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osmosis
diffusion of water across membrane; always moves from where there is LESS solute to MORE solute
isotonic
if the amount of solute surrounding the cell is the same as amount inside the cell
hypertonic
the amount of solute in the liquid surrounding the cell is greater than the amount of solute inside the cell
hypotonic
the amount of solute in the liquid surrounding the cell is less than the amount of solute inside the cell
turgor
swelling of cells against the cell wall; helps keep plants upright
osmoregulation
balancing water and solute concentration to prevent cells from bursting; animal cells
solvent
water is the universal__________.
solutes
anything that is dissolved
osmosis
movement of water
diffusion
movement of the SOLUTE from an area of higher concentration to lower concentration
passive transport
diffusion of a molecule (solute) across a membrane
concentration gradient
substance move from where there is more solute to where there is less
facilitated diffusion
helps the movement of larger molecules across a membrane with the help of transport proteins; does not require energy; goes from higher solute concentration to lower solute concentration
active transport
requires energy; movement of molecules across a membrane from an area of lower solute concentration to an area of higher solute concentration
cytoplasm
everything in a cell, except for the contents of the nucleus
cytosol
everything inside the cytoplasm that is not inside any organelles
nucleus
the organelle in eukaryotes that contains the DNA that is packaged as chromatin
chromatin
DNA wound around proteins
nuclear envelope
separated from the rest of the cell by a double membrane; contains nuclear pores that allow movement of molecules in and out
nucleolus
where ribosomes are made
endomembrane system
system of organelles in eukaroytic cells where proteins and lipids are made and transported throughout the cell
endoplasmic reticulum
connected to the nuclear envelope, where proteins and lipids are made
rough ER
covered in ribosomes, proteins and membranes are made
smooth ER
no ribosomes, makes steroids, and detox enzymes
Golgi apparatus
series of stacked membrane discs that package proteins and prepare them for transport
vesicles
connected to the ER; small membrane-bound sacs that carry items around the cell
lysosomes
membrane-bound sacs that contain digestive enzymes; found in animal cells
vacuoles
large sacs of membrane that function as storage for nutrients, water, etc.
cytoskeleton
protein fibers that extend throughout the cytoplasm, anchored at the plasma membrane and throughout the cell
mitochondria
organelle responsible for important energy-conversion reactions in eukaryotes
chloroplast
plant and algae specific organelle that is the site of photosynthesis
endosymbiotic theory
chloroplasts and mitochondria evolved from bacteria that were engulfed by larger bacteria; size is comparable to prokaryotes; each have two membranes
energy
the capacity to cause change; ability to work
conservation of energy
principle that energy cannot be created or destroyed, but is transformed from one form to another
kinetic energy
energy of motion or movement
potential energy
energy on an object because of the location or structure
heat energy
kinetic energy generated by the range of movements of atoms
chemical energy
potential energy stored in the bonds of biological molecules that can be released by chemical reactions
heat
All energy conversions generate some _________.
entropy
measure of the amount of disorder, or randomness of a system
calorie
the unit of energy in food
enzymes
proteins that speed up chemical reactions without being consumed by the reaction
activation energy
the energy that must be invested to start a reaction
substrate
any molecule to which an enzyme binds and acts on
active site
the part of an enzyme that binds to substrates
cellular respiration
aerobic harvesting of chemical energy from organic molecules
aerobic
requires oxygen
NADH
molecule that transfers electrons from one part of a cell to another
glycolysis
1 molecule of glucose is split into 2 molecules of pyruvic acid
citric acid cycle
final breakdown of pyruvic acid into CO2 occurs; pyruvic acid is converted to acetyl CoA
electron transport chain
electrons are transferred from NADH and FADH2 to a series of proteins
fermentation
occurs when there is not enough oxygen
anaerobic process
occurs without oxygen
photosynthesis
stomata
pores in leaves that allow for the exchange of CO2 and O2
stroma
inner compartment of chloroplast
thylakoids
small membrane sacs where chlorophyll, the pigment that is used to harvest solar energy, is found
wavelength
distance between peak-peak
electromagnetic spectrum
the range of radiation energy
photon
a unit of light energy
photosystems
clusters of pigment molecules
cell division
when a cell undergoes reproduction and two "daughter" cells are produced that are genetically identical
asexual reproduction
organisms that reproduce by making copies of themselves
sexual reproduction
requires fertilization of an egg and sperm
chromosomes
most of a cell's DNA is organized into structures called_____________
chromatin
chromosomes are made up of _____________
histones
DNA wrapped around proteins called _________
nucleosome
small sections of DNA wrap around a set of histones, forming something that looks like a bead
interphase
includes the stages of the cell cycle in which cells spend their time preparing for cell division; cells spend most of their time here
G1 phase
rapid cell growth and metabolism
S phase
DNA replication occurs
G2 phase
production of new organelles; cell prepares for division
sister chromatids
two copies of chromosomes
centromere
region of a chromosome where sister chromatids are joined
m phase (mitotic phase)
the part of the cell cycle when the cell is actually dividing
mitosis
the nucleus and its contents divide and are evenly distributed into two nuclei
cytokinesis
the cytoplasm along with the organelles is divided into two
interphase
chromosomes are relaxed; nuclear envelope is intact
prophase
chromosomes condense into "x"; nuclear envelope breaks down; mitotic spindle forms
mitotic spindle
structure made of microtubles that guides the separation of chromosomes
metaphase
spindle fibers that attach to the centromeres of the chromosomes; chromosomes line up at the center of the cell
anaphase
spindle fibers shorten, pulling sister chromatids apart to opposite sides of the cell
telophase
begins when the chromosomes reach the opposite sides of the cell; opposite of prophase; nuclear envelope reforms; chromosomes decondense; spindle fibers disapper
cytokinesis
begins during telophase; divides the cytoplasm
