Cell Bio Test 3
E₂ conformations Active Transport/Na⁺ / K⁺ ATPase Pump
- is open to the outside, with a high affinity to potassium ions -phosphorylation of the pump by ATP triggered by Na and stabilizes in the E₂ conformations
fermentation taps only a fraction of the substrate's free energy
- no external electron acceptor is involved and no net oxidation occurs -fermentation only yields 2 ATP per glucose; most of the free energy of the glucose molecule is still present in the lactate or ethanol
aerobic respiration
--glucose oxidation, in the presence of oxygen
the citric acid cycle: CAC 1
-2 carbon acetate group is transferred from acetyl CoA to oxaloacetate, 4C, to form citrate 6C -this reaction is catalyzed by citrate synthetase 6C
glycolysis phase 2: oxidative sequence, the first ATP generating event
-2 molecules of glyceraldehyde-3-phosphate are oxidized to 3-phosphoglycerate.Some of the energy from this oxidation is conserved as 2 ATP and 2 NADH molecules are produced -Step GLY6 and GLY7
phase 3: pyruvate formation and ATP generation 3-phosphoglycerate + ADP → pyruvate + ATP
-3-phosphoglycerate → 2-phosphoglycerate -2-phosphoglycerate → phosphoenolpyruvate (water molecule lost) -phosphoenolpyruvate → pyruvate using kinase 9ADP + P → ATP
glycolysis phase 1: preparation and cleavage
-6 carbon glucose molecules is phosphorylated twice by ATP and split to form 2 molecules of glyceraldehyde-3-phosphate. Requires an input of 2 ATP per glucose -Steps GLY1-GLY5
The cytochrome b6/f Complex Transfers electrons from Plastoquinone to Plastocyanin
-7 integral transmembrane proteins including two cytochromes and an iron-sulfur protein
the citric acid cycle: CAC 5
-ATP, bacteria and plants, or GTP, animals, is generated when succinyl CoA is converted to succinate
Noncyclic electron flow or Z-pathway photophosporylation
-Components of the chloroplast ETS provide a continuous unidirectional flow of electrons from -noncyclic electron flow
CAM Plants Minimize Photorespiration and Water Loss by Opening Stomata Only at NIght
-Crassulacean acid metabolism -co2 enters mesophyll cells and goes through the first two steps of the
F-type transport ATPase AKA ATP Synthase
-F for factor membrane: inner mitochondria membrane, plasma membrane, thylakoid membrane organism: plants, bacteria, eukaryotes function: uses H gradient to drive ATP synthase, proton gradient
The Calvin Cycle: CO2 fixation and reduction
-In plants, CO2 enters the leaves through special pores called stomata -Once inside a leaf, CO2 diffuses into mesophyll cells and usually travels into the stroma -The stroma is the site of carbon fixation
related transporters
-MDR transport protein and cystic fibrosis transporter -Multidrug Resistant Transport Protein
8.5 examples of Active Transport
-Na⁺ / K⁺ ATPase pump -Na⁺/glucose symporter -proton transport
P-type transport ATPase
-P is for phosphorylation membrane: plasma membrane organism: bacteria, archaea, plants, fungi, eukaryotes, animals function: transport of Na/K, Cu, Zn, Cd, Pb, H, Ca -pumps, maintains membrane potential, maintains asymmetry of lipid bilayer
photosystems I
-PSI -maximum absorption 700nm -
photosystems II
-PSII -maximum absorption 680nm
Photosynthetic Energy Transduction III: ATP Synthesis
-Potential energy stored in a proton gradient is used to synthesize ATP -process called photophosphorylation -ATP synthase complex (CF0CF1 complex, very similar to the F0F1 complexes of mitochondria and bacteria 4H+lumen + ADP + Pi ----> 4H+stroma + ATP
Calvin Cycle Stages
-The carboxylation of ribose-1, 5-bisphosphate, and generation of 2 3-phosphoglycerate molecules -Reduction of 3-phosphoglycerate into glyceraldehyde-3-phosphate -Regeneration of the original acceptor
Rubisco's Oxygenase Activity Decreases Photosynthetic Efficiency
-The primary reaction catalyzed by rubsico is the addition of CO2 and H2O to ribulose-1, 5-bisphosphate, forming two 3-phosphoglycerate -At high oxygen levels rubisco can add oxygen rather than CO2 --- result is phosphoglycolate (not used in the Calvin cycle; wasteful)
V-type transport ATPase
-V for vacuole membrane: vacuolar membrane, lysosomes, secretory vesicles organism: animals, plants, fungi function: uses H, keeps pH low that activates hydrolytic enzymes
Cyclic Photophosphorylation
-When more ATP is needed for sugar production, cyclic electron flow can divert the excited electrons of PSI into ATP -No water is oxidized nor O2 released (PSII is not involved)
direct active transport/primary active transport
-accumulation of solute molecules on one side of the membrane is coupled directly to exergonic chemical reaction most common: hydrolysis of ATP e.g. outward transport of protons establishing electrochemical gradient
ATP: the primary energy molecule in cells
-adenosine triphosphate -reaction 1: hydrolysis, spontaneous -𝜟Gº'=-7.3 kcal/mol -reaction 2: ATP synthesis, nonspontaneous 𝜟Gº'=+7.3 kcal/mol ATP⁴⁻ + H₂O ⇆ ADP³⁻ + Pi²⁻ + H⁺
Now What? different pathways
-aerobic conditions and anaerobic conditions
cancer cells ferment glucose to lactate even in the presence of oxygen
-aerobic glycolysis -despite its inefficiency, it allows cancer cells to outgrow normal cells -excessive glucose consumption -carbon skeleton synthesis e.g. cancer harnesses the carbons to build and divide to form new cancer cells
other types of chlorophyll
-all plants and green algae contain both chlorophyll a & b -brown algae, diatoms, and dinoflagellates supplement chlorophyll a with chlorophyll c -red algae have chlorophyll d
indirect active transport-sodium symport drives the uptake of glucose
-although most glucose transport into and out of our cells occurs by facilitated diffusion, some cells use a Na⁺/glucose symporter -maintained by Na⁺/K⁺ pump -transporting 2 Na⁺ for every 1 glucose molecule AKA SGLT protein
Aerobic respiration: summing it all up
-as carbohydrates and fats are oxidized to generate energy, coenzymes are reduced -these reduced coenzyme represent a storage from of the free energy released during oxidation -this energy can be used to drive ATP synthesis as the enzymes are reoxidizes by the ETS -as electrons are transported from NADH or FADH₂ to O₂, they pass thru respiratory complexes where proton pumping is coupled to electron transport
facultative organisms
-can function under aerobic or anaerobic conditions
obligate anaerobes
-cannot use oxygen as an electron acceptor; oxygen is toxic to these organisms
the citric acid cycle: CAC 2
-citrate is converted to isocitrate -the enzyme aconite catalyzes the reaction -isocitrate has a hydroxyl group that is easily oxidized or dehydrogenated in the next step
mesophyll cells
-co2 fixation here uses an enzyme other than rubisco; these cells are exposed to co2 and o2
co enzyme Q and cytochrome c
-coenzyme Q is the "funnel" that collects electrons from virtually every oxidation reaction the cell -coenzyme Q and cytochrome c are both small molecules that can diffuse rapidly within the membrane coenzyme Q or on its surface cytochrome c
electron transport and ATP synthase
-electrochemical proton gradient -ATP synthesis is coupled to electron transport -respiratory control -chemiosmotic model
electron transport and coenzyme oxidation
-electron transport involves the highly exergonic oxidation of NADH and FADH₂ with O₂ as the terminal electron acceptor and so accounts for the formation of water
indirect active transport
-favorable movement of one solute down its gradient drives the unfavorable movement of the other up its gradient e.g. inward movement of protons against the electrochemical gradient exergonic TYPES: -symport -antiport
the electron transport system consists of five kinds of carriers
-flavoproteins -iron-sulfur proteins -cytochromes, iron heme -copper containing cytochromes -coenzyme Q, most abundant, big role in disorders
chlorophyll
-found in nearly all photosynthetic organisms -chlorophyll a & b each have a central porphyrin ring which absorbs light -their strongly hydrophobic phytol side chains anchor the chlorophylls the thylakoid membranes
the citric acid cycle: CAC 7
-fumarate is hydrated to produce malate by fumarate hydratase -hydration reaction
the oxidation of glucose is highly exergonic
-glucose is a good source of energy because its oxidation is a highly exergonic process -𝜟Gº'=-686 kcal/mol for complete conversion of glucose to carbon dioxide and water, with oxygen as the final electron acceptor C₆H₁₂O₆ + 6O₂ → 6CO₂ +H₂O
Phase 1: preparation and cleavage glucose + 2ATP → 2 glyceraldehyde-3-phosphate + 2 ADP
-glucose → glucose-6-phosphate using hexokinase ATP hydrolysis -glucose-6-phosphate → fructose-1,6-biphosphate using phosphofructokinase-1 ATP hydrolysis -fructose-1,6-biphosphate split into dihydroxyacetone phosphate and glyceralderhyde-3-phosphate
phase 2: oxidation and ATP generation glyceraldehyde-3-phosphate + NAD⁺ + ADP + Pi → 3-phosphoglycerate + NADH + H⁺ + ATP
-glyceraldehyde-3-phosphate → 1, 3-biphosphoglycerate (NAD⁺ → NADH) -1, 3-bisphosphoglycerate → 3-phosphoglycerate (ADP + P) ATP using substrate level phosphorylation -happens twice from starting glucose; no net loss or gain at this point
obligate aerobes
-have an absolute requirement for oxygen
calculating 𝜟G for the transport of ions
-if S𝙯 is a solute with charge z, then 𝜟G inward = +RT ln [S] inside / [S] outside + zFVm -for a typical cell Vm is negative, so a positive ion will give a negative 𝜟G for inward transport, and a negative ion will give positive 𝜟G
the glyoxylate cycle
-in plants
aerobic conditions
-in the presence of oxygen, many organisms convert pyruvate to an activated form of acetate known as Acetyl-CoA. In this reaction, pyruvate is both oxidized (with NAD⁺ being reduced to NADH) and decarboxylated (liberation of a carbon atom as CO₂). Acetyl-CoA then becomes the substrate for aerobic respiration, where NADH is oxidized back to NAD⁺ by molecular oxygen
E₁ conformations Active Transport/Na⁺ / K⁺ ATPase Pump
-is open to the inside of the cell and has a high affinity for sodium ions -dephosphorylation is triggered by K and stabilizes in the E₁ conformations
the citric acid cycle: CAC 3, CAC 4
-isocitrate is oxidized by isocitrate dehydrogenase to oxalosuccinate, with NAD⁺ as the electron acceptor -oxalsuccinate immediately undergoes decarboxylation to form 𝛂-ketoglutarate 5C CAC 3 -𝛂-ketoglutarate is oxidized to succinyl CoA, by 𝛂-ketoglutarate dehydrogenase CAC 4
the bacteriorhodopsin proton pump uses light energy to transport protons
-it creates electrochemical proton gradient that powers synthesis of ATP by an ATP syntheses -retinal and photo activation, has to have light absorbing pigment retinol
photosynthetic energy: light harvesting system
-light behaves asa stream of particles called photons, each carrying a quantum indivisible packet of energy
Sugar/Carbohydrate Synthesis
-location in cell
the citric acid cycle: CAC 8
-malate is converted to oxidation oxaloacetate as electrons are accepted by NAD⁺ produce NADH
symport mechanisms of indirect active transport
-most cells continuously pump either sodium ions or protons out of the cell e.g. Na/K pump
NAD+ nicotinamide adenine dinucleotide
-most common co enzyme involved in metabolism -electron acceptor e.g. niacin aka vitamin B
fructose-2, 6-biphosphate
-most important regulator of both glycolysis and gluconeogenesis -activatesPFK-1(phosphorylates fructose-6-phosphate and it inhibits FBPase which catalyzes the reverse reaction
8.4 Active Transport
-moves solutes up the concentration gradient, away from equilibrium -direct and indirect active transport e.g. directionality FUNCTIONS: -uptake of essential nutrients -removal of water -maintenance of non equilibrium concentrations of certain ions
reduction-oxidation pair
-negative # good electron donors +positive # good electron acceptors
anaerobic respiration
-no oxygen required, use S, H, or Fe as electron acceptors -glycolysis -fermentation
classification based on need for oxygen
-obligate aerobes, obligate anaerobes, and facultative organisms
alcoholic fermentation
-often accomplished by plant cells, yeast, when oxygen is not around -plant cells, yeasts, other microorganisms 2 pyruvate + 2 NADH + 4 H⁺ → 2 ethanol + 2 CO₂ + 2 NAD⁺ so starting with glucose: glucose + 2 ADP + 2 Pi + 2 H → 2 ethanol + 2 CO₂ + 2 ATP
glycolysis overview
-or glycolytic pathway is a ten step reaction sequence that converts one glucose molecule into 2 molecules of pyruvate -both ATP and NADH are produced -oxygen is not involved -3 phases
other sugars and glycerol are also catabolized by the glycolytic pathway
-other sugars that go thru glycolysis, other molecules can also form pyruvate -disaccharides like lactose, maltose, sucrose, galactose, mannose, glycogen, starch, glycerol
conversion of pyruvate
-oxidative decarboxylation in the mitochondrial matrix, exergonic -negative 𝜟G -symporter transport pyruvate from matrix to cytosol
Mitochondrial Respiratory complex III
-passes e from CoQH₂ to be cytochrome c via cytochrome b and c₁ and an Fe-S protein. CoQH₂ carries 2 H⁺ across the inner membrane and 2 more H⁺ are pumped out of matrix
role of pigments
-photo-excitation, energy transferred from a photon energizes the electron from its ground state in a low energy orbital/state, to an excited state, unstable, in a high energy orbital/state e.g. chlorophyll
C4 plants can fix CO2 at lower concentrations;
-plants in hot, arid environments are affected by rubisco's oxygenase activity -Hatch-Slack Cycle
organisms without chloroplasts
-plasma membrane folds inward to form photosynthetic membranes -cyanobacteria, free living chloroplasts, endosymbiont theory
protein as a source of energy and amino acids
-proteins can be catabolized to produce ATP if necessary when carbohydrate and lipid stores are depleted -proteolysis -amino acids
MDR transport protein / ABC Transporter
-pumps hydrophobic drugs out of cells -the MDR protein of some bacteria renders them resistant to antibiotics
Mitochondrial Respiratory complex IV
-receives e from cytochrome c and via cytochrome a and a₃, passes them to molecular oxygen then reduced to H₂O as 2 more H⁺ are pumped from the matrix
Mitochondrial Respiratory complex I
-recieves 2 e from NADH and passes them to CoQ via FMN and an Fe-S protein. 4 H⁺ are pumped out of the matrix by complex I
cystic fibrosis transporter
-similar in structure to ABC but in function to ion channel
the citric acid cycle: CAC 6
-succinate is oxidized to fumigate by succinate dehydrogenase CAC 6 this transfers electrons to FAD
the citric acid cycle also plays a central role in the catabolism of fats and proteins
-the CAC represents the main conduit of aerobic energy metabolism for a variety of substrates besides sugar-in particular, fats, and proteins -fats, glycerol is channeled into the glycolytic pathway -fatty acids are linked to coenzyme A to form fatty acyl CoAs, then degraded 𝛃 beta oxidation
cellular respiration: maximizing ATP yields
-the flow of electrons thru or within a membrane, from reduced coenzymes to an external electron acceptor usually accompanied by the generation of ATP -up to 38 ATP molecules per glucose
gluconeogenesis
-the process of glucose synthesis -pyruvate and lactate are the most common starting materials -the GLY1, GLY3, and GLY10 steps of glycolysis are thermodynamically the most difficult to reverse and so much differ for gluconeogenesis (bypass reactions)
the electron carriers and reduction potentials
-the standard reduction potential (E'₀) for an electron carrier is a measure, in volts V, of its affinity for electrons -reduction potentials are determined experimentally for a redox pair, reduction -oxidation
coenzyme oxidation pumps enough protons to form 3 ATP molecules per NADH and 2 ATP molecules per FADH₂
-the transfer of 2 electrons from NADH is accompanied by the pumping of a total of 10 protons, 12 if the Q cycle is operating -the number of protons required per molecule of ATP is thought to be 3 or 4, with 3 regarded as most likely
glycolysis phase 3: pyruvate generation and the second ATP generation event
-the two 3-phosphoglycerate molecules are converted to pyruvate, with accompanying synthesis of 2 more ATP molecules, resulting in a net gain of 2 ATP per glucose -Steps GLY8-GLY10
𝜟G of inward transport
-the 𝜟G of inward transport simplifies to 𝜟G = +RT ln [S] inside / [S] outside -if [S] inside < [S] outside, 𝜟G is negative and the transport is exergonic -but, if [S] inside > [S] outside, 𝜟G is positive and transport is against the concentration gradient
the chemiosmotic model involves dynamic transmembrane proton traffic
-there is continuous, dynamic 2-way proton traffic across the inner membrane -NADH sends 10 protons across via complexes I, III, and IV; FADH₂ sends 6 across, via complexes II, III, IV -assuming that 3 protons must return thru F₀ F₁ per ATP generated, this means 3 ATP per NADH and 2 per FADH₂ are generated
bundle sheath cells
-these are relatively isolated from the atmosphere, and the entire Calvin cycle is confined to these cells
aerobic respiration is a highly efficient process
-to determine efficiency of respiration, we need to determine how much of the energy of glucose is preserved in the resulting 36 or 38 ATP -𝜟Gº' for glucose → CO₂ + H₂O = -686 kcal/mol -ATP hydrolysis under cellular conditions is about -10 to -14 kcal/mol
Complex I NADH - coenzyme Q oxidoreductase/NADH dehydrogenase 4 protons 1 FMN / 6-9 Fe-S centers
-transfers electrons from NADH to COQ and is called the NADH coenzyme Q oxidation complex or NADH dehydrogenase
Complex IV cytochrome c oxidase 2 protons 1 FMN / 6-9 Fe-S centers
-transfers electrons from cytochrome c to oxygen and is called cytochrome c oxidase
structure of the Na⁺ / K⁺ ATPase
-trimeric transmembrane protein with one α alpha, one β beta, and one 𝛾 gamma subunit -exergonic hydrolysis -α alpha subunit, most important: binding sites for sodium and ATP on the cytoplasmic (inside) side and potassium and ATP on the external side -E₁ and E₂ conformations
Leaf structure of C4 plants:
-two types of photosynthetic cells in their leaves (mesophyll and bundle sheath) -carbon assimilation in a C4 plant uses 5 ATP rather than the 3 used in C3 plants -when temp. exceed about 30deg.C, the efficiency of a C4 plant may be twice that of a C3 plant -C4 plants are also less affected by conditions of low [CO2}
ATP synthase
-uses the energy from the proton gradient during electron transport to synthesize ATP from ADP and Pi
anaerobic conditions
-when oxygen is absent pyruvate is reduced so that NADH can be oxidized to NAD⁺, the form of this coenzyme required in Reaction GLY6 of glycolysis. Common products of pyruvate reduction are lactate (in most animal cells and many bacteria) or ethanol and CO₂ (in many plant cells and in yeast and other microorganisms).
the citric acid cycle
-with each round of the citric acid cycle, 2 carbons atoms, acetyl CoA, enter in organic form as acetate and leave in inorganic form as carbon dioxide -8 formal reactions in the cycle
summing up the TCA
1. 2 C enter the cycle as acetyl CoA 2. decarboxylation occurs at 2 steps to balance the input of 2 C by releasing CO₂ 3. oxidation occurs at 4 steps, with NAD⁺ the electron acceptor in 3 steps and FAD in 1 step 4. ATP is generated at one point 5. one turn of the cycle is completed as oxaloacetate is regenerated
Na⁺ / K⁺ Pump conformation steps
1. 3 Na⁺ from inside the cell bind to E₁ 2. Na⁺ binding triggers autophosphorylation of the α subunit using ATP, ADP released 3. conformational change to E₂ expels 3 Na⁺ to outside of cell 4. 2 K⁺ from outside cell bind to E₂ 5. K⁺ binding triggers dephosphorylation causes conformational change back to E₁ 6. 2 K⁺ expelled to the inside as ATP binds and pump returns to initial state
types of transport ATPases/direct active transport
1. P-type 2. V-type 3. F-type 4.ABC-type
lactate fermentation
2 pyruvate + 2 NADH + 2 H⁺ ⇆ 2 lactate + NAD⁺ -so starting with glucose: glucose + 2 ADP + 2 Pi → 2 lactate + 2 ATP e.g. in cheese or cell muscles
Na⁺ / K⁺ pump subunits
2 α alpha subunits, 1 β beta subunit, 1 𝛾 gamma subunit
oxidative decarboxylation in the citric acid cycle
3 times CO₂ is released
chlorophyll b
A type of yellow-green accessory photosynthetic pigment that transfers energy to chlorophyll a.
ATP and ADP are higher energy than AMP
ATP + H₂O → ADP + Pi + H⁺ 𝜟Gº'=-7.3 kcal/mol 𝜟Gº': -10 ro -14 kcal/mol ADP + H₂O → AMP + Pi + H⁺ 𝜟Gº'=-7.3 kcal/mol AMP + H₂O → adenosine + Pi + H⁺ 𝜟Gº'=-3.6 kcal/mol -so, ATP and ADP are both higher energy compounds than AMP
allosteric points that are highly regulated in the Citric Acid Cycle 4 steps
CAC 1 CAC 3 CAC 4 CAC 8
with FADH₂
FADH₂ + ½O₂ → FAD⁺ + H₂O -negative𝜟G = -45.9 kcal/mol oxygen → water highly exergonic drives synthesis of ATP
the 3 conformations of the Binding Change Model
L - loose T - tight O - open focus on 𝛃 beta subunits
with NADH
NADH + H⁺ + ½O₂ → NAD⁺ +H₂O -negative𝜟G = -52.4 kcal/mol oxygen → water highly exergonic drive synthesis of ATP
phosphorylation
The production of ATP by chemiosmosis during the light reactions of photosynthesis, adding phosphate group
allosteric regulation
activator or inhibitor binds to a site other than an active site
mitochondrion
aerobic energy metabolism in eukaryotes cells that takes place within this
inter membrane
between the inner and outer membrane
proteolysis
breaking down proteins
fats
can also be oxidized for energy
light independent reactions
carbon fixation reactions, carbohydrates are formed from CO₂ and H₂O, dark reactions, carbon assimilation reactions
accessory pigments
carotenoids and phycobilins
ATP hydrolysis is highly exergonic
charge repulsion, resonance stabilization, increased entropy
absorption spectrum of pigments
chlorophyll a and chlorophyll b
matrix
citric acid cycle happens here, ribosomes are in matrix
most of the carriers are organized into 4 large Mitochondrial Respiratory complexes
complex I, III, IV and how they function -H⁺ is pushed to the inter membrane space from the matrix
inner membrane
contains cristae, electron transport and oxidative phosphorylation, is also a barrier
chemotropic energy metabolism
describes the reactions and pathways by which cells catabolize nutrients and conserve the released energy in the form of ATP e.g. synthetic work, concentration work, electrical work, mechanical work, bioluminescent work, heat
beta oxidation
each cycle involves : 1. oxydation 2. hydration 3. reoxidation 4. thiolysis -the result is the production of 1 FADH₂, 1 NADH, and 1 acetyl CoA per cycle
FAD
flavin adenine dinucleotide, a lower energy co enzyme than NAD⁺ -FAD reduction FADH₂, -coenzyme riboflavin B vitamin
Positron Emission Tomography / PET
fluorodeoxyglucose, a radioactive glucose analogue, is given to patients and then imaged as it accumulates in cancer cells
the citric acid cycle AKA Krebs cycle
for every pyruvate that enters the cycle you generate 3 CO₂, 4 NADHs, 1 FADH₂, and 1ATP
summary of glycolysis reactions GLY1 - GLY10
glucose + 2 NAD⁺ + 2 ADP + 2 Pi → 2 pyruvate + NADH + 2H⁺ + 2 ATP 𝜟G' in a cell = -20 kcal/mol
key enzyme: allosteric regulation
glycolysis: hexokinase, phosphofructokinase, and pyruvate kinase gluconeogenesis: fructose-1, 6-biphosphotase, pyruvate carboxylase
summing up the citric acid cycle continued
including glycolysis, pyruvate decarboxylation, and the citric acid cycle, the overall reaction is as follows: glucose + 10 NAD⁺ + 2 FAD + 4 ADP + 4 Pi → 6 CO₂ + 10 NADH + 2 FADH₂ + 4 ATP
the maximum yield of aerobic respiration is 38 ATP molecules per glucose continued
including the summary reactions of glycolysis and the citric acid cycle to this gives: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O 38 ADP + 38 Pi → 38 ATP
catabolic pathways
involved in the breakdown of cellular constituents - exergonic, release of energy
Phosphoglycolate
is channeled into the glycolate pathway, which returns about 75percent of it to the Calvin Cycle as 3-phosphoglycerate
glyconeogenesis
lactate produced in muscles under hypoxic conditions is transferred to the liver where it is converted back to glucose
outer membrane
layers of membrane has porins also has inner membrane folds, cristae, that increases surface area
photosynthesis involves 2 major biochemical processes: light + 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
light dependent reactions and light independent reactions
light dependent reactions
light energy is captured and converted into chemical energy, light reaction, energy transduction reactions
ATP is synthesized and collected in the
matrix
ABC-type ATP Binding Cassette/ATPase
membrane: plasma membrane, organellar membrane organism: bacteria, archaea, eukaryotes function: imports nutrients and B₁₂, exports toxins, multidrug resistance transporter, removes drugs/antibiotics from cell
Chapter 9 Chemotrophic Energy metabolism: Glycolysis and Fermentation
metabolism: collection of all chemical reactions in a cell -anabolic pathways and catabolic pathways
phototrophs
organisms that convert solar energy into chemical energy as ATP and reduce coenzymes
mitochondrion structure
outer-membrane, inter membrane, inner membrane, and matrix
charge repulsion
phosphate group negative, a lot of repulsion
aerobic respiration in bacteria
plasma membrane and cytoplasm perform the same functions as the inner membrane and matrix of mitochondria
amino acids
potentially be converted into pyruvate
increased entropy
remove phosphate group from ATP you get +𝜟S more chaos
resonance stabilization
resonance stabilization of the carboxylate group
chloroplast: photosynthetic organelle
similar to mitochondria in plants/algae -outer membrane -inner membrane -inter-membrane space -stroma, like matrix -thylakoids, pancake -stacks, grana
respiration stages: aerobic respiration
stage 1: the glycolytic pathway stage 2: pyruvate is oxidized to generate acetyl CoA stage 3: citric acid cycle stage 4: electron transport stage 5: oxidative phosphorylation
anabolic pathways
synthesize cellular components - endergonic
quantum
the amount of energy needed to move an electron from one energy level to another
summing up the citric acid cycle
the citric acid cycle can be summarized as follows: acetyl CoA + 3 NAD⁺ + FAD + ADP+ Pi → 2 CO₂ + 3 NADH + FADH₂ + CoA-SH + ATP
photosynthesis
the conversion of light energy to chemical energy and its subsequent use in synthesis of organic molecules
chlorophyll a
the green pigment of photosynthesis; this is the principal pigment of all photosynthetic organisms
the maximum yield of aerobic respiration is 38 ATP molecules per glucose
the maximum ATP yield per glucose under aerobic respiration: 10 NADH + H⁺ + 2 FADH₂ + 6 O₂ + 34 ADP + 24 Pi → 10 NAD⁺ + 2 FAD + 12 H₂O 34 ATP
in aerobic respiration
the terminal electron acceptor is oxygen, and the reduced form is water
resonance energy transfer
transfer energy from chlorophyll
photochemical reduction
transferring this excited electron from the photon to another molecule
Binding Change Model Loose
which binds ADP and Pi loosely
Binding Change Model Tight
which binds ADP and Pi tightly and catalyzes the formation of ATP
Binding Change Model Open
with little affinity for either substrates of product
glucose catabolism
yields much more energy in the presence of oxygen than in its absence -aerobic respiration and anaerobic respiration
calculate 𝜟G for Cl⁻ intake
𝜟G inward = +RT ln [S] inside / [S] outside + zFVm = +(1.987)(273+25) ln (0.05/0.10) +(-1)(23,062)(-0.06) = +592 ln (0.05) + (23,062)(0.06) = -410 + 1384 = 974 cal/mol +0.97 kcal/mol -so, though Cl⁻ concentration is higher outside the cell, energy is still required for import
lactose uptake
𝜟G inward = +RT ln [lactose] inside / [lactose] outside =+(1.987)(273+25) ln 0.010/0.0002 =+592 ln 50 =+2316 cal/mol =+2.32 kcal/mol -for outward transport of lactose, [S] inside and [S] outside must be interchanged
outward transport: uptake of chloride ions
𝜟G outward = -𝜟G inward -consider a nerve cell with [Cl⁻] inside = 50 mM, in a solution with [Cl⁻] = 100 mM and membrane potential of -60 mV -the inward movement of Cl⁻ ions is down the concentration gradient but up the charge gradient