Bio 1 Lec, Spring 08

784 terms by mradigan

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cell

organism's basic units of structure and function

cell theory

fundamental unit; all calls come from preexisting cells; contain hereditary information which is passed from cell to cell during cell division; All known living things are made up of cells

prokaryotic cells

lack membrane-bound organelles; lack a nucleus; contain DNA, butplasma membrane present not in a separate compartment); smaller than eukaryotic; almost always have tough external wall; single-celled organisms (Archaea and Bacteria);

eukaryotic cells

have membrane-bound organelles; have membrane-bound nucleus (with DNA inside); larger than prokaryotic; some have a tough outer wall (plants); single and multicellular (animals, plants, fungi, protists); plasma membrane present

taxonomic scheme

kingdom, phylum, class, order, family, genus, species

three domains

Bacteria (prokaryotic cells); Archaea (prokaryotic cells); Eukarya (eukaryotic cells)

bacteria

single-celled organisms; diverse and widespread; less extreme environments

archaea

single-celled organisms; extreme environments (salty lakes, hot springs)

eukarya

single- and multi-celled organisms

hierarchy of organization (micro)

(in order) atoms, complex biological molecules (macromolecules), subcellular organelles, cells, tissues, organs, organ systems, complex organism

hierarchy of organization (macro)

(in order) population, community, ecosystem, biome, biosphere

properties & processes associated with life

order, reproduction-biogenesis, energy utilization (processing), growth and development, response to environment, homeostasis, evolutionary adaptations

cells (history)

1665 Robert Hooke named them; 1600's Antonie van Leeuwenhok first saw a live cell; 1839 Matthias Schleiden & Theodor Schwann came up with the cell theory

cytoplasm

The entire contents of the cell, exclusive of the nucleus, and bounded by the plasma membrane.

nucleus

the chromosome-containing organelle of a eukaryotic cell

organelle

Structure inside eukaryotic cells that performs specialized functions.

eukaryotic kingdoms

plantae; animalia: fungi; protists

plante

part of (1 of 4) the eukaryotic kingdom, multicellular, phtosynthetic autotrophs

animalia

part of (2 of 4) the eukaryotic kingdom, multicellular, ingest other organisms

fungi

part of (3 of 4) the eukaryotic kingdom, decomposers, absorb nutrients after breaking them down

protists (multiple kingdoms)

unicellular and simple multicellular

what links all forms of life (similarities)?

universal genetic code, similarity in cell structure, glycolysis is a widespread metabolic pathway, regulatory mechanisms, evolution

glycolysis

The splitting of glucose into pyruvate. This is the one metabolic pathway that occurs in all living cells, serving as the starting point for fermentation or aerobic respiration.

homeostasis

the ability to maintain a relatively constant internal environment in the presence of a changing external environment (steady-state physiological condition of the body). uses negative and positive feedback

matter

anything that takes up space and has mass; organisms are composed of matter

atoms

the smallest component of an element that still has properties of the element, consisting of a positively charged nucleus surrounded by a charged cloud of electrons.

96% and 4% of living matter are made of these elements

C, O, H, N and P, S, Ca, K, Na, Cl, Mg

isotope

atoms with the same number of protons and electrons, but different numbers of neutrons

ion

atom or molecule that has a change due to gain or loss of an electron

element

matter composed of atoms that all have the same atomic number (protons)

compound

substance consisting of 2 or more elements in a fixed ratio (does not necessarily have the same traits as its elements)

valence

indicates how many electrons an atom is missing from its outermost shell (2 for first ring, 8 for all rings after that). Indicates the number of bonds an atom is likely to form

energy

capacity to cause change

potential energy

energy mater has because of its location or structure (electrons of an atom differ in their amounts of potential energy)

energy level (electron shell)

an electron's state of potential energy

What is the chemical behavior of an atom determined by?

the distribution of electrons in the levels/shells (by the valence) (elements with full outer shells are chemically inert)

what is the valence of oxygen (atomic #8)?

-2

what is the valence of carbon (atomic #6)?

-4

orbital

three-dimensional space where electrons are found 90% of the time (each electron shell (level) has a specific number of orbitals (2 and 8))

electronegativity

an atom's attraction for the electron in a bond; the more electronegative an atom, the more strongly it pulls shared electrons toward itself

covalent bonds

sharing of outermost electrons between atoms, very strong; nonpolar covalent bond and polar covalent bond

nonpolar covalent bond

electrons equally distributed between atoms of molecule; not water soluble (hydrophobic); most common in biological matter

polar covalent bond

electrons pulled toward more electronegative atom of molecule; water soluble (hydrophilic)

Ionic bonds

one atom strips electrons from bonding partner; compound held together by attraction between cation & anion; weaker than covalent bonds

cation

ion with a po, positively charged ion (lost electrons)

anion

negatively charged ion (gained electrons)

hydrogen bond

weak attraction between a slightly positive H and another slightly negative atom (usually O or N). results in many properties of water

hot spots

electrons distributed asymmetrically in molecules or atoms

van der Waals interactions

attractions as a result of hot spots between molecules that are close together

proton

particle in the nucleus with a positive charge of +1 and an atomic mass number of 1 Dalton.

neutron

a non-charged nuclear particle with the same mass as the proton

electron

negatively charged particle (-1) with a mass 1/1837 of that of a proton

list bond strength from highest to lowest

nonpolar covalent bonds; polar covalent bonds; ionic bond; hydrogen bond; van der Waals interactions

strongest bonds in organisms

covalent bonds, form cell's molecules

what do the weak chemical bonds do?

reinforce shapes of large molecules and help molecules adhere to each other

charged molecules, what kind of bonds?

ionic or polar covalent (water, salt)

uncharged molecules, what kind of bonds?

nonpolar covalent (oils)

molecular shape

biological molecules reconize and interet with each other based on molecular shape; similar shapes, similar functions; change the shape, change the function

reaction (rxn)

makinga nd breaking chemical bonds, leads to changes in composition of matter

chemical equilibrium

point at which there is no net change of concentrations of reactants and products

water facts

3/4 of planet; organisms are 70-95% water; could be prerec for life

water characteristics

cohesive behavior; ability to moderate temp; expansion upon freezing; versatile solvent

cohesion

clinging together of molecules of same substance

adhesion

clinging together of molecules of different substances

surface tension

measure of how difficult to stretch/break surface of liquid

kinetic energy

energy of motion

heat

measure of total amount of kinetic energy due to molecular motion

temperature

measures intensity of heat due to average kinetic energy of molecules

calorie (cal)

amount of heat required to raise temp of 1g of water by 1C

kcal

kilocalories (1,000cal); what you see on food packages

joule (J)

unit of energy where 1J = 0.239 cal; 1 cal = 4.184 J

specific heat

amount of heat that ust be absorbed or lost for 1g of substance to change temp by 1 degree C

water's specific heat

1 cal/g/degree C; (very high, water is resistant to temp change)

why is water's specific heat high?

breaking H bonds in water requires energy before you even get the actual molecules to move faster (to heat up)

implications of water's specific heat

moderates coastal temp; stabilizes earth temp; organisms can maintain stable temp

evaporative cooling

hottest molecule in liquid is most likely to leave, so temp decreases

properties of ice

floats in liquid water because H bonds in ice are more ordered; water reaches greatest density @4C

ice implications

if ice sank, no life in the oceans because lakes/ocean would not thaw out

solution

a solute dissolved in a solvent (ex: salt water = salt (solute) in water (solvent)

mole

Avogadro's number (6.023 * 10^23) of molecules

1 molar solution

1 mole of molecules dissolved in solvent to make 1L total solution

water's solvent properties

polar molecule; small; can deal with cations and anions; can also dissolve other polar molecules

hydration shell/sphere

when ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules

hyrophillic

water-loving (ionic, polar molecules)

hydrophobic

water-fearing (oily molecules)

acid

solution with H+ higher than water (ex: vinegar). release H+

base

solution with H+ lower than water (ex: bleach); soak-up H+

pH

=log 1/H+

key to an atom's chemical characteristics

electron configuration, which determines the kinds and number of bonds an atom will form

tetravalence

having 4 valence electrons

3D shape of carbon atom with 4 single covalent bonds

the bonds angle toward the corners of an imaginary tetrahedron (~109.5 degrees)

3D shape of molecule with two carbon atoms that are joined by a double bond

flat (all bonds are on the same plane)

carbon's most frequent partners

oxygen, hydrogen and nitrogen

four major atomic components of organic molecules

carbon, oxygen, hydrogen and nitrogen

hydrocarbons

organic molecules consisting of only carbon and hydrogen; hydrophobic; can undergo reactions that release a large amount of energy

adipose cells

fat cells: long hydrocarbon tails attached to a nonhydrocarbon component

isomers

compounds that have the same numbers of atoms of the same elements but different structures and hence different properties (three types: structural isomers, geometric isomers, enantiomers)

structural isomers

differ in the covalent arrangements of their atoms

geometric isomers

have the same covalent partnerships, but they differ in their spatial arrangements (cis isomer and trans isomer)

geometric isomers arise from what?

the inflexibility of double bonds

enantiomers

isomers that are mirror images of each other; biological enzymes act on only 1 enantiomer

asymmetric carbon

a carbon atom that is attached to four different atoms or groups of atoms

steroid

organic molecules with a common carbon skeleton in the form of 4 fused rings

functional groups

characteristic groups often attached to skeletons of organic molecules, determine chemical properties; most commonly involved in chemical rxns

The functional groups most important in the chemistry of life

hydroxyl; carbonyl; carboxyl; amino; sulfhydryl; phosphate; methyl (not as important)

hydroxyl group

structure = -OH; compound = alcohols; ex: ethanol; functional properties: polar, can form hydrogen bonds with water, helping dissolve organic compounds such as sugars

carbonyl group

structure: >CO; compound: ketones (within a carbon skeleton) and aldehydes (at the end of the carbon skeleton); ex: acetone (ketone) and propanal (aldehyde); a ketone and an aldehyde may be structural isomers with different properties, also found in sugars, giving rise o two major groups of sugars: aldoses and ketoses

carboxyl group

structure: -COOH; compound: carboxylic acids; ex: acetic acid; properties: acidic,found in cells in the ionized (-1) form

amino group

structure-NH2; name of compound: amines; ex: glycine; properties: basic, ionized (+1) under cellular conditions

sulfhydryl group

structure: -SH; compound: thiols; ex: cysteine; properties: two sulfhydryl groups can react, forming a covalent bond, which helps stabilize protein structure. cross=linking of cysteines in hair proteins maintains the curliness or straightness of hair

phosphate group

structure: -OPO3(-2); compound: organic phosphates; ex: glycerol phosphate; properties: contributes negative charge to the molecule of which it is a part, has the potential to react with water, releasing energy

methyl group

structure: CH3; compound: methylated compounds; ex: 5-methyl cytidine; properties: addition of a methyl group to DNA affects expression of genes, arrangement of methyl groups in male and femal sex hormones affects their shape and function

adenosine triphosphate (ATP)

one of the three phosphates may be split off as a result of a reaction in water, releasing energy

macromolecule

a giant molecule formed by the joining of smaller molecules, usually by a condensation reaction (a covalent connection)

polymer

long molecule consisting of many similar or identical building blocks linked by covalent bonds

monomers

repeating units that serve as the building blocks of a polymer

condensation synthesis

a reaction in which 2 monomers are combined covalently through the removal of a small molecule (when the small molecule is water, it is called dehydration reaction)

enzymes

specialized macromolecules that speed up chemical reactions in cells

hydrolysis

disassembles polymers into monomers, a reverse of the dehydration reaction

four main classes of large biological molecules? What are their monomer forms?

carbohydrates (sugar), lipids (fatty acids), proteins (amino acids), nucleic acids (nucleotides);

carbohydrate

general form = CH2O; names end in "ose"; water soluble, form rings in water; taste sweet; often pentoses or hexoses (5,6 carbons)

monosaccharides

the simplest carbohydrate. known as simple sugars, monosaccharides have molecular formulas that are generally some multiple of CH2O; classified by location of carbonyl group and # of carbons in carbon skeleton

disaccharide

2 monosaccharides strung together

monosaccharide examples

glucose; fructose; galactose

disaccharide examples

sucrose (glucose + fructose); lactose (glucose + galactose); maltose (glucose + glucose)

when do sugars often form into rings?

in aqueous solutions

polysaccharide

polymer of more than 2 monosaccharides; important in metabolism; sometimes used for cell I.D.; store energy; structure/function determined by monomers & locations of bonds between monomers

starch (amylose) & glycogen

polysaccharides of thousands of glucoses; store energy; allows organisms to store thousands of glucoses in 1 polysaccharide molecule. The glycogen breaks down glucose in the digestive tract, and is synthesized from glucose in the liver

what do plants use for energy storage?

starch

what do animals use for energy storage

glycogen

cellulose

a polymer of glucose; a major component of the tough wall of plant cells

∝ glucose

are helical; form starch

ß glucose

are straight; form cellulose; H atoms on one strand can bond with OH groups on other strands. parallel cellulose molecules held together this way are grouped into microfibrils, which form strong building materials for plants

why does cellulose in human food passes through the digestive tract as insoluble fiber?

enzymes that digest starch by hydrolyzing ∝ linkages can't hydrolyze ß linkages in cellulose

why can many herbivores, from cows to termites, digest cellulose (∝ glucose)?

have symbiotic relationships with microbes that use enzymes to digest cellulose

chitin (pronounced "kite-en")

a structural polysaccharide; found in the exoskeleton of arthropods; provides structural support for the cell walls of many fungi; used to make surgical thread; Like cellulose, but with nitrogen

lipids

only class of large biological molecules that do not form polymers; hydraphobic (consist mostly of hydrocarbons, which form nonpolar bonds); some are 'polymers' of fatty acid

important lipids

fats; phospholipids; steroids

triglycerides

composed of glycerol and fatty acids; OH from glycerol and H from fatty acid break off in a dehydration reaction

saturated fats

no C=C double bonds; have max # of hydrogen atoms; animal fats; solid at room temp

unsaturated fats

one or more C=C double bonds; vegetable fats; fish fats; liquid at room temp

fats related to diet

saturated fats contribute to cardiovascular disease through plaque deposits; trans fats (hydrogenated unsaturated fats) may be even more unheathly

hydrogenation

process of converting unsaturated fats to saturated fats by adding hydrogen

trans fats

partially hydrogenated oils (margarine, crisco); solid at room temp; found in almost all processed food (cis = H on same side of C=C bond; trans = opposite sides)

fat's function

energy storage (stored in adipose cells); adipose tissue also cushions vital organs and insulates the body

phospholipids

two fats and a phosphate group attached to glycerol; fat tail = hydrorphobic. phosphate group & its attachments = hydrophilic; examples: membranes, soaps; when added to water, self-assemble into micelles, liposomes, bilayers; major component of all cell membranes

micelles

polar heads interact with water; nonpolar tails 'hide' inside (looks like little balls with the tails inside)

steroids

lipids characterized by a carbon skeleton consisting of four fused frings

cholesterol

an important steroid, component in animal cell membranes; acts as a precursor molecule for the synthesis of other biologically important steroids, such as hormones

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