Kin 470 Exam 1 Study Guide 1. What is homeostasis and how does it differ from steady state? - Homeostasis is the maintenance of a constant internal environment despite a changing external environment. Steady state is the balance between demands placed on body and the physiological response to those demands.- During both homeostasis and steady state the input is equal to the output, however, during steady state the body needs to adjust to the increasing demands and therefore needs to input more in order to keep the body at homeostatic levels.- Homeostasis oscillates around a set point, when certain levels in the body get too high or too low the body works to correct them back toward the set point.- The reason for oscillation is feedback via biological control systems.o Biological control systems: Receptor/sensor Integrating/control center effector- During steady state exercise, the body’s temperature will increase with longer duration. It maintains a level temperature but it is increased from the normal temp of the body.2. What do enzymes do in a reaction and what is common about their nomenclature? - Enzymes are catalysts that regulate the speed of reactions by lower the energy of activation required.- Enzymes are regulated by temperature and pH. Temperature increases are associated with an increase in enzyme activity. Acidosis (decreased pH) impairs enzyme activity.- Enzymes interact with specific substrates (like a lock & key). Some are more simple than others. (ex. substrate A + enzyme  substrate B + substrate C +enzyme or substrate A + substrate B + enzyme  substrate C + substrate D + enzyme)- Their nomenclature consists of as “ase” suffix.- There are oxidoreductases (redox reactions), transferases (transfers elements), and ATPases(hydrolyze ATP).- MyosinATPase couples the hydrolysis of ATP to generation of force and motion in muscle.3. What is and endergonic reaction and how does it differ from an exergonic reaction? - An endergonic reaction is one that requires energy in order to build products. An exergonic reaction is a reaction in which the reactants release energy.- Exergonic reactions occur spontaneously. Endergonic reactions use the energy released from an exergonic reaction to drive it (this is known as a coupled reaction). 4. What is meant by coupled reactions?- Exergonic reactions occur spontaneously. Endergonic reactions are a part of coupled reactions in which the energy released from an exergonic reaction drives an endergonic reaction.5. What is gained and lost during a redox reaction? - Redox reactions are also known as oxidation-reduction reactions in which electrons are transferred between chemical species. During the reaction, one electron is removed from a molecule and this is called oxidation. This is what is lost. Anothermolecule gains the electrons and this is called reduction (reduce the charge of the molecule).- The reactions are always coupled.6. What is the role of NADH in metabolism? Where is it made and what is the purpose of its oxidation? - The role of NADH in metabolism is to accept hydrogen atoms. It is formed during theproduction phase of glycolysis as well as the Kreb’s cycle.- Oxygen takes the hydrogen off of the NADH during the electron transport chain in the mitochondria. If oxygen isn’t available the hydrogen will be accepted by pyruvic acid to form lactic acid. In this case, NADH is an enzyme for the reaction. This converts NADH to NAD+ so that glycolysis may continue.- It is made in the mitochondria.- The purpose of its oxidation is to be used in the electron transport chain; it creates aproton gradient and power ATP production via hydrogen and electron flow from oxygen to form water.7. What is the function of the ETC? - The function of the electron transport chain is to create ATP via a proton gradient. The proton gradient is created by NADH and FADH2. There are 4 cellular proteins in the inner membrane of the mitochondria. Hydrogen atoms on the inside are pumped out via these proteins in order to create a high concentration gradient in the outer membrane of the mitochondria. This concentration gradient gets the ATPsynthase to spin, this causes ATP to be created from a phosphate and ADP.- Each NADH creates 2.5 ATP.- Each FADH2 creates 1.5 ATP8. How does ATP synthase drive the formation of ATP? - ATP synthase drives the formation of ATP by allowing hydrogen to move inside of the membrane. There is a high concentration gradient on the outside. The spinning of ATP synthase causes a phosphate and ADP to move into the mitochondria and create ATP.- ATP synthase has a rotary motor.9. What are the possible fates of pyruvate and what determines its fate? - The possible fates of pyruvate are going through the Kreb’s cycle (where it is oxidizedand becomes Acetyl CoA) or it becomes lactic acid. It can only go through the Kreb’s cycle if NAD is available to remove hydrogens. NAD may not be available if there is not enough oxygen available. Oxygen removes a hydrogen from NADH during the electron transport chain to create the byproduct, water. NAD is recycled to be used during the Kreb’s cycle. When NAD can’t accept hydrogens due to lack of oxygen, pyruvic acid will accept hydrogens to form lactic acid.10. What are the rate limiting enzymes of glycolysis and the Kreb’s cycle? - The rate limiting enzymes of glycolysis are PFK and HK. - The rate limiting enzymes of the Kreb’s cycle is Isocitrate dehydrogenase.- High levels of ATP inhibit ATP production- Low levels of ATP and high levels of ADP + P stimulate ATP production11. What products are generated by the complete breakdown of glucose and what pathwaysdo these products come from? - The products generated by the complete breakdown of glucose are:o Glycolysis 2 ATP 2 NADHo Pyruvic Acid – Acetyl CoA 2 NADHo Kreb’s Cycle 2 GTP (create 2 ATP total – 1 each) 6 NADH 2 FADH- Total ATP from one glucose = 32- The byproducts of the breakdown of glucose are CO2 and water.- Overall efficiency of aerobic respiration is 34%- 66% released as heat12. Plot the percentage energy derived from each system over time -- short term, high intensity activities have a greater contribution of anaerobic energy systems- long term, low to moderate intensity exercise has a majority of ATP produced form aerobic sources- at rest, almost 100% of ATP is produced by aerobic metabolism & blood