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biology chap 1-4
bio
259
Biology
Undergraduate 4
03/02/2015

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Term
Archaea
Definition
simple cells without a nuclei (methanogen)
Term
protista
Definition
cell contain nucleus (multicellular algae)
Term
Fungi
Definition
contain non-photosynthetic organisms, multicellular usually. Digest food externally. (Mushroom)
Term
Plantae
Definition
photosynthetic multicellular organism primary terrestrial (Flowering plant)
Term
animalia
Definition
non-photosynthetic multicellular organism digest food internally (ram)
Term
six kingdoms of life
Definition
archaea, bacteria, protista, fungi, plantae, animalia
Term
5 basic properties of life
Definition
cellular organization, metabolism, homeostasis, growth +reproduction, heredity
Term
Cellular organisation
Definition
cell is a tiny compartment with a thin convering called the membrane. Humans have 10-100 trillion cells
Term
Metabolism
Definition
Use of energy. Transfer of energy from one form to another. photosynthesis + animals.
Term
homeostasis
Definition
Keeping stable internally from the environment. Keeping interior conditions relatively constant.
Term
Growth and Reproduction
Definition
Offspring, bacteria growth, increasing cell growth.
Term
Heredity
Definition
DNA, transmission of characteristics
Term
(organization of life) the 3 general levels of complexity
Definition
cellular level, organismal level, population level
Term
(organization of life) 13 hierarchical levels
Definition
atoms, molecules, macromolecules, organelles, cells, tissues, organs, organ systems, organism, population, species, community, ecosystem, emergent properties
Term
atoms
Definition
hydrogen, carbon, nitrogen
Term
molecules
Definition
atoms joined together into complex clusters (adenine)
Term
macromolecules
Definition
large complex molecules (DNA)
Term
organelles
Definition
complex biological molecules assembled into tiny compartments within cells (nucleus)
Term
cells
Definition
membrane bound units of organelles + other elements. Smallest level of organization that can be considered alive.
Term
tissues
Definition
most basic level (nerve tissue) composed of cells called neurons that carry electrical signals
Term
organs
Definition
tissues are a group of organs (brains) composed of nerve cells + tissues which protect as covering + distribute blood
Term
organ system
Definition
(nervous system) sensory organs, the brain + spinal cord, neurons that convery signals through body + supporting cells
Term
organism
Definition
organ system functions + forms organism
Term
population
Definition
most basic group of organism living in the same place (flock of geese) in a pond
Term
species
Definition
all populations of a certain kind (canadian geese)
Term
community
Definition
all populations of different species living in one area (in a pond: geese, ducks, fish, grasses, insects)
Term
ecosystem
Definition
highest tier. biological community + soil + water
Term
emergent properties
Definition
more complex functional properties such as metabolism
Term
evolution
Definition
change in species overtime
Term
charles darwin in 1859....
Definition
proposed natural selection
Term
natural selection
Definition
organisms that progress overtime, reproduce offspring
Term
artificial selection
Definition
selection of breeders to exhibit exaggerated characteristics
Term
flow of energy
Definition
all organisms need energy. sun is source. photosynthesis. sugars. food chain. tropic levels. key factor in shaping organisms
Term
cooperation
Definition
role of interaction between species
Term
symbiosis
Definition
organisms of 2 diff species live in direct contact that form a relationship ex: ant + plant
Term
structure determines function
Definition
adjustment in the environment from physical characteristics evolution suiting organisms to meet challenges of the living
Term
homeostasis
Definition
the act to maintain stable in an internal environment
Term
6 stages of scientific investigation
Definition
observation, hypothesis,predictions, testing, controls, conclusion
Term
predictions
Definition
an expected consequence if hypothesis is true
Term
testing
Definition
experiment (test of hypothesis)
Term
controls
Definition
variable, control experiment
Term
variable
Definition
each factor that might influence a process
Term
control experiment
Definition
no alter in variable but altered in the beginning to test hypothesis
Term
conclusion
Definition
hypothesis testing + not rejected + tentatively accepted. Theory.
Term
theory
Definition
collection of related hypothesis with many past tests + not rejected. higher degree of certainty.
Term
Robert Hooke in England 1665....
Definition
discovered cells using one of the first microscopes. magnified 30 times
Term
anton van laeuwenhoek....
Definition
used microscope magnified 300 times. discovered single celled life in a drop of pond water
Term
matthias schleiden german 1839 + Theodor Schwann
Definition
concluded that all living organisms consist of cells (cell theory)
Term
nucleotides
Definition
DNA formed from 2 long chains of building blocks A T C G
Term
gene theory
Definition
proteins in RNA molecules encoded by an organisms genes determine what it will be like
Term
A human cell has __ chromosomes
Definition
46
Term
Gregor Mendel + theory of hereditary
Definition
First advanced theory 1865. Genes of an organism are inherited as discrete units
Term
chromosomal theory of inheritance
Definition
genes of mendels theory are physically located on chromosomes because they are parceled out in a regular manner during reproduction
Term
mendelian segregation
Definition
regular duplication of these chromosomes during sexual reproduction responsible for pattern of inheritance
Term
Eukarya in the kingdom of life contains
Definition
protista, plantae, fungi, animalia
Term
Theory of evolution was advanced by
Definition
Charles Darwin 1859
Term
theory of evolution
Definition
diversity of the living world to natural selection. different life forms. offspring. genes.
Term
potential energy
Definition
energy of position in elections. opposite attraction - +. cells use to drive atoms for chemical reactions
Term
An atom is described by the number of
Definition
protons in its nucleus or overall mass of the atom
Term
Mass:
Definition
amount of substance
Term
Weight:
Definition
force gravity exerts on a substance
Term
Element:
Definition
any substance that cannot be broken down into any other substance by ordinary chemical means
Term
Mass Number:
Definition
Number of protons and neutrons in the nucleus of the atom
Term
Electrons determine the
Definition
chemical behavior of atoms
Term
Orbital
Definition
volume of space around a nucleus where an electron is most likely found
Term
electron shell
Definition
energy level of an atom. Specific number of orbitals
Term
ions
Definition
electrically charged atoms that number of electrons does not equal number of protons because it gained or lost one or more electrons
Term
cation:
Definition
loses an electron. unbalanced charge
Term
Anions
Definition
gains electron(s) negatively charged ions
Term
isotopes
Definition
atoms with same number of protons but different numbers of neutrons, same atomic number, different mass number
Term
most common isotope:
Definition
carbon
Term
radioactive decay
Definition
nucleus breaks up into particles with lower atomic numbers. used in dating fossils. medical procedures.
Term
chemical bond
Definition
energy or force holding 2 atoms together
Term
3 principal kinds of chemical bonds
Definition
ionic, covalent, hydrogen
Term
ionic bond
Definition
force is generated attraction of oppositely charged ions
Term
covalent bond
Definition
force results from sharing of electrions
Term
hydrogen bond
Definition
force is generated by sttraction of opposute partial electrical charges
Term
single covalent bond
Definition
only one pair of electrons is shared between 2 atoms
Term
double covalent bond
Definition
2 pairs of electrons shared strong bond
Term
triple covalent bond
Definition
3 pairs shared very strong
Term
Vander Waal forces
Definition
2 atoms are very close to one another. Attraction is very weak. Disappears if moved apart.
Term
cohesion
Definition
when the other polar molecules is another water molecule. created by surface tension of water
Term
surface tension
Definition
is the force that causes water to bead or supports the wight of an insect
Term
adhesion
Definition
other polar molecules is a different substance. is why things get wet.
Term
Hydrogen bond
Definition
water clings to any substance
Term
Waxy substances are...
Definition
non-polar which means does not get wet
Term
high polarity
Definition
water molecules in solution form. Maximum number of hydrogen bonds possible and gather around polar molecules or molecules with an electrical charge.
Term
hydration shell
Definition
water molecules orient around each ion, preventing ions from re-associating
Term
soluble
Definition
polar molecules that dissolve in water
Term
hydrophobic
Definition
non-polar molecules shy away in water, forced into association
Term
hydrophillic
Definition
(water loving) polar molecules
Term
ionization
Definition
covalent bond breaks. proton dissociates from molecule as positively charged ion. rest of molecule if negatively charged
Term
pH
Definition
way to express hydrogen ion concentration from solution
Term
pH scale
Definition
highest pH is 0 lowest is 7 ranges from 0 to 14
Term
acids
Definition
any substance that dissociates in water to increase the concentration of H+. pH values below 7
Term
bases
Definition
A substance that combines with H+ when dissolved in water. Alkaline solutions. Above 7 in the pH scale sodium hydroxide NaOH have pH value of 12 or more
Term
Buffers
Definition
pH in almost all living cells is a chemical substance. minimizes changes in concentrations of H+ and OH- by taking up or releasing hydrogen ions into solution.
Term
Organic molecules
Definition
formed by living organisms and consist of carbon based core with special groups attached large molecules found in food. Lipids, Fats, Cholesterol
Term
Functional groups
Definition
act as units during chemical reactions and confer specific chemical properties on the molecules that possess them
Term
body is made up of 4 kinds of organic molecules"
Definition
proteins, nucleic acids, carbohydrates, and lipids
Term
macromolecules
Definition
organic molecules... very large building material of cells
Term
monomers
Definition
macromolecules are assembled by sticking smaller bits in
Term
polymer
Definition
molecules built up of long chains of similar subunits
Term
dehydration synthesis
Definition
covalent bond formed between two subunits in which a hydroxyl group (OH) is from one subunit + a hydrogen (H) is removed from the other
Term
enzymes
Definition
taking away water
Term
hydrolysis
Definition
breaking up of a polymer. hydrogen bond becomes attached to one subunit and a hydroxyl to another which breaks covalent bond.
Term
proteins
Definition
complex macromolecules within the bodies of all organisms
Term
Most important type of protein
Definition
enzyme
Term
collagen
Definition
contains protein (cartilage, bones, tendons) other proteins can be messengers within brain to body
Term
structural protein (keratin)
Definition
forms hair, nails, feather, and components of horns
Term
structural protein (collagen)
Definition
bones, tendon cartilage
Term
contractile proteins
Definition
actin + myoscin in muscles
Term
transport proteins
Definition
red blood cells contain protein hemoglobin, transports oxygen in the body
Term
defensive proteins
Definition
white blood cells destroy foreign cells in the body and make antibody proteins that attack invaders
Term
amino acids
Definition
small molecules with simple basic structure (a central carbon atom attached to an amino group, carboxyl group, and hydrogen atom)
Term
R group
Definition
determines chemical properties of amino acids some are polar + some are nonpolar
Term
peptide bond
Definition
covalent bond linking 2 amino acids togethar
Term
polypeptides
Definition
long chains of amino acids linked by peptide bonds
Term
primary structure
Definition
the sequence of amino acids of a polypeptide chain
Term
secondary structure
Definition
hydrogen bonds forming between different part of the polypeptide chain stabalize the folding of the polypeptide
Term
tertiary structure
Definition
nonpolar polypeptide chain folds up in water. 3 dimensional shape. folded+twisted in the case of a globular molecule. Determined by exactly where in a polypeptide chain the nonpolar amino acids occur
Term
quaternary structure
Definition
protein is composed of more than one polypeptide chain
Term
denatured
Definition
unfolding protein from proteins environment changing by either increafsing temp or lswering the pH in which is altered hydrogen bonding
Term
Nucleic Acids
Definition
very long polymers that serve as the genetic information storage devices of cells
Term
3 parts of nucleotides
Definition
5 carbon sugar (in blue), phosphate group (in yellow), organic nitrogen containing base (in orange)
Term
polynucleotide chains
Definition
individual sugars with their attached nitrogenous bases that are linked through dehydration reactions in a line
Term
RNA=
Definition
sugar ribose, uracil nucleotide,
Term
DNA=
Definition
hydroxyl group replaced with hydrogen atom that contains thymine nucleotide
Term
Carbohydrates
Definition
polymers that make up structural framework of certain cells and play a critical role in energy storage. Any molecule that contains carbon, hydrogen, and oxygen in the ratio 1:2:1
Term
monossacharides
Definition
consist of one subunit: Glucose
Term
dissacharide
Definition
forms when 2 monossacharides form together through dehydration reaction. Table sugar. Sucrose.
Term
polyssacharides
Definition
linking the sugars together into long polymer chains. Plants+Animals store energy.
Term
True or False
Plants= starch
Animals= glycogen
Definition
true
Term
True or False
Plants= cellulose
Animals= chitin
Definition
true
Term
lipids
Definition
fats and all other biological molecules that are not soluble in water. Non polar. Cluster together
Term
2 subunits of fats
Definition
fatty acids glycerol
Term
fatty acid
Definition
long chain of carbon and hydrogen atoms
Term
saturated
Definition
maximum # of hydrogen atoms
Term
hydrogenated
Definition
artificial industrial add of hydrogens extends shelf life of food like p.b
Term
trans fat
Definition
type of unsat rated fat linked to heart disease
Term
steriod
Definition
cholesterol, phospholipids, testosterone, estradiol
Term
Robert Hook 1665
Definition
the cell theory
Term
Cork
Definition
think slice of nonliving plant tissue
Term
cellulae
Definition
compartments in the cork. cells.
Term
matthias schleidan 1838
Definition
developed first statement of cell theory " all plants are aggregrates of fully individualized independent separate beings namely the cell themselves"
Term
1839 Theodor Schwann
Definition
reported all animal tissues also consist of individual cells
Term
the cell theory
Definition
all organisms are composed are composed of cells
Term
3 principles for cell theory
Definition
1. all organisms are composed of 1 or more cells, life process. 2. cells are the smallest living things. nothing alive is smaller than a cell. 3. cells arise only by division of a previous existing cell. life on earth represents of continuous line of descent from those of early cells.
Term
axons
Definition
cells of the nervous system that have long thread life extensions
Term
microvilli
Definition
structural feature that increases surface area are small finger life projections that dramatically increase a cells surface area
Term
resolution
Definition
the minimum distance two points can be apart and still be distinguished as two separate points
Term
microcope
Definition
a way to increase resolution of small objects
Term
modern light microscopes
Definition
uses 2 magnifying lenses to focus on the receptor cells
Term
compound microscopes
Definition
microscopes that magnify in stages using several lenses 200 NM
Term
transmission electron microscope TEM
Definition
resolving objects only 0.2 nanometers apart. twice the diameter of hydrogen atom
Term
scanning electron microscope SEM
Definition
beams the electrons onto the surface of the specimen. Amplified electrons. image is transmitted and photography. producing 3 dimensional picture
Term
two main groups of prokaryotics
Definition
bacteria and archaea
Term
almost all bacteria and archaea is a...
Definition
cell wall
Term
capsules
Definition
additional layer that encloses the cell wall
Term
true or false
archaea=diverse
bacteria= abundant
Definition
true
Term
ribosomes
Definition
scattered throughout the cytoplasm of prokaryotic cells that are small spherical structures sites where proteins are made. not considered organelles. lack membrane boundary. not considered nucleus. not enclosed within internal membrane
Term
flagellum
Definition
prokaryotics use to move. long thread like structures. made of protein fibers that project from surface of cell. used in locomotion and feeding.
Term
prokaryotic
Definition
relatively uniform interior that is not subdivided by internal membranes into separate compartments. don't have organelles or nucleus.
Term
pili/pilus
Definition
short flagella. pili helps prokaryotic cell attach to appropriate substrates and in the exchange of genetic information between cells.
Term
eukaryotic
Definition
larger with complex interior organization
Term
plasma membrane
Definition
plant cells/animal cells. encases a semi fluid matrix
Term
cytoplasm
Definition
plant cells/animal cells. semifluid matrix that contains the nucleus and other organelles
Term
organelle
Definition
a specialized structure within which particular cell processes occurs
Term
mitochondrian
Definition
plant cells/animal cells. specific function in eukaryotic cell. organelle in which energy is extracted from food during oxidative metabolism
Term
cytoskeleton
Definition
supports organelles and cell shape and plays a role in cell motion
Term
microtubule
Definition
tube of protein molecules present in cytoplasm, centriole, cilia and flagella.
Term
intermediant filament
Definition
intertwined protein fibers that provides support and strength
Term
actin filament
Definition
twisted protein fibers that are responsible for cell movement
Term
nucleus/nuclei
Definition
plant cells/animal cells. command center of the cell inside the DNA is wound around proteins and into compact units (chromosomes)
Term
nucleolus
Definition
site where ribosomes are produced
Term
nuclear envelope
Definition
opening embedded with proteins that regulates passe into and out of the nucleus
Term
ribosomes
Definition
small complexes of RNA and protein that are sites of protein synthesis.
Term
the hallmark of eukaryotic cell is
Definition
compartmentalization
Term
endomembrane system
Definition
plant cells/animal cells. smooth+ rough endoplasmic reticulum
Term
smooth endoplasmic reticulum
Definition
system of internal membranes rhat aids in the manufacture of carbohydrates and lipids
Term
rough endoplasmic reticulum
Definition
system of internal membranes that studded with ribosomes that carry out protein synthesis. weaves through cell interior
Term
vesicles
Definition
plant cells/animal cells. small membrane bound sacs that store and transport materials form closed off compartments in the cell allowing different processes to process simultaneously without interfering with one another
Term
peroxisome
Definition
vesicles that contains enzymes that carry out particular reactions such as detoxifying potentially harmful molecules
Term
lysosomes
Definition
organelles that are recycling centers that have acidic interior in which old organelles are broken down and their component molecules recycled. destructive if released into cytoplasm.
Term
cell walls
Definition
only in plant cells. outer layer in some organisms that provides support. composed of cellulose or chitin fibers
Term
chloroplasts
Definition
only in plant cells. organelle containing thylakoids the sires of photosynthesis. protists. photosynthesis occurs.
Term
central vacuoles
Definition
in plant cells only. inplants, storage compartment for water, sugars, ions, pigments
Term
tonoplast
Definition
membrane surrounding the central vacuole
Term
plasmodesmata
Definition
plant cells only. openings in the cell wall that function in cell-cell communication. creates cytoplasmic connections between cells
Term
centrioles
Definition
in animal cells only. complex assembly of microtubles that occurs in pairs
Term
plasma membrane
Definition
encasing all living cells is a delicate sheet of molecules
Term
fluid mosaic model
Definition
all plasma membranes have the same basic structure of proteins embedded in a sheet of lipids
Term
phospholipids
Definition
the lipid bilayer that forms the foundation of a plasma membrane is composed of modified fat molecules
Term
lipid bilayer
Definition
forms spontaneously. collection of phospholipi molecules placed in water
Term
bilayer
Definition
double layer phospholipid molecules has polarhead facing water and its nonpolar tail facing away from water
Term
cholesterol
Definition
nonpolar lipid molecule that resides in the interior portion of the bilayer. multiringed molecule that affects the fluid nature of the membrane. can accumulate in blood vessels forming plaques that leads to cardiovascular disease.
Term
cell surface proteins
Definition
act as markers to identify particular types of cells or as beacons to the cell
Term
transmembrane proteins
Definition
proteins that extend all the way across the bilayer that can provide passageways that extend all the way across the bilayer that can provide passageways for ions and polar molecules like water so they can pass into and out the cell
Term
nuclear envelope
Definition
bounds the surface of the nucleus that is a special kind of membrane. two membranes one outside the other acts as a barrier between the nucleus and the cytoplasm
Term
nuclear pores
Definition
acts as a passageway for the nucleur envelope. scattered over the surface. forms when 2 membranes layers of the nuclear envelope pinch together. not an empty opening. has many proteins embedded within that permits proteins and RNA to pass into and out the nucleus
Term
chromatin
Definition
eukaryotic chromosomes uncoil and fully extend into threadlike strands. available for protein synthesis
Term
process (protein synthesis)
Definition
RNA copies genes made from the DNA in the nucleus. RNA molecules leave the nucleus through pores and enter cytoplasm where proteins synthesize
Term
ribosome
Definition
the cell employs a special structure to make its many proteins. reads the RNA cope of a gene and use into to direct the construction of a protein.
Term
ribosomeal
Definition
special form of RNA rRNA bound up within a complex of several dozen different proteins
Term
nucleolus
Definition
ribosome subunits are assembled in a region within the nucleus
Term
endoplasmic reticulum
Definition
extensive system of internal membrane ER within the cytoplasm. little net. creates a series of channels and interconnection
Term
vesicle
Definition
isolates spaces as a membrane enclosed sacs
Term
rough ER
Definition
ER devoted to the synthesis of such transported proteins that is heavily studded with ribosomes and appears pebbley like the surface of sandpaper
Term
smooth ER
Definition
ER bound ribosomes that are relatively scarce correspondingly. embedded with ensymes that aid in the manufacture of carbohydrates and lipids
Term
golgi bodied
Definition
new molecules that are made on the surface of the ER then passed from the ER to flattened stacks of membranes. few to twenty in animals cells. Several hundred in plant cells
Term
golgi complex
Definition
Golgi bodies collectively scattered though the cytoplasm. collect, package, and distribute molecules manufactured in the cell
Term
rough ER + Smooth ER + golgi =
Definition
endomembrane transport system in the cell
Term
transport system in the cell (1)
Definition
proteins and lipids manufactured on the ER membranes transported through channels of the ER and packaged into transport vesicles that bud off form the ER
Term
transport system in the cell (2)
Definition
molecules become tagged with carbohydrates. molecules collect at ends of the membranous folds of golgi bodies (cisternae)
Term
transport system in the cell (3)
Definition
vesicles pinch off from cisternae carry molecules to different compartments of the cell
Term
transport system in the cell (4)
Definition
OR the inner surface of the plasma membrane = molecules secreted and released to the outside
Term
lysosome
Definition
arise from the golgi body complex and contain a concentrated mix of the powerful enzymed
Term
vacuoles
Definition
interior of plants and many protist cell contain membrane bounded storage compartments
Term
central vacuole
Definition
center of plant cell that contains large empty space. has large amounts of water and other materials. functions as storage center
Term
symbiosis
Definition
bacteria taken up by ancestral eukaryotic cells in the distant past and remained living inside the last cell forming a relationship
Term
oxidative metabolism
Definition
complex series of chemical reactions in which eukaryotic organisms extract energy from organic molecules "food"
Term
mitochondria
Definition
sausage shaped organelles size of bacterial cell bounded by 2 membranes
Term
outermembrane
Definition
smooth derives from the plasma membrane of the host cell that first took up bacterium long ago
Term
inner membrane
Definition
plasma membrane of the bacterium that gave arise to the mitochondrion. bent into numerous folds
Term
cristae
Definition
part of inner membrane the numerous folds various groups of bactera
Term
inner matrix
Definition
middle of innermembrane. cutaway. into 2 compartments capturing centers.
Term
compartment
Definition
intermembrane space
Term
thylakoids
Definition
inside the chloroplast another series of membranes that are fused to form stacks of closed vesicles
Term
granum
Definition
thylakoids that are stacked on top of another to form a column
Term
stroma
Definition
interior of a chloroplast that is bathed with a semiliquid substance
Term
theory of endosymbiosis
Definition
some of todays eukaryotic organelles evolved by a symbiosis in which one cell of a prokaryotic species was engulfed by and lived inside the cell of another species of prokaryote that was a precursor to eukaryotes
Term
cytoskeleton
Definition
a dense netowrk of protein fibers. proved framework that supports the shape of the cell. anchors organelles like the mitochondria to fixed location within the cell interior
Term
3 different kinds of protein fibers that make up cytoskeleton
Definition
microfilaments (actin filaments), actin, microtubules.
Term
microfilaments
Definition
long fibers about 7 nanometers in diameter each filament is composed of 2 protein chains loosely twined together like 2 strands of pearls
Term
actin
Definition
each subunit on the chains is the glubular protein. are found throughout the cell but are most highly concentrated just inside the plasma membrane. responsible for cellular movements such as contraction, crawling, pinching, during division and forming of cellular extensions
Term
microtubules
Definition
cytoskeletal elements that serve to organize metabolism and intercellular transport in the non-dividing and stabilize cell structure. responsible for the movement of chromosomes in mitosis.
Term
intermediate filaments
Definition
composed overlapped staggered tetramers of protein bundled into cables. stable and usually do not break down. provide structural reinforcement to the cell and organelles
Term
centrioles
Definition
complex structure assembled microtubules from tubulin subunits in the cells of animals and most protists. occurs in pairs within the cytoplasm. usually located at right angles to one another. usually found near the nuclear envelope and are among the most structurally complex microtubular assemblies of the cell
Term
flagella
Definition
some eukaryotic cells contain it. fine long threadlike organelles protruding from the cell surface
Term
basal body
Definition
microtubular structures groups arranged in rows of 3 shown in the cross sectional view. some extend up to the flagellum. circle of 9. surrounding 2 central microtubules.
Term
cilia
Definition
flagella in numerous and organized in dense rows. do not differ in structure from flagella but usually shorter. breathing tube, trachea, move mucus, dust particles out of respiratory trae and into the throat
Term
diffusion
Definition
the net movement of molecules down a concentration gradient toward regions of lower concentration as a result of random motion
Term
aquaporins
Definition
small channel water molecules pass through that traverse the membrane so water freeley across the plasma membrane. blocks passages of protons
Term
osmosis
Definition
water passes across a cell membrane down is concentration gradient
Term
osmotic concentratation
Definition
concentration of all molecules dissolved in a solution
Term
isotonic
Definition
if osmotic concentrations of two solutions are equal
Term
hypertonic
Definition
2 solutions have unequal osmotic concentration solution with higher solute concentration
Term
hypotonic
Definition
lower solution
Term
osmotic pressure
Definition
movement of water into a cell by osmosis creates pressure. can cause a cell to swell and burst. most animal cells cannot withstand osmotic pressure unless plasma membrane is braced to resist the swelling. if in water it will burst
Term
turgor pressure in plants
Definition
important for plant cells to maintain shape. without water plants wilt. cell walls.
Term
endocytosis
Definition
cells of many eukaryotes take in food and liquids by extending their plasma membranes outward toward food particles. membrane engulfs the particle and forms a vesicle a membrane bounded sac around it
Term
phagocytosis
Definition
material the cell takes place in its particulate such as an organism like red bacterium or some other fragment of organic water
Term
pinocytosis
Definition
material the cell takes in is liquid or substances dissolved in a liquid like small particles common among animal cells
Term
exocytosis
Definition
discharge of material from vesicles at the cell surface proteins and other molecule are secreted from cells in small pockets called secretory vesicles membrane fuse with plasma membrane
Term
selective permeability
Definition
cells contain what enters and leaves
Term
selective diffusion
Definition
equalizes concentration of such molecules on both sides of the membrane with molecules moving toward the side where they are scarcest
Term
facilitated diffusion
Definition
1 particular membrane can bind to special protein carriers in plasma membrane 2 protein carrier helps diffusion process and does not require energy 3. molecule is released on the far side of the membrane.
transport of molecules across a membrane by a carrier protein in the direction of lowest concentration
Term
active transport
Definition
movement of molecules across membrane to a region of higher concentration by expenditure of energy
Term
sodium potassium pump
Definition
most important active transport protein
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