Biology
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jumpingjordy on October 20, 2012
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Test 2
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55 terms
Terms | Definitions |
|---|---|
 Catabolic pathways | breaking down complex molecules to simpler compounds "breakdown pathways" |
| Anabolic pathway | consumes energy to buld complicated molecules from simpler ones "biosynthetic pathways" |
| Bioenergetics | the study how energy flows through living organisms |
| Engery | capacity to cause change |
| Kinetic engery | energy can be associated with the relative motion of objects |
| Heat/thermal energy | kinetic energy associated with the random movement of atoms or molecules |
| Potential energy | energy that matter possesses because of its location or structure |
| Chemical energy | term used by biologists to refer to the potential energy available for release in a chemical reaction |
| thermodynamics | the study of energy transformation that occur in a collection of matter |
| first law of thermodynamics | the energy of the universe is constant: energy sn be transferred and transformed, but it cannot be created or destroyed. also known as the principle of conservation of energy |
| entropy | measure of disorder, or randomness |
| second law of thermodynamics | every energy transfer or transformation increases the entropy of the universe |
| spontaneous process | a process that can occur without an input of energy |
| free energy | the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell |
| exergonic reaction | "energy outward" proceeds with a net release of free energy. energy released, spontaneous |
| endergonic reaction | "energy inward" one that absorbs free energy from its surroundings.energy required, non spontaneous |
| chemical work | the pushing of endergonic reaction that would not occur spontaneously, such as the synthesis of polymers from monomers |
| transport work | the pumping of substances across membranes against the direction of spontaneous movement |
| mechanical work | such as the beating of cilia, the contraction of muscle cells, and the movement of chromosomes during cellular reproduction |
| energy coupling | the use of exergonic process to drive an endergonic one |
| ATP | responsible for mediating most energy coupling in cells, and in most cases it acts as the immediate source of energy that power cellular work |
| enzyme | macromolecule that acts as a catalyst |
| catalyst | a chemical agent that speeds up a reaction without being consumed by the reaction |
| activation energy | the initial investment of energy for starting a reaction |
| active site | a pocket or groove on the surface of the enzyme where catalysis occurs |
| induced fit | chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction |
| substrate | the reactant an enzyme acts on is referred to as the enzyme's _____ |
| enzyme-substrate complex | the enzyme binds to its substrate |
| competitive inhibitor | reduce the productivity of enzymes by blocking substrate from entering active sites |
| noncompetitive inhibitors | do not directly compete with the substrate to bind the enzyme at the active site . Instead they impede enzymatic reactions by binding to another part of the enzyme. this interaction causes the enzyme molecule to change its shape in such a way that the active site becomes less effective at catalyzing the conversion of substrate to product |
| feedback inhibitor | a metabolic pathway is switched off by the inhibitor binding of its end product to an enzyme that the inhibitory binding of its end product to an enzyme that acts early in the pathway |
| cell division | unicellular organisms reproduce by this |
| cell cycle | an order sequence of events in the life of a cell form its origin until it divides into daughter cells |
| genome | a cell's endowment of DNA, its genetic information |
| chromosomes | DNA is manageable because the DNA molecules are package into structures called ___ |
| chromatin | the entire complex of DNA and proteins that is the building material of chromosomes |
| stomatic cell | any body cell except the reproductive cells |
| gametes | sperm or eggs |
| sister chromatids | duplicated chromosome, which are joined copies of the original chromosome |
| centromere | a region containing specific DNA sequences where the chromatid is attached most closely to its sister chromatid |
| Mitosis | the division of the genetic material in the nucleus |
| cytokinesis | the division of the cytoplasm |
| mitotic (M) phase | includes both mitosis and cytokinesis, usually the shortest part of the cell cycle |
| G1 phase | first gap in cell cycle |
| S phase | synthese in cell cycle |
| G2 phase | second gap in cell cycle |
| cell cycle | In a dividing cell, mitotic (M) phase alternates with interphase, a growth period. the first part of the interphase (G1) is followed by the S phase, when the chromosomes duplicate; G2 is the last part of interphase. In the M phase mitosis distributes the daughter chromosome to daughter nuclei and cytokinesis divides the cytoplasm producing two daughter cells, the relative duration of G1, S, and G2 may vary |
| Stages in mitosis | prophase, prometaphase, metaphase, anaphase and telophase |
| mitotic spindle | apparatus of microtubles that controls chromosome movement during mitosis |
| centrosomes | a subcellular region containing materials that functions throughout the cell cycle to organize the cell's microtubles. spindle microtubules start here |
| aster | a radial array of short microtubules, extends from each centrosome |
| kinetochore | a structure of proteins associated with specific sections of chromosomal DNA at each centromere |
| cleavage | animals carrying out mitosis in cytokinesis |
| cell plate | plants carrying out mitosis in cytokinesis |
| binary fission | A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size |
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