Unit 1

Atom

smallest unit of element composed of electrons, protons, and neurons.

Molecule

union of two or more atoms.

Tissue

group of cells with common structure and function.

Organ

tissues functioning together for specific task

Organ system

several organs working together

Organism

complex individual contain organ systems

Species

group of similar, interbreeding organisms

Population

organisms of same species in particular area

Community

interacting populations in an area

Ecosystem

community plus physical environment

Biosphere

zone of air, land, and water where organisms exist.

Energy

is capacity to do work.

Metabolism

is all chemical reactions that occur in a cell.

Systematics

study of evolutionary relationships.

Steps in scientific method

observation, development of hypothesis, experimentation and data collection, forming conclusion

Standard error

How far off the average of the data is

Standard deviation

statistical analysis that measures how much the data can vary

Emerging diseases

new diseases from human activity

Metabolically diverse

Absorb, photosynthesize, or chemo synthesize food

Scientific method

standard series of steps used in gaining new knowledge through research

Matter

anything that has mass and occupies space; four states (solid, liquid, gas, plasma)

Element

substance that cannot be broken down without changing properties, one type of atom, 94 naturally occurring

CHNOPS

95% body weight of organisms

Atom

smallest part of element that display the property of element; contain protons, neutrons, and electrons

Isotopes

same element but differ in neutrons (different mass)

Low levels of radiation

allow researchers to trace the location and activity of the element in living tissues (tracers)

High levels of radiation

can destroy cells and cause cancer; careful use of radiation can sterilize products and kill cancer cells.

Bohr model

useful way to visualize electron location, 2 in first shell and 8 in all others

Valence shell

outermost energy shell of any atom; determines the chemical properties

Octet rule

states that the outermost shell is most stable when it has 8 electrons (full)

Bonds

interactions between electrons in outermost energy shells.

Compound

molecule containing at least two different element bonded together

Formula

tells number of each kind of atom in a molecule

Ionic bond

forms when electron are transferred; gained or lost; EX: salt

Ion

atom that has lost or gained an electron.

Covalent bond

two atoms share electrons so each atom has an octet; hydrogen atom sharing

Nonpolar covalent bond

electrons are shared equally; electrons don't have greater attraction to any degree

Polar covalent bond

shared unequally; affects how they interact with other molecules; EX: water

Electronegativity

ability of an atom to attract electrons towards itself in a chemical bond

Hydrogen bond

weak attraction between a slightly positive hydrogen atom and a slightly negative atom

Properties of water

high heat capacity, high heat of evaporation, solvent, cohesive and adhesive, ice is less dense

Solution

contains dissolved substances (solutes)

Hydrophilic

ionized or polar molecule attracted to water

Hydrophobic

nonionized or nonpolar molecule that cannot attract water

Cohesion

ability to cling to each other; flow freely

Adhesion

ability to cling to other polar surfaces; positive and negative poles

pH

measure of hydrogen ion concentration in solution

Acids

substances that dissociate in water, releasing hydrogen ions (high H+ concentration)

Bases

substances that either take up hydrogen ions or release hydroxide ions (low H+ concentration)

Buffer

chemical or combination of chemicals that keeps pH within normal limits

Organic molecules

contain both carbon and hydrogen atoms bonded to other atoms

Biomolecules

four types in organisms; carbohydrates, lipid, proteins, and nucleic acids

Skeleton/backbone

carbon chain of an organic molecule

Functional groups

clusters of specific atoms bonded to the carbon skeleton with characteristic structures and functions

Isomers

organic molecules with identical molecular formulas but different arrangements

Monomer

building blocks of polymers

Polymer

long chained molecule composed of monomers

Dehydration (synthesis) reaction

chemical reaction which subunits are joined together by the formation of a covalent bond and water is produced (taken away)

Hydrolysis reaction

chemical reaction in which a water molecule is added to break a covalent bond.

Enzymes

molecule that speeds up a chemical reaction.

Monosaccharide

ready energy; single sugar molecule, simple sugar, backbone of 3 to 7 carbon atoms

Hexose

6 carbons; glucose, fructose, and galactose (all isomers of one another)

Pentoses

5 carbons; ribose (RNA) and deoxyribose (DNA)

Disaccharide

contains two monosaccharides joined together during a dehydration reaction.

Disaccharides (ex)

maltose (2 glucose), Sucrose (glucose and fructose), Lactose (galactose and glucose)

Polysaccharides

energy-storage and structural; polymers of monosaccharides; not soluble in water and don't pass through membrane

Polysaccharides (ex energy)

starch (plants) and glycogen (animals)

Polysaccharides (ex structural)

cellulose (cell wall, forms microfibrils), chitin (exoskeleton of crabs), peptidoglycan (found in bacteria)

Lipids

hydrocarbons; insoluble in water; no polymers

Triglycerides

long-term energy storage; fats (animals) and oils (plants) contain glycerol and fatty acids joined by dehydration

Fatty acids

long hydrocarbon chain; 16 to 18 carbons

Saturated fatty acid

lack double bond between carbons; solid at room temp

Unsaturated fatty acids

contain double bonds in carbon chains; liquid at room temp

Glycerol

water soluble compound w/ 3 hydroxyl groups

Phospholipids

Membrane components; nonpolar tails face each other with polar heads face towards water

Steroids

four fused rings; cholesterol, testosterone

Waxes

long-chain fatty acids; waterproof, protective

Protein

polymers of amino acids linked together by peptide bonds; folded into specific shape

Protein functions

metabolism, support, transport, defense, regulation, motion

Metabolism

most enzymes are proteins that act as catalysts to accelerate chemical reactions within cells.

Keratin and collagen

supportive proteins (k- hair/nails, c- ligaments/skin)

Hemoglobin protein

transports oxygen to tissues and cells.

Defense

antibodies are proteins of out immune system that bind to antigens and prevent them from destroying cells.

Regulation

hormones are regulatory proteins that influence the metabolism of cells.

Myosin and actin

proteins that allow parts of cells to move

Amino acids

acidic group (-COOH) and amino group (-NH2); differ with R group; 20 different types

Peptide bond

is a covalent bond between amino acids.

Peptide

two or more amino acids bonded together

Polypeptide

long chains of many amino acids

Primary structure

linear sequence of amino acids, tons of different polypeptides can be built , changing the sequence can produce different proteins

Secondary

characterized by the presence of alpha helices and beta (pleated) sheets held in place with hydrogen bonds

Tertiary

overall 3D shape of a polypeptide, stabilized by presence of hydrophobic interactions, hydrogen, ionic, and covalent bonding

Quaternary

consists of more than one polypeptide

Denaturation

when a protein loses it proper shape

Nucleic acids

polymer of nucleotides, store info in cells

DNA (deoxyribonucleic acid)

genetic material that stores info for its own replication and the sequence of amino acids in proteins

RNA (ribonucleic acid)

wide range of functions within cells which include protein synthesis and regulation of gene expression; translation of genetic code

ATP

called the energy currency of the cell; used to supply energy for synthetic reactions

Coenzyme

molecules that facilitate enzymatic reactions

Nucleotides

molecular complex of phosphate, pentose sugar and nitrogen bas