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115 Cards in this Set
- Front
- Back
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ligand
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binds to receptors
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endocrine
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communicates with distant target and releases land into the blood
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paracrine
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communicates with distant target through tissue coordination and doesn't release ligand into the blood
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cell to cell contact
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cells permanently attached with no diffusable ligand.
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autocrine
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produces a ligand that directly feeds back on the cell that produced it
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cell surface receptor
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when the ligand binds, it causes the protein to change shape and results in the cytoplasmic domain aquiring physiological action
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intracellular receptors
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binds to hydrophobic ligand that can cross the membrane
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intracellular receptors
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-bind to hydrophobic ligands
-5-10k/cell -800 amino acids long -3 separate domains |
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mechanism of intracellular receptors
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1) ligand binds and changes protein shape
2) imports to nucleus 3) binds to specific DNA sequence 4) N-terminus promotes transcription of that gene 5) mRNA's exported 6) translation |
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cell surface plasma membrane receptor types
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ion channel linked (ligand-gated channels)
G-protein linked enzyme linked |
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curare
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plant toxin that blocks nicotinic cholinergic receptors (ligand-gated Na+) and results in paralysis
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what can G proteins bind to?
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gtp or gdp
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signal transduction steps
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1)ligand binds to receptor and it changes shape
2) receptor alters interaction with protein 3) G-protein releases GDP and bonds to GTP instead which activates the G-protein |
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alpha subunit
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binds guanine nucleotides
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beta gamma subunit
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interacts with receptor
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active G-protein function
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-turn on enzyme
-open/close ion channels -promote production of intracellular signal molecules |
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things g- protein is linked to
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An isoprene and fatty acid
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active g-protein function
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-turn on an enzyme
-open/close ion channels -promote production of intracellular signal molecules |
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reasons to have multiple steps in signal cascades
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1) amplify the signal
2) precise regulation |
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what does g-protein do after inactivation?
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alpha-gdp binds to beta gamma subunits to form heterotrimer complex
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Gs
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- increases adenyl cyclase, which increases cAMP
- opens Ca2+ channel, which increases Ca2+ -closes Na+ channel, which creates voltage |
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Gi
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-decreases adenyl cyclase, which results in decreased cAMP
- increases K+ channel, which creates a voltage |
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Gq
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increases phospholigase C, such brings IP3 and DAG
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Gt
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increases phosphodiesterase, which results in decreased cGMP
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PKA synthesis
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1) receptor activates Gs
2) alpha-GTP detaches and activates adenyl cyclase 3) adenyl cyclase converts ATP to cAMP 4) cAMP binds to kinase |
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PKA subunits
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2 are catalytic and 2 are regulatory
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role of PKA
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phosphorylation
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types of pka
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-serine/threonine kinase
-tyrosine kinase (doesn't phosphorylate it though) - Sugar kinase -lipid kinase |
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adipose
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ligand: epinefrin
results in breakdown of triglyceride |
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liver
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ligand: glucagon
results in glycogen breakdown |
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ovarian follicle
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follicle stimulating hormone that results in estrogen synthesis
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Bone cells
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ligand: parathyroid hormone
results in Ca2+ absorption |
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intestine epithelio
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-PKA phosphorylates Cl- channel
-NaCl flux into intestinal lumen |
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cholera toxin
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enzyme that modifies alpha subunit of Gs G-protein, which results in loss of GTPase activity. It's constantly bound to GTP, which increases AC, cAMP, PKA, and the Cl- channel's always open
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liver
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glycogen storage, short-term energy storage, glucagon, increased pka, and pka phosphorylation
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glycogen phosphorylase kinase
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phosphorylates and activates glycogen phosphorylase
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cAMP response element (CRE)
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DNA sequence
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CRE binding protein (CREB)
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will only bind to CRE when CREB is phosphorylated
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bordetella pertussis
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-enzyme that's a toxin
-modifies the Gi -can't release GDP -Gi is permanently inactivated -results in more cAMP |
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Calcium regulation
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1) 7-transmembrane receptor
2) activates Gq 3) alpha-GTP 4) Gq activates phospholipase C 5) PLC cleaves Phosphatidyl inositol 4,5 biphosphate, which increases IP3 in the cytoplasm 6) IP3 can bind to IP3 receptors, which is a ligand-gated Ca2+ channel on the ER 7) increases Ca2+ in the cytoplasm |
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conventional protein kinase C
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requires Ca2+ DAG and phosphatidyl serine, which drives it to the plasma membrane
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novel protein kinase C
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doesn't require Ca2+, but it needs DAG
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atypical Protein kinase C
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doesn't require Ca2+ or DAG
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CaM (calcium/calmodulin complex) kinase
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autophosphorylates (maintains activity even if there's not a lot of Ca2+
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calmodulate
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-kinase
-acticates contraction in smooth muscle -acticates synaptic proteins -activates transcription factors |
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calcium
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1) receptor
2) G-protein 3) plc 4) phosphatidyl inositol + 2 P --> IP3 + DAG 5) IP3--> opens Ca2+ channels on ER 6) Ca2+ flux from ER--> cyto...acticates PKC and CaM kinase |
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cytoplasm Ca2+ concentrations
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10^-7 M
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ER Ca2+ concentrations
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10^-3 M
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ECF Ca2+ concentration
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10^-3 M
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Ras superfamily
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-not linked to 7-transmembrane domain receptors
- small - over 100 members - regulatory mechanisms consist of GTPase activating protein, which turns off G-protein |
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GAP (GTPase activating protein)
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turns G-protein off
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GEF (guanine nucleotide exchange factor)
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turns G-protein on
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5 branches of the family
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1) Ras- transcriptional activity (related to cancer)
2) Rho- cytoskeletal organization 3) Rab- vesiculation membrane fusion 4) Ran- import/export from nucleus 5) Arf- vesiculation fusion of membranes |
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receptor tyrosine kinase
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- common ligands are growth factors
- ligand binds and receptor forms a dimer |
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SH2 binds to...
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phosphate
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cycle
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sos (guanine nucleotide exchange factor)--> Ras (GTP)--> Raf (kinase)--> MEK (phosphate)--> Erk (phosphate)--> transcription factors change erk to TF-PO4--> imported to nucleus --> transcription--> new mRNA--> new proteins
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AKT
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enzyme that results in tissue development and is dependent on cell environment
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phospholipase D
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R group phosphatidic acid
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phospholipase C
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cuts between phosphate and fatty acids to get IP3 diacylglycerol
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PLA2
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releases an unsaturated FA (eicosanoid), which is used to produce paracrine molecules
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prostaglandins
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associated with inflammation and activated by cycloxygenase
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PLA1
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cuts off saturated fatty acid
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cyclo-oxygenase
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comes from eicosanoids. leads to prostaglandins (smooth muscle control inflammation)
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lipo oxygenase
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from eicosanoids. leads to leukotrienes (smooth muscle control)
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aspirin
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non -steroidal anti-inflammatory
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corrisol
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promotes transcription of a protein that blocks PLA2
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ATP energy release
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7.3 kcal/mol
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cellular respiration steps
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1) substrate --> oxygen
--> organic fuel 2) fuel is oxidized, which releases energy and powers ATP production 3) products are ATP, CO2, and H2O |
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fuel
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sugars, fatty acids, and amino acids
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glycolysis
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- oxidation
-lytic event - small amount of ATP |
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kreb Chile
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- utilizes glycolytic products
- mitochondrial matrix - oxidation - small amount of ATP |
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two ways to make ATP
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1) substrate level phosphorylation (phosphotylator needs more energy than ATP)
2) oxidative phosphorylation |
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phosphenol pyruvate delta G value
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-14.8 kcal/mol
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1, 3 diphosphoglycerate delta G value
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-11.8 kcal/mol
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phospjocreatine (muscle) delta G value
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-10.3 kcal/mol
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glucose-6-phosphate delta G value
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-3.3 kcal/mol
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regulation of glycolysis
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1) regulated steps tend to be those with a high -delta S value
2) specific control: a) glucose concentration (3-4 mM) b) hexokinase c) phosphofructo kinase |
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pyruvate reduction
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leads to lactic acid in us and ethanol in yeast
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phosphatidyl inositol 4,5 biphosphate
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creb cycle
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CREB--> CREB-PO4--> goes to nucleus--> binds to CRE--> transcription
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F0F1-ATPase
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makes ATP
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pyruvate after oxidation and loss of CO2
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acetyl-CoA
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pyruvate dehydrogenase
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-enzyme that catalyzes oxidation of pyruvate
- regulated allosterically - inhibited by NADH and ATP - activated by high NAD+ |
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triglycerides
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adipose tissue that liberates FAs
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fatty acids
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supplies acetyl-CoA by beta- oxidation
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kreb cycle
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feeds 2C acetyl subunits into the cycle and the cycle will release 2 CO2 electrons
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2 acetyl-CoA
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turns off the kreb cycle
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kreb cycle outcome
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4 CO2
2 NADH 2 FADH2 2 ATP |
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glucose energy harvested
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680 kcal/mol
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4 ATP energy harvested
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30 kcal
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NADH energy harvested
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52.6 kcal/mol
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FADH2 energy harvested
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43.4 kcal/mol
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electron transport system
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1) NADH dehydrogenase complex accepts electrons from NADH and uses that energy to pump 4 protons across the inner mitochondrial membrane
2) NADH dehydrogenase donates electrons to ubiquinone (co-enzyme Q and membrane lipid) 3) Co-enzyme Q donates electrons to cytochrome b-C1 complex and uses that energy to pump 4 protons across the inner mitochondrial membrane 4) cytochrome b-C1 complex donates electrons to cytochrome C 5) cytochrome C transfers electrons to cytochrome C-oxidase complex, which uses every to pump 2 protons across the inner mitochondrial membrane 6) cytochrome C oxidase transfers electrons to oxygen |
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NADH
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10 protons pumped across the inner mitochondrial membrane
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FADH2
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6 protons pumped across the inner mitochondrial membrane and bypasses the NADH dehydrogenase
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F0 segment
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proton channel
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F1 segment
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attached to the matrix side and spins as protons go through matrix
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kreb cycle produces...
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4 CO2
6 NADH 2 FADH2 2 ATP |
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F0F1 ATPase conformational states
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1) high affinity binding for ADP and phosphate
2) condensation state 3) low affinity ATP binding |
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every 120 degree turn of F0F1 ATPase results in...
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1 ATP released. turn is promoted by H+
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NADH
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energy to pump 10 H+ across inner mitochondrial membrane and produce 3 ATP
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FADH2
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pumps 6 H+ across the membrane to make 2 ATP
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10 NADH
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produces 30 ATP
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2 FADH2
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makes 4 ATP
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glycolysis
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results in 2 ATP
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theoretical vs actual yield of ATP
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theoretical: 38
real: 27-28 |
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ways to lose energy in ATP synthesis
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1) ADP goes in and H+ goes out
2) pyruvate and H+ go in the matrix 3) phosphate and H+ go in the matrix 4) creatine and H+ go in the matrix (only happens in muscle) 5) transport of glycolytic NADH electrons into the matrix |
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ways to lose energy
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1) transport ATP into matrix and H+ out
2) pyruvate and H+ go in at the same time 3) phosphate and H+ go in at the same time 4) creatine and H+ go in at the same time 5) transport of glycolytic NADH electrons into the matrix |
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energy that can't be used to power the F0F1 ATPase
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ADP in
ATP out phosphate in pyruvate in NADH electrons in |
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Brown fat
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highly vascularized, lots of mitochondria, and produces a protein called thermogenin is m the mitochondria
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artificial protonophore
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H+ channels
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DHP
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artificial H+ channel that increases oxygen consumption, ETS, fuel consumption, and takes down ATP production
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cyanide
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electron transport blocker. blocks the cytochrome C
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result of everything backing up
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- all become reduced upstream
- no H+ pumping - electrochemical gradient collapses - no oxidative ATP produced - death |
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PI-3 kinase
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phosphorylates C #3 on inositol
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