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Key Terms Perry Biology Unit 1

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Biology
the study of life
organization
the high degree of order within an organism's internal and external parts and in its interactions with the living world
cell
the smallest unit that can perform all life's processes
unicellular
organisms made up of only one cell
multicellular
organisms made up of more than one cell
organs
structures that carry out specialized jobs within an organ system
tissues
groups of cells that have similar abilities and that allow the organ to function
organelles
tiny structures that carry out functions necessary for the cell to stay alive
biological molecules
the chemical compounds that provide physical structure and that bring about movement, energy use, and other cellular functions
homeostasis
the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing
metabolism
the sum of all the chemical reactions that take in and transform energy and materials from the environment
division
the formation of two new cells from an existing cell
development
the process by which an organism becomes a mature adult
reproduction
the process by which organisms produce new organisms like themselves
gene
a short segment of DNA that contains the instructions for a single trait of an organism
domains
three major subdivisions of all organisms. (bacteria, archaea, eukarya)
kingdoms
six major categories that divide all life. ( Animalia, Plantae, Fungi, Protista, Archaea, bacteria
)
ecology
the branch of biology that studies organisms interacting with each other and with the environment
ecosystems
communities of living species and their physical environments
natural selection
the process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do; a theory to explain the mechanism of evolution
adaptations
traits that improve an individual's ability to survive and reproduce
scientific method
the series of steps followed to solve problems, including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions
observation
the act of perceiving a natural occurrence that causes someone to pose a question
hypothesis
a proposed explanation for the way a particular aspect of the natural world functions
prediction
a statement that forecasts what would happen in a test situation if the hypothesis were true
experiment
used to test a hypothesis and its predictions
control group
provides a normal standard against which the biologist can compare results of the experimental group
experimental group
identical to the control group except for one factor, the independent variable
independent variable
the variable that is manipulated or changed
dependent variable
the variable that is affected by the independent variable
theory
when a set of related hypotheses is confirmed to be true many times, and it can explain a great amount of data, it is called a
peer review
when scientists who are experts in the field anonymously read and critique a research paper
compound light microscope
a microscope that shines light through a specimen and has two lenses to magnify an image
eyepiece (ocular lens)
magnifies the image, usually 10 times
objective lens
enlarges the image of the specimen
stage
a platform that supports a slide holding the specimen
light source
a light bulb that provides light for viewing the image
magnification
the increase of an object's apparent size
nosepiece
the structure that holds the set of objective lens
resolution
the power to show details clearly in an image
scanning electron microscope (SEM)
passes a beam of electrons over the specimen's surface; three-dimensional images
transmission electron microscope (TEM)
transmits a beam of electrons through a very thinly sliced specimen; magnetic lenses
metric system
standard system of measurement based on powers of 10
base units
describe length, mass, time, and other quantities
matter
anything that occupies space and has mass
mass
the quantity of matter an object has
elements
substances that cannot be broken down chemically into simpler kinds of matter
atom
simplest particle of an element that retains all of the properties of that element
nucleus
central region of an atom
proton
a subatomic particle that has a positive charge that is located in the nucleus of an atom
atomic number
the number of protons in an atom
mass number
the total number of protons and neutrons in an atom
electron
small, negatively charged particles
orbital
a three-dimensional region around a nucleus that indicates the probable location of an electron
isotopes
atoms of the same element that have different numbers of neutrons
compounds
a substance that contains two or more elements chemically combined in a fixed proportion
chemical bonds
the attractive forces that hold atoms together
covalent bond
forms when two atoms share one or more pairs of elections
molecule
the simplest part of a substance that retains all of the properties of that substance and can exist in a free state
ion
an atom or molecule with and electrical charge
ionic bond
the attractive force between oppositely charged ions, which form when electrons are transferred from one atom to another
energy
the ability to do work
chemical reaction
a process in which one or more substances are changed to form one or more different substances
reactants
a chemical substance that is present at the start of a chemical reaction
products
the elements or compounds produced by a chemical reaction
metabolism
all the chemical reactions that occur in an organism
activation energy
the minimum amount of energy required to start a chemical reaction
catalysts
reduce the amount of activation energy that is needed for a reaction to take place
enzyme
a protein or RNA molecule that speeds up metabolic reactions without being permanently changed or destroyed
redox reaction
A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction.
oxidation reaction
when a reactant loses one or more electrons, thus becoming more positive in charge
reduction reaction
when a reactant gains one or more electrons, thus becoming more negative in charge
polar
an uneven distribution of charge
hydrogen bond
the force of attraction between a hydrogen molecule with a partial positive charge between a hydrogen molecule and another atom or molecule with a partial or full negative charge
cohesion
the attractive force that holds together the molecules in a solid or liquid
adhesion
the attractive force between two particles of different substances
capillarity
the attraction between molecules that results in the rise of the surface of a liquid when in contact with a solid
solution
a homogeneous mixture of two or more substances
solute
substance that is dissolved in a solvent
solvent
a liquid substance capable of dissolving other substances
concentration
a measure of the amount of solute dissolved in a fixed amount of the solution
saturated solution
a solution that cannot dissolve any more solute
aqueous solutions
Solutions in which water is the solvent
hydroxide ion
negatively charged ion made of oxygen and hydrogen (OH-)
hydronium ion
H3O+ ion
acid
any compound that increases the number of hydronium ions when dissolved in water
base
Any compound that increases the number of hydroxide ions when dissolved in water
pH scale
a range of values that are used to express the acidity or alkalinity of a substance
buffer
chemical substances that neutralize small amounts of either an acid or a base added to a solution
organic compounds
any compound containing carbon
functional groups
clusters of atoms
monomer
small unit that can join together with other small units to form polymers
polymer
a naturally occurring or synthetic compound consisting of large molecules made up of a linked series of repeated simple monomers
macromolecules
large polymers
condensation reaction
monomers link to form polymers through a chemical reaction
hydrolysis
when water is used to break down a polymer
adenosine triphosphate (ATP)
a nucleotide derived from adenosine that occurs in muscle tissue
carbohydrates
Organic compounds made of carbon, hydrogen, and oxygen atoms in the proportion of 1:2:1.
monosaccharide
a monomer of a carbohydrate
dissacharide
A molecule made of two monosaccharides.
proteins
Organic compounds composed mainly of carbon, hydrogen, oxygen, and nitrogen.
amino acids
Simple forms of protein normally used to build tissues or, under some conditions, burned for energy
peptide bond
covalent bond formed between amino acids
polypeptides
a peptide containing 10 to more than 100 amino acids
enzymes
RNA or protein molecules that act as biological catalysts
substrate
the reactant being catalyzed
active site
the part of an enzyme or antibody where the chemical reaction occurs
lipids
large, nonpolar orgainic molecules
fatty acids
unbranched carbon chains that make up most lipids
phospholipids
Have two, rather than three, fatty acids attached to a molecule of glycerol
wax
a type of structural lipid consisting of a long fatty-acid chain joined to a long alcohol chain
steriod
A lipid that is composed of 4 fused carbon rings, commonly found in cell membranes.
nucleic acids
very large and complex organic molecules that store and transfer important information in the cell
deoxyribonucleic acid (DNA)
Contains information that determines the characteristics of an organism and directs its cell activities.
ribonucleic acid (RNA)
stores and transfers information from DNA that is essential for manufacturing of proteins
nucleotide
made of a phosphate group, a five-carbon sugar,and a ring-shaped nitrogenous bade