notes for chapter 7-10
notes for chapter 7-10 BIOL 1020
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This 12 page Class Notes was uploaded by Kendall Mansfield on Wednesday October 7, 2015. The Class Notes belongs to BIOL 1020 at Auburn University taught by Min Zhong in Fall 2015. Since its upload, it has received 118 views.
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Date Created: 10/07/15
Biology test 2 Qhapter 7 the cell s contents from environment lipid portion exchange of essential substances lipid portion with other cells protein portion attachment within and between other cells protein portion a surface for biochemical reactions protein portion 0 Protein oating an a double layer of phospholipids o the Phospholipid Bilayer o hydrophilic phosphate heads hydrophobic fatty acids tails 0 Two dimensional uids I an increase in unsaturated fatty acids at lower growth temperatures and an increase in saturated fatty acids at high temperatures stabilizes membrane uidity Make the bilayer at higher temperatures at lower temp to watersoluble substance Membrane Proteins 0 Proteins are embedded in the phospholipid bilayer o on surface of the membrane 0 O OOOO penetrate the membrane Transmembrane proteins o Receptor proteins Recognition proteins Enzymatic proteins Attachment proteins Transport proteins O 0 Random Motion of particles 0 Net movement of particles from an the amount of a solute that is dissolved in a solvent a difference in properties Diffusion is in response to a concentration gradient to get to a window No energy needed Moves downs its concentration gradient Three types facilitated diffusion simple diffusion osmosis o to get an air conditioner Needs energy Transport proteins Moves against its concentration gradient Simple Diffusion through the phospholipid bilayer O O O O O 0 Small molecules No proteins needed Through phospholipid bilayer No energy needed The higher the temperature the faster the rate of diffusion The greater the concentration gradient the faster the rate of diffusion Diffusion cannot move molecules rapidly over long distances 0000 O O Diffusion of water across a selectively permeable membrane Net movement Free water Osmotic Pressure concentration is the same on both sides of membrane no net ow of water higher concentration of solutes lower water concentration water moves towards inside cell o lower concentration of solutes higher water concentration water moves away outside cell diffusion of certain solutes diffusion of solvent 0 Large moleculesions 0 Through channelcarrier proteins 0 No energy needed water channel rapidly move water drives simple diffusion facilitated diffusion and osmosis o Activetransport membrane proteins using ATP Proteins span the entire membrane Often have a molecule bonding site and an ATP binding site Often referred to as pumps o Sucrose H cotransport in plant cells 0 0 Chapter 8 Cells import large particles or substances cell drinking bring in smaller dissolved materials eat speci c molecules cell eating moves large particles or whole cells freshwater protest engulfs a paramecium using phagocytosis a white blood cell ingest bacteria using move material out of the cell What is energy E move the capacity to do work force acting on an object that causes the object to Your body weight represents the balance between all the energy you get and all the energy you use the study of energy Two types of energy the energy of movement Ex light heat electricity moving objects stored energy Ex chemical energy in bonds battery membrane potential a rock on the top of a hill energy molecule in your body an energy currency in cells energy is never gained or lost but is only transformed Energy is often transformed into heat all energy transformations are inefficient the amount of useful energy in the universe is decreasing and the amount of disorder is increasing measure of the energy not available for useful work in a thermodynamic process Expression of randomness disorder and lessuseful energy Organisms are very ordered low entropy So they require energy to maintain order Suanht Living organisms use solar energy to create the lowentropy conditions of life Each step is catalyzed by a speci c enzyme Release energy Ex cellular respiration Consume energy Ex protein synthesis Chemical Reactions Form or break bonds between atoms Convert reactants to products All chemical reactions require an initial energy input activation energy to get started Ea Free Energy energy available to do work in a chemical reaction such as create a chemical bond Change in G Reactions with change in G are spontaneous A measure of a system s instability downhill reactions Energy Reactants contain more energy than products Ex the burning of glucose 1m reactions of energy Products contain more energy than reactants Ex photosynthesis Often occur at different places within a cell Energycarrier molecules used to transfer the energy within cells Cellular energy carriers Act as intermediates to carry energy between exergonic and endergonic reactions Only used within the cells because they are unstable Nucleotide with adenine base ribose sugar and a chain of 3 phosphate groups Two phosphate bonds unstable release high energy during hydrolysis Hydrolysis of ATP ATP H20 l ADP Pi The amount of energy released When ATP hydrolysis is coupled to a reaction to provide energy The Pi is transferred onto another compound rather than being released immediately In a higher energy state ATP powers cellular work Couples exergonic reactions to endergonic reactions Overall the coupled reactions are exergonic Overall ATP is typically created in catabolic reactions and used in anabolic reactions linking those aspects of metabolism Energy can be transferred to electrons in glucose metabolism and photosynthesis transport highenergy electrons Two common electron carriers 0 Nicotinamide adenine dinucleotide NAD o Flavin adenine dinucleotide FAD A biological catalysts proteins can speed up chemical reactions in cells without using up themselves Reduce activation energy Synthesized by cells Why are enzymes important for us Enzyme Structure Enzymes have a pocket called an active site Reactants substrates bind to the active site The shape of the active site is complementary to the substrate shape lnhibitor substance that interferes with an enzymes activity A competitive inhibitor molecule occupies the active site and blocks entry of the substrate Threedimensional structure of an enzyme is sensitive to pH salts temperature etc Range of tolerance narrow Each has an optimal temperature Each has an optimal pH Most enzymes work best in pH between 6 and 8 Exception pepsin works in stomach acid Temperature in uences enzyme activity Nonprotein enzyme helpers May be inorganic or organic Coenzyme organic cofactor allow or enhance catalytic activity reduce or eliminate catalytic activity Feedback inhibition The last product in a metabolic pathway binds to an allosteric site of an enzyme in an early step of the pathway The product inhibits activity of the enzyme Chapter 9 Plants algae and some bacteria The overall equation 6C02 12H20 l C6H1206 6H20 602 Glucose is a key energy storing molecule C6H1206 602 I 6C02 6H20 ATP Aerobic respiration Anaerobic respiration Fermentation a substance that has lost one or more electrons a substance that has gained one or more electrons a redox process coupled reactions that directly phosphorylate ADP or GDP redox reactions that transfer hydrogens to NAD or FAD carboxyl groups are removed 0 O and releases as C02 0 molecules are rearranged to prepare for other reactions NAD and FAD accept electrons and hydrogens to become NADH and FADH2 Deliver electrons and hydrogens to the electron transport chain Occurs in the cytosol Does not require oxygen Breaks glucose into pyruvate 2 ATPs per glucose NADs converted to NADHs OOOOOO Consume 2 ATPs Products 2 G3P molecules Produce 4 ATPs Products 2 pyruvates 2 NADH 0 NAD reduced to NADH o Pyruvate changed into acetyl CoA and C02 0 Net ATPs 2 ATP 0 Acetyl CoA l C02 0 NAD reduced to NADH o FAD reduced to FADH2 o in the mitochondria o NADH and FADH2 are oxidized in the ETC electrons are passed down a chain of proteins 0 ETC pumps hydrogen ions across an inner membrane of the mitochondria 0 Final electron accepter 02 l H20 0 28 ATPs Movement of protons o Pumping of protons through special proteins Protons passing down across ATP synthase Driving force to produce ATPs o Takes place in the mitochondria o H accumulates in the intermembrane 0 Oxygen in the form of water is the nal electron acceptor 0 ATP synthesis takes place in the ATP synthase H channel by chemiosmosis o 28 ATP produced by ETC Energy carriers l H concentration gradient stored energy form energy carriers l cell uses 0 Amino Acids o Deamination remove amino groups 0 Join glycolysis to further breakdown OGlycerol G3P OFatty Acids acetylCoA by B oxidation OOver twice as much energy as glucose ATP concentration 0 Phosphofructokinase Switch enzymes in glycolysis Inhibitors ATP and citrate Activator AMP Bacteria Doesn t use oxygen Has electron transport chains Use other compounds as nal electron acceptors Produce ATPs but less than aerobic respiration does not produce more ATPs but regenerates NAD Doesn t use oxygen 2 ATP Products lactic acid or beer o Lactic Acid Fermentation bacteria and mammal muscle 0 Alcohol Fermentation yeast Chapter 10 the ability to capture sunlight energy and convert it to chemical energy store in complex organic molecules releasing oxygen as a byproduct Equation 6C02 6H20 light energy sunlight l C6H1206 602 Occurs in plants algae and some prokaryotes bacteria Photosynthetic organisms are autotrophs Photosynthesis in plant cells occurs within chloroplasts Photosynthesis and cellular respiration are interconnected 1 Plants 2 Multicellular algae 3 Unicellular protists 4 Purple sulfur bacteria 5 Cyanobacteria o Flattened leaf shape exposes large surface area to catch suanht 0 Leaf coat upper and lower leaf surfaces compromise the epidermis which are covered by waxy waterproof cuticle reduces water evaporation o Stomata leaf mouth pores in the leaf that let carbon dioxide in and water and oxygen out contain chlorophyll and accessory pigments attened membrane bound sac in the interior of a chloroplast diskshaped sacs where light reaction occurs chlorophyll and other pigments of the thylakoids capture sunlight energy then is converted to the energy carrier molecules ATP and NADPH oxygen gas is released as a byproduct o stack of thylakoids O o Fluid within the chloroplast surrounds the thylakoids where dark reaction occurs Calvin Cycle Enzymes in the stroma synthesize glucose and other organic molecules from C02 using the chemical energy stored in ATP and NADPH the sun radiates electromagnetic energy Visible light is radiation falling between 400750 nanometers of wavelength Packets of energy called photons with very different energy levels 0 Shirtwavelength photons are very energetic o Longerwavelength photons have lower energies 0 Absorption of certain wavelengths light is trapped 0 Re ection of certain wavelengths light bounces back 0 Transmission of certain wavelengths light passes through molecules that absorb certain wavelengths of light and re ecttransmit others o Main pigments of photosynthesis Absorb all wavelengths of light except for yellow green and green wavelengths l re ect these 0 Carotenoids absorb blue and green light but re ect yellow orange or red hence they appear yelloworange Reaction center Lightharvesting complex Two types PS II is positioned before PS in thylakoids 0 Has a chlorophyll a absorption peak at 700 nm p700 Generates NADPH 0 Has a chlorophyll a absorption peak at 680 nm P680 Generates ATP photophosphorylation a resembles a pinball game O O O O O O 0 Primary pathway Involve both photosystems Produce ATP and NADPH Purple sulfur bacteria Use only PS I Produce ATP but not NADPH No 02 released 1 Take places in the thylakoid 2 Light energy is converted to high energy molecules ATP and NADPH 3 Water is split providing oxygen that provides the basis for aerobic life Light dependent reactions produce ATP and NADPH which is used to drive lightindependent reactions Depleted carriers ADP and NADP return to lightdependent reactions for recharging Takes place in the stroma Light not directly necessary Glucose synthesis 0 O O Carbon xation Carbon reduction RuBP regeneration O 0 Carbon xation carbon capture rubisco Carbon reduction synthesis G3P Energy is donated by ATP and NADPH PGA l G3P O O O 10 of 12 G3P molecules converted into 6 RuBP molecules 2 of 12 G3P molecules used to synthesize 1 glucose ATP energy used for these reactions O 0 Once cycle of the C3 Cycle produces two quotleft overquot G3P molecules Two G3P molecules 3 carbons each used to form 1 glucose 6 carbons Glucose may later be broken down during cellular respiration or stored in chains as starch or cellulose Sugar glucose is the product 6C02 used to synthesize 1 glucose C6H1206 C02 is captured and linked to RuBP by Rubisco 0 ATP and NADPH from light dependent reactions used to power C3 reactions Low C02 and high 02 Rubisco add 02 to RuBP in Calvin Cycle Cell release C02 as product Produce ATP no sugars C4 plants have chloroplasts in bundle sheath cells as well as mesophyll cells C4 plants reduce photorespiration C4 pathway is an evolutionary adaption to hot dry climates Twostage carbon xation pathway 0 PEP carboxylase 4carbon molecule instead of PGA O Release C02 C3 Cycle h 0 Temporal separation of carbon xation Open their stomata at night x C02 into organic acids 0 Stomata close during the day C02 is released for the Calvin Cycle 0