Life 102 Exam Study Guide
1. Be able to identify the four main types of components that make up the cell membrane. What influences the fluidity of the cell membrane?
Phospholipid Bilayerbarrier to permeabilityflexible matrix, semipermeable, animal cell membranes contain cholesterol
Transmembrane Proteinintegral membrane proteinsproteins that float in lipid bilayer, transport and communications across membrane, most can move around
Interior Protein Networkperipheral or intracellular membrane proteinsmembranes are supported structurally by intracellular proteins that reinforce membrane shape. Membranes use other proteins to control movements of some key membrane proteins, anchor to points
CellSurface Markersglycoproteins or glycolipidsthe ER adds sugar molecule chains to membrane proteins and lipids, turning the, into glycoproteins and glycolipids. Different varieties of these make different cell identity markers.
3 Types of Lipidsglycerol phospholipids, sphingolipids, and sterols(I.E. cholesterols)
Fluid Mosaic Modelmosaic of proteins floats in/on fluid lipid bilayer. Influences: saturated fatty acids make membrane less fluid than unsaturated fatty acids, warm makes it more fluid than cold temperatures(cold tolerance in bacteria low due to fatty acid desaturates)
2. Be able to explain the six functions of membrane proteins. How does the structure of these proteins influence their function?
Attachment to cytoskeleton and extracellular matrix
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Transportmovement of molecules across a membrane
3. Be able to explain the differences between passive transport, facilitated diffusion, osmosis, active transport, and mass transport. Give examples of each.
Passive transportmovement of molecules through membrane in which no energy is required and molecules move in response to a concentration gradient
Facilitated diffusionmolecules that can’t easily cross membrane may move through proteins, move from high to low concentration, have channel proteins(hydrophilic channel when open)
Osmosiscytoplasm of cell is an aqueous solution. Water is solvent while substances dissolved are solutes. Net diffusion of water across a membrane toward a higher solute concentration
Active transportrequires energy to fuel active transport, moves substance from low to high concentration, requires highly selective carrier proteins, active transport 2
Mass transportnet movement of mass from one location to another
1. Be able to define the two redox reactions and show where electrons are moving in each. Oxidationatom/molecule loses an electron Don't forget about the age old question of Episodic memory means what?
Reductionatom/molecule gains an electron
2. Be able to explain the difference between endergonic and exergonic reactions. How do you identify what type of reaction you are dealing with? What is ΔG? How does the ATP cycle fit into this picture?
EndergonicPositive change in energy, products have more free energy than reactants, not spontaneous, H is higher or S is lower If you want to learn more check out Where is brazil located on the world map?
ExergonicNegative change in energy, products have less free energy than reactants, H is lower or S is higher or both, spontaneous
ΔGchange in energy available to do work
ATP stores energy, while endergonic/exergonic are forms of reactions that create energy
3. Be able to recognize the role that biological catalysts play in reactions. What are enzymes and catalysts typically made of? Explain the structure of enzymes and different ways they can be activated or inhibited.
Catalystssubstances that influence chemical bonds in a way that lowers activation energy Enzymes are biological catalysts mainly made of protein, initiate reactions in substances
1. Be able to list the four stages of the oxidation of glucose. Where in the cell are these taking place? What are the beginning and end products of each stage?
Glycolysisglucose to 2 pyruvate, 2ATP, 2 NADH
Pyruvate Oxidationpyruvate to 1 CO2, 1 NADH, 1 AcetylCoA
Krebs CycleacetylCoA into 6 CO2, 4 ATP, 10 NADH, 2 FADH2
Electron Transport Chain and ChemiosmosisATP Don't forget about the age old question of What is a channel issue?
Occurs in the mitochondria
2. Be able to explain what the theoretical net ATP yield is for each stage of glucose oxidation. Explain what the P/O ratio tells us.
Pyruvate Oxidation+4 ATP
Krebs Cycle+6 ATP If you want to learn more check out How does one compute for revenue?
Electron Transport Chain and Chemiosmosis+34 ATP
P/O Ratiophosphatetooxygen ratioamount of ATP synthesized per O2 molecule 32 ATP per glucose for bacteria, 30 ATP per glucose for eukaryotes
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3. Be able to describe some of the strategies for organisms that exist in the absence of oxygen. What are some commonalities between lactic acid and alcohol fermentation?
Anaerobic respiration and fermentation: anaerobic uses inorganic molecules other than oxygen as final electron acceptor. Fermentation uses organic molecules as final electron acceptor, CO2 reduced to methane, reduces organic molecules in order to regenerate NAD+.
lactic acid and alcohol fermentation both occur in anaerobic conditions to produce small amounts of ATP and convert pyruvate into substances(lactic acid for lac. Ferm., ethanol and C02 for alch. ferm.).
1. Be able to list which organisms carry out photosynthesis. In eukaryotes, what organelle is carrying out photosynthesis? List the different structures in this organelle and what they do.
Photosynthesis occurs in plants, algae, bacteria, and some animals. The chloroplast carries them out, using the thykaloid(stores chlorophyll), thykaloid membrane(where light reactions of photosynthesis occur), granum(stacks of thykaloids), and stroma(fluidfilled space around grana that synthesize molecules from H20 and CO2).
2. Be able to describe the different stages of photosynthesis. Explain what is happening during the lightdependent reactions and the lightindependent reactions. What is the purpose of Photosystem II vs. Photosystem I?
1. Capture energy from sunlight
2. Make ATP and reduce NADP+ to NADPH
3. Use ATP and NADPH to synthesize organic molecules from CO2 chloroplast
Photosystem 1absorbs longer wavelength of light(700nm), gets electrons from photosynthesis 2
Photosystem 2absorbs shorter wavelength of light(680nm), gets electrons from water
3. Be able to sum up the processes of the Calvin cycle. Are these reactions light dependent or independent? Where do they take place?
Calvin Cyclelight independent reactions in stroma(inner space of chloroplasts) Carbon fixationRuPB + CO2 = PGA
Reduction phasePGA reduced to G3P
Regeneration phasePGA used to regenerate RuBP. 3 turns = new G3P, 6 turns = 1 glucose
4. Be able to describe some of the major differences between C3, C4 & CAM plants. C3fix carbon using only Calvin cycle
C4Adds CO2 to PEP to form 4 carbon molecule, use PEP carboxylase, fix carbon using PEP carboxylase, produces oxaloacetate, converts to malate transported to bundle sheath cells then decarboxylated to malapyrovate and CO2. 2 pathways occur in different cells
CAMAdds CO2 to PEP to form 4 carbon molecule, #1use PEP carboxylasestromata open at night, close during day, fix CO2 using PEP carboxylase at night in vacuole, #2stromata close during day while organic acids are decarboxylated to yield high CO2 levels, drive Calvin cycle. C4 pathway happens at night, C3 during the day
phospholipid bilayer barrier between cytoplasm and exterior
concentration gradient he thermal motion of all
Osmosisnet diffusion of water across a
(liquid or gas) particles at temperatures above absolute zero.
membrane toward a higher solute
fluid mosaic modelmosaic of proteins that floats in/on fluid lipid bilayer
Diffusionthe movement of molecules across a membrane
Hypertonichigher solute concentration
cell surface markersspecial proteins and carbohydrates attached to the cell
membrane. While some proteins have the task of allowing the transport of molecules across the membrane, cell surface markers play a role in intercellular communication and recognition.
channel proteinsion channels that allow
passage of ions
Isotonicequal amount of solute and solvent
Exocytosismovement of substances out of a cell that requires energy
carrier proteinsbind specifically to molecules they assist, membrane is selectively permeable
Endocytosismovement of substances into cell
Kinetic energyenergy of motion
Reactantsubstance that undergoes a change in a reaction
Potential energystored energy
substance from a
Multienzyme complexseveral copies of one or more enzymes
Oxidationatom/molecule loses an electron
RibozymesRNA molecules that can catalyze certain
Reductionatom/molecule gains an electron
Enzymesbiological catalysts not changed or consumed in reaction
influence chemical bonds in a way that lowers activation energy
Entropymeasure of thermal energy
molecule similar enough to a substrate that it can bind to the enzyme's active site to stop it from binding to the substrate
quantity equivalent to the total heat
Noncompetitive inhibitora molecule unable to stop an
content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.
enzyme from binding to the substrate
Spontaneousa reaction that occurs in a set of conditions without interventions
changing of shape of a site when binded to an enzyme
Endergonicpositive change in free energy
Hydrolysischemical breakdown of a
compound due to
reaction with water
Allosteric activatorbinds to the enzyme of a site other than the active site
Exergonicnegative change in free energy
Active sitepockets or clefts for substrate
binding that form
Activation energythe minimum quantity of energy needed to cause a reaction
Substratereacts with a reagent to generate a product
decreasing of effectivity of a molecule due to an enzyme binding
Anabolismthe turning of simple molecules to complex ones
Catabolismbreakdown of complex molecules into simpler ones
Autotrophable to produce their own organic molecules through photosynthesis
Heterotrophlive on organic compounds produced by other organisms
Oxidizedloss of electrons
Reducedgain of electrons
electrons are accompanied by protons
aerobic respirationrespiration where oxygen is available as final electron acceptor
respiration that takes place without the presence of oxygen
Fermentationanaerobic respiration that creates
oxidative phosphorylation NADH to O2 resulting in the form of ATP
glucose by enzymes causing the
conversion of pyruvate into
Krebs cycleoxidizes the acetyl group from pyruvate in
release of energy and pyruvic acid
chemiosmosiselectrochemical gradient can be used to
electron transport chainthe transfer of electrons NADH to oxygen
ATP synthasemitochondrial enzyme that creates ATP from ADP and phosphate
P/O ratiophosphate to oxygen ratio
feedback inhibitionbinds to enzyme and decreases
Methanogensbacterium that produces methane
Facultativeperforms aerobic respiration and anaerobic when oxygen is not available
Obligateorganism that can’t live without oxygen
thylakoid membranecontains the thykaloid, where light dependent parts of
Chlorophylla green pigment that absorbs light to provide energy for photosynthesis
chloroplast a plastid that contains chlorophyll and in which
photosynthesis takes place.
Granastacks of flattened sacs of thykaloid membrane
surrounding thykaloid membranes
stroma lamellaconnect grana
photosynthesis: a series of biochemical redox reactions that take place in the stroma of chloroplast in photosynthetic organisms.
Pigmentmolecules that absorb light energy in the visible range
photoelectric effectremoval of an electron from a molecule by light
Mesophyllthe inner tissue containing chloroplasts
Photosystem IIOne of two light capturing units in a chloroplast's thylakoid membrane; it has two
molecules of P680 chlorophyll a at its reaction center, makes ATP and uses electrons from light.
Photosystem IP700, makes NADPH, does not take place first
stomataa tiny opening or pore that is used for gas exchange
C3plants that fix carbon using only the Calvin cycle
C4type of photosynthesis that is good for hot dry climates
CAMC4 pathway at night and C3 during