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65 Cards in this Set
- Front
- Back
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Na K pump an example of a "p" pump
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phosphorylation of transport protein from ATP hydrolysis
1) changes shape of protein molecule, changing affinity as a result 2) exposes binding sites |
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glucose co-transport
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coupled to Na, Na goes in apical PM form high to low and using a symport glucose goes against its conc gradient. then at basal PM glucose goes passively by diffusion down its gradient
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sperm cell
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mitochondria wrapped around cytoskeleton of flagella, energy for swimming for survival
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mito outer membrane
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-porous to ATP, NAD+ and CoA
-porin proteins-large integral proteins -lipid synthesis |
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mito intermembrane space
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similar to cytoplasm
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mito inner membrane
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folded into cristae to increase SA, electron transport, ATP synthesis, transport proteins
similar to bacterial PM (similar lipid comp, carrier proteins, highly impermeable) |
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mito matrix
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citric acid cycle, genetic system
-DNA, RNA, ribosomes -some mitochondrial proteins made in mitochondria (some of complexes encoded in mito itself) |
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mitochondrial growth (arise by fission)
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-lipids from ER
-some proteins made in matrix -most proteins imported (encoded in nucleus, made in cytoplasm) |
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mitochondiral protein import
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-synthesized as a precursor with an N terminal amphipathic alpha helix targeting sequence serving as the address, once into mito, clip off sequence and toss away (MPP mitochondrial processing peptidase)
-import into matrix at contact sites where two membranes meet |
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glycolysis
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glucose to pyruvate, makes ATP and NADH
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pyruvate is transported across innner mito membrane and into matrix where...
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it is decarboxylated to form 2C acetyl group that is transferred to make Acetyl CoA
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acetyl CoA is fed into the TCA cycle where get...
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NADH and FADH2 from reactions where electrons are passed from substrate to electron accepting coenzyme, with Co2 as waste
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pyruvate --> acetyl CoA is independent step...
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linking glycolysis to TCA cycle
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electron transport chain
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high energy electrons passed from NADH (and FADH2) to O2, pump protons across the membrane into intermembrane space, H20 as waste
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REDOX rxns, rank compounds by electron-transfer potential
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NADH (reduced form) has HIGH electron transfer potential, high energy
H20 -low electron transfer potential, does not readily donate electrons 02- readily accepts electrons |
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more on electron transport chain
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step-wise passing of electrons runs a "current", from higher electron transfer potential to receiver with higher affinity for electron
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three coupling sites
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three places with large enough energy changes to pump H+, coupling movement of electron to movement of proton
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double bonds to single bonds example of conformation change
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oxidized to redufced can mean double bonds to single bonds, change in conformation of protein, can do work with it
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electron tunneling in
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cytochrome c (cytochrome c peroxidase)
also...heme to heme, tunneling along amino acids |
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how proton pumps work..
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1) protein has H+ binding site, it binds
2) changes conformation 3) dumps out H+ on the other side of membrane |
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two pathways, four major complexes
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1) I to UQ to III to cytochrome c to IV
2) II to UQ to III to cytochrome c to IV |
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Complex I
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NADH dehydrogenase (pull off H+), integral membrane protein (iron-sulfur centers, flavoprotein)
electrons passed from NADH to ubiquinone ubiquinone-lipid soluble carrier (non-protein) pumps protons? YES! (electrons move thru system, protons get pumped) |
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Complex III
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cytochrome bc1, integral membrane protein (iron-sulfur complex, hemes)
electrons passed from UQ to cytochrome c cytochrome c- peripheral membrane protein pumps protons? YES! |
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Complex IV
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cytochrome c oxidase, integral membrane protein (heme, copper)
electrons passed from cytochrome c to O2 pumps AND consumes protons (consumes some in the matrix, contributing to the gradient) |
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Complex II
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succinate dehydrogenase, IMP that is part of the TCA cycle (iron-sulfur complex, FADH2
electrons passed from FADH2 to UQ rest of pathway is the same... |
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electron transport chain in a nutshell
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electrons from NADH and FADH2 to O2
current used to pump protons into intermembrane space consumption of protons in matrix adds to gradient water produced as waste product |
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inner membrane impermeable to H+ important because...
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allows concentration gradient to build up H+ on outside, creates proton-motive force that comes in and drives ATP synthase in inner membrane
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ATP synthase lollipop
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Fo portion embedded in intermembrane space, proton channel
F1 ATP synthesizing portion in matrix |
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ATP synthesizing mechanism
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proton movement does not drive ADP phosphorylation, but changes binding affinity (spontaneous reaction when reactant and product are tightly bound to ATP synthase)
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F1 active stie goes thru 3 states
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Open state, low affinity for nucleotides
-->O to L transition by proton passing thru F0 Loose state, higher affinity ---> L to T transition by proton passing Tight state, tight binding of substrates (in tight state, spontaneous ATP formation) T--->O transition by proton passing, release of ATP |
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experimental proof of rotational catalysis
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glue down F1 portion, glue actin to bottom as flag, add ATP and flag spins around due to hydrolysis of ATP driving the enzyme
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rotational catalysis model
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proton entry thru "a" subunit, conformational change in "c" subunit causes 30 degree rotation, 12 protons --> 360 degrees and 3 ATPs
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pH gradient drives two symports...
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Pyruvate and H+ in
inorganic phosphate and H+ in |
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voltage gradient drives antiport...
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ADP in and ATP out
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Leber's hereditary optic neuropathy
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decrease in efficiency of oxidative phosphorylation (needed for optic nerve, cardiac muscle and nerve cells)
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Peroxisomes
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simple single membrane organelle with matrix, no genetic system, regulatory organelle
-carry out oxidative reactions to remove reactive oxygens (H2O2 and other reactive oxygen species) -use catalase to generate O2 and H20 out of peroxide and detoxify; oxidize and break down very long chain fatty acids -increase in number by growth and division, all proteins imported from cytoplasm, proteins contain c-terminal amino acid sequence that serves as targeting address -proteins going in are already folded |
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peroxisomes disease connection
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zellweger syndrome, rare inherited
neurological, visual and liver abnormalities mutations effect peroxisomal protein import machinery adrenoleukodystrophy -adrenal and neurological abnormalities, single enzyme missing and peroxisomes can't import long chain fatty acids, accumulation |
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evolution order
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glycolysis then photosynthesis then aerobic respiration
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heterotrophs
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used external source of energy, reduced C derived abiotically
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autotrophs
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generate energy to reduce Co2
chemo-use ammonia, HS, etc auto-use sunlight |
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photosynthesis in a nutshell
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boost energy of electrons using sunlight, make NADPH and ATP
use carbohydrates from CO2, H20, ATP and NADPH O2 as waste |
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plastids
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plant specific organelles
ex. amyloplasts-starch storage chloroplasts-capture of sunlight/energy production |
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chloroplast function
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ATP production
CO2 to carbohydrates Amino acid synthesis Fatty acid and lipid synthesis Assimilation of nitrogen |
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chloroplast structure composition/functions
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Outer membrane contains porins: fairly permeable
Intermembrane space Inner membrane: highly impermeable Stroma: Enzymes for carbon fixation Thylakoids: Membrane used in light harvesting -highly impermeable Thylakoid lumen |
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chloroplast genetic system: stroma
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DNA, RNA and ribosomes
Prokaryotic -- endosymbosis theory Some chloroplast proteins made here |
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chloroplast growth
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Arise by fission
Chloroplast growth: -Lipids synthesized in chloroplast and ER -Some proteins made in stroma Most proteins imported: (Encoded in nucleus, made in cytoplasm) |
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chloroplast protein import
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Synthesized as a precursor (or preprotein) with N-terminal alpha helix
-Not well characterized -Transit sequence serves as address (removed after import) |
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photosynthesis equation
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6CO2 + 6 H20 --> C6H12O6 + 6 O2
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light dependent reactions
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energy form the sun is absorbed and stored as chemical energy in ATP and NADPH
(Light-driven electron current Electrons from H2O to NADPH Pump protons ATP synthase) |
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light independent reactions
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carbohydrates are synthesized from CO2 using the energy stored in the ATP and NADPH molecules
(NADPH and ATP in stroma Fix CO2 into sugar) |
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Z scheme
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Photolysis (light splitting) of water to produce electrons
Boost electron with light Pass down electron transport chain Boost electron with light Pass down electron transport chain to NADPH Move protons |
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pigments
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molecules that absorb light in the visible range
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chlorophyll
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Like heme, but contains Mg2+
Absorbs photon of light Energy excites electron |
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carotenoids
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Accessory pigments
Can collect other wavelengths of light Also gives colors of carrots, autumn leaves |
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absorption spectrum
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Chlorophylls -- blue and red
Carotenoid -- blue and green |
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photosynthetic unit
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many antenna chlorophyll molecules collecting photon energy, all attached to membrane proteins...the single reaction center chlorophyll is where all transmit to for energized electron production
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PS II mechanism
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electrons from H20 boosted in PSII to PQ to cytb6f to PC to PSI
Light energy from LHCII to P680 chlorophyll, boosts electron energy Energized electrons passed to Plastoquinone (lipid-soluble electron carrier) and PQH2 consumes proton in stroma Plastoquinone passes electron to cytochrome b6f (Heme, iron-sulfur complex) and PQH2 releases H+ into thylakoid lumen Cytochrome b6f passes electron to plastocyanin (PC) a peripheral membrane protein in the thylakoid lumen Plastocyanin passes electron to Photosystem I (Integral membrane protein complex) |
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photosystem II mechanism
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electrons from PC Boosted in PSI to Ferredoxin to NADP+ reductase
Electron boosts by light energy in P700, Quinone (A1), iron-sulfur complexes in PSI pass electron to ferredoxin (Iron-sulfur complex, soluble protein in stroma) Ferredoxin passes electron to NADP+ Reductase Production of NADPH and consumption of proton in stroma |
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cyclic phosphorylation
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like fermentation, needs NADP+ for pathway
Production of ATP in absence of C02 and NADP+, No oxygen production, no NADPH production goes to ferredoxin but then passed back to PQ |
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calvin cycle-carbon fixation
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Key points: Stroma
CO2 in Produces 3 carbon compound to sucrose for transport to starch for storage Energy intensive, ATP NADPH reduces CO2 |
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cellulose laid down...
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at right angles and crosslinked by hemicellulose
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pectin
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produced in golgi, resists compression, heterogeneous polysaccharides, polymers of neg charged sugars, absorbs water to form hydrated gel
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cell to cell communication/junctions between plant cells
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Plasmodesmata
-- connect the cytoplasm between two cells -- connect the endoplasmic reticulum membrane |
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collagen
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all are trimers of 3 polypeptide chains, alpha chains
chains are wound around eachother to form a triple helix Large amounts of proline and lysine Hydroxylated after synthesis Lots of H-bond interactions Scurvy Tooth loss, brittle bones, internal bleeding Lack of Vitamin C – (needed to hydroxylate amino acid in collagen) |
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proteoglycans
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Huge protein core
Large amounts of sugars, sulfated and carboxylated Bind lots of water to form hydrated gel Compressive forces Can be linked to larger polysaccharides hyaluronic acid in synovial fluid in knee, shock absorption and lubrication |
