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| defines the periphery of the cell |
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| the internal volume of the cell enclosed by the plasma membrane that is composed of an aqueous solution (cytosol) & a variety of suspended particles with specific functions |
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| supramolecular structures that are the sites of protein synthesis; example of one of the suspended particles in the cytoplasm of the cell |
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| hundreds of small organic molecules that are intermediates in biosynthetic & degradative pathways found in the cytosol of the cell |
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| the part of the cell in which the genome (the complete set of genes composed of DNA) is replicated & stored along with its associated proteins |
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| cells in which the nucleus is enclosed within a double membrane |
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| microorganisms without nuclear membranes; divided into two groups: bacteria & archaea |
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| 2 large groups of single-celled microorganisms that can be distinguished on genetic & biochemical grounds |
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| Are eukaryotes more closely related to archaea or bacteria? |
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Definition
| archaea; all eukaryotic organisms evolved from the same branch that gave rise to archaea |
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| habitats with a plentiful supply of oxygen; organisms derive energy from the transfer of electrons from fuel molecules to oxygen within the cell |
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| environments that are virtually devoid of oxygen; microorganisms adapt to the environment by obtaining energy by transferring electrons to nitrate, sulfate, or CO2 |
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| 2 categories based on energy sources |
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Definition
1. phototrophs (trap & use sunlight)
2. chemotrophs (derive their energy from oxidation of a chemical fuel) |
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| 2 further divisions of phototrophs & chemotrophs |
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Definition
1. autotrophs (can synthesize all of their biomolecules directly from CO2)
2. heterotrophs (require some preformed organic nutrients made by other organisms) |
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| the plasma membrane & the layers outside it |
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| smaller, circular segments of DNA found in the cytoplasm |
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| the site of most of the energy-extracting reactions of the cell; example of an organelle |
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| several types of protein filaments crisscrossing the eukaryotic cells that form an interlocking three-dimensional meshwork |
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Definition
| segregates specific metabolic processes & provides surfaces on which certain enzyme-catalyzed reactions occur |
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| 2 mechanisms of transport that involve membrane fusion & fission to provide paths between the cytoplasm & surrounding medium to allow for secretion of substances produced in the cell & uptake of extracellular materials |
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Definition
1. exocytosis
2. endocytosis |
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Definition
| small molecules found in vascular plants in addition to the universal set that play roles specific to plant life |
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| the entire collection of small molecules in a given cell under a specific set of conditions (think: sounds like "genome") |
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| the systematic characterization of the metabolome under very specific conditions |
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| polymers with molecular weights above ~5,000 that are assembled from relatively simple precursors; many biological molecules fall into this category |
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| long polymers of amino acids; constitute the largest fraction of a cell |
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| the sum of all the proteins functioning in a given cell; characterized under a specific set of conditions in "proteomics" |
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| DNA & RNA; polymers of nucleotides |
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| the characterization of the comparative structure, function, evolution, & mapping of genomes |
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| polymers of simple sugars such as glucose; 3 major functions are energy-rich fuel stores, rigid structural components of cell walls, & extracellular recognition elements that bind to proteins on other cells |
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| all of a cell's carbohydrate-containing molecules |
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| water-insoluble hydrocarbon derivatives; serve as structural components of membranes, energy-rich fuel stores, pigments, & intracellular signals |
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| the lipid-containing molecules in a cell |
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| Why are proteins & nucleic acids referred to as "informational macromolecules"? |
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Definition
| they have information-rich subunit sequences |
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Definition
| molecules with the same chemical bonds & same formula but different configuration (the fixed arrangement of atoms); carbon-containing compounds are commonly stereoisomers |
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Definition
| interactions between biomolecules that require specific configurations in the interacting molecules |
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| geometric isomers (cis-trans isomers) |
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Definition
| compounds that differ in the arrangement of their substituent groups with respect to the nonrotating double bond |
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Definition
| asymmetric carbons that have four different substituents |
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| stereoisomers that are mirror images of each other |
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Definition
| pairs of stereoisomers that are not mirror images of each other |
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Definition
| an equimolar solution of two enantiomers that rotate the plane of plane-polarized light in opposite directions in separate solutions but when mixed together show no optical rotation |
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Definition
| the spatial arrangement of substituent groups that, without breaking an bonds, are free to assume different positions in space because of the freedom of rotation about single bonds; distinct from configuration! |
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Definition
| all the constituent reactants & products, the solvent that contains them, & the immediate atmosphere for chemical reactions occurring in solution; everything within a defined region of space |
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Definition
| the system & its surroundings |
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Definition
| if the system exchanges neither matter nor energy with its surroundings |
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Term
| What is the difference between a closed & open system? |
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Definition
closed = if the system exchanges energy but not matter with its surroundings
open = if it exchanges both energy & matter with its surroundings |
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| 2 ways in which organisms obtain energy from their surroundings |
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Definition
1. take up chemical fuels from the environment & extract energy by oxidizing them
2. absorb energy from sunlight |
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Term
| oxidation-reduction reactions |
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Definition
| reactions involved in electron flow in which one reactant is oxidized as the other is reduced |
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Definition
| the randomness (disorder) of the components of a chemical system |
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Term
| 3 quantities in which the free-energy constant (G) of a closed system can be defined |
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Definition
1. enthalpy (H) (the number & kinds of bonds)
2. entropy (S)
3. the absolute temperature (T) |
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Term
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Definition
| thermodynamically unfavorable, energy-requiring reactions; carried out by cells through coupling them to other reactions that liberate free energy (exergonic reactions) so that the overall process is exergonic & the sum of the free-energy changes is negative |
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Term
| In closed systems, when do chemical reactions stop proceeding spontaneously? |
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Definition
| when equilibrium is reached |
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Term
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Definition
| biocatalysts that greatly enhance the rate of specific chemical reactions without being consumed in the process; virtually every chemical reaction in a cell occurs at a significant rate only because of the presence of enzymes |
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Term
| What is first required before the breaking of existing bonds & the formation of new ones? |
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Definition
| a distortion of the existing bonds to create a transition state of higher free energy than either reactant or product |
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Definition
| the difference in energy between the reactant in its ground state & in its transition state (the highest point in the reaction coordinate diagram) |
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Definition
| sequences of consecutive reactions into which the thousands of enzyme-catalyzed chemical reactions in cells are functionally organized; the product of one reaction becomes the reactant in the next |
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Definition
| the degradative, free-energy-yielding reactions in which organic nutrients are degraded into simple end products in order to extract chemical energy & convert it into a form useful to the cell |
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Definition
| synthetic pathways which require the input of energy |
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Definition
| the overall network of enzyme-catalyzed pathways (both catabolic & anabolic) |
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Term
| How does feedback inhibition benefit the cell? |
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Definition
| it keeps the production & utilization of each metabolic intermediate in balance |
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