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43 Cards in this Set
- Front
- Back
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Under anaerobic conditions, many microorganisms metabolize pyruvate to what?
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They metabolize pyruvate to lactate or to ethanol and CO2.
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What is the bacterial strain Streptococcus cremoris used for?
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It is used commercially to make cheese by producing larger amounts of lactate from pyruvate.
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What is the brewers yeast Saccharomyces cerevisea used for?
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It is used to produce carbonated beer from germinated barley seeds.
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Biochemically speaking, an organism at equillibrium with the environment is what?
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No longer alive
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What must a living organism be able to do in order to maintain a steady-state condition (homeostatis) that is far from equilibrium?
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A living organism mnnust be able to extract energy from the surroundings.
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What 3 things can we think of energy conversion or transduction in terms of?
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It can be thought of as chemical work in the form of macromolcular biosynthesis of organic molecules. It can be thought of as osmotic work to maintain a concentration of intracellular salts and organic molcules that is different than the extracellular milieu. It can be thought of as mechanical work in the form of flagellar rotation of muscle contraction.
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What is the first law of thermodynamics?
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It states that energy cannot be created or destroyed, only converted from one form to another.
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How can the energy potential of a compound be determined?
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It can be determined using a bomb calorimeter to measure heat transfer as a result of combustion of pure oxygen (O2).
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How can we write the equation used for bomb calorimetry?
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C6H12O6 + 6 O2 00> 6 CO2 + 6 H2O + heat
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What is the unit of energy in the bomb calorimetry example known as?
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It is a Calorie (kcal).
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What is a calorie defined as?
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It is defined as the amount of heat energy required to raise 1 kilogram of water from 14.5 degrees Celsius to 15.5 degrees Celsius.
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How is the definition of a calorie expressed as an international unit of measurement?
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It is expressed as a Joule (J)
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What is a Joule defined as?
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It is defined as 1 kcal, or Calorie, equalling 4.184 kJ.
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What does the second law of thermodynamics say?
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It says that all natural processes in the Universe tend towards disorder (randomness) in the absence of energy input.
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Why is energy required thermodynamically?
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Because a live cell is highly ordered as compared to the surroundings, which requires energy to restrain the natural tendency toward disorder.
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How is the concept of disorder defined?
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It is defined by the term entropy (S).
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What the change in standard free energy?
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It is the change in free energy between a reacting system under standard conditions (reactants initially at 1.0 M, the pressure if 1 atmosphere and the temperature is 298K = 25 degrees Celsius), and the same system once the reaction reaches equilibrium.
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What is sunlight?
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It is the ultimate source of energy
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What is the biochemical process of energy conversion of light energy into chemical energy called?
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It is called photosynthesis
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What are reactions where intermediary metabolites are oxidized and coenzymes are reduced, are sometimes called what?
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Redox reactions.
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What do redox reaction involve?
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They involve the transfer of electrons from one compound to another
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By definition, the oxidation of one compound results in what?
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The reduction of another.
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What are metabolic redox reaction catalyzed by?
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They are catalyzed by enzymes called dehydrogenases and oxidases.
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What coenzymes do metabolic redox reactions employ?
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They employ nicotinamide adenine dinucleotide (NADH and NAD+) and flavin adenine dinucleotide (FADH2 and FAD) that serve as electron donors and acceptors
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What is the adenylate system used for?
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It is used for short term energy storage
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What drives an ATP synthesis reaction that captures redox energy in the form of phosphoanhydride bond energy?
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Energy obtained from photosynthesis and oxidation of metabolic fuels drives the ATP synthesis reaction.
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What can the ratio of the concentration of ATP to the concentration of ADP and AMP in the cell at any given time be used as a measure of?
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It can be used as a measure of the energy state of the cell.
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What can this relationship be expressed in terms of?
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In can be expressed in terms of the Energy Charge (EC) of the cell.
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What does the EC of the cell take into account?
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It takes into account the number ofphosphoanhydride bonds available for work.
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What is the formula for Energy Charge?
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EC = [ATP] + 0.5[ADP] / [ATP] + [ADP] + [AMP]
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What is the regular range of EC?
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The regular range is between 0.7 and 0.9
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What does a larger EC number infer as opposed to a smaller number?
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The larger the number, the higher the concentration of ATP.
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What is a metabolic pathway?
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It is a set of linked reactions
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What do metabolic pathways consist of?
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They consist of a series of reactions that are coupleed together through the metabolism of shared intermediates
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What can metabolic pathways be linked together to form?
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They can form linear pathways, cyclic pathways, and branched pathways
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What is the definition of flux?
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The flow of metabolites
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What are the three items needed for an extended trip?
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A map to figure out where we are. An itinerary to keep on schedule. A guidebook to point out the important landmarks
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The metabolic map we have includes what?
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Four classes of macromolecules (proteins, nucleic acids, carbohydrates, and lipids). Six primary metabolites (amino acids, nucleotides, fatty acids, glucose, pyruvate, acertyl CoA). Six small biomolecules (NH4+, CO2, NADH, O2, ATP, H2O.
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What are the four questions needing to be asked when exploring a new pathway?
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What does the pathway accomplish for the cell? What is the overall net reaction of thew pathway? What are the key enzymes in the pathway? What are examples of this pathway in real life?
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What does reaction coupling permit?
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It permits energetically unfavorable reactions to form more favorable in the context of a pathway
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How is life on earth made possible?
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It is made possible by the biochemical reactions of photosynthesis, carbon fixation, and aerobic respiration, which together convert solar energy into ATP (and NADPH) which is used to synthesize carbohydrates from CO2 and H2O.
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What is lactose intolerance caused by?
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It is caused by reduced levels of the digestive enzyme lactase, which is required to hydrolize the dissacharide sugar lactose to form glucose and galactose.
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What does purified lactase enzyme, which is commercially available, accomplish for its users?
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It reduces the symptoms that occur when bacteria of the Lactobacillus family convert lactose to methane and hydrogen gases in the small intestine.
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