Study Guide for Exam 2
Study Guide for Exam 2 Biology 003
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This 10 page Study Guide was uploaded by Faith M Elissague on Sunday October 2, 2016. The Study Guide belongs to Biology 003 at Los Angeles Valley College taught by Yousef Harfouche in Fall 2016. Since its upload, it has received 34 views. For similar materials see Intro Biology in Biology at Los Angeles Valley College.
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Date Created: 10/02/16
Study Guide for Exam 2 Chapter 5 In this chapter we learned about how cells work, how molecules move, why energy is important, and how membranes function. Energy: the capacity to cause change. Remember when Professor held the book over the student’s head? When he did this, he was using energy against the force of gravity. ● Kinetic Energy: the energy of motion. Kinetic energy is fire, energy in the form of muscle movement in a runner, or anything that is in “current” motion. ● Conservation Energy: this principle states that it is not possible to either create or destroy energy. The energy is converted from one form to another. (i.e. kinetic energy to potential energy). So when a runner is about to set out for a race, while he waits, he is practicing otential energy. ● Potential Energy: the energy an object has because its location or stru emember the energy contained by water behind a dam or compressed spring. ● First Law of Thermodynamics: energy cannot be created nor destroyed, only converted from one form to another ● Second Law of Thermodynamics: with every energy conversion, some energy will be lost in the form of heat ○ Heat: a type of kinetic energy contained in the random motion of atoms and molecules. All energy conversions generate some heat. ● Energy in food is found in the C-H bonds and it is an example of potential energy. This energy is called chemical energy. Fats has the highest amount of stored energy. ○ Calorie: units of energy ● Living organisms use ATP energy. ATP stands for Adenosine triphosphate. TP consists of an organic molecule plus hree(tri) phosphate groups. ○ To explain how this generates energy for the cell we shou emember the analogy of the two phosphates in a relationship and the other phosphate at the end that is the third wheel. The tail ends (the phosphate groups) are negatively charged. Like repels like. And the crowding of all these tails contributes to the energy of ATP. Back to the analogy, the two phosphates are in a relationship and the third is the annoying roommate. Because of the negative tension the last phosphate gets kicked out. Now it is ADP (adenosine diphosphate (di-two).) That released phosphate therefore creates energy. But the phosphate that was kicked out doesn’t just live on the streets and dies, instead he finds a new home and rooms with two other roommates and they become happy of the newcomer and are energized. But just like what happened at the last living situation, tension rises and another phosphate gets kicked out. ■ This is a cycle. The cycle itself also needs energy in order to keep going and that energy comes from the food we eat. ● Exergonic is reaction that releases energy ● Endergonic is a reaction that requires energy ● Metabolism: the total of all the chemical reactions in an organism. ○ No metabolic reaction happens on its own. Most require help from enzymes. Enzymes are proteins that speed up chemical reactions. ● Activation energy does two things ○ Activates the reactants ○ Triggers a chemical reaction ● Enzymes reduce the amount of activation energy required to break bonds of reactant molecules. The enzyme brings the amount of activation energy down (think of it as a wall a reactant is trying to jump over) to allow the reactant to jump over the barrier easier and become the product ○ The enzyme is very selective in the reaction it catalyzes ○ Each enzyme recognizes a s ubstrate, a specific reactant molecule ○ The active site: the shape and chemistry that fits the molecule. ■ Think like the substrate is the key and the active site is the lock ■ When the substrate slips into the docking station of the active site, the active site changes slightly to embrace the substrate and catalyze the reaction: Known as the i nduced fit ● Certain molecules can inhibit a metabolic reaction by binding to an enzyme and disrupting its function. ○ Enzyme inhibitors are substrate imposters that plug up the active site. ■ Some enzyme inhibitors disrupt the enzyme by altering its shape. Many beneficial drugs work by inhibiting enzymes Molecules are restless and are constantly vibrating around. They want space to do this though. If it is too crowded they can’t go as crazy. So they will move from a place where there is a lot of them to a place where there are a few of them. Diffusion: the movement of molecules spreading from a place of high concentration to an area of low concentration Passive transport: passive because the cell does not need energy. Small molecules pass through easier than larger ones. Moves from high to low concentration Facilitated diffusion: uses transport proteins but does not require energy to move the molecules Active transport: requires both energy and proteins because it moves molecules from areas of low concentration to areas of high concentrations: it is like moving the molecules up a hill Osmosis: movement of water from high to low concentration Bio 3 Chapter 5 Study Questions 1.Why do molecules move? What influences the direction of movement across a membrane or within a space? Molecules are restless and are constantly vibrating around. They want space to do this though. If it is too crowded they can’t go as crazy. So they will move from a place where there is a lot of them to a place where there are a few of them. 2. What kinds of molecules can move easily without help across the plasma membrane? Small molecules like salt, sugars, and oxygen 3. What is the name we use for passive diffusion of water? How does this process work? Passive transport. Does not need energy to move molecules from high concentration to low concentration 4.What is meant by the terms hypotonic, hypertonic, and isotonic? Which solution is good for animal cells? Which solution is good for plant cells? Hypertonic: higher levels of solute in a solution: makes the cell shrink and/or shrivel Hypotonic: lower levels of solute. Makes the cell swell Isotonic: both solute and solvent are the same concentration 5. ehydrated patients are rehydrated with a saline solution that is isotonic to red blood cells. What would you expect to happen to the size of the red blood cells if the patients were rehydrated with pure water instead of saline solution? The blood cells would burst 6.What is facilitated diffusion? Chart explains What types of molecules must undergo facilitated transport for transport across the membrane? Large amounts of Water molecules 7.What is active transport? Chart explains 8.hat is the difference between passive diffusion, facilitated diffusion and active transport? Fill in the blanks in the following chart. Passive Facilitat Active diffusion ed transport diffusion From high Form of passive Goes from high How do molecules move? concentration to diffusion and to low. (like moves just like it low moving up concentration stream) no yes yes Is a membrane protein required? no no yes Is energy required? 9.How are very large substances moved into and out of the cell? Large substances are moved in by endocytosis which means is takes materials in its vesicles. There are two types of endocytosis: phagocytosis and pinocytosis. And large materials can move outside the cell through exocytosis. 10.hat are the differences between pinocytosis, and phagocytosis? Pinocytosis: is the consumption of dissolved particles and liquids. It drinks it Phagocytosis: is the consumption of entire organisms. It eats it 11. What is energy and why is it important for life? What are the two basic forms of energy? Everything needs energy to do work and function, it is what makes our world go ‘round. The two basic forms of energy are kinetic energy and potential energy. 12.escribe the first and second law of thermodynamics. The first law of thermodynamics is that energy cannot be created nor destroyed, only converted from one form and into another The second law of thermodynamics is with every energy conversion, some energy will be lost in the form of heat. 13.hat is the structure and function of ATP? Why is it important that ATP can be regenerated? ATP has a molecule called adenosine and a tail of three phosphate groups. It is important that ATP can be regenerated because it is the basic resource of energy that makes things happen on the cellular level 14. hat are enzymes? How do they work? What are competitive and non-competitive inhibitors? Enzymes are proteins that serves as a biological catalyst, changing the rate of a chemical reaction without itself being changed in the process. They reduce the amount of activation energy needed so that the reactant can jump over the activation energy easier and become the product. Competitive inhibitors: bind at the active site on the enzyme. They look just like the substrate, but isn’t actually it. They compete with the substrate. It is more easily reversible Non-competitive inhibitors: bind at a different site than the active site. But because they bind at that site, the active site changes shape and the substrate can no longer fit into the active site. Chapter 6 Autotrophs: (producers) self feeders. Uses photosynthesis, the sun, water, and CO2, to produce food for itself Heterotrophs: (consumers) organisms that cannot make organic molecules from inorganic ones. Obtain food by taking in other plants and/or animals that have taken in plants. ● Cellular respiration is the main way that chemical energy is harvested from food and converted into ATP energy. Cellular respiration is the opposite of photosynthesis. There are three steps in cellular respiration 1. Glycolysis 2. Citric Acid cycle 3. Electron transport chain ● Glycolysis(happens in the cytoplasm): a glucose molecule is split into two molecules of a compound called pyruvic acid. Here are the steps of what this system looks like. ○ Six carbon glucose molecule is broken in half creating 2-3 carbon molecules ○ Two ATPs are donated for the glucose split ○ The 2-3 carbon molecules then donate high-energy electrons to NAD+, forming NADH. (it is reduced which means it gained an electron) ○ In addition to NADH, glycolysis also makes 4 ATP molecules directly when enzymes transfer phosphate groups from fuel molecules to ADP. Glycolysis therefore has a net of 2 ATP per molecule of glucose. ○ The products at the end are: 2 (net) ATP, 2 NADH, and 2 pyruvate molecules ● After glycolysis the two pyruvate molecules that remain are ready to enter into the citric acid cycle until they are transformed. This step is not considered a step of its own, instead it is deemed as the linking step into the next cycle. ○ Each pyruvate acid loses a carbon as CO2. ( This is the first waste product we’ve seen so far in the breakdown of glucose) The remaining fuel molecules each with only 2 carbons left are called acetic acid ○ Electrons are then stripped away from these molecules and transferred to another molecule of NAD+, forming more NADH. ○ Each acetic acid is attached to a molecule called coenzyme A (COA) ○ Input Output ○ Pyruvic ACID Acetyl CoA ● The Citric Acid Cycle ○ Acetic Acid joins a 4 carbon acceptor molecule to form a 6- carbon product called citric acid ○ 2 CO2 leave as waste. The citric acid harvests energy from the fuel. ○ Some energy is used to make ATP ○ But it captures more energy in the form of NADH ○ Another form of NADH is FADH2 and the cell also makes this here. Input Output Acetic Acid 2 CO2 ADP + P ATP 3 NAD+ 3 NADH FAD FADH2 ● Electron Transport Chain- ATP synthase: makes ATP by pumping H+ ions across the inner membrane of a mitochondria ○ Electrons are pumped at the first electron train “stop” and they go through a channel and push out hydrogens down against the concentration gradient (high to low) ○ Then the electrons go through the second channel and the same thing happens. ○ And then it will go through the third one ○ At the end of the chain, oxygen will pick up hydrogen to make water ● Fermentation- relies on glycolysis ○ Ethyl alcohol Fermentation ■ Formation of ethanol and carbon dioxide to produce energy from pyruvate- yeast(Fermentation) ○ Human muscle cells Fermentation ■ Formation of lactic acid to produce energy from pyruvate– human muscle Chapter 7 Photosynthesis: A process whereby plants, algae, and certain bacteria transform light energy into chemical energy. ● Chloroplasts: light absorbing organelles. All green parts of the plant have chloroplasts and thus can carry out photosynthesis. ● Chlorophyll: a pigment in the chloroplasts that plays a central role in converting solar energy to chemical energy ● Stomata: the leaves pores or “mouth” through which gases are exchanged ● Stroma: fluid within the chloroplast ● Thylakoids: within the stroma there are these interconnected membranous sacs ● Grana: stacks of thylakoids Two photosystems cooperate in the light reactions. 1. Light reaction a. Water is split to provide electrons b. Sunlight energy is absorbed by chlorophyll is used to excite these electrons c. Energy and energized electrons are used to make the energy-storing molecules ATP and NADPH 2. The Calvin Cycle a. Needs ATP, NADPH, CO2(enters into series) b. Grabbed by Rubisco (enzyme) to make RuBPH sugar then slot it in half to make three molecules each. This is called fixation c. Next is the sugar creation. This is where we use the energy of ATP and NADPH to make G3P(a sugar molecule.) d. Regeneration: G3P sugar is then remade and reformatted using ATP to create glucose and other raw materials. Biology 3 Chapter 5,6,7 Study questions 1.How do photosynthesis and cellular respiration work together to provide the energy necessary for life? The plant needs both photosynthesis and cellular respiration to survive. Photosynthesis makes a storable energy source, while respiration converts for individual cells. They need each other because they both make what the other needs. 2.hat is photosynthesis? What is the chemical equation of photosynthesis? Photosynthesis is a process whereby plants, algae, and certain bacteria transform light energy into chemical energy, using carbon dioxide and water as starting materials and releasing oxygen gas as a by-product. 3.W hat do we call organisms that are able to undergo photosynthesis? Autotrophs 4.How do the reactants CO 2 and H 2O reach the chloroplasts in the leaves? Through the stomata where the gasses reach through the pores and into the chloroplasts 5. What occurs in a redox reaction? In photosynthesis, which molecules are oxidized (loss of electrons)? Which molecules are reduced (gain of electrons)? A redox reaction is an oxidized half and a reduced half. In photosynthesis, the reductions are carbon dioxide and glucose. The oxidation is water and oxygen. The redox process for cellular respiration is that oxidation is glucose and carbon dioxide. The reduction is water and oxygen. 6.What are the two stages of photosynthesis? Light reaction and the Calvin cycle 7. Why are plants green? What are the light--absorbing pigments found in chloroplasts? Which visible wavelengths of the electromagnetic spectrum are absorbed by these pigments? The pigment is green because chlorophyll and other pigments in chloroplasts absorb many different colors except for green, so they appear green to us. Chlorophyll a, the pigment that participates directly in the light reactions, absorbs mainly blue-violet and red light. A similar molecule, chlorophyll b. absorbs mainly blue and orange light. Chlorophyll b does not participate directly in the light reactions, but it conveys absorbed energy to chlorophyll a, which then puts the energy to work in the light reactions. The third kind of pigment is the carotenoids, which absorb mainly blue-green light. - - CAM photosynthesis- has a stomata that is completely closed during the day. At night, stomata open, CO2 let in and temporarily binds to a holding molecule. Requires more energy and has slow growth 15. What is a greenhouse gas? What is global warming? CO2, N2O, CH4, H2O. Global warming is the slow but steady rise in the earth’s temperature 16. How is cellular respiration related to breathing? Cellular respiration requires a cell to exchange two gasses with its surroundings. Respiration results in the exchange of these same gases between your blood and the outside air. 17. hat is the chemical equation of cellular respiration? About how much of the potential energy in glucose is transformed into the chemical energy of ATP? What happens to the rest of the energy not transformed into ATP? C6H12O6+6O2 18. In cellular respiration, which molecule loses electrons (is oxidized) and which molecule gains electrons (is reduced)? C6H12O6 is oxidized 6O2: is reduced 19. hat are the three main stages in cellular respiration, and where in the cell to they occur? Glycolysis: cystol Citric Acid Cycle (Krebs): matrix Electron Transport Chain: inner mitochondria membrane Fill in the following chart: Glyc Kre Electron olysi bs Transport Chain s cycl e Purpose To split the glucose Finishes extracting the Last step in the molecule energy of sugar by process to breaking apart the acetic transform glucose into acid all the way down to oxygen and CO2 eventually make water Location Cystol Matrix Inner membrane of the mitochondria Reactant Glucose Acetic acid, ADP+P, 3 Electrons from s NAD+, FAD food Product 2 pyruvic acids 2 CO2, ATP, 3 NADH, Water s FADH2 what is the purpose of NADH and FADH 2? To where do they bring electrons? The NADH and FADH2 is the high energy electron carrier. They bring the electrons to the 20.What stages of cellular respiration produce carbon dioxide? Where does this carbon dioxide go? Pre-step of citric acid and the krebs cycle, and the second stage of ethyl alcohol fermentation. The CO2 goes into the atmosphere. 21.What stages make ATP? Where is the most ATP produced? Krebs cycle and the electron transport chain. The most ATP is produced in the Krebs cycle 22.What happens to cellular respiration when there is no oxygen? The cells begin to work anaerobically and after 15 seconds they will begin a process called fermentation. 23.What occurs during fermentation? What are the two types of fermentation? Glycolysis happens which invests two ATP molecules and makes a net worth of two ATP and the 2 pyruvic acids that are produced comes in the form of 2 lactic acid molecules. 2 ATPs can be produced from one molecule of glucose.
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