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T1 - Ch3 Cell Bio
Energy, Catalyst, and Biosynthesis
| Question | Answer |
|---|---|
| Describe the relationship between life and disorder | living things create and maintain order on every level in a unverise that is always tending towards greater disorder |
| What fufills cells with thier needs? | the break down or modification of amino acids cids, sugars, nucleotides, and lipids |
| Millions of reactions are performed every second inside a cell - What is required in order for cells to do this? Where do these come from? | reactions need a 1) food source and an 2) atomic energy source Both come from a nonliving environment (sunlight) |
| What are enzymes? What do they do? | a major energy boost that acts like a catalyst in living things. Typically in series, they are the key to controlling metabolism |
| What is metabolism? | the sum of all the chemical reactions a cell needs to carry out in order to survive, grow, and reproduce |
| What is catabolism? | a set of enzyme-catalyzed reactions where complex molecules are broken down to simpler ones with the release of energy. Heat is lost |
| What are catabolites? | intermediates in a catabolic reation |
| What is anabolism? | a set of metabolic pathways where complex molecules are made from smaller ones. Energy required |
| What is biosynthesis? | another word for anabolism |
| _______ breeds disorder | time |
| How is order maintained? | through elaborate molecular mechanisms that extract energy from the environment and convert it into the energy storred in chemical bonds |
| Define thermodynamics | the study of the relationship between work, heat, and other energy forms |
| What is the 2nd law of thermodynamics | systems will change spontaneously toward arrangements with greater possibilities, and therefore disorder in the unveirse can only increase |
| What is entropy? What happens is entropy increases? | the meausre of a systems disorder. If entropy inc, disorder inc |
| Why do living cells not defy the 2nd law of thermodynamics? | because a cell is NOT an isolated system and can use energy from its environments (food, inorganic molecules, light photons) to restore order within itself. As a result, the entropy of the universe inc |
| What is the most disordered form of energy? | heat |
| What is the effect of released heat energy produced by metabolic pathways? | after dispersing to the cell's surroundings, outside heat will increase the intensity of thermal motion in molecules, continuing to increase entropy in the outside environment |
| What is the 1st law of thermodynamics? | enegry cannot be created or destroyed, only converted - total amount of energy in the universe must always be the same |
| How do cells carry out heat production and an increase of order in the cell? | heat production and increasing order are coupled in order to take place |
| What kind of initial energy do organisms rely on? | all organisms live on the potential energy storred in chemical bonds present in organic molecules |
| Why is photosynthesis so important to all living things - not just plants? | all life either: 1) gets energy directly from sunlight 2) eats plants for energy who rely on sunlight or 3) consume those who consume the plants who rely on sunlight |
| Define photosynthesis | a process that plants use to convert electromagnetic energy in sunlight into chemical-bond energy in cells |
| Describe the 2 stages of photosynthesis | stage 1 - sunlight energy is captured and storred as chemical bond energy in activated carriers, oxygen we break is generated by H2O splitting in photosynthesis stage 2 - activated carrier help drive a carbon-fixation process where sugars r made from CO2 |
| Give stage 1 of photosynthesis chemical equation | light energy + CO2 + H2O --> sugars + O2 + heat energy |
| What is cellular respiration? | - complex, stepwise process where food molecules are broken fown to produce energy - energy in food molecules is harvested with O2, CO2 is realsed |
| What is the relationship between cellular respiration and photosynthesis? | they are complementary processes (they reverse eachother) |
| What is the biosphere? Why is it important to Carbon atoms> | the collection of living things on earth Carbon atoms pass through a huge cycle involving the entire biosphere as they move between organisms and the environment |
| What do Oxidation and Reduction reactions have in common? | - both involved electron transfers - both use enzyme catalysts |
| What is Oxidation? | LOSS/removal of electrons from an atom to add an oxygen molecule |
| What is Reduction? | GAIN/addition of electrons from an atom to either add H, C, or remove O |
| Can RedOx reactions occur with partial or only full electron shifts? | they CAN occur with partial electrion shifts |
| Why do Oxidation and Reduction reactions always occur simultaneously? | because the number of electrons is alwys conservd in a chemical reactions |
| What are the partial charges on the reduced and oxidzed atoms? | the reduced atom has a partial negative the oxidized atom has a partial positive |
| In a RedOx reaction, where does the electron attach? | to the atom with the greater electronegativity |
| Explain this equation: A + (e-) + (H+) --> AH | when a molecule picks up an electron, it also picks up a proton at the same time |
| Are hydrogenation reactions reduction or oxidations? | reductions |
| Are dehydrogenation reactions reduction or oxidations? | oxidations |
| What does an increase or decrease of C-H bonds tell you about a redox reaction? | if the number of C-H bonds: Increase = reduction reaction, Decrease = oxidation reaction |
| What do enzymes do for reactions specifically? What can they not do? | - enzymes are proteins that catalyze a specific reaction by lowering the activation energy - they cannot force energetically unfavorable reaction (they are not an energy source) -they direct molecules through pathways while being unchanged |
| Chemical reactions proceed in the direction that causes a _______ of free energy (the spontaneous direction). | loss |
| Describe the relationship between free energy and disorder | the greater the free energy change, the greater amount of created universal disorder |
| Energetically, when does a reaction occur? | if the activation energy = total energy of the reactants |
| What is a substrate? How does it work? | a molecule on which an enzyme acts to catalyze a chemical reaction - they hold 1-2 molecules in a way that significantly reduces the activation energy |
| What is a catalyst? How do they relate to enzymes? | a substance that accelerates a chemica reaction by lowering its activation energy. Enzymes are catalysts in cells, whos enzymes convert substrates to desired products. |
| How are substrates converted more easily with an enzyme? | enzymes allow a much larger proportion of random collisions to break the energy barrier |
| What is free energy? | G, Delta G is the change in free energy (dG) - energy that can be harnessed to do work, such as driving a chemical reaction |
| Give the favorability, disorder change, and spontineity of a -dG | - energetically favorable - create disorder - spontaneous |
| Give the favorability, disorder change, and spontineity of a - +dG | - energetically unfavorable - create order - nonspontaneous |
| What do cells do to carry out nonspontaneous reactions? | they couple them with spontaneous ones so that the net dG is negative |
| What is equilibrium? | the state in which the rate of the forward and reverse reactions are equal and there is no net concentrational changes |
| What is the dG at equilibrium? | 0 |
| How do cells avoid the chemical inactivity normal reactions experience at equilibrium? Give an example | they expend energy to avoid the equilibrium state by exchanging materials with their environent - Ex: expelling waste, replenishing nutrients |
| What is dG* (knot)? | the dG measured at a defined concentration (1 mole per liter aqueous), temperature, and pressure |
| What is K? | equilibrium constant, the ratio of substrate to product at equilibrium - [products]/[substrate] |
| In a cell, there is a scarce amount of enzymes and their substrates. So how do these molecules find eachother quickly? | through diffusion and random walk - particles can explore the cytosolic space more rapidly than imaginable called random walk |
| What determines the speed of particles moving in a cell? Explain | the size of the particles smaller=faster, bigger=slower |
| What is the first step in an ezyme catalyzed reaction? How? | substrates are binded to enzymes through weak bonds |
| How do enzymes and substrates 'stick' together? | they use weak bonds of hydrogen bonding, Vander Waals, and electrostatic attraction |
| What prevents unwanting binding? | poor, noncovalent bonds |
| Thermodynamically, what determines if molecules will bind? | if the free energy of the result is lower than the sum of both unbound |
| the larger the K (affinity constant), the ___________ the drop in free energy, and the ______ the molecule will bind. | greater, tighter |
| What are activated carriers? How do they work? | they are small molecules that store energy or chemical groups in energy rich covalent bonds that can be then donated to unfavorable reactions |
| Where does ATP get energy from? | its 3rd, and sometimes 2nd, phosphate group |
| Describe ATP synthesis. | ADP and energy from food or sunlight is converted to ATP and H20 (positive dG). Then, ATP hydrolysis occures, the ATP and H2O is converted back into ADP, a phosphate group, and energy release (larger, negative dG) |
| What is a phosphorilation reaction? | any reaction that invoves the transfer of a phosphate group to a moleucle |
| Explain chemically how ATP hydrolysis is coupled with other reactions to fuel them | In the rxn: A-OH + B-H --> A-B + H2O What actually occurs is: A-OH + ATP --> A-O-P + ADP --> A-O-P + B-H --> A-B + P + ADP (second rxn called condensation step) |
| What are NADH and NADPH broadly? | activated electron carrier that carry energy in the form of 2e- and an H+ to form an H- |
| What is the difference in NADH and NADPH? | the single phosphate group difference causes them to have slightly different shapes. This makes it possible for them to react with 2 different sets of enzymes |
| Describe the production and break down of NADPH? Which is more common NADPH or NADP+? | it is produced in a redox cycle where the substrate is oxidized and NADP+ is produced - the hydride ion is readily given up because the nicotinamide ring is more stable without it -there is also a large negative dG -NADPH is more common |
| What is the main job of NADPH? | it is typically a reducing agent for enzymes that catalyze anabolic reactions |
| What is the main job of NADH? | NADH is an oxidizing agent intermediate in the catabolic system of reactions used to generate ATP - this is why NAD+ is more commonly foudn in cells |
| What is FADH2? | similar to NADH/NADPH, using to carry H+ and high energy electrons |
| What is Acetyl CoA? | an activated carrier that donates carbon atoms in its acetyl group to metabolize reactions |
| How does acetyl CoA carry energy? | the acetyl group is linked to CoC by a thioester bond that releases a large amount of energy when hydrolyzed |
| Many activated carriers carry energy in only a small area of the molecule. What is the purpose of the bulk of it then? | the bulk of the molecule facilitates the recognition of the carrier with specific enzymes |
| What are macromolecules made of? How are they made? | monomer subunits form macromolecules through enzyme catalysed condensation |
| How are macromolecules broken down? | through enzyme catalysed hydrolysis reactions |
| Example of condensation reaction. energetically favorable? | A-OH + H-B --> A-B + H2O energetically unfavorable |
| Example of hydrolysis reaction. energetically favorable? | A-B + H2O --> A-OH + H-B energetically favorable |
Created by:
MSchmitt23
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