolar covalent bond – equal sharing of electrons
bet. atoms
Nonpolar molecules – molecules with symmetrical
electrical charge
Hydrogen Bonds
§ Weak attraction bet the oppositely charged
regions of polar molecules
Molecules and Compounds
Molecule – two or more atoms that are chemically
combined
Reversible Rxns
§ Reactants can form products, products can form
reactants
Energy and Chemical Rxns
Energy – capacity to do work
Potential Energy – stored energy
Kinetic Energy – energy caused by movement
Chemical Energy – form of potential energy stored in
chemical bonds
Rate of Chemical Rxns (RCTC)
1. Reactants
2. Concentration
3. Temperature
4. Catalysts (increases the rate of chem rxn without
itself being permanently changed or depleted)
Acids and Bases
Acid – proton donor
Base – proton acceptor
The pH Scale
§ Indicates the H+ concentration of a solution
Ø Neutral – equal no. of H+ and OH-; pH of 7.0
Ø Acidic – H+ > OH-; pH less than 7.0
Ø Basic – H+ > OH-; pH greater than 7.0
7.35 – 7.45 – normal pH range of blood
Acidosis – blood pH drops beow 7.35
M o r a n o ,
M .
A .
Alkalosis – blood pH rises above 7.45
Salts
§
Forms when an acid reacts with a base
Polyunsaturated fats – two or more double covalent
bonds; safflower, sunflower, corn, fish oils
Trans fats – unsaturated fats tha have been altered by
addition of H atoms
Buffer
§ Chemicals that resist changes in pH
Phospholipids – phosphorus containing molecues
Inorganic Molecules
§ Do not contain Carbon
Hydrophilic – water loving; polar end of molecules are
attracted to water
Oxygen and Carbon Dioxide
Oxygen – involved with the extraction of energy from
food molecules
Hydrophobic – water fearing; non polar end is repelled
by water
Carbon Dioxide – by-product of the breakdown of food
molecules
Water
1.
2.
3.
4.
Stabilizing body temperature.
Protection; lubricant/cushion.
Facilitating chemical reactions.
Transporting substances
Organic Molecules
§ Carbon containing
Carbohydrates
§ CHO
Monosaccharides – smallest carbohydrates; simple
sugars
Ø Glucose – blood sugar
Ø Fructose – fruit sugar
Disaccharides – 2 monosaccharides
Ø Sucrose – table sugar
Polysaccharides – many monosaccharides
Ø Glycogen – animal starch
v Plant starch
v Cellulose
Lipids
§ Substances that dissolve in non polar solvents
§ CHO + P + N
Fats – important energy-storage molecules; pad and
insulate the body
Eicosanoids – important chemicals derived form fatty
acids; important regulatory molecules
Prostaglandins – regulates secretion of hormones, blood
clotting, and some reproductive functions
Steroids – carbon atoms in four ring-like structures
Cholesterol – important steroid bcos steroid molecules
are synthesized from it; important component of cell
membranes
Proteins
§ CHON + S
§ Regulate chemical reactions
§ Serve as structural components
§ Cause muscle contraction
Amino acids – building blocks of proteins; amine group
+ carboxyl group; 20 basic types: 12 simple org.
molecules + 8 obtained in diet
Denaturation – change in shape caused by abnormally
high temp. or change in pH
Enzymes – protein catalysts; lower the activation energy
Activation energy – energy needed to start a chem rxn
Lock-and-key model – the shapes of an enzyme and
those of the reactant allow the enzymes to bind easily to
the reactants
Nucleic Acids: DNA + RNA
Deoxyribonucleic acid (DNA) – genetic material of cells
Glycerol & Fatty Acids – building blocks of fats
Ribonucleic acid (RNA) – important role in gene
expression/protein synthesis
Triglycerides – most common type of fat molecules
Nucleic acid – large molecules composed of CHONP
Saturated Fatty Acid – single covalent bond; beef, pork,
whole milk, cheese, butter, eggs, coconut oil, palm oil
Nucleotides – basic building clocks of DNA + RNA
Unsaturated Fatty Acid – one of more double covalent
bonds
Mono-unsaturated fats – double covalent bonds bet.
carbon; olive and peanut oil
Adenosine Triphosphate (ATP)
§ Important organic molecule
§ Energy currency of cells
§ Stores and provides energy
M o r a n o ,
M .
A .
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