Exam 1 Flashcards
scientific method
observation, question, hypothesis, prediction, experiment, conclusion.
hypothesis
a testable explanation that has not yet been proven true. hypothesis is either supported or not, NOT proven.
biology
the study of life.
variables
conditions or factors subject to change in an experiment.
dependent variable
variable that changes in response to the experiment.
independent variable
“variable I change”. variables we modify at the start of the experiment.
control group
receives no change (NO MANIPULATION) in any variable. this is used as a baseline to compare to the treatment group.
treatment group
receives a change (MANIPULATION) in one variable, but all others remain the same.
8 characteristics of life
assimilate energy
respond to the environment
maintain a relatively constant internal environment
reproduce
possess an inherited information base, encoded in DNA
are composed of one or more cells
are evolved from other living things
are highly organized compared to inanimate objects.
hierarchical organization of life
Atom → Molecule → Cell → Tissues → Organs → Organ systems → Organism → Population → Community → Ecosystem → Biomes → Biosphere
atom
the smallest unit of an element that retains the element’s distinctive properties. the building blocks of all matter.
proton
a positively charged particle found in the nucleus of an atom.
neutron
an electrically neutral particle found in the nucleus of an atom.
electron
a negatively charged particle found in the nucleus of an atom.
atomic number
the number of protons in an atom’s nucleus.
element
any substance that cannot be reduced to simpler substances through chemical means.
isotope
two or more forms of an element that have the same number of protons but a different number of neutrons.
electronegativity
the measure of an atom’s power to attract electrons.
ion
an atom that has lost or gained electrons and therefore is either negatively or positively charged.
solution
a homogenous mixture of two or more kinds of substances.
solute
the compound dissolved in solution.
solvent
the compound doing the dissolving.
acid
any substance that loses hydrogen ions in solution.
base
any substance that accepts hydrogen ions in solution.
polarity
the distribution of electrical charge over the atoms joined by the bond.
ionic bond
the chemical attraction between a negatively charged ion and a positively charged ion. (medium)
covalent bond
the sharing of electrons between two atoms. (strongest)
hydrogen bond
the weak electrical attraction between a hydrogen atom with a partial positive charge and a neighboring atom with a partial negative charge.
hydrophobic
“water-fearing”, nonpolar, do not have a charge and cannot mix with water.
hydrophilic
“water-loving”, polar, have a charge and can mix with water.
four main types of biological molecules
Proteins, Carbohydrates, Nucleic acids, Lipids