chapter 2 - cellular level

chemistry

science of structure and interactions of matter

proteins

large molecules containing C, H, O, N, S

fibrous proteins

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

structural functions include

collagen (strengthens bones, ligaments, and tendons), elastin (provides stretch in skin, blood vessels, and lung tissue)

keratin (forms structure of hair and nails and waterproofs the skin),

dystrophin (reinforces parts of muscle fibers), fibrin (forms blood clots),

and actin and myosin (are involved in contraction of muscle fibers,

division in all cells, and transport of substances within cells).

—

quarternary structure is not present in all proteins

carbohydrates classified on.. .

size

sulfhydryl

helps stabilize shape of proteins

blood is a

suspension

matttr

anything that occupies space and has mass, does not change

weight

force of gravity acting on matter does change

chemical elements

substance that cannot be split into a simpler substance by ordinary chemical means c

chemical symbol

one or two letters of element’s name

major elements

96% of the human body mass, consisting primarily of oxygen, carbon, hydrogen, and nitrogen. These elements are essential for life.

lesser elements

3.6% of the body

Ca, P, K, S, Na, Cl, Mg, Fe

trace elements

14 elements present in tiny amounts.

ex. iodine needed for thyroid hormones

atoms

smallest unit of matter that retain properties and characteristics of the element

subatomic particles

compose individual atoms n

nucleus

dense central core of an atom, surrounded by electron cloud

proton) +

neutron) 0

electron) -

electron shells

depicted as simple circles around nucleus

shell 1) max 2

shell 2) max 8

shell 3) max 18

atomic number

number of protons in the nucleus

mass number

sum of protons and nuetrons

isotopes

atoms of an element that have different numbers of neutrons and diferent mass numbers

dalton

standard unit of measuring mass of atoms and subatomic particles

atomac mass

average mass of all its naturally occurring isotopes

ion

particle that has positive and negative charge because it has unequal numbers of protons and electrons i

ionization

process of giving up or gaining electrons

molecule

when two or more atoms share electrons

compound

substance that contains atoms of two or more different elements

free radical

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

ex. superoxide

consuming more antioxidants can slow the damage of free radicals

chemical bonds

forces that hold together the atoms of a molecule or compound vale

valence shell

electrons in the outermost shell

chemically stable) atom with shell holding eight electrons

octet rule

two or more atoms can interact in ways that produce a chemically stable arrangement of eight valence electrons for each atoms.

one atom is more likely to interact with another if they will both have eight electrons.

ionic bond

force of attraction that holds together ions with opposite charges

cation

positively charged ion

anion

negatively charged ion

electrolyte

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

covalent bond

two or more atoms share electrons rather than gaining or losing electrons

single covalent bond

two atoms share one electron pair d

double covalent

two atoms share two pairs of electrons

triple covalent bond

three paris of electrons shared

nonpolar covalent bond

two atoms share electrons equally

polar covalent bond

sharing of electrons between two atoms is unequal, nucleus of one atoms attracts shared electrons more strongly than nucleus of other atom

electronegativity

power to attract electrons to itself

hydrogen bond

• hydrogen atom with partial positive charge attracts partial negative charge of neighboring electronegative atom, often larger oxygen and nitrogen atoms su

surface tension

measure of the difficulty of stretching or breaking the surface of a liquid.

chemical reaction

occurs when new bonds form or old bonds break between atoms.

reactants

starting substance e

products

ending substances

metabolism

all the chemical reactions occurring in the body

energy

capacity to do work po

potential energy

stored energy kine

kinetic energy

energy in motion

chemical energy

potential energy stored in bonds of compounds and molecules

law of conservation of energy

energy can neither be created nor destroyed

exergonic reactions

release more energy than they absorb

endergonic

absorb more energy than they release

activation energy

collision energy needed to break chemical bonds of reactants

concentration

• the more particples of mattter present, the greater chance of collision.

ex. crowded subway train

temperature

as temp rises, particles of matter move about more rapidly and collide more forcefully, greater chance of a reaction

catalysts

chemical compounds that speed chemical reactions by lowering activation energy

synthesis reactions

when atoms or ions combine to form new/larger molecules

anabolism

all synthesis reactions in the body

usually endergonic reactions because they absorb more than they release

decomposition reactions

split up large molecules into smaller atoms, ions, or molecules

catabolism

decomposition reactions in body.

exergonic, release more energy than absorm ex

exchange reactions

consist of body synthesis and decomposition reactions

reversible reaction

products can revert to original reactants

oxidation

loss of electrons red

reduction

gain of electrons, reduced substance gains energy o

oxidation-reduction reactions..

are always parallel. when one substance is oxidized, another is reduced at the same time

inorganic compounds

lack carbon, simple structure. cannot be used to perform complicated biological functions

organic compounds

contain carbon, usually hydrogen, always covalent bonds

water

most important and abundant inorganic compound.

water as solvent

in solution, the solvent dissolves the solute . usually more solvent than solute.

hydrophilic

solutes that are charged or contain polar covalent bonds;dissolve easily in water hy

hydrophobic

nonpolar covalent bonds, not water soluble

hydrolysis

breakdown larger molecules by the addition of water molecules

dehydration synthesis reaction

two smaller molecules join to form a larger molecule

water high heat acapacity

large number of hydrogen bonds,

mixture

combination of elements/compounds physically blended together but not bound by chemical bonds

colloid

has solute particles that are enough to scatter light,

example ; milk

concentration %

relative mass of a solute in a given volume of solution

moles per liter (mol/L)

molarity, total # of molecules in a given volume of solution

mole

amount of any substance that has a mass in grams equal to the sum of atomic masses of all its atoms

dissociate

when inorganic acids, bases, salts dissolve in water, they separate into ions and are surrounded by water molecules

acid

substance that dissociates into one or more hydrogen H+ ions and one or more anions

also called proton donor b

base

removes H+ from a solution and is a proton acceptor . dissociates into hydro

pH scale

potential of hydrogen, 0 -14

buffer systems

convert strong acids/bases into weak acids/bases

buffers

chemical compounds that can convert strong acids or bases into weak ones, remove or add H+

carbonic acid bicarbonate system

carbonic acid (H2CO3) acts as a weak acid, bicarbonate (HCO3-) can act as a weak base. this buffer system can compensate for excess or shortage of H+

carbon skeleton

chain of carbon atoms in an organic molecule

hydrocarbon

carbon bonded to hydrogens

functional groups

other atoms or molecules bound to the hydrocarbon skeleton

macromolecules

large molecules, usually polymers, formed by covalent bonding of many identical/similar small molecules called monomers

dehydration synthesis

hydrogen atom is removed from one monomer and hydroxyl group is removed from another to form a molecule of water

pH of blood

7.35-7.45

isomers

same molecular formula but different structures

ex. glucose and fructose are both C6H12O6

carbohydrates

sugars, glycogen, starches, cellulose; provide most of the energy needed for life

monosaccharides

simple sugars with 3-7 carbon atoms

disaccharides

simple sugars formed from the combination of two monosaccharides by dehydration synthesis

sucrose) glucose + fructose

lactose ) glucose + galactose

maltose) glucose + glucose

polysaccharides

tens of hundreds of monosaccharides joined by dehydration synthesis

ex) glycogen (stored carbs in animals)

starch (stored carbs in plants/main carb in food)

cellulose (cell wall in plants)