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218 Cards in this Set
- Front
- Back
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How many characteristics are there for living things?
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Seven
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Organisms tend to be..?
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Highly complex and organized
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What do living organisms have the ability to do?
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Take energy from the environment and change it from one form to another
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Organisms tend to be homeostatic. What does this mean?
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They regulate their bodies and other internal structures to certain normal parameters
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What do living creatures respond to?
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Stimuli
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Living things make copies of themselves for what?
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Reproduction
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Living organisms tend to grow and what?
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Develop
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Life adapts and evolves in step with what?
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It's external environment
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What is cell theory?
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All organisms are composed of one or more cells, the cell is the smallest unit that has all properties of life, and cells arise only from the growth and division of previously existing cells
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What was obtained from the Miller-Urey experiment?
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Urea, amino acids, lactic acid, formic acid, acetic acid, and nucleotides
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What did the Miller-Urey experiment allow? What was found?
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Allowed a change in the internal atmosphere, and found many organic molecules being formed
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What is a polymer?
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A molecules built out of smaller single unit monomers
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What are polypeptides made from?
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Amino Acids
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What types of reactions form peptide bonds?
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Condensation reactions between amino acids or phoshodiester bonds between nucleotides
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What are proteins made out of?
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Amino acids --> polypeptides --> proteins
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What is a polysaccharide?
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Monosaccharides linked together
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What are the monomers which make up nucleic acids?
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Nucleotides
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What is a condensation reaction?
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Common chemical reaction removing an H+ off of one molecule and an OH- off another, joining them together and creating a water molecule.
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What is a probiont ?
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An organic molecule separated from its environment, allowing for a separate internal environment full of key nutrients
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What was the first hereditary molecule with the ability to copy itself?
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RNA
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What is a ribozyme?
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RNA with enzymatic properties
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What are polynucleotides good for? What do they lack?
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Very good at storing and transmitting information, but lack the versatility for all the chemical reactions in the cell
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What has more functions, DNA or RNA? Which does them better?
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RNA has more functions than DNA, but DNA does its functions better
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What are the sugars in DNA? RNA?
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Deoxyribose, and ribose sugars
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How stable is DNA?
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Very stable
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Can DNA repair itself?
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Yes
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Is RNA stable?
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No
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What do polynucleotdes show a tendency for?
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Copying themselves using complimentary base pairing
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What are single stranded polynucleotides equivalent to?
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RNA
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What is reverse transcriptase?
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The enzyme used by retro viruses
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What is the DNA central dogma?
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DNA - RNA copy - ribosomes - proteins
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What is chemiosynthesis?
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A chemical form of photosynthesis not including light
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What is the chemical formula from chemiosynthesis?
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O2 + 4H2S + CO2 --> CH2O + 4S + 3H2O
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What is the phylogenic relationship for viruses?
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It is unknown, though they may be relics of an RNA world, a reduction of parasites, or selfish genes that escaped the genome
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What are the proteins in plasma membranes used for?
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Transport, enzymatic activity, signal transduction, intracellular joining, cell-cell recognition, and attachment to the extracellular matrix and cytoskeleton
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What are the parts of a phospholipid?
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A phosphate group, a glycerol sugar, and two fatty acids
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What does hydrophobic mean?
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Water hating
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What does hydrophilic mean?
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Water loving
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What is the freeze fracture technique? Why is it useful?
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Cells are frozen in liquid nitrogen, and the cells can be broken or fractured. They commonly fracture on predictable lines, usually where the hydrophobic tails meet
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What are peripheral proteins?
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Proteins not embedded in the membrane, loosely bounded to the surface, often connected to the population of embedded proteins
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What are integral proteins?
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Proteins which penetrate the phospholipid bilayer, often completely spanning the membrane
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What is one main role of proteins in the cell membranes?
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Reinforce the shape of the cell and provide a strong framework
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What is cell to cell recognition?
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The ability of a cell to distinguish one type of neighboring cell from another
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What does the permeability of a molecule through a membrane depend on?
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The interaction of that molecule with the hydrophobic core
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What is a transport protein specific to?
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The substances it will move
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How do transport proteins allow movement through the membrane?
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Some have a hydrophilic channel that some molecules or ions can use as a tunnel through the membrane, others bind to these molecules and carry their passengers physically.
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What is facilitated diffusion?
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The passive movement of molecules down its concentration gradient via a transport protein
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What does a channel protein allow?
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Fast transport
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What is an aquaprorin?
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Water channel protein
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What is active transport?
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Molecules are accumulated in the cell against a concentration gradient, energy is required
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What is passive transport?
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Some molecules are allowed to freely pass
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What is uniport?
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Single solute carried across membrane by transport protein
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What is symport?
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Two different solutes carried across membrane at same time in same direction by transport protein
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What is antiport?
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Two different solutes carried across membrane in opposite direction by transport protein
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How do large molecules often cross the membrane?
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Via vesicles
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What is exocytosis?
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Transport vesicle budded from the Golgi apparatus is moved by the cytoskeleton to the plasma membrane
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What is endocytosis?
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Cell brings in macromolecules and particulate matter by forming new vesicles from the plasma
membrane, a small area of the plasma membrane sinks inward to form a pocket |
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What is phagocytosis?
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Cell engulfs a particle by extending pseudopodia around it and packaging it in a large vacuole, cellular eating
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What is pinocytosis?
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Cell creates a vesicle around a droplet of extracellular fluid, cellular drinking
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What is receptor-mediated endocytosis?
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A very specific process, triggered when extracellular substances bind to ligands, on the membrane
surface, especially near coated pits, triggering the formation of a vesicle |
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What is bioenergetics?
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The study of energy in living systems (environments) and the organisms (plants and animals) that utilize it
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What is potential energy?
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Energy that matter occupies because of it’s location, arrangement, or position
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What is kinetic energy?
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Energy in the process of doing work
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What is an isolated system? Example?
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No matter or energy can move in an out, such as a thermos bottle
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What is a closed system? Example?
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Energy is exchanged with the environment but not matter, such as Earth
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What is an open system? Example?
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Energy and matter may be exchanged with the environment, such as a living organism
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What is the First Law of Thermodynamics?
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Energy cannot be created or destroyed, only converted into different forms, meaning the amount of energy in the universe is constant
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What is the Second Law of Thermodynamics?
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All energy transformations are inefficient because every reaction results in an increase in entropy and the loss of usable energy as heat
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What is entropy?
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The amount of disorder in a system, energy that is no
longer available to perform useful work within the current environment |
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What is free energy?
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Part of a system’s total energy that can perform work
when the temperature is uniform, as in a living cell, represented by G |
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What does delta G show?
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The change in free energy in a system changing from one state to another
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What is an endergonic reaction? Example?
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Chemical reaction that requires a net input of energy, such as photosynthesis,
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What is delta G in an endergonic reaction?
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Greater than 0
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What is an exergonic reaction? Example?
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Chemical reactions that releases energy, such as cellular respiration
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What is delta G in an exergonic reaction?
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Less than 0
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What is a coupled reaction?
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Use of an exergonic process to drive an endergonic one, allows life to overcome some of its energetic barriers
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What is a redox reaction?
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Chemical reactions that involve the transfer of one or more electrons (e-) from one reactant to another
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What happens in oxidation?
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The species oxidized contains less electrons
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What happens in reduction?
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The species reduces contains more electrons
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What is the electron donor called?
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Reducing agent
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What is the electron acceptor called?
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Oxidizing agent
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What is cellular metabolism?
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The sum total of the chemical activities
of all cells, endergonic and exergonic reactions |
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What is an anabolic pathway?
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Metabolic reactions, which consume energy (endergonic), to build complicated molecules from simpler compounds
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What is a catabolic pathway?
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Metabolic reactions which release energy (exergonic) by breaking down complex molecules in simpler compounds
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What is a hydrolysis reaction?
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The addition of water into a reaction in order to break down a molecule
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What is phosphorylation?
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Direct chemical transfer of a phosphate group
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What do chemical reactions between molecules involve?
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Both bond breaking and bond forming
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What is activation energy?
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Amount of energy necessary to push the reactants over an energy barrier
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How does an enzyme speed up a reaction?
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Lowers the activation energy, but does not actually change the rate of reaction
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What is a substrate?
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A reactant which binds to an enzyme
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What happens when a substrate binds to an enzyme?
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The enzyme catalyzes the conversion of the substrate to the product, the enzyme changes shape leading to a tighter induced fit, bringing chemical groups in position
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What is the active site on an enzyme?
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A pocket or groove on the surface of the protein into which the substrate fits
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Is there a limit on how fast a reaction can occur?
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Yes
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What is the only way to increase enzyme productivity?
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Add more enzyme molecules
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What do changes in enzyme shape affect?
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Rate of reaction
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Binding by some molecules, inhibitors prevent what?
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Enzymes from catalyzing reactions
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If the inhibitor binds to the same site as the substrate, what does it block?
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Substrate binding via competitive inhibition
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If the inhibitor binds somewhere other than the active site, it blocks substrate binding how?
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Noncompetitive inhibition
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What is feedback inhibition?
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metabolic pathway is turned off by its end product, end product acts as an inhibitor of an enzyme in the pathway
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What is the wavelength?
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The distance between crests of electromagnetic waves
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What is a photon?
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A particle of light with a fixed amount of energy
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Do shorter or longer wavelengths have the most energy?
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Shorter
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What does autotrophic mean?
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Self-feeding, does not use other organisms as an energy source, uses light for energy
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What does heterotroph mean?
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Consumes other organisms as a food source
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Where is chlorophyll a found?
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All photosynthetic organisms except bacteria
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Where is chlorophyll b found?
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All higher plants, green algae
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Where is chlorophyll c found?
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Brown algae
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Where is chlorophyll d found?
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Red algae
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Where are carotenoids often found?
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As major pigments in flowers and fruits
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What is the absorption spectrum?
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Measures the percent absorption of a particular pigment versus a particular wavelength of light
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What is used in the lab to measure absorption spectrum?
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A spectophotometer
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What is the action spectrum?
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Plots some measure of photosynthetic rate against wavelength of light
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What is the difference between the absorption spectrum and the action spectrum?
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In the action spectrum, pigments other than chlorophyll are also present
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Do all plants have the same amounts or concentrations of thylakoids?
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No, all plants are different
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A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are not being absorbed by this pigment?
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Red and yellow
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When a product molecule attaches to the allosteric site of an enzyme molecule, what is the consequence?
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A chance in the conformation of the enzyme molecule, inactivation of the enzyme molecule, inhibition of the reaction, and negative feedback inhibition
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What is another name for the light dependent reactions?
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Light reactions
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Where are the light dependent reactions occurring?
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Thylakoid membranes
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What is NADPH?
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Serves as an electron acceptor in the enzymatic removal of hydrogen ions from specific substrates
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What are the reaction centers?
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P680 and P700
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What are the accessory pigments? What are they used for?
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Chlorophyll b, c, d, and caroteniods. They are used to pass energy to the reaction center
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What is a photosystem?
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Chlorophyll organized with proteins and smaller organic molecules within the thylakoid membranes
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What do antenna pigments absorb?
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Photons of light
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What removes an excited electron from the reaction centers?
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A primary electron center
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An electron will move through a photosystem until what?
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it is accepted by a primary electron acceptor
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What is the reaction center of photosystem I?
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P700
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What is the reaction center of photosystem II?
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P680
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What do the photosystems work together to do?
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Use light energy to generate ATP and NADPH
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What type of electron flow is predominant in the light reactions?
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Noncyclic electron flow
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What does noncyclic eletron flow produce?
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ATP and NADPH
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How many electrons are released when one molecule is split?
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Two
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When photosystem II absorbs light, what happens to th excited electron?
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it is captured by the primary electron acceptor, leaving th e reaction center oxidized
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What happens to the electrons that are enzymatically extracted from water?
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They are supplied to the oxidized reaction center
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Photoexcited electrons pass along an electron transport chain, and then what?
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End up at an oxidized photosystem I reaction center
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What happens as electrons are passed along the electron transport chain?
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Their energy is harnessed to produce ATP
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What do electrons do at the bottom of the electron transport chain?
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Fill an electron "hole" in an oxidized P700 center
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How is hole created in the P700 center?
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When photons excite electrons on the photosystem I complex
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When is cyclic electron flow used?
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Under certain conditions, electrons from phososystem I undertake cyclic electron flow
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What does cyclic electron flow allow?
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The chloroplast to generate enough surplus ATP to satisfy the higher demand for ATP in the Calvin Cycle
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What is the chemical formula for photosynthesis?
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6CO2 + 6H2O --> C6H12O6 + 6O2
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What is another name for RuBP carboxylase?
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Rubisco
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What is one of the most abundant proteins on Earth?
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Rubisco
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What does the Calvin cycle use ATP and NADPH for?
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To convert CO2 to sugar
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What is the sugar product of Calvin cycle?
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G3P, glyeraldehyde-3-phosphate
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How many phases does the Calvin Cycle have?
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Three
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What happens in the carbon fixation phase?
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Each CO2 molecule is attached to a five carbon sugar, RuBP
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What happens in the reduction phase of the Calvin Cycle?
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Each 3-phosphoglycerate receives another phosphate group from ATP to form 1, 3 biphosphoglyceate
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What is left after fixation and reduction in the Calvin Cycle?
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Six molecules of G3P
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What happens in the regeneration phase of the Calvin Cycle?
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Five G3P molecules are rearranged to form 2 RuBP
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What are the three alternative mechanisms of carbon fixation?
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C3 plants, C4 plants, CAM plants
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Why do plants close stomata on hot dry days? Why is this a problem?
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To conserve water, because a factor of photosynthesis is limited
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What are examples of C3 plants?
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Cotton, rice, spinach, lettuce, carrots, petunia, apples, quackgrass, cocklebur, and beans
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What happens to C3 plants their their stomata are closed?
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CO2 levels drop, as CO2 is consumed in the calvin cycle
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When stomata are closed in C3 plants, when happens to oxygen?
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Levels drop
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When happens to rubisco when oxygen levels in C3 plants are high and CO2 levels are low?
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Rubisco attempts to add O2 to RuBP
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What is photorespiration?
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When rubisco adds O2 to RuBP, it splits into a 3 carbon piece and two carbon piece
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What does photorespiration decrease?
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Photosynthetic output by siphoning organic material from the Calvin Cycle
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What are examples of C4 plants?
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Sorghum, corn, sugarcane, St. Augustine grass, crabgrass, pigweed, Russian thistle
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What do mesophyll cells do in C4 plants?
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Incorporate CO2 into organic molecules, they pump these four-carbon compounds into bundle-sheath cells
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What do bundle sheath cells do in C4 plants?
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Strip a carbon, as CO2 from the four-carbon compound and return the three carbon remainder to the mesophyll cells, then start the Calvin Cycle with abundant CO2
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What does C4 photosynthesis minimize? What does it enhance?
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Phosorespiration, sugar production
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What are examples of CAM plants?
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Cactus, pineapple, jade plant, sansevieria agave
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What do CAM plants do to minimize phosorespiration?
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Open stomata during the night and close them during the day
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What are the limiting factors of photosynthesis?
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Light, CO2, temperature, water
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What is the light compensation point?
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The point in light intensity that the plant is making just enough sugar to run
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What type of producers of consumers are bacteria?
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Autotrophs or heterotrophs
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What type of producers of consumers are plants?
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Autotrophs
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What type of producers of consumers are fungi?
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Heterotrophs
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What type of producers of consumers are protists?
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Autotrophs or heterotrophs
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What type of producers of consumers are animals?
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Heterotrophs
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Is cellular respiration anabolic or catabolic?
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Catabolic
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Is cellular respiration endergonic or exergonic?
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Exergonic
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What molecule does cellular respiration require to begin?
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Oxygen
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Where does cellular respiration get its energy from?
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Marcomolecules such as glucose
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What is the chemical formula for cellular respiration?
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C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O + energy
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What is an autotroph?
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Harvesting sunlight and converting radiant energy into chemical energy
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What is a heterotroph?
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Living off the energy produced by autotrophs by digestion and catabolism
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In how many ways can glucose be catabolized?
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Two, substrate level phosphorylation and anaerobic respiration
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What are the basic steps of cellular respiration?
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Glycolysis, pyruvate oxidation, krebs cycle, electron transport chain
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Where does glycolysis occur?
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In the cytosol
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What is the total net yield of glycolysis?
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2 pyruvate (3 carbon), 2 ATP, 2 NADH
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Which organelle does most cellular aerobic respiration?
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Mitochondria
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What types of cells have mitochonrdia?
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Almost all eukaryotic
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What happens in the first step of krebs cycle?
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A two carbon group carried by coanzyme A is transfered to oxaloacetate, forming citrate
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What happens in the second step of krebs cycle?
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Citrate is rearranged into its isomer isocitrate
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What happens in the third step of krebs cycle?
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Isocitrate is oxidized to alpha-ketoglutarate, one carbon is removed and released as CO2 and NAD+ is reduced to NADH + H+
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What happens in the fourth step of krebs cycle?
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Alpha-ketogluterate is oxidized to succinyl-CoA, one carbon is released as CO2,and NAD+ is reduced to NADH + H+
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What happens in the fifth step of krebs cycle?
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The release of CoA from succinyl-CoA produces succinate, energy converts GDP to GTP, converting ADP to ATP
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What happens in the sixth step of krebs cycle?
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Succinate is oxidized to fumarate, two electrons and two protons are removed from succinate and produce FADH2
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What happens in the seventh step of krebs cycle?
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Fumarate is converted into malate by the addition of water
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What happens in the last step of krebs cycle?
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Malate is oxidized to oxaloacetate reducing NAD+ to NADH H+, oxaloacetate can react and re-enter the cycle
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Where in the cell is electron transport chain located?
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Inner mitochondrial membrane
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What is electron transport chain?
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A collection of molecules embedded in the inner membrane of the mitochondria
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For every 2 NADH molecules, one O2 molecule is used to reduce how many water molecules?
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2
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What does FADH2 do?
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Adds its electrons at the transport chain a lower level energy
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Does the electron transport chain make ATP?
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Not directly
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What created ATP in the electron transport chain?
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Chemiosmosis
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What are the products of the krebs cycle?
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4 ATP, 10 NADH, 2 FADH2, 6CO2
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What does glucose catabolism involve?
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A serious of redox reactions that release energy by the re-positioning of electrons
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Where does NADH carry electrons to?
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The inner mitochondrial membrane, where they transfer electrons to a series of membrane associated proteins
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What is fermentation?
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Electrons that result from the glycolytic breakdown of glucose are donated to an organic molecule
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During oxidative phosphorylation, water is formed. Where do the oxygen atoms in the water come from?
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Molecular oxygen
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How many carbon atoms feed into the krebs cycle?
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2
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Does fermentation create a net gain of ATP?
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Yes
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What characteristics would all prontobiont have had in common?
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A surrounding membrane or membrane-like structure
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The Miller-Urey experiment was a huge breakthrough in our understanding of the origins of life. What was its major conclusion?
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That abiotic synthesis of organic molecules was possible
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How do noncompetitive inhibitors render an enzyme helpless?
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Alter their shape thereby making their active site inoperable
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How do white blood cells engulf bacteria in out bloodstream?
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Phagocytosis
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Reactions that require a net imput of energy are known as what?
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Endergonic
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Where is the electron transport chain found in plant cells?
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Thylakoid membranes of chloroplasts
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What does carbon fixation involve the addition of carbon dioxide to?
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RuBP
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The stomata of CAM plants are generally open under which conditions?
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All night
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Why are C4 plants able to photosynthesize with no apparent photorespiration?
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They use PEP carboxylase to initially fix CO2
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The Calvin cycle is sometimes called the light-independent or dark reactions. This is misleading since the Calvin cycle ill stop operating after a plant is placed in the dark. Why?
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The Calvin cycle requires a constant supply of ATP generated by the light reactions
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What are the end products of glycolysis?
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NADH, pyruvate, and ATP
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What does one turn of the krebs cycle produce?
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3 NADH, 1FADH2, 1 ATP
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What kind of metabolic poison would most directly interfere with glycolysis?
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An agent that closely mimics the structure of glucose but is not metabolized
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What two processes in cellular respiration are sources of CO2?
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Pyruvate oxidation and Krebs cycle
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