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142 Cards in this Set

  • Front
  • Back
Biology
The scientific study of life processes and living things
Cell
The smallest structural unit of an organism that is capable of independent functioning.
Emergent Property
Properties that appear at a certain level because of the specific arrangemen/interaction of the parts on the levels below.
Organelle
A body within the cell with specialized function, sustended in the sytoplasm or eukaryotic cells.
Cell Theory
All living things are made of cells. Cells arise only by the division of already existing cells.
electron microscope
A microscope that uses a beam of electrons rather than light, increasing resolution greatly
eukaryotic
a type of a cell with a membrane enclosed nucleus and membrane enclosed organelles
Micrometer
1/1000 of a milimeter, a common unit of measurement for cells
Nanometer
1/1000 of a micrometer
Prokaryotic Cell
A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea
Resolution
A measure of clarity of an image
Atom
The smallest unit of matter that retains the properties of an element.
Atomic Number
The number of protons in the nucleus of an atom, unique for each element and designated by a subscript to the left of the elemental symbol.
Compound
A substance consisting of two or more elements in a fixed ratio.
Covalent Bond
A type of strong chemical bond in which two atoms share one pair of valence electrons.
Double Covalent Bond
A type of covalent bond in which two atoms share two pairs of electrons; symbolized by a pair of lines between the bonded atoms.
Electron
A subatomic particle with a single negative charge; one or more move around the nucleus of an atom.
Element
Any substance that cannot be broken down to any other substance.
Molecule
Two or more atoms held together by covalent bonds.
Proton
A subatomic particle with a single positive electrical charge, found in the nucleus of an atom.
Structural Formula
A type of molecular notation in which the constituent atoms are joined by lines representing covalent bonds.
Electronegativity
The attraction of an atom for the electrons of a covalent bond.
Hydration Shell
The sphere of water molecules around each dissolved ion.
hydrogen bond
A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.
hydrophilic
Having an affinity for water.
hydrophobic
Having an aversion to water; tending to coalesce and form droplets in water.
hydrophobic interaction
A type of weak chemical bond formed when molecules that do not mix with water coalesce to exclude the water.
ion
An atom that has gained or lost electrons, thus acquiring a charge.
ionic bond
A chemical bond resulting from the attraction between oppositely charged ions.
polar covalent bond
A type of covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.
polar molecule
A molecule (such as water) with opposite charges on opposite sides.
salt
Compounds resulting from the formation of ionic bonds, also called an ionic compound.
acid
A substance that increases the hydrogen ion concentration of a solution.
aldehyde
An organic molecule with a carbonyl group located at the end of the carbon skeleton.
amino
A functional group that consists of a nitrogen atom bonded to two hydrogen atoms; can act as a base in solution, accepting a hydrogen ion and acquiring a charge of +1.
base
A substance that reduces the hydrogen ion concentration of a solution.
carbonyl
A functional group present in aldehydes and ketones and consisting of a carbon atom double-bonded to an oxygen atom.
carboxyl group
A functional group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group.
functional group
A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and usually involved in chemical reactions.
hydrocarbon
An organic molecule consisting only of carbon and hydrogen.
hydroxyl
A functional group consisting of a hydrogen atom joined to an oxygen atom by a polar covalent bond. Molecules possessing this group are soluble in water and are called alcohols.
ketone
An organic compound with a carbonyl group of which the carbon atom is bonded to two other carbons.
pH
A measure of hydrogen ion concentration equal to –log [H+] and ranging in value from 0 to 14.
phosphate group
A functional group important in energy transfer.
sulfhydryl
A functional group consisting of a sulfur atom bonded to a hydrogen atom (—SH).
glycoprotein
A protein covalently attached to a carbohydrate.
integral protein
transmembrane proteins with hydrophobic regions that completely span the hydrophobic interior of the membrane.
lipid
One of a family of compounds, including fats, phospholipids, and steroids, that are insoluble in water.
peripheral protein
Protein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer.
phospholipid
A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.
fatty acid
A long carbon chain carboxylic acid. Fatty acids vary in length and in the number and location of double bonds; three fatty acids linked to a glycerol molecule form fat.
fluid mosaic model
The currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of individually inserted protein molecules drifting laterally in a fluid bilayer of phospholipids.
coenzyme
An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions.
cofactor
Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis.
competitive inhibitor
A substance that reduces the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics.
cooperativity
An interaction of the constituent subunits of a protein whereby a conformational change in one subunit is transmitted to all the others.
feedback inhibition
A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.
noncompetitive inhibitor
A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.
actin
the protein microfilaments are made of
basal body
A eukaryotic cell organelle consisting of a 9 + 0 arrangement of microtubule triplets; may organize the microtubule assembly of a cilium or flagellum; structurally identical to a centriole.
centriole
A structure in an animal cell composed of cylinders of microtubule triplets arranged in a 9 + 0 pattern. An animal cell usually has a pair of centrioles involved in cell division.
centrosome
Material present in the cytoplasm of all eukaryotic cells, important during cell division; the microtubule-organizing center.
cilium
plural, cilia) A short cellular appendage specialized for locomotion, formed from a core of nine outer doublet microtubules and two inner single microtubules ensheathed in an extension of plasma membrane.
cytoskeleton
A network of microtubules, microfilaments, and intermediate filaments that branch throughout the cytoplasm and serve a variety of mechanical and transport functions.
flagellum
(plural, flagella) A long cellular appendage specialized for locomotion, formed from a core of nine outer doublet microtubules and two inner single microtubules, ensheathed in an extension of plasma membrane.
intermediate filament
A component of the cytoskeleton that includes all filaments intermediate in size between microtubules and microfilaments.
microfilament
A solid rod of actin protein in the cytoplasm of almost all eukaryotic cells, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction.
microtubule
A hollow rod of tubulin protein in the cytoplasm of all eukaryotic cells and in cilia, flagella, and the cytoskeleton.
tubulin
what microtubules are made of
amphipathic molecule
A molecule that has both a hydrophilic region and a hydrophobic region.
glycerol
A three-carbon alcohol with a hydroxyl group on each carbon.
secondary structure
The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between peptide linkages.
activation energy
The amount of energy that reactants must absorb before a chemical reaction will start.
pleated sheet
One form of the secondary structure of proteins in which the polypeptide chain folds back and forth, or where two regions of the chain lie parallel to each other and are held together by hydrogen bonds.
Primary Structure
The level of protein structure referring to the specific sequence of amino acids.
tertiary structure
Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.
quaternary structure
The particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide.
anabolism
a chemical reaction requiring energy
active site
The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds.
catabolism
an exergonic reaction releasing energy
catalyst
A chemical agent that changes the rate of a reaction without being consumed by the reaction.
change in free energy
net change in energy taken or released in a chemical reaction
endergonic reaction
A nonspontaneous chemical reaction in which free energy is absorbed from the surroundings.
exergonic reaction
A spontaneous chemical reaction in which there is a net release of free energy.
induced fit
The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.
metabolism
The totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways.
substrate
The reactant on which an enzyme works.
Denaturation
For proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. For DNA, the separation of the two strands of the double helix. It occurs under extreme conditions of pH, salt concentration, and temperature.
Amino Acid
An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of proteins.
condensation reaction
A reaction in which two molecules become covalently bonded to each other through the loss of a small molecule, usually water; also called dehydration reaction.
enzyme
A protein serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction.
hydrolysis
A chemical process that lyses, or splits, molecules by the addition of water; an essential process in digestion.
monomer
The subunit that serves as the building block of a polymer.
peptide bond
The covalent bond between two amino acid units, formed by a dehydration reaction.
polymer
A long molecule consisting of many similar or identical monomers linked together.
polypeptide
A polymer (chain) of many amino acids linked together by peptide bonds.
Protein
A three-dimensional biological polymer constructed from a set of 20 different monomers called amino acids.
disulfide bridge
Strong covalent bonds formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer.
aquaporin
A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis).
facilitated diffusion
The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients.
gated channel
A protein channel in a cell membrane that opens or closes in response to a particular stimulus.
hypertonic
In comparing two solutions, referring to the one with a greater solute concentration.
osmosis
the diffusion of water across a membrane
plasmolysis
A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall when the cell loses water to a hypertonic environment.
selective permeability
A property of biological membranes that allows some substances to cross more easily than others.
transport protein
A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.
turgid
Firm. Walled cells become turgid as a result of the entry of water from a hypotonic environment.
apoptosis
programmed cell death
endomembrane system
The collection of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
endoplasmic reticulum (ER)
An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.
Golgi apparatus
An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum.
nuclear envelope
The membrane in eukaryotes that encloses the nucleus, separating it from the cytoplasm.
ribosome
A cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits.
rough ER
That portion of the endoplasmic reticulum studded with ribosomes.
transport vesicle
A tiny membranous sac in a cell's cytoplasm carrying molecules produced by the cell.
vesicle
A sac made of membrane inside of cells.
ATP (adenosine triphosphate)
An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.
mitochondrion
An organelle in eukaryotic cells that serves as the site of cellular respiration.
nucleotide
The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.
respiration
the aerobic harvest of energy from food molecules by cells.
carbohydrate
A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides).
cellulose
A structural polysaccharide of cell walls, consisting of glucose monomers joined by b-1, 4-glycosidic linkages.
chitin
A structural polysaccharide of an amino sugar found in many fungi and in the exoskeletons of all arthropods.
fat (triacylglycerol)
A biological compound consisting of three fatty acids linked to one glycerol molecule.
glucose
sugar
glycogen
An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.
mitochondrial matrix
The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle.
saturated fatty acid
A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that can attach to the carbon skeleton.
triacylglycerol
Three fatty acids linked to one glycerol molecule.
unsaturated fatty acid
A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.
ATP synthase
A cluster of several membrane proteins found in the mitochondrial crista (and bacterial plasma membrane) that function in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion concentration gradient to make ATP.provide a port through which hydrogen ions diffuse into the matrix of a mitrochondrion.
chemiosmotic phosphorylation
An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Most ATP synthesis in cells occurs by this method
NAD+
a coenzyme present in all cells that helps enzymes transfer electrons during the redox reactions of metabolism.
NADH
The reduced form of nicotinamide that is one of the products of glycolysis.
oxidation
The loss of electrons from a substance involved in a redox reaction.
oxidative phosphorylation
The production of ATP using energy derived from the redox reactions of an electron transport chain.
redox reaction
A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction.
reduction
The addition of electrons to a substance involved in a redox reaction.
The addition of electrons to a substance involved in a redox reaction.
The formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.
electron transport chain
A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.
glycolysis
The splitting of glucose into pyruvate. Glycolysis is the one metabolic pathway that occurs in all living cells, serving as the starting point for fermentation or aerobic respiration.
Krebs cycle
A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules to carbon dioxide; occurs within the mitochondrion; the second major stage in cellular respiration.