Bio Study Guide

4 more common elements in human body

CNOH

isotopes

same p+, different neutrons

atomic number

number of protons, determines chemical identity

mass number

protons + neutrons

atomic mass

average of all isotopes for an element based on relative abundance

valence electrons

in outermost shell, define chemical behavior, determine how many bonds an atom will establish

electronegativity

an atom’s tendency to attract electrons

covalent bond

atoms with incomplete valence shells share with other atoms to reach octet,

structure of water

tetrahedral, 104.5 degrees (105)

polar covalent bond

electrons shared unequally, EN: 0.4 to 1.8

nonpolar covalet bond

electrons shared equally, EN: less than 0.4

ionic bond

attraction between an anion and a cation

emergent properties

result from the arrangement and interaction of parts within a system

reductionism

reduction of complex systems to simpler components that are more manageable to study

system

combination of components that function together, constructs models for the dynamic behavior of whole biological systems

elements

matter in pure form, one type of atom present, cannot be broken down to other substances through chemical reactions

compounds

combinations of different elements, two or more elements in a fixed ratio

chemical reactions

make and break chemical bonds

atom

smallest unit of matter that still retains the properties of an element

energy

the capacity to cause change

potential energy

energy matter has because of its location or structure

electron shell

atom’s state of potential energy

bonding capacity

atom’s valence

hydrogen bond

hydrogen atom covalently bonded to one electronegative atom is alsoattracted to another electronegative atom, usually oxygen or nitrogen

van der waals

weak chemical interactions as a result of charge hot spots when electrons are distributed asymmetrically

water

unique to earth, covers ¾ surface, 60-70% wt of the living world, regenerates and is redistributed through water cycle, essential to life

liquid

fragile, disorganized hydrogen bonds, last few trillionths of a second, constantly reforming

solid

organized hydrogen bonds, four neighbors in 3d space, crystal is more spacious than liquid, ice floats

gas

single molecules liberated from others by the addition of energy

cohesion

hydrogen bonds hold water molecules together, helps the transport of water against gravity in plants

adhesion

attraction between different substances

surface tension

how hard it is to break the surface of a liquid

1 cal

4.184 J

specific heat

amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by 1 degree C

when hydrogen bonds break

heat is absorbed

when hydrogen bonds form

heat is released

evaporative cooling

as a liquid evaporates, its remaining surface cools

heat of vaporization

heat a liquid must absorb for 1g to be converted to gas

water reaches its greatest density at

4 C

hydration shell

when an ionic compound is dissolved in water, each ion is surrounded by this

colloid

stable suspension of fine particles in a liquid

1 mole

6.02 × 10²³ molecules

molarity

moles of solute/ liter of solution

water’s dynamic equillibrium

water molecules dissociate at the same rate which they are being reformed

acid

increase hydrogen ion concentration

base

reduce hydrogen ion concentration by accepting an H or providing an OH

buffer

internal ph must remain close to 7, minimize concentration changes

organic molecules

contain carbon

carbon

enters the biosphere through plants

tetravalence

carbon’s ability to form 4 bonds, makes it so versatile

single carbon bond

can rotate about the plane of single bond, tetrahedral geometry, 109.5 degrees

double carbon bond

trigonal planar geometry, 120 degrees

triple carbon bond

linear, 180

hydrocarbons

organic molecules consisting only of carbon and hydrogen

isomers

same molecular formula but different structures and properties

structural isomer

different covalent arrangement of atoms

stereoisomer

different arrangement in space

cis- same side

trans- opposite side

genome

complete set of genetic material present in an organism

enantiomer

mirror images of each other

carbohydrates

source of energy

monosaccharides

single sugars, monomer of carbohydrates, molecular formulas usually multiples of CH2O, fuel for cells and raw material for building molecules

aldose

carbonyl group on end

ketose

carbonyl group in middle

disaccharide

dehydration reaction joins two monosaccharides

glycosidic linkage

joins monosaccharides

polysaccharides

polymers of sugars, energy storage, structural

starch

storage polysaccharide of plants, consists entirely of glucose monomers, surplus is stored as granules within chloroplasts and other plastids, unbranched

glycogen

more branched, storage polysaccharide in animals, stored mainly in liver and muscle cells

cellulose

major component of the tough wall of plant cells, differences in ring forms for glucose, passes through the digestive tract as insoluble fiber

alpha glucose

helical, oh on same side

beta glucose

straight, oh on opposte side

chitin

exoskeleton of arthropods, structural support for the cell walls of many fungi

lipids

mix poorly with water, some polar parts but generally hydrocarbons

fats

constructed from glycerol and fatty acids, major function is energy storage

fatty acid- carboxyl group attached to a long carbon skeleton

glycerol- three carbon alcohol with a hydroxyl group attached to a long carbon skeleton

triglyceride

three fatty acids joined to glycerol by an ester linkage

saturated fatty acids

maximum hydrogen bonds and no double bonds, solids at room temperatire, animal fats

unsaturated fatty acids

one or more double bonds, liquids at room temperature, plant and fish fats

hydrogenation

adding hydrogen to create saturated compounds, extends shelf life

phospholipids

two fatty acids and a phosphate group attached to glycerol, amphipathic molecule (polar head group and non polar fatty acid tail)

hydrophobic tail

two fatty acids

hydrophillic head

phosphate group and its attachments

bilayer

hydrophobic tails point towards interior, cell membranes

steroids

lipids characterized by a carbon skeleton consisting of four fused rings, signal gene expression

cholesterol

buffer in animal cell membranes to regulate fluidity, synthesized in liver

amino acids

organic molecules with carboxyl and amino groups, differ in properties due to differing side chains

enzymes

act as a catalyst to speed up chemical reactions

r groups

non polar: equal distribution of electrons

polar: unequal distribution of electrons

charged: acidic of basic

polypeptide

amino acids linked by peptide bonds

primary structure

unique sequence of amino acids, determined by inherited genetic information

secondary structure

coils and folds in the polypeptide chain resulting from hydrogen binds between repeating constituents of the polypeptide backbone, aplhpa helix or beta pleated sheet

nonpolar side chains

C-H only, C-S-C, C-N-C

polar side chains

O-H, N-H, S-H

tertiary structure

interactions between R groups, creates 3D structure

quaternary structure

polypeptide chains come together to form macromolecule

collagen

fibrous protein consisting of three polypeptides coiled like a rope

disulfide bridge

may reinforce protein’s structure (tertiary)

denaturation

loss of a protein’s native structure, biologically inactive

chaperonin

protein molecules that assist the proper folding of other proteins

nucleic acids

store and transmit hereditary information

gene

unit of inheritance, programs amino acid sequence