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32 Cards in this Set
- Front
- Back
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What is metabolism? |
All chemical reactions in an organism |
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Metabolic reaction are organized into pathways of enzyme controlled ________________________. |
Chemical reactions |
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Metabolic pathways begin with a specific _______________ and end with a __________________. |
molecule(s) product |
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What is the role of catabolic pathways? |
To break down complex molecules into simple molecules |
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Catabolic reactions ___________ energy, while anabolic reactions __________ energy. |
produce
require |
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Types of cellular work (3) |
i. mechanical ii. transport iii. chemical |
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Define free energy |
Energy that can preform work - available energy under the conditions of a biochemical reaction |
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What is bioenergetics? |
The study of energy flow through living organisms |
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How is energy extracted? (4) |
photoautotrophy chemeoautotrophy photoheterotrophy chemoheterotrophy |
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What are forms of energy? (4) |
kinetic energy heat potential energy chemical energy
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What are the two laws of thermodynamics? |
1st Law - Energy can be transferred and transformed but cannot be created or destroyed. 2nd Law - Every energy transfer or transformation increases the entropy (i.e., randomness) of the universe. |
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What is thermodynamics? |
The study of energy transformation that occur in a collection of matter |
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Organisms are _________ systems |
open
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What does the free energy change of a reaction determine? |
Whether or not the reaction will be spontaneous |
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only reactions with _________ free energy change are spontaneous. |
negative |
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Define an exergonic reaction |
Exergonic (exothermic) releases free energy -- will occur spontaneously |
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Define endergonic reactions |
Endergonic (endothermic) absorbs free energy -- will NOT occur spontaneously |
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Why are cells an open system? |
Once systems reach equilibrium they will do no more work. Therefor is a cells metabolism reaches equilibrium, it dies. |
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What is energy coupling? |
energy released by catabolic processes is used to drive anabolic processes |
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What are the steps in an exergonic chemical reaction? |
1. Absorption of activation energy 2. Transition state 3. Reaction state |
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What is energy coupling? |
energy released by catabolic reactions used to deive anabolic processes |
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When will reactions occur spontaneously? |
When delta G is smaller than 0 |
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What are the steps involved in an exergonic reaction? |
1. Absorption of Activation Energy 2. Transition state 3. Reaction occurs
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How can the activation energy barrier be overcome? |
The introduction of catalysts |
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Explain how enzymes are substrate specific? |
The shape ( or 3D conformation) of an enzyme determines which substrates it may act upon |
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What are the three features of enzymes? |
1. Substrate specific 2. Catalysts occurs in the active site 3. catalytic cyle |
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What is the catalytic cycle? |
Substrate + enzyme --> ES complex --> product + enzyme produced enzyme becomes reactant enzyme |
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What are mechanisms for lowering activation energy? |
1. proper positioning of 2+ reactants 2. distort chemical bonds 3. provides appropriate microenvironment (e.g. pH) 4. Participation of R-groups in reaction |
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Factors affecting the rate of enzymatic reactions |
1. enzyme turnover number 2. Initial substrate concentration 3. Physical factors (pH, temp) 4. Chemical factors (cofactors, inhibitors)
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What are control mechanisms of metabolism? |
1. Gene expression 2. Enzyme activity 3. compartmentalization |
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What is allosteric regulation? |
The proterin function at one site is afectec by binding of a regulatory molecule to a separate site on the protein. May be inhibitors or activators Most composed of 2+ polypeptides |
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What is feedback inhibition? |
A metabolic pathway is switched off by its end products. Think negative feedback |
