Study Biology Test 2 Flash Cards

 
Pile Management Card
Biology Test 2

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A smaller amount of ATP is formed directly in a few reactions of glycolysis and the citric acid cycle by a mechanism called _________.
substrate-level phosphorylation
Mode of ATP synthesis because it is powered by the redox reactions of the electron transport chain.
oxidative phosphorylation
_________ takes place within the mitochondrial matrix of eukaryotic cells or simply in the cytosol of prokaryotes, completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.
citric acid cycle
_________ occurs in cytosol, begins the degradation process by breaking glucose into two molecules of compound called pyruvate.
glycolysis
Respiration uses an _________ to break the fall of electrons to oxygen into several energy releasing steps.
electron transport chain
Hydrogen atoms are not transferred directly to oxygen, but instead are usually passed first to an electron carrier, a coenzyme called ______.
NAD+
Substance Y, the electron acceptor is the _________; it oxidizes Xe- by removing its electron.
oxidizing agent
In generalized reaction, substance Xe-, the electron donor is called ______; it reduces Y, which accepts the donated electron.
reducing agent
In redox reaction the addition of electrons to another substance is known as _________.
reduction
In redox reaction, the loss of electrons from one substance is _______.
oxidation
Electron transfer are called oxidation-reductions or _______.
redox reaction
Includes both aerobic and anaerobic processes.
cellular respiration
A catabolic pathway in which oxygen is consumed as aa reactant along with the organic fuel.
aerobic respiration
A catabolic process that is a partial degradation of sugars that occurs without the use of oxygen.
fermentation
A metabolic pathway is switched off by the inhibitory binding of its end product to an enzyme that acts early in the pathway .
feedback inhibition
Mechanism amplifies the response of enzymes to substrates: one substrate molecule primes an enzyme to accept additional substrate molecules more readily.
cooperativity
The term used to describe any case in which a protein's function at one site is affected by the binding of a regulatory molecule to a separate site. May result in either inhibition or stimulation of an enzyme's activity.
allosteric regulation
Do not directly compete with the substrate to bind to the enzyme at the active site.
noncompetitive inhibitors
Mimics that reduce the productivity of enzymes by blocking substrates from entering active sites.
competitive inhibitors
If the cofactor is an organic molecule it is more specifically called a _________.
coenzyme
These adjuncts may be bound tightly to the enzyme as permanent residents, or they bind loosely and reversibly along with the substrate.
cofactors
A chemical agent that speeds up a reaction without being consumed by the reaction.
catalyst
A macromolecule that acts as a catalyst.
enzyme
The recipient of the phosphate group. The key to coupling exergonic and endergonic reactions is the formation of this, which is more reactive (less stable) than the original.
phosphorylated
A key feature in the way cells manage their energy resources to do this work is ____, the use of an exergonic process to drive an endergonic one. ATP is responsible for mostly this.
energy coupling
A cell does three main kinds of work:
chemical work, transport work, mechanical work
Absorbs free energy from its surrounds. Such reactions are non spontaneous and the magnitude of G is the quantity of energy required to drive the reaction.
endergonic reaction
Represents the amount of work the reaction can perform. This is outward energy. It proceeds with a net release of free energy.
exergonic reaction
The formula for free energy is:
tri.G = tri.H - T tri.S
free energy = total energy - temperature x entropy

anytime free energy is negative then spontaneous.
anytime 0 or positive is then not spontaneous
The portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system.
free energy (triangle G)
Every energy transfer or transformation increases the entropy of the universe. Also for a process to occur spontaneously, it must increase the entropy of the universe.
second law of thermodynamics
A measure of disorder or randomness.
entropy
According to the ____________, the energy of the universe is constant. Energy can be transferred and transformed, but it cannot be created or destroyed.
first law of thermodynamics
The study of the energy transformations that occur in a collection of matter is __________.
thermodynamics
A term used by biologists to refer to the potential energy available for release in a chemical reaction.
chemical energy
An object not presently moving may still possess energy. Energy that is not kinetic is _______.
potential energy
Kinetic energy associated with the random movement of atoms or molecules.
Heat or thermal energy
Energy associated with the relative motion of objects.
kinetic energy
The capacity to cause change.
energy
The study of how energy flows through living organisms.
bioenergetics
_______ consume energy to build complicated molecules from simpler ones.
anabolic pathway (up hill)
The degradative process is ________ or breakdown pathways. A major pathway is cellular respiration.
catabolic pathway (down hill-stored)
A ______ begins with a specific molecule which is then altered in a series of defined steps, resulting in a certain product.
metabolic pathways
The totality of an organism's chemical reactions. It is an emergent property of life that arises from interactions between molecules within the orderly environment of the cell.
metabolism
Human cells use this for cholesterol.
receptor mediated endocytosis
The cell "gulps" droplets of extracellular fluid into tiny vesicles. It is not the fluid itself that is needed by the cell, but the molecules dissolved int eh droplets. Because any and all included solutes are taken into the cell.
pinocytosis
A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a membrane enclosed sac that can be large enough to be classified as a vacuole fuses with a lysosome containing hydrolytic enzymes.
phagocytosis (cell eating)
LDLs acts as _____, (a term for any molecule that binds specifically to a receptor site of another molecule) by binding to LDL receptors on plasma membranes and then entering the cells by endocytosis.
ligands
What are the three types of endocytosis?
phagocytosis, pinocytosis, and receptor-mediated endocytosis
The cell takes in biological molecules and particulate matter by forming new vesicles from the plasma membrane.
endocytosis (reverse of exocytosis - import)
The cell secretes certain biological molecules by the fusion of vesicles with the plasma membrane.
exocytosis (export)
A single ATP -powered pump that transports a specific solute can indirectly drive the active transport of several other solutes in a mechanism.
contransport
The main electrogenic pump of plants, fungi, and bacteria is _______.
proton pump
A transport protein that generates voltage across a membrane is called an _________.
electrogenic pump
Two forces drive the diffusion of ions across a membrane; chemical and electrical force. A combination of forces acting on an ion is called _________.
electrochemical gradient
The voltage across a membrane.
membrane potential
Hydrophobic molecules and (at a slow rate) very small uncharged polar molecules can ______ through the lipid bilayer.
diffuse/diffusion
This transports system exchanges sodium for potassium across the plasma membrane of animal cells.
sodium-potassium pump (active transport)
______ supplies the energy for most active transport.
ATP
The energy to pump a solute across a membrane against its gradient.
active transport
Channel proteins that open or close in response to stimulus.
ion channels function as gated channels
Polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane.
facilitated diffusion
Lose water to its surroundings and shrink. Plasma membrane pulls away from the walls. This causes a plant to wilt and die.
plasmolysis
If plant cells and their surroundings are isotonic, there is no net tendency for water to enter, and the cells become ______ or limp.
flaccid
Very firm, which is the healthy state for most plant cells.
turgid
The control of water balance.
osmoregulation
Water will enter the cell faster than it leaves, the cell will swell and burst.
hypotonic
The cell will lose water to its environment, shrivel, and probably die.
hypertonic
This is when a cell has no net movement of water across the plasma membrane.
isotonic
The diffusion of water across a selectively permeable membrane is _______.
osmosis
The diffusion of a substance across a biological membrane is _______ because the cell does not have to expend energy to make it happen.
passive transport
The region along which the density of a chemical substance decreases.
concentration gradient
The passage of water molecules through the membrane in certain cells is greatly facilitated by channel proteins known as _______.
aquaporins
Cell membranes are permeable to specific ions and a variety of polar molecules. These hydrophilic substances can avoid contact with the lipid bilayer by passing through _______ that span the membrane.
transport proteins
Proteins that are not embedded in the lipid bilayer at all. They are appendages loosely bound to the surface of the membrane, often to exposed parts of integral proteins.
peripheral proteins
Protein that penetrates the hydrophobic core of the lipid bilayer.
integral proteins
A phospholipid that has both a hydrophilic region and a hydrophobic region.
amphipathic molecule
Allows some substances to cross the plasma membrane more easily than others.
selective permeability
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