Physiology - Chapter 2

Chemistry

science of the structure and interactions of matter

Matter

anything that has mass and occupies space.

Mass

a measure of the amount of matter in an object.

Weight

the force exerted by gravity on an object's mass.

Atom

the smallest unit of matter

Isotopes

atoms of an element that have different numbers of neutrons and therefore have different atomic masses

Radioactive isotopes

are unstable

Half life of an isotope

the time required for half of the radioactive atoms in a sample of that isotope to decay into a more stable form

Ion

a particle that has a positive or negative charge because it has an unequal number of protons and electrons

Ionization

the process of giving up or gaining electrons

Molecule

two or more atoms that share electrons

Free Radical

an atom or group of atoms with an unpaired electron in the outermost shell

Electrolyte

ionic compound that breaks apart into positive and negative ions in a solution

Non-polar bond

two atoms that share the electrons equally

bonds between two identical atoms

Polar bonds

sharing of electrons between two atoms is unequal

Electronegativity

the power to attract electrons to itself

Hydrogen bond

a weak attraction between a hydrogen atom and a highly electronegative atom, typically oxygen or nitrogen

Chemical reaction

occurs when new bonds form or old bonds break between atoms

Energy

the capacity to do work or produce heat, existing in various forms such as kinetic and potential energy

Potential energy

stored energy

Kinetic energy

energy in motion

Chemical energy

form of potential energy that is stored in the bonds of compounds and molecules

Exergonic reactions

release more energy than they absorb

Endergonic reactions

absorb more energy than they release

Activation energy influences

• concentration - more particles of matter present in a confined space = the greater chance that they will collide

• temperature - as temp rises, particles of matter move about more rapidly creating greater chance for them to run into each other

Catalysts

chemical compounds that speed up chemical reactions by lowering the activation energy

Oxidation

loss of electrons or increase in oxidation state of a molecule, atom, or ion (releases energy)

Reduction

gain of electrons or decrease in oxidation state of a molecule, atom, or ion (absorbs energy)

Inorganic compounds

lack of carbon and structurally simple

cannot be used by cells to perform complicated biological functions

Organic compounds

always contain carbon 

usually contain hydrogen

always have covalent bonds

Colloid

solute particles are large enough to scatter light so usually appear translucent or opaque

Dissociate

separate into ions and become surrounded by water molecules

Acid

a substance that increases the concentration of hydrogen ions (H+) in a solution, often having a pH less than 7

dissociates into one or more hydrogen atoms and one or more anions

Base

proton acceptor

dissociate into one or more hydroxide ions and one or more cations

Isomers

molecules that have the same molecular formula but different structures

Hydroxyl functional group characteristics

R —O— H

alcohols contain an —OH group

polar and hydrophilic

Sulfhydrl functional group characteristics

R —S— H

thiols have an —SH group

polar and hydrophilic

Carbonyl functional group characteristics

ketones containa carbonyl group within the carbon skeleton

polar and hydrophilic

Carboxyl functional group characteristics

carboxylic acids contain a carboxyl group —COOH group, which is polar and hydrophilic

Ester functional group characteristics

eters predominate in dietary fatsand contain a carbonyl group bonded to an oxygen atom. They are generally nonpolar

Phosphate functional group characteristics

(—PO4-2)

very hydrophilic

important example is ATP

Amino functional group characteristics

—NH2

can act as a base and pick up a hydrogen atom to give the amino a positive charge

Monosaccharides

major carbohydrate group

simple sugars that contain 3-7 carbon atoms

examples: glucose, RNA

Disaccharides

major carbohydrate group

simple sugars from the combination of two monosaccharides by dehydration synthesis

examples: sucrose, lactose

Polysaccharides

major carbohydrate group

from ten to hundreds of monosaccharides by dehydration synthesis

examples: glycogen, starch

Fatty acids

type of lipid

used to synthesize triglycerides and phospholipids or generate ATP

Triglycerides

type of lipid

fats and oils

protection, insulation, and energy storage

Steriods

type of lipid

cholesterol, bile salts, vitamin d, adrenocortical hormones, sex hormones

Eicosanoids

type of lipid

have diverse effects on modifying responses to hormones, blood clotting, inflammation, immunity, stomach acid secretion, etc

Proteins

contain carbon, hydrogen, oxygen, and nitrogenand are composed of amino acids. They play vital roles in cell structure, function, and regulation

Structural

type of protein

form structural framework of various parts of the body

Regulatory

type of protein

function as hormones that regulate various physiological processes, control growth and development, and mediate responses of the nervous system

Contractile

type of protein

allow shortening of the muscle fibres which produces movement

Immunological

aid responses that protect body against foreign substances and invading pathogens

Transport

type of protein

carry vital substances throughout body such as hemoglobin

Catalytic

type of protein

acts as enzymes that regulate biochemical reactions

Peptide bond

one amino acid is joined to a second, then third is added

covenant joining

always between the carbon and carboxyl group (—COOH)

Primary Structure

one dimensional and the unique sequence of amino acids are linked together by covalent peptide bonds to form a polypeptide chain

Secondary Structure

two dimensional and refers to the repeated twisting or folding of neighbouring amino acids in the polypeptide chain

Tertiary Structure

three dimensional arrangement of a polypeptide chain that results from interactions among the side chains (R groups) of amino acids

Quaternary Structure

bond that hold polypeptide chains together

Fibrous proteins

insoluble in water and their polypeptide chains form long strands that are parallel to each other

many structural functions

Collagen

strengthens bones, ligaments, and tendons

Elastin

provides stretch to the skin, blood vessels, and lung tissue

Keratin

forms structure of hair and nails and waterproofs the skin

Dystrophin

reinforces parts of muscle fibres

Fibrin

forms blood clots

Actin & Myosin

involved in contracting of the muscle fibres, division in all cells, and transport of substances within cells

Globular proteins

soluble in water and their polypeptide chains are spherical in shape

Denaturation

no longer functional

Enzymes

catalysts are protein molecules

apoenzyme or a cofactor

Apoenzyme

protein portion of an enzyme that requires a cofactor to become active

Cofactor

non-protein portion

can be a metal or organic molecule

Nucleic Acids

huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus

either DNA or RNA

DNA

deoxyribonucleic acid

forms the inherited genetic material inside each human cell

RNA

ribonucleic acid
plays a crucial role in protein synthesis and gene regulation

pentose ribose

Nucleotides

repeating units of a nucleic acid

each consist of a nitrogenous base, pentose sugar, and phosphate group

Nitrogenous bases

DNA: adenine, thymine, cytosine, guanine

a & g are larger double ring bases called purines

c & tare smaller single ring bases called pyrimidines

Pentose sugar

a five carbon sugar called deoxyribose attaches to each base in DNA

Phosphate group

alternate with pentose sugars to form the backbone of DNA

ATP

adenosine triphosphate

transfers the energy liberated in exergonic catabolic reaction to power cellular activities that require energy

consists of three phosphate groups attached to adenosine, a unit composed of adenine and the five carbon sugar ribose

Creation of Adenosine diphosphate (ADP) equation

ATP + H20 ——> ADP + P + energy

Anaerobic phase

do not require oxygen

glucose is partially broken down by a series of catabolic reactions into pyruvic acid. each glucose molecule that is converted into a pyruvic acid molecule yields two molecules of ATP

Aerobic phase

the phase of cellular respiration that requires oxygen, where glucose is fully broken down into carbon dioxide and water, producing up to 30 to 32 ATP molecules per glucose