IB 150 exam1 Updated and Graded A+ 2022

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What is the smallest unit that we recognize as "being alive"? - ANSWER cell Which of the following structures is only associated with eukaryotic cells? SELECT ALL THAT APPLY - ANSWER 1. Mitochondri ... a and other organelles 2. Nucleus containing the DNA One general attribute that sets life apart from non-living matter - ANSWER Those that require the ability to pass on hereditary information -reproduction and growth -evolution Another general attribute that sets life apart from non-living matter - ANSWER Those that require the input of energy in order to proceed -homeostasis -reproduction and growth -reacting to the environment First law of Thermodynamics - ANSWER Energy is conserved Second law of thermodynamics - ANSWER Any isolated system, left to its own devices, has a natural tendency to move towards equilibrium, with maximum entropy (potential for disorder) What happens to kinetic energy when a ball is thrown in the air and comes to a halt as it hits the table? - ANSWER -The energy was converted into thermal kinetic energy -The energy was converted into sound -The energy was converted into chemical potential energy Reactions are energetically favorable when... - ANSWER The change in free energy of the system is negative (deltaG < 0) When is the change in free energy (triangle G) negative? - ANSWER When their potential energy has decreased (deltaH < 0) and/or the disorder after the reaction has increased (deltaS > 0) Exergonic reaction - ANSWER A chemical reaction that releases energy (deltaG < 0) Endergonic reaction - ANSWER A nonspontaneous chemical reaction, in which free energy is absorbed from the surroundings (deltaG > 0) Will water naturally flow into or out of a fish? - ANSWER Water will have the tendency to move INTO the fish True or False: When equilibrium is reached, water molecules stop moving across the semipermeable cell membrane. - ANSWER False Which of these states requires ONLY exergonic chemical reactions? - ANSWER A decaying mouse What can you do to provide the necessary energy to overcome the activation energy? - ANSWER Increase temperature After you add a catalyst, what do you expect to happen to the reaction rate? - ANSWER Increase How can the enzymes in your cell catalyze your endergonic metabolic reactions? - ANSWER The enzyme has to couple the endergonic reactions with exergonic reactions. Which of the following molecules provides energy that can be used to power endergonic reactions? - ANSWER ATP True or False: The presence of activation energy changes the deltaG of an exergonic reaction, and turns otherwise exergonic reactions into endergonic reacitons. - ANSWER False Why might an enzyme stop catalyzing a reaction before all of the hydrogen peroxide decomposed into water and oxygen? - ANSWER Enzyme denatures Enzymes can only catalyze endergonic reactions if... - ANSWER They are in the presence of an energy coupling agent such as ATP. What do cells need to obtain in order to perform aerobic cellular respiration? - ANSWER Oxygen and Glucose What is diffusion? - ANSWER The movement of a chemical through a medium through random, thermal motions How does diffusion result in the movement of chemical substances form one medium into another? - ANSWER The direction of diffusion is from a region of high concentration to low concentration, simply do to probability as these molecules are moving randomly about. Diffusion formula: Surface area (A) - ANSWER The larger the surface area, the higher the diffusion rate. Diffusion formula: Concentration Gradient (Phigh - Plow) - ANSWER The higher the concentration gradient, the higher the diffusion rate. Diffusion formula: Length (L) - ANSWER The shorter the length of the diffusion path, the higher the diffusion rate. Diffusion formula: Diffusion coefficient (D) - ANSWER The higher the permeability, the higher the diffusion rate. Can we change another variable in Fick's law of diffusion so diffusion rate suffices, to make up for larger L in bigger organisms? - ANSWER No, the organism is stuck with whatever oxygen concentration happens to be in the environment. What is the effective surface area of an organism for gas exchange? - ANSWER The surface area available per unit volume for gas exchange. How might a non-flat organism, like humans, reduce the diffusion length between the high oxygen concentration in the air and reach their body cells? - ANSWER Examples of mass flow - ANSWER -Blood flow in a circulatory system -Pulling air into a lung by contracting your diaphragm -Water moving over gills How do respiratory pigments increase the rate of diffusion from alveoli into the blood fluid in adjacent capillaries? - ANSWER By reducing the concentration of oxygen dissolved in the blood fluid. What is the highest percent oxygenation of the blood that can be achieved if blood and water flow are in the same direction? - ANSWER 50% What is the crucial difference between bird lungs and mammalian lungs that prevents us mammals from engaging in countercurrent flow? - ANSWER Mammals do not have unidirectional air flow through their lungs. Which variable of the ficks law of diffusion equation is optimized by moving respiratory gases largely via mass flow in the circulatory system? - ANSWER L is minimized In terms of variables in ficks law, what function does hemoglobin play in the delivery of oxygen? - ANSWER It maintains a positive concentration gradient for longer by preventing equilibrium. How does hemoglobin support the oxygen concentration gradient in the pulmonary capillaries (capillaries in your lungs)? - ANSWER Maintains low p(low) in blood plasma. How does hemoglobin support the oxygen concentration gradient in the systemic capillaries (rest of the body's tissue)? - ANSWER Maintains high p(high) in plasma of blood. [Show More]

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