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Cell Biology
Cornell 1350 Cell Biology
97
Biology
Undergraduate 1
02/20/2011

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Term
resolving power
Definition
Term
fluorophore
Definition
Term
prokaryote
Definition
Major category of living cells distinguished by the absence of a nucleus. Prokaryotes comprise the archea and the eubacteria (commonly called bacteria), two of the three domains of life.
Term
antibody
Definition
Protein produced by B lyphocytes in response to a foreign molecule or invading organism. Binds to the foreign molecule or cell very tightly, thereby inactivating it or marking it for destruction.
Term
cytoskeleton
Definition
System of protein filaments in the cytoplasm of a eukaryotic cell that gives the cell shape and the capacity for directed movement. Its most abundant components are actin filaments, microtubules, and intermediate filaments.
Term
endoplasmic reticulum
Definition
Labyrinthe, membrane-enclosed compartment in the cytoplasm of eukaryotic cells, where lipids aresecreted and membrane bound proteins are made.
Term
mitochondria
Definition
Membrane-enclosed organelle, about the size of a bacterium, that carries out oxidative phosphorylation and produces most of the ATP in eukaryotic cells.
Term
chloroplast
Definition
Specialized organelle in algae and plants that contains chlorophyll and in which photosynthesis takes place.
Term
nuclear pore
Definition
Channel through the nuclear envelope that allows selected large molecules to move between the nucleus and cytoplasm.
Term
cytosol
Definition
Contents of the main compartment of the cytoplasm, excluding membrane enclosed organelles such as endoplasmic reticulum and mitochondria. The cell fraction remaining after membranes, cytoskeletal components, and other organelles have been removed.
Term
cytoplasm
Definition
Contents of the cell that are contained within its plasma membrane but, in the case of eukaryotic cells, outside the nucleus.
Term
central dogma
Definition
The principle that genetic information flows from DNA to RNA to protein.
Term
disaccharide
Definition
A link of two sugars
Term
nucleic acid
Definition
RNA or DNA, consists of a chain of nucleotides joined together by phospholipids.
Term
ribosome
Definition
Particle composed of ribosomal RNAs and ribosomal proteins that associates with messenger RNA and catalyses the synthesis of protein.
Term
transcription
Definition
The process that uses one strand of DNA as the template to synthesize a complementary RNA sequence, sometimes termed the primary transcript, catalysed by the enzyme RNA polymerase.
Term
translation
Definition
Process by which the sequence of nucleotides in a messenger RNA molecule directs the incorporation of amino acids into protein, occurs on a ribosome.
Term
double helix
Definition
The typical conformation of a DNA molecule in which two polynucleotide strands are wound around eachother with base pairing between the strands.
Term
condensation reaction
Definition
Type of chemical reaction in which two organic molecules become linked to each other by a covalent bond with concomitant removal of a molecule of water.
Term
antiparallel
Definition
Describes two similar structures arranged in opposite orientations, such as two strands of DNA in a double helix.
Term
tRNA
Definition
Set of small RNA molecules used in protein synthesis as an interface (adaptor) between mRNA and amino acids. Each type of tRNA molecule is covalently linked to a particular amino acid.
Term
mRNA
Definition
RNA molecule that specifies the amino acid sequence of a protein. Produced by RNA splicing (in eukaryotes) from a larger RNA molecule made by RNA polymerase as a complementary copy of DNA. It is translated into protein in a process catalyzed by ribosomes.
Term
enzyme
Definition
A protein that catalyses a specific chemical reaction.
Term
hydrophilic
Definition
Polar molecule or part of a molecule that forms enough hydrogen bonds to water to dissolve readily in water.
Term
side chain
Definition
Portion of an amino acid not involved in making peptide bonds; the side chain gives each amino acid its unique properties.
Term
ribosome
Definition
Particle composed of ribosomal RNA's and ribosomal proteins that associates with messenger RNA and catalyzes the synthesis of protein.
Term
conformation
Definition
Spacial location of the atoms in a moleculerelative to each other. The precise shape of a protein or other macromolecule in three dimensions.
Term
codon
Definition
Sequence of three nucleotides in a DNA or messenger RNA molecule that represents the instruction for incorporation of a specific amino acid into a growing polypeptide chain.
Term
beta sheet
Definition
Folding pattern found in many proteins in which neighboring regions of the polypeptide chain associate side by side with each other through hydrogen bonds to give a rigid, flattened structure.
Term
coil-coil
Definition
Especially stable rod-like protein structure formed by two or more alpha-lelices coiled around each other.
Term
anticodon loop
Definition
Sequence of three nucleotides in a transfer RNA molecule that is complementary to the three-nucleotide codon on a messenger RNA molecule; each anticodon is matched to a specific amino acid covalently attached elsewhere on the transfer RNA molecule.
Term
prion
Definition
Term
tertiary structure
Definition
Term
domain
Definition
Small discrete region of a structure. A protein domain is a compact and stable folded region of polypeptide. A membrane domain is a region of bilayer with a characteristic lipid and protein composition.
Term
disulfide bond
Definition
Term
activation energy
Definition
The extra energy that must be acquired by a molecule to undergo a particular chemical reaction.
Term
reaction coupling
Definition
Term
phosphorylation
Definition
The covalent addition of a phosphate group to a side chain or a protein catalysed by a protein kinase. Phosphorylation usually alters the activity or properties of the protein in some way.
Term
ATP
Definition
Nucleoside triphosphate composed of adenine, ribose, and three phosphate groups that is the principal carrier of chemical energy in cells. The terminal phosphate groups are highly reactive in the sense that their hydrolysis, or transfer to another molecule, is accompanied by the release of a large amount of free energy.
Term
feedback inhibition
Definition
A form of metabolic control in which the end product of a chain of enzymatic reactions reduces the activity of an enzyme early in the pathway.
Term
GTP binding protein
Definition
An allosteric protein whose conformation and activity are determined by its association with either GTP or GDP. Includes many proteins involved in cell signaling, such as Ras and G proteins.
Term
homology
Definition
Term
microtubule
Definition
Long, stiff, cylindrical structure composed of the protein tubulin. Used by eukaryotic cells to regulate their shape and control their movements.
Term
actin
Definition
Protein filament, formed from a chain of globular actin molecules. A major constituent of the cytoskeleton of all eukaryotic cells and especially abundant in muscle cells.
Term
tubulin heterodimer
Definition
Term
centrosome
Definition
Centrally located organelle of animal cells that is the primary microtubule-organizing center and separates to form the two spindle poles during mitosis. In most animal cells in contains a pair of centrioles.
Term
kinesin
Definition
A large family or motor proteins that use the energy of ATP hydrolysis to move along a microtubule
Term
dyenin
Definition
Member of a family of large motor proteins that undergo ATP-dependant movement along microtubules. Dynein is responsible for the bending of cilia.
Term
plus end
Definition
Term
retrograde transport
Definition
Term
retrograde transport
Definition
Term
sarcomere
Definition
Repeating unit of a myofibril in a muscle cell, composed of an array of overlapping thick (myosin) and thin (actin) filaments.
Term
myosin
Definition
Type of motor protein that uses ATP to drive movements along actin filaments. Myosin II is a large protein that forms the thick filaments of skeletal muscle. Smaller myosins, such as myosin I, are widely distributed and are responsible for many actin-based movements.
Term
plasma membrane
Definition
The membrane that surrounds a living cell.
Term
amphipathic
Definition
Having both hydrophilic and hydrophobic components. A phospholipid or detergent molecule in an example.
Term
glycolipid
Definition
Membrane lipid molecule with a short carbohydrate chain attached to a hydrophobic tail.
Term
receptor
Definition
A cell (such as the photoreceptor cell of an eye) or cellular component (such as a receptor protein) that detects an external signal and triggers a specific cellular response.
Term
transmembrane protein
Definition
They extend through the bilayer, with part of their mass on either side. They have hydrophobic and hydrophilic regions. Their hydrophobic regions lie on the interior of the bilayer near the hydrocarbon tails and the hydrophilic regions are exposed to the aqueous environment on either side of the membrane
Term
alpha helix
Definition
Common structural motif of proteins in which a linear sequence of amino acids folds into a right-handed helix stabilized by internal hydrogen bonding between backbone atoms.
Term
lateral mobility
Definition
the ability for lipid proteins to move within their monolayer
Term
photobleaching
Definition
Term
cell cortex
Definition
Specialized layer of cytoplasm on the inner face of the cell membrane. In animal cells it is an actin rich layer responsible for cell-surface movements.
Term
glycosidic link
Definition
the link between two monosaccharides (covalent) that allows it to grow into an oligosaccharide or a polysaccharide
Term
cellulose
Definition
A part of plant cell walls, it is a polysaccharide of glucose.
Term
glycolipid
Definition
A small oligosaccharide that is linked to a protein, found in cell membranes
Term
carboxyl group
Definition
-COOH, behaves as an acid, can be ionized into solution, and is very hydrophilic and chemically reactive. These are what links two fatty acids (covalently) in a cell.
Term
unsaturated bonds
Definition
In some tails of fatty acids there are these bonds, which create kinks in the tails, interfering with their ability to pack closely. This also affects the fluidity of the membrane.
Term
triacylglycerol molecules
Definition
stores of fatty acids in the cytoplasm - made up of three fatty acids chains joined to a glycerol molecules
Term
phospholipid
Definition
small molecules that are made up of glycerol attached to two fatty acid chains and a hydrophilic phosphate group, which in turn is attached to a small hydrophilic compound
Term
amino acid
Definition
they all possess a carboxylic acid group and an amino acid group, both linked to the same carbon called the alpha-carbon. Their variety comes form the side chain which is also attached to the carbon
Term
peptide bonds
Definition
the bond that attaches two amino acids covalently, they are formed through a condensation reaction
Term
structure of a polypeptide
Definition
always has a amino group at one end, its N-terminus (NH2), and a carboxyl group (COOH) at the other end, its C-terminus
Term
nucleoside
Definition
a molecule made up of a nitrogen-containing ring compound linked to a five-carbon sugar which can be either deoxyribose or ribose
Term
nucleotide
Definition
a nucleoside containing one or more phosphate groups attached to the sugar
Term
pyramidines
Definition
derived from a six membered ring: cytosine, thymine, and uracil
Term
purines
Definition
have a second five membered ring attached to the six membered ring; guanine, adenine, purine
Term
RNA bases
Definition
A, G, C, U
Term
change RNA to DNA
Definition
the hydroxyl at the 2' position of the ribose carbon ring is replaced by a hydrogen
Term
DNA nucleotides
Definition
A, G, C, T
Term
noncovalent bond purpose
Definition
to form the shapes (conformations) of proteins and macromolecules, these bonds form between various parts of the macromolecule. Include electrostatic attractions and hydrogen bonds.
Term
abilities of living cells
Definition
1. Exist as independent organisms
2. All things are made up of cells
3. Ability to grow, reproduce, convert energy, control their inner workings, respond to the environment.
Term
capability of the light microscope
Definition
can magnify cells up to 1000 and resolve details as small as 2um
Term
3 things needed to view cells in a light microscope
Definition
1. A bright light must be focused onto the specimen by lenses in the condenser.
2. The specimen must be prepared to allow light to go through.
3. An appropriate set of lenses must be arranged to focus the image into the eye.
Term
Difference between light microscope and fluorescence microscope.
Definition
These two are very similar except that in a fluorescent microscope light is passed through two sets of filters, the first passing only wavelengths through that excite the particular fluorescent dye.The second blocks out all light and passes only that emitted when the dye fluoresces, so the dyed objects show up on a dark background.
Term
size of cells
Definition
2-200um
Term
size of organelles
Definition
200nm to 2um
Term
size of molecules
Definition
0.2nm to 20nm
Term
size of atoms
Definition
0.2nm
Term
function of the mitochondria
Definition
They harness the energy from the oxidation of food particles to produce ATP.
Term
function of the endoplasmic reticulum
Definition
The site where most cell membrane components, as well as materials destined for export from the cell are made.
Term
function of Golgi apparatus
Definition
Receives and often chemically modifies the molecules made in the ER and then sends them out or to another organelle.
Term
function of lysosome
Definition
intracellular digestion occurs here, and it releases nutrients from food particles and breaks down unwanted molecules for recycling or excretion
Term
function of peroxisomes
Definition
provide a contained environment for reactions in which hydrogen peroxide is generated or degraded
Term
endosomes
Definition
presort materials headed for lysosomes, recycle some of it
Term
detergents
Definition
small, ampipathic, lipid-like molecules; they only have a single hydrocarbon tail, they're shaped like cones, and in water they tend to aggregate into small droplets called micelles; when mixed with membranes, the hydrophobic tail binds to membrane spanning hydrophobic region of the transmembrane proteins and phospholipid molecules, separating the bilayer.
Term
the most plentiful positively charged ion outside the cell
Definition
Na+, balanced by Cl-
Term
the most plentiful positively charged ion inside the cell
Definition
K+, balanced with a variety of negatively charged intracellular ions
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