Background & Biochem

Anatomy

study of structure

Macroscopic anatomy

gross anatomy

Microscopic anatomy

need a microscope; e.g. cytology, histology

Cytology

study of cells

Histology

study of tissues

Physiology

study of function

Pathology

study of disease

Homeostasis

maintenance of a constant internal environment, keep variables within a normal range to enable function

Brings materials into the body

respiratory, digestive systems

Transport within body

circulatory system

Brings materials out of the body

respiratory, urinary systems

Feedback

a response within a system that influences the continued activity or productivity of that system.

Negative feedback

decrease the deviation from an ideal normal value, decreasing the stimulus to return to homeostasis, typical method of regulation in humans

Positive feedback

amplifies the deviation from an ideal normal value, amplifies the stimulus to return to homeostasis, must have a method to turn off, may cause a response more quickly and/or to a greater extent

Feed forward

amplification of a signal or change in the response when there is GOING TO be a new challenge to homeostasis (anticipation)

Element

pure substance comprised on atoms of only one kind

Bulk elements

13 most abundant elements in the body; top three: CHO

Trace elements

14 elements present in the body in trace amounts

Atoms

smallest unit of an element (?), composed of subatomic particles

Nucleus

central part of atom, protons and neutrons

Electron shells

encircle nucleus, occupied by electrons

Atomic number

number of protons, each element has a unique one

Mass number

number of protons and neutrons, electrons do not significantly contribute to the mass of the atom

Isotopes

have the same atomic number but different mass numbers

Octet rule

8 electrons to fill shells (except 1st)

Ion

charged atom

Cations

positively charged ion

Anion

negatively charged ion

Molecules

particle formed when two or more atoms chemically combine through bonding

Electronegativity

the measure of the ability of an atom to attract electrons

Ionic bond

bonds formed by attraction of ions with opposite charge, electrons are donated

Covalent bond

chemical bond between atoms formed by sharing electrons

Nonpolar covalent bond

electrons shared equally (e.g. H2)

Polar covalent bond

electrons unequally shared between atoms, molecule has slightly charged negative and positive ends (e.g. H2O)

Hydrogen bonds

attraction between positive hydrogen end of a polar molecule and a negative end of another polar molecule

Solution

homogeneous mixture

Solvent

solution component into which does the dissolving

Solute

solution component that is dissolved

Aqueous solution

solution where water is the water

Hydration spheres

solvent interface of any chemical compound or biomolecule that constitutes the solute in water

Molarity (M)

moles/L

Osmolarity (Osm)

osmoles/L

Osmole

the number of particles into which a solute dissociates in solution

Weight/volume (%)

grams of solute/100 mL solvent

Equivalents (Eg)

Equivalents/Liter

Equivalent

the number of moles of ionized solute multiplied by the valence of the ion

Valence

charge of ion

Electrolyte

an ionized solute, capable of conducting an electrical current in solution

Electrolyte homeostasis

body tightly regulates electrolyte composition of extracellular fluid

Total body water (TBW)

60% body weight, varies with state of hydration and sodium balance (and individuals)

Interstitial fluid

ECF, fluid that surrounds cells

Acid

solute that dissociates in solution and releases hydrogen ions

Base

solute that removes hydrogen ions from solution

pH

concentration of hydrogen ions expressed on a logarithmic scale, -log[H+]

TBW Division

60% water, 40% ICF, 20% ECF

ECF

high: Na+ Cl- Ca2+
low: K+

ICF

high: K+
low: Na+ Cl- Ca2+

Typical osmolarity

300 (290) mOsm/L

Plasma

ECF, the fluid component of blood

Normal range of blood pH

7.35-7.45

Alkalosis

pH > 7.45, hemoglobin has too high affinity to oxygen

Acidosis

pH < 7.35, hemoglobin has too low affinity to oxygen

Carbon

element most abundant by dry mass in all cells

Organic molecules

molecules that contain carbon

Macromolecule

polymer of repeating subunits

Hydroxyl group

-OH

Carbonyl group

-C=O

Carboxyl group

-COOH

Amino group

-NH2

Carbohydrate

organic molecule that contains CHO in 1:2:1 ratio

Carbohydrate functions

Important source of calories
Energy storage
Component of nucleic acid
Structural component of cell wall in plants, bacteria
Modify protein to alter its function
Mediate recognition events at cell surface

Monosaccharides

monomers of carbohydrates

Disaccharides

two monosaccharides

Oligosaccharides

2-10 monosaccharides

Polysaccharides

>10 monosaccharides

Hexoses

6 carbons, e.g.: glucose, fructose, galactose

Pentoses

5 carbons, e.g.: ribose, deoxyribose

glycosidic bond

sugar bond

condensation reaction

ehydration synthesis, removal of water forms a glycosidic bond

sucrose

glucose + fructose

lactose

glucose + galactose

maltose

glucose + glucose

Starch

storage form of glucose in plants

Cellulose

structural component of plant cell walls

Glycogen

storage form of glucose in animals, branched polymer of glucose, found in liver and skeletal muscle

Lipids

water insoluble group of organic molecules, diverse groups (fatty acids, glycerides, phospholipids & glycolipids, steroids, eicosanoids), CH ratio 1:2 (much less O)

Fatty acids

long chain carbons attached to hydrogen, carboxyl group (COOH) at one end, methyl group (CH3) at the other, incorporated into larger lipid molecules, conversion to energy

Saturated fatty acids

no double bonds in chain, e.g.: butter

Unsaturated fatty acids

at least one double bond in chain, e.g.: oil

Transfats

take unsaturated fat and move hydrogen bonded to other side of double-bonded carbon, act as saturated fat, very unhealthy

Glycerides

carbohydrate backbone (glycerol) with fatty acid chains, formed by dehydration synthesis

Glycerol

3 carbon sugar in glycerides

Types: mono, di, and triglycerides

Triglycerides

stored at lipid droplets in cells of the body (adipocytes)

Amphipathic

hydrophobic and hydrophilic

Lipid Functions

cell membrane structure/function, transport of other lipids

Steroid

lipid with many carbons arranged in 4 ring structure

Steroid Functions

chemical messengers (hormones), cell membrane structure (cholesterol)

Eicosanoids

20 carbon compounds derived from arachidonic acid, typically produced in small amounts in tissues as opposed to production by discrete glands, chemical signaling (usually local)

Proteins

polymers of amino acids connected by peptide bonds