Biology chapter 5

• When analysing markets, a range of assumptions are made about the rationality of economic agents involved in the transactions
• The Wealth of Nations was written

  1776
• Rational


  (in classical economic theory) economic agents are able to consider the outcome of their choices and recognise the net benefits of each one
• Rational agents will select the choice which presents the highest benefits
• Consumers act rationally by


  Maximising their utility
• Producers act rationally by


  Selling goods/services in a way that maximises their profits
• Workers act rationally by


  Balancing welfare at work with consideration of both pay and benefits
• Governments act rationally by


  Placing the interests of the people they serve first in order to maximise their welfare
• Groups assumed to act rationally


  • Consumers
  • Producers
  • Workers
  • Governments
• Rationality in classical economic theory is a flawed assumption as people usually don't act rationally
• Marginal utility


  The additional utility (satisfaction) gained from the consumption of an additional product
• If you add up marginal utility for each unit you get total utility
• Thursday March 14, 2024 is the date of the Chapter 5 Lecture
• Next week is Spring Break - no assignments due
• The following week, 3/28 is the second exam, which is in person and the entire class (4-5:15) will be available to complete it
• The topic of the Chapter 5 Lecture is The Working Cell
• Cells control their chemical environment using energy, enzymes, and the plasma membrane
• Energy


  The capacity to cause change or the ability to do work
• Kinetic energy


  The energy of motion
• Potential energy


  Stored energy, energy that an object has because of its location or structure
• Chemical energy


  Energy stored in molecules based on the arrangement of atoms, can be released by a chemical reaction
• Cellular respiration


  The energy-releasing chemical breakdown of fuel molecules, the storage of that energy in a form the cell can use to perform work
• ATP


  Acts like an energy shuttle, stores energy obtained from food, releases it later as needed
• ATP (adenosine triphosphate)


  Consists of an organic molecule called adenosine plus a tail of three phosphate groups, is broken down to ADP and a phosphate group releasing energy
• The ATP-ADP cycle


  Cellular work spends ATP continuously, ATP is recycled from ADP and a phosphate group through cellular respiration, a working muscle cell spends and recycles up to 10 million ATP molecules per second
• Phosphate transfer


  ATP energizes other molecules by transferring phosphate groups, this energy helps cells perform mechanical work, transport work, and chemical work
• Metabolism


  The total of all chemical reactions in an organism
• Enzymes


  Proteins that speed up chemical reactions, all living cells contain thousands of different enzymes, each promoting a different chemical reaction
• Enzymes


  • They reduce the amount of activation energy required to break bonds of reactant molecules
• Substrate


  A reactant molecule that an enzyme recognizes
• Active site


  The site on an enzyme that fits to the substrate, causing the enzyme to slightly change shape
• Induced fit


  The interaction where the entry of the substrate induces the enzyme to change shape slightly
• Enzyme inhibitors


  Can prevent metabolic reactions by binding to the active site or near the active site, resulting in changes to the enzyme's shape so that the active site no longer accepts the substrate
• Feedback regulation


  When products of a reaction may inhibit the enzyme required for its production, preventing the cell from wasting resources
• Diffusion


  The movement of molecules so that they spread out evenly into the available space
• Passive transport


  The diffusion of a substance across a membrane without the input of energy
• Concentration gradient


  A region in which the substance's density changes
• Simple diffusion


  Diffusion of substances that are small and nonpolar
• Facilitated diffusion


  The passage of a substance that can't diffuse on its own with the help of a protein
• Osmosis


  The diffusion of water across a selectively permeable membrane