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135 Cards in this Set
- Front
- Back
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Anabolic Rx
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Requires E to work. Links simple molecules together to create more complex ones
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Catabolic
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E Released. Rx breaks down complex molecules into simpler ones
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What causes a energy conversions?
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NOt driven by E content, but by the desire of E to be dispersed
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1sr Law of thermodynamics
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E can't be created or destroyed
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2nd Law of Thermodynamics
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E spontaneously disperses from being localized to becoming spread out if it is not hindered from doing so
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Entropy
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Amount of disorder in a Rx
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Free Energy
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E available for use in Rx. available to do work
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Enthalpy
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thermodynamic potential (calculated)
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Exergonic Rxs
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Heat released, disorder increases, spontaneous (most catabolic)
• Heat released, disorder decreases, only spontaneous below certain temps |
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Endergonic Rxs
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Heat used, disorder increases, spontaneous above certain temps
HEat used, disorder decreases, NEVER spontaneous (most anabolic, unfavorable) |
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ATP
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Adenine Triphosphate
used for capture, transfer, storage of E Used in coupling exergonic with endergonic Rx. Delta G must be neg |
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If delta G is known, ________ can be predicted, but _______ cannot
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direction
Rate |
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Activation Energy
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Energy needed to pull molecules into transition state
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Catalyst
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Any substance that speeds up a chem Rx w/o being itself used up (enzymes)
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Only Rxs with ____________ can be catalyzed
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neg delta G. **actual delta G isn't changed
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Enzymes
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Substrates bind to Enzymes on Active Site>catalysis takes place> Enzymes can bind molecules together ***VERY SPECIFIC
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Enzymes catalyze Rxs by:
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1) Orienting Substrates
2) Inducing strain on substrates (melding substrates) 3) Adding charges to substrates to alter rate of chem rx. ** charge is transferred back after Rx so overall charge never changes |
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Cofactors
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Some enzymes require them to function ***team mate
ie) metal ions, Termp/permanet bound organic molecules, NO AMINO ACIDS |
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Saturated Enzymes
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all binding sites occupied
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Principles of Metabolic Pathways
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1) Each Rx in the pathway is catalyzed by a specific enzyme
2) the operation of each metabolic pathway can be regulated by the activities of key enzymes |
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Feedback Inhibition
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When the appropriate amount of amino acids/nutrients is produced, no point in producing amy morek, so the nezyme that catalyzes a certain production for a substance is stopped (inhibited
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Enzyme Regulation
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Enz activity can be inhibited by nature and artificial binders
Metablolism regulation by natural inhibitors |
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Irreversible Inhibition
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occurs when the ihibitor destroy the enzyme's ability to interact with its normal substrate
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Competitive Inhibitor
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when an inhibitor binds reversibly to an enzyme's active site, it competes with the substrate for the binding site
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Noncompetitive Inibitor
aka negative allosteric regulator |
binds irreversibly to sire distinct from the active site, altering it shape and therefore the active site cannot bind to substrate
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Positive Allosteric Regulation
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Can stabilize the inactive form and inactive form
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Cooperative Allosteric Transitions
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2+ substates. Usually multiple enzymes being regulated
** 1st molecule difficult to reg cuz it has to instill change>2nd inhibitor molecule easier because conformation is already in shaped *** move much more quickly than noncooperative |
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Most Efficient Metabolic Pathway
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Multi-substrates negatively regulated by coop allosteric transition
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Catabolic Pathways
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in Glycolysis...
Long and complex because E is needed to release slowly. Need to store ATP not release it all @ once |
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Delta G for complete oxidation of Glucose
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-686 (1/2 of E is stored as ATP)
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Glycolysis is followed by:
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1) Cellular Respiration (w. O2)
2) Fermentation (w.o O2) |
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For Plants>
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photosynthesis>stored ATP>glycolysis> fermentation/respiration
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Fermentation overview
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Anaerobic
Incomplete oxidation Waste product = organic compounds Net E trapped-= 2ATP |
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Respiration Overview
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Aerobic
Complete oxidation Waste= H20 and CO2 Net E trapped = 36 ATP |
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Reduction vs Oxidation
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Gain e-s/ H atoms
Lose e-s./ H atoms When one material is reduced, it's then oxidized (redox) |
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Rule for Oxidation of organic molecules
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Decrease in # of C-H bonds
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NAD
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cofactor, essential e- carrier in cellular Redox rx
Stores E in forms of e-s Like ATP (but in diff form) has alternating double bonds (Energetically favorable) |
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Redox Potential
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Tendency to lose/gain e-s
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w/ O2 present, 4 major pathways:
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Glycolysis
Pyruvate Oxidate Citric Acid Cycle E-Transport Chain |
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2 stages of Glycolysis
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1) investment of ATP to activate the sugar by splitting C6> 2 C3
2) Oxidation of C3, giving NADH and H+ and ATP followed by initial ATP investment (Final product = pyruvate) |
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For ___________ Rxs, delta G values are ______________
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sequential , additive
(positive delta G coupled with neg delta G rxs) |
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Pyruvate- oxidized to _________, which is then converted to ________ and then fed to _______________
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acetate, acetyl CoA, fed to Citric Acid Cycle
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Substrate Level Phosphorylation
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During glycolysis when 2 rx yield each yield one ATP per G3P molecule
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Locations of Rxs
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ETC- inner mitochondrial membrane
Citric Acid Cycle- mito matrix Glycolysis= cytoplasm Fermentation-= cytoplasm |
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Citric Acid Cycle General pts
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Occurs when Pyruvate is Oxidized into Acetyl CoA and then fed into the Citric Acid Cycle
** technically no O2 needed, but it uses it indirectly because the amount of NADH needed cannot be generated without O2 ***note that this cycle produces electron- carrying NADH and FADH2 that feed into the electron transport chain |
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Products of Citric Acid Cycle
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3 NADH
1 FADH 1 GTP (converted into ATP) |
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ETC
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makes use of the reduced NADH and FADH electron carriers generated in earlier steps
turns these into ATP via oxidative phosphorylation |
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Oxidative Phosphorylation
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occurs in ETC, e- transferred from donors (NADH+, FADH) to acceptors (O2)
***** ATP synthesis occurs here due to e- transport |
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Step 1 ETC
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e- flow in a series of redox rxs causes ACTIVE TRANSPORT OF PROTONS ACROSS INNER MITO MEMBRANE= P+ CONCENTRATION GRADIENT
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Step 2 ETC
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P+ s diffuse through proton channels down concentration/electricla gradient BACK TO MITO MATRIX
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Step 3 ETC
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ATP created due to transfer of e-s across the proton gra
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PROTon motive force
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force the drives P+ back to Mito Matrix in ETC, which in turn creates energy
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Cytochrome C
Ubiquione |
Hydrophobic carriers present in ETC that shuttle H atoms/e- form one protein complex to the next
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How does ETC stop??
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once the cyanide binds to the active site on the HEME group
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Chemiosmotic Mechanism
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ATP Synthase. Transports H+ ions across mio membrane.
**Also reversible (hydrolysis) if there are anaerobic conditions 3 H+= 1 ATP |
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Other uses for ETC
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1) in absence of e- transport, an artificial H+ gradient is suffiecient for ATP synthesis for mitochondria
2) ETC can be uncoupled from ATP production by H+ channel> produce heat used for BROWN FAT (not ATP) 3) The P+ gradient drives an ADP/ATP cotransporter that can bring ATP out of the MITO MAtrix as well |
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Regulating Glycolysis
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Main control= kinase (adds 2nd phosphate to C6)
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Kinase
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Regulates glycolysis
Enzyme that is inhibited by hight ATP levels, if there is an excess it will shut off glycolysis |
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Regulating the citric acid cycle
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If there is and excess of NADH+ + H+, it will be shut off
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When there is an absence of O2
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1) ETC shuts down cuz no e- acceptors (O2) available
2) Pyruvate oxidation/CAC stop too! |
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Fermentation:
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Cells avoid it cuz only produces 2 ATP
Cells continue glycolysis> pyruvate> fermentatino w. lack of O2 |
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Respiration
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yields more E than glycolysis
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Gluconeogenesis
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an anabolic interconversion
** Process b which INTERMEDIATES OF GLYCOLYSIS AND CAC are used to form glucose ** occurs when body runs out of cglucose |
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If body runs out of food molecules
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1st: Glucogen stored in muscles/liver
2nd: FATS (but brain can only function w. glucose, so must produce it via gluconeogenesis 3rd: Proteins |
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Photosynthesis divided into 2 pathways
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1) Light Rx
2) Calvin Benson Cycle |
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Light RX (photosynthesis)
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Driven by direct light E
Captured by chlorophyll Produces ATP/NADH+ H+ |
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Calvin Benson Cycle
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doesn't used light directly
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NAD vs NADP
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Similar properties, occur in both palnts and animals
made by sep pathways Ind regulated NADP= used for only anabolic pathways NAD= used for catabolic |
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Exciting a Molecule
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Chlorophyll a has alternating double bonds= delocalized e-> can become excited easily
Excited e- has potential energy |
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Action Spectrum
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indicated that chlorophyll excitation needed for photosynthesis
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Once e- is excited by photon it is transferred and decayed by:
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1) giving off light/heat
2) Resonance (E transfer) 3) Successive e- transfers ( redox rxs) 2 +3 occur only when molecules are adjacent to each other |
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Light Harvesting Complex
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Light excites a chlorophyll, all chloro packed together to improve chances of absorbing a photon (packed within thylakoid)
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Antenna Systems
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packed chlorophyll w/in the thylakoid that absorb photon's E
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Rx Center/ Central pigment Molecule
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Chloro A that is attached to the e- acceptor
has Lowest E (680 nm) compared to 670 nm |
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Transfer of Light E> Chem E happens when:
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Rx center chlorophyll gives up excited e- to reduce first member of the ETC
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NOncyclic e- transport
vs Cyclic e- transport |
produces NADPH+ H+, ATP, O2, requires constant absorption of light
produces only ATP transforms light into ATP |
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Photosynthesis Regulation
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If they wanna grow: non-cyclic because they need NADPH
If they don't wanna grow; only need ATP, so cyclic |
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Photophosphorylation
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-proton gradient formation by e- transport chain synthesis of ATP in the thylakoid membrane
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Calvin Benson Cycle
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Occurs in Stroma of Chloroplasts
doesn't use sunlight directly, but require ATP/NADPH+ H+ which is produced in the light rxs which cannot by stockpiled |
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Rubisco
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Most abundant protein in plants (world)
Fixes carbon into 6 C skeleton Carboxylase or oxygenase |
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Steps in the Calvin Benson Cycle
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1) CO2 in, carbon fixed
2) Reduction and sugar production 3) Sugar produced (starch and sucrose) 4) Cyclic> Regeneration of RuBP |
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Photorespiration
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when there is low amount of O2, Rubisco runs in reverse
- uses ATP, w.o producing anything |
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To avoid photorespiration plants used ___________
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cellular respiration in mitochondria
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histones
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proteins that aid in the conglomeration of DNA, keep strands of DNA tightly packed
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Chromatin
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proteins (histones) plus DNA
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INterphase
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G1= rest
S= DNA replication G2= prepping to divide |
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Cyclin/ Cdks
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proteins whose concentrations fluctuate w. the cell cycle. Their concentrations affect the ability of the cell to proceed through cycle
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Crucial Checkpoint=
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G1>S
looks for external signals from other cells...during pregnancy, cyclin E becomes active due to hormones which leads to the proliferation of breast cells |
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G2
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Replication of the centrisome
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Prophase
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- centrosomes move to poles
- spindles form - Chromosome condensation- chromatids become evident - kinetochores form (protein structure where spindle fibers attach to pull chromosomes apart) |
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Prometaphase
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- Nuclear envelop breaks down
- polar microtubules and kinetochore microtubules form - chromosomes arrive at metaphase plate |
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Metaphase
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Chroms line up on plate
Sister Chromatids bound to kinetochore microtubule on opp spindles |
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Anaphase
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Centromeres sep
Kinetochore microtubules shorten>tighten> sep centromeres |
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Telophase
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- Spindles break down
- chroms decondense - nuclei form |
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Cytokinesis
Animals vs Plants |
OPtional
animals: actin/myosin form a drawstring that constrict and divide the cell Plants; vessicles fuse to make cel membrane and cell plate, eventually becomes cell wall |
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Syncytial
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no cytokinesis
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Prophase 1
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DNA begins to compact
synapsis chiasmata form |
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synapsis
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in Prophase 1, pairing of homologous chromosomes
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Chiasmata
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Crossing Over (prophase 1)
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Metaphase 1
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Microtubules attach to kinetochore (one per homolog not per chromatid)
- Chroms line up @ meta plate, held together by chiasmata |
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Anaphase 1
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Sep of homologous chroms into sep cells
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Telophase 1
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optional
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meiosis 2
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basically same as Mitosis except in Metaphase 2
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Metaphase 2
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Chroms line up on plate and chromatids sep to end up in diff cells
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NOn disjunction event
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(down syndrome)
instead of separating, both chrom 21 end up in a single gamete |
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Law of Segregation
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Separation of alleles into each gamete
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Law of independent assortment
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Genes are sorted independently and are not attached (dihybrid cross proved this)
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NOn-functional genes
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cant properly make a protein
** vast majority of recessive alleles are nonfuncitonal because they have been mutated (color blindness) |
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hemizygous
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gene is missing from a chrom
(like Y chrom and colorblindness) |
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Wild type vs mutant
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- funcitonal allele
- disfunctional allele |
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polymorphic
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when two clearly diff phenotypes exist in the population
ex. light vs java leopards |
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Thomas Hunt MOrgan
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discovered LINKAGE. Correctly surmised that it was the result of 2 genes being on the same chromosome
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Cis vs Trans
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alleles on the same chrom
vs Alleles on the diff Chrom |
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Recombination
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linkage w. crossing over
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FarTHER apart 2 genes are> ______________
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more likely recombination will occur
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Recombination Rate
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measure of physical distance along the chrom.
measured in cM 100x( #recombinants/total progeny) |
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Linkage Group
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genes linked together on the same chrom
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Components of Continuous Variation
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1) INcomplete dominance
2) Variations depend on which combination of alleles is present in a single locus 3) Enviro 4) Multiple genes contributing to one trait 5) Epistasis |
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allelic series
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alleles placed in order of severity of their corresponding phenotype
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Epistasis
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How genes interact
*** variations in color |
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To purify a gene need:
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1) method of isolation cell components
2) an assay for genetic material |
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Freidrich Meischer
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found how to isolate the nucleii
and the main constitute is nuclein |
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nuclein
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DNA
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Structure of DNA suggests the following properties:
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1) Sequence of nucleotides doesn't affect overall structure and info can be encoded arbitrarily
2) 2 strands bind by complementary base pairings, so two strands contain identical INfo |
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DNA replication
3 possibilities |
Conseravative
Semi conservative Dispersive |
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Conservative replication
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each strand replicates,
2 orig bind to eachother 2 new bind to eachother |
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Semi-conservative
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old strands bind to new strands
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Dispersive
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mix of old/new
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Meselson and Stahl
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proved it was semiconservative
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DNA polymerase
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Zipper
breaks bonds between alpha and beta phosphate attaches alpha phosphate to 3' hydroxyl group on last strand being extended |
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Helicase
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expends energy to unwind DNA
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Primase
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adds a bit of RNA (like a primer for DNA polymerase 3)
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DNA Polymerase I
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chews up RNA, fills in gaps
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DNA Ligase
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joins the ends of the newly synthesized strands
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Excision repair
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works the rest of the time to repair DNA
ex) if thymine dimers form due to UV light |
