L06 GRQs - 6th GRQs UNC Chapel Hill Bio101 PDF

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6th GRQs UNC Chapel Hill Bio101...

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Energy and Enzymes and Cellular Respiration Guided Reading Qs (Do these before the Mastering Assignment.) (Reading 5.10-5.16 and 6.1-6.6) Reading Objectives:  Differentiate kinetic, potential, and chemical energy. In subsequent lessons, identify how these types of energy relate to cellular respiration and photosynthesis.  Compare and contrast cellular respiration and photosynthesis as energy reactions.  Explain the relationship between ATP and ADP.  Identify functions of enzymes and the conditions they work best at.  Explain how enzyme reactions are inhibited. Explain the purpose of aerobic respiration and name the inputs and outputs. Describe the significance of coenzymes in aerobic respiration. 1. The two basic forms of energy are: a. Kinetic energy (energy of motion) b. Potential energy (energy that matter possesses as a result of its location or structure) Match each type of energy to one of these two forms you listed above: The spinning movement of a protein as protons move through its channels (kinetic energy) The energy stored in the chemical bonds of glucose (chemical energy which is potential energy) The release of heat from your body when you exercise. (thermal energy which is kinetic energy) The sunlight that powers photosynthesis. (Light, which is kinetic energy) Energy in the universe can be transferred or transformed but it cannot be _created__ or _destroyed____. 2. Why is a plant cell thought of as an energy transformer? It converts light energy to chemical energy through photosynthesis 3. How is burning fuel in your car or burning wood similar to how your body uses fuel? How is it different? Some energy in any conversion is lost to thermal energy which is expelled into the environment and no longer available for use. -In both burning fuel in your car and a cell using fuel, a lot is lost to heat energy. -In both burning wood and cellular respiration, the process is exergonic, or releases energy into the atmosphere Define cellular respiration: process through which chemical energy stored in organic molecules is used to produce ATP, which the cell can use to perform work 4. Fill out the table below:

Photosynthesis

List the reactants. Are these “energy-rich” or “energy-poor”? Carbon dioxide + Water (energy poor)

List the products. Are these “energy-rich” or “energy-poor”? Glucose + Oxygen (energy rich because photosynthesis ABSORBS energy from sun to occur,

Cellular Respiration

Glucose + Oxygen (energy rich)

so the products are energy rich) Carbon dioxide + Water (energy poor, because cellular respiration is exergonic so energy is released as a separate byproduct)

5. How do the structures of ATP and ADP differ? ATP consists of an organic molecule called adenosine and a triphosphate tail of three phosphate groups, all of which are negatively charged (the polarity of the negative tails makes ATP comparable to a compressed spring, ready for action. ADP is the product of ATP going through hydrolysis. Hydrolysis breaks the bonds of the 3 phosphate groups of ATP and adding water INTO the reaction causes not only one of the phosphate groups of ATP to break off, but causes ENERGY to be a product. ADP = ATP minus one phosphate group, so ADP = the organic molecule adenosine + 2 phosphate groups in its tail. 6. How does phosphorylation lead to cellular work? What are examples of “cellular work”? -Hydrolysis of ATP is EXERGONIC (energy is released) so how does this do energy coupling / how does it relate to an endergonic reaction in contrast? **by transferring a phosphate group from ATP to another molecule Phosphorylation: the transfer of a phosphate group from ATP to another molecule. ATP goes through hydrolysis to have one of its phosphate groups broken off, and whats left is it becomes ADP and the ENERGY that is created from that is cycled because that phosphate group that was taken from ATP can then be in an ENGERGONIC reaction where it is ADDED to a different molecule to MAKE ATP -Examples of cellular work: chemical work (forming new products), transport work (transport proteins that go against concentration gradient, and mechanical work (a motor protein moving parts of a cell)

7. What does the activation energy of a chemical reaction specifically do to reactants? What do enzymes do to the activation energy? Activation energy contorts or weakens bonds in reactant molecules so that they can break, and new bonds can form. It is the amount of energy that the reactants must absorb before a chemical reaction can start. Enzymes function as biological catalysts, which lowers the activation energy for a reaction to begin. It is necessary because it is like an in-between so that the cells that DON’T need to begin a reaction don’t spontaneously break down. Almost all enzymes are proteins.

8. Draw a graph with two lines. One line will represent a reaction without an enzyme and the other will represent an enzyme-catalyzed reaction. Your Y-axis should be labeled as increasing energy and your X-axis should be labeled “progress of reaction”. Be sure to label the activation energy for both reactions.

9. True or False? Defend you answer for each (i.e. state why a particular statement is true or correct a false statement). _false__ Enzymes are consumed in reactions. (they are not a product or a reactant but just there to lower the activation energy) _false__ Enzymes are always proteins. (almost all enzymes are proteins) _false?__ “Substrate” is another word for reactant. (it is a reactant that is specifically acted on by an enzyme) _yes__ Enzymes are specific (there shape is specific to what kind of molecule they are catalyzing) _yes__ An enzyme may have multiple types of active sites to bind multiple types of substrates. 10. What conditions do most enzymes work best at? Higher temperatures denature the enzyme, so most enzymes work best at 35-40 degrees Celsius, close to our normal body temperatures. The optimal pH is fairly neutral in the range of 6-8. 11. The cereal you ate this week, even if it was Fruit Loops, contained metals found on the periodic chart such as zinc and iron. What are these metals doing in your cereal? And wait…is there a connection between chemistry and biology??? These metals are coenzymes (cofactors that are organic molecules) and are important because many enzymes require cofactors such as these to bind to the active site and function in catalysis. 11. Examine figure 5.15. Explain in your words what this illustration describes, being sure to define all the vocabulary words from this illustration. The figure described how inhibitors interfere with substrate binding. Some inhibitors, called competitive inhibitors and shown in the figure, are similar in structure to the intended substrate and can actually replace that substrate that needs to be there or make them compete for the spot. Or, noncompetitive inhibitors bind elsewhere on the enzyme, but that binding changes the shape of the enzyme so that the intended substrate cannot fit into the active site.

12. The books discusses how the same enzyme that transmits nerve impulses can be inhibited in insects and lead to death but when inhibited in a slightly different way in humans can be used as anesthesia for surgical procedures. What is the difference in this inhibition? The difference is that the enzyme inhibited in insects performs an irreversible inhibition, whereas some drugs such as those used in anesthesia can reversibly inhibit the same enzyme, so that eventually, when the problem is fixed, the enzyme can function again.

Chapter 6: Overview of Respiration 1. How does energy cycle through an ecosystem, as shown in Figure 6.1? Light energy is absorbed through the chloroplast in photosynthesis, and then converted into products including oxygen. Oxygen is used in cellular respiration in the mitochondria, which creates ATP/energy as byproducts. The waste products are carbon dioxide and water, which are then used in the chloroplast for photosynthesis. What is different about how matter cycles? In any energy cycle, some amount of energy is always lost as heat and lost from the system. But with matter, all of it is always recycled. What organisms can perform cellular respiration? All kingdoms of life can use cellular respiration 2. Deep breath in…. deep breath out. How is breathing related to cellular respiration? Cellular respiration is more specifically the harvesting of energy from food molecules by cells. The two processes are closely related because as we breathe in air, our lungs take up oxygen and our blood takes it to our other cells where cellular respiration occurs, while our lungs dispose of carbon dioxide. What is the chemical equation for cellular respiration? Glucose + 6 (Oxygen gas)  6 (Carbon dioxide) + 6 (water) + ATP + heat

Only 34% of the energy is captured from the bonds stored in glucose. What happens to much of the energy originally stored in glucose? The rest of the energy is lost to heat 3. Late night pizza run in the dorms—you have already eaten plenty for the day so these two slices are “extra” that you promise to burn off tomorrow in the gym with some walking around campus. If each pizza slice is about 475kcal, and you weigh approximately 150lbs, how many hours will you walk around campus at 3mph? ____ Those two pizza slices will total to 950 kcal. Walking 3 mph for an hour at 150 pounds burns 245 kcal. 950kcal / 245 kcal = 3.88 hours.

4. Ultimately electrons are passed from glucose to oxygen. Glucose is oxidized/reduced? oxidized Oxygen is oxidized/reduced? reduced What happens to the energy lost through these electron transfers? Some of the energy lost through oxidation is captured by the cells to make ATP 5. Co-enzymes are a bit like taxi drivers in the process picking up and releasing electrons. When NAD+ gains electrons from glucose and other molecules, we say it has been _reduced_______________. It is now in the form NADH (it has picked up one proton from hydrogen too). When NADH gives up (loses) these electrons to the electron transport chain we say that this molecule has been _oxidized____________. Let’s end this set of GRQs with the overview of cellular respiration in eukaryotes. Be attentive to details like the color coding that your book uses. You will see these same symbols/colors in the animation too. (Prokaryotes don’t have mitochondria—can they make ATP? Yes or no? Do they have energy needs?) Overview: in a eukaryote A. Stage 1: Glycolyis: occurs where in the cell? _cytoplasm (that’s where glucose is found) ____ Glucose is split into two molecules of a 3-carbon compound called _pyruvate___________. Is any ATP made? (yes or no) B. Stage 2: _Pyruvate Oxidation_________ and __Citric Acid Cycle_________. This takes place where in the cell? _mitochondria_____________ Pyruvate is now broken ultimately to _CO2_______________ (a one-carbon compound) which you eventually breathe out. Is any ATP made? (yes or no) Stages 1 and 2 importantly supply _Oxygen___________ (little blue balls) to the third stage. C. Stage 3: Oxidative __phosphorylation_________________. Located where in cell? _mitochondria__________________ Is any ATP generated? (yes or no) How does this compare to stages 1 and 2? __much more is made (Majority)________.

Tip: Watch the BioFlix animation in the study area of Mastering in this chapter. Then, put it on mute and see if you can narrate it!...