Anatomv and Physiology
Chemistry
Chemistry - the study of matter
Chemical elements - building units for all matter
109 differed ones: 92 occur naturally; ref periodic table For humans C, O, H, N, Ca and P make up 99% body weight
Atoms - building blocks of elements
Smallest unit of matter that enter chemical reactions with an identifying characteristic
a. Components
Protons - positive charged particle, found in nucleus
Neutrons - no charged particle, found in nucleus
Electrons - negative charged particle, orbiting around the nucleus
b. Atomic weight - #of protons +# of neutrons (electrons weight is negligible)
Isotope - different number of neutrons than listed on periodic table
Due to unsuitability tends to be radioactive
c. Atomic number - # of protons
Neutrality = number of protons = number of electrons
d. Atomic Organization
Nucleus - center of atom where protons and neutrons are found
Pathways/Orbital - Electrons move around nucleus
in concentric circles at
varying distances from nucleus. They reflect energy
levels; closer to nucleus
the lower the potential energy
Each shell has a maximum number of electrons it can hold: 1=2,
2=8,3 if
< 20=8;if >20=18
Must fill innermost shell before moving to
next.
Quantum - amount of energy needed or
released to move from one shell to the
next.
Atoms always attempt to have its outermost shell
with the maximum # of
electrons. This is the basis for chemical interaction.
Valance (combining capability)=number of extra or deficient
electron in the outermost shell
Inert elements atoms with completely filled outer shells
e. Chemical Reactions - when atoms interact with other atoms
Molecules when 2 or more of the same
kind of atoms combine
Compounds when 2 or more of different kinds of atoms combine
2
f. Chemical Bonds - force of attraction which holds
atoms together
Types:
Ionic - attraction between oppositely charged ions
Ions - charged particles
Loss of electrons = a positive charged ion (cations)
Gain of electrons = a negative charged ion (anions)
Covalent - attraction resulting in the sharing of electron pairs
Single, double, triple
Hydrogen
- covalently bond hydrogen with another atom; weakest of all bond
types
g. Chemical Reaction
Type:
Anabolism (Synthesis)
Reactants Products
A+B -> AB - water: dehydration synthesis
SS + SS
-> Disaccharide water
Catabolism
(decomposition)
AB - water -> A - B : hydrolysis
h. Energy forms Types:
Kinetic- energy of motion
Potential - energy stored Forms: Chemical Mechanical Electrical Radiant. Solar. Nuclear
i. Chemical Compounds
Major classes
Inorganic - lacks carbon: e.g. waier. salts, acids and bases
(CO,
CaCO3. NaHCO3 )
Organic
- contains carbon: has unique properties
II Inorganic Compounds
a. Water
Most abundant mater; 60-70% of body weight
Excellent solvent and suspending medium
Solvent - medium
Solute - what is being dissolve (dissociates)
Solution - resulting combination of solvent and solute
High specific heat
Absorbs and releases heat very slowly
Moderates external environmental fluctuations in temperature
Lubricant
Major parts of mucus, moistens food and lubricates joints
b. Acids and Bases
When compounds dissolve, they break apart
into ions (electrolytes)
Acids - substances when dissociate increase hydrogen
ions
3
Bases - substance when dissociate increase
hydroxyl ions
Acid + Base = Salt + Water (Neutralization)
pH - scale to measure acidicness and basicness of a solution
0-14; range is exponential
Buffer system - mechanism to maintain homeostatic pH in body
Buffers- chemicals that replace strong acid or bases with weak
Ones
Carbonic Acid-Bicarbonate buffer system- primary one in ECF;
H2CO3 -weak acid and NaHCO3 -weak base
III Organic Compounds
a. Carbohydrates
Made of C, H and O in the ratio of 1:2:1;
primary role is immediate energy
Role: energy source
Types
Monsaccharides:
Pentose (5C) - ribose, deoxyribose
Hexose
(6C) glucose, galactose, and fructose
Disaccharide
Sucrose= glucose + fructose
Maltose = glucose + glucose
Lactose
= glucose + galactose
Polysaccharides
Structural = chitin, cellulose
Storage = glycogen, starch
b. Lipids
Consists of C, H and O in no particular
ratio; are insoluble in polar solvents
and soluble in nonpolar
Roles are stored energy, protection and insulation
Types
·
Triglycerides
(neutral fats)
Consists of glycerol + 3 fatty acids
Saturated
Unsaturated
Polyunsaturated
·
Steroids - Ex cholesterol, sex hormones, myelin
sheath
·
Eicosanoids Derived form arachidonic acid
(20C)
Prostaglandin - membrane associated lipid
produce in all nucleated
Cells; modulation of most hormonal responses, aid in inflammatory
responses
Leukotrienes allergic and inflammatory
response
·
Phospholipids - Replace fatty acids with phosphate group -> water soluble;
major
component of all cell membranes
4
c. Proteins
Major organic compound consist of amino acid: Amine = NH2, acid=COOH
Roles
Structural - cell membrane, collagen
Regulator - hormones
Contractile - actin, myosin
Immulogical - antibodies
Transport - hemoglobin
Catalytic- salivary amylase. lipase
Types of AA
20 in total; 8 are essential: leucine, lysine, isoleucine, methionine, threonine, phenlyalanine. tryptophan, and valine (histidine=conditional)
Glycoproteins -combinations of protein and CHO molecules
Act as enzymes, antibodies, and hormones, help identify normal cells via surface properties
Proteoglycans - large polysaccharide molecules linked to polypeptide chains
Coat surfaces of respiratory and digestive tracts for lubrication
d. Nucleic Acids
Large organic compound consists of C, H, O N
and P; made up of nucleotides
Nucleotide: phosphate group, 5 C sugar, and
nitrogenous bases: adenine, guanine, cytosine. thymine,
and uracil
Types
DNA - deoxyribonucleic acid
Contains all heritable info (genes)
Double stranded no uracil
RNA - ribonucleic acid
Aids in communication of heritable info
Single stranded no thymine
ATP - adenosine triphosphate
Energy source for cells
Cyclic AMP - adenosine monophosphate
Assists in cell/hormonal communication