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136 Cards in this Set
- Front
- Back
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Functions of a membrane
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-seperates compartments
-controls molecules coming in and out of the cell -is selectively permeable |
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Composition of a membrane
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-phospholipid bilayer that constantly moves and switches
-made of fatty acids -proteins embedded in the bilayer |
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Feedback inhibition
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the initial enzyme is inhibited by the final product
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fluidity of the membrane depends on:
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-level of saturation of fatty acid tails (saturated=less fluid)
-temp (cold/hot=less fluid) |
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Cholesterol
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helps keep membrane fluid at low temps/
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peripheral proteins
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anchored to the bilayer and move with it in 1 layer
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integral proteins
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go from 1 side of the membrane to the other and must have a hydrophobig tail
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Functions of membrane proteins (6)
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-transporters
-enzymes -cell surface receptors -identity markers -cell-to-cell adhesion -attaches to cytoskeleton |
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passive transport
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-no energy required
-from high to low concentration -spontaneous via diffusion -molecules diffuse ind. of each other |
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facilitated diffusion
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-usese channel or carrier transport protein (very specific)
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channel proteins
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-faster transport
-used in facilitated diffusion |
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active transport
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-must have protein
-requires energy-ATP can go against concentration gradient -used when the body needs a concentration of something |
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proton pump
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moves protons out of the cell against concentration gradient
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simple diffusion
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-passive
-uncontrolled movement across the membrane |
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hypertonic
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more solutes (shriveled)
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hypotonic
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less solutes (lysed, bulging)
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isotonic
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equilibrium
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osmosis
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the passive transport of water across a membrane
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apolar molecules
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molecules that can diffuse directly across the bilayer
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diffusion
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movement across the membrane
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Bifacial
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membranes always have a specific inside and outside
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why are membranes bifacial?
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proteins have to be oriented
correctly |
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membrane proteins and lipids
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synthesized in the ER and Golgi and transported out in vesicles
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catabolism
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breaking down--decomposition reaction
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Types of Energy:
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-potential (stored)
-kinetic (moving) -chemical (stored in bonds) -radiation (light) -nuclear (within an atom) -heat (kinetic) |
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Kilocalories
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heat energy is measured in them
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Law of energy conservation (first law of thermodynamics)
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energy cannot be destroyed or created it can only be transferred
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Second law of thermodynamics
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disorder is more likely than order (entrophy)
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energy transformations
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result in a loss of useful "free" energy
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Phinocytosis
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the cell takes in fluid
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phagocytosis
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the cell takes in matter
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osmosis
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the diffusion of water across a membrane
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free energy
(TriangleG) |
the amount of energy needed for a reaction to proceed
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Activation energy
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the amount of extra energy needed to get a reaction started
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catalyst
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substance that lowers the activation energy of a reaction (enzyme)
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ATP
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adenosine triphosphate- ribose + adenine + 3 phosphates =energy!
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substrate
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reactant that binds with an enzyme in a reaction
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membrane:
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surrounds all cells and organelles and creates a physical and chemical barrier
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competitive inhibitors:
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-regulatory molecules compete with the substrate for bindage to the same site
-always on until turned off |
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noncompetitive inhibitors:
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bind to the BACK of the enzyme away from the active site
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activators
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regulatory molecule that binds to the enzyme and increases activity
-always off until turned on |
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cofactors
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non protein molecule required for enzyme activity (coenzyme=vitamin)
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inhibitors and activators
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regulate how much product is formed not too much or too little
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pathways:
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the product of one is the substrate of another
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exergonic reaction:
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reaction that releases energy
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endergonic reaction
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reaction requiring an input of energy (like photosynthesis)
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receptor mediated endocytosis
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specific molecules are taken in after they bind to a receptor
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endocytosis
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-phagocytosis
-phinocytosis -receptor mediated endocytosis |
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endocytosis
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movement into the cell
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exogcytosis
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movement out of the cell
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sodium potassium pump:
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electrical impulse in muscle tissue (active transport)
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carrier proteins
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made for a specific molecule-changes shape and allows molecule through
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metabolism
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sum of all biochemical reactions in a cell
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anabolism
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synthetic reaction (building)
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cell identity marker
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lets other cells know the identity of the cell (self)
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cell surface receptor
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transmit messages from outside the cell
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proteins
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transprt material in and out of the cell
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enzymes
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facilitate chemical reactions (catalysts) lower activation energy
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enzymes DO:(2)
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-lower the activation energy
-need ideal pH and remp to react |
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enzymes DO NOT:
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-add energy to the reaction
-change the free energy -change the equilibrium -get changed themselves |
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equilibrium:
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when 2 solutions have equal solutes, there is still movement but no net osmosis and no change
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enzymatic reaction rate depends on:
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-enzyme concentration
-substrate concentration -environment -regulatory molecules |
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cell to cell and cell to cytoskeleton:
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attachments to support the cell and surrounding tissue
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uniporters:
symporters: |
move 1 molecule
-move 2 molecules in the same direction |
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antiporters:
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move molecules in the opposite direction (carrier proteins)
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Cellular respiration
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Way a cell gets energy from food. it is a metabolic process that captures the chemical energy from foods in the form of ATP.
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Autotrophs
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are able to produce their own organic molecules through photosynthesis
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Heterotrophs
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live on organic compounds produced by other organisms
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Cellular respiration
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used by all organisms in all tissues at all times
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cellular respiration
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C6H12O6 + 6O2 -> 6CO2 + 6H2O + 38 ATP
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ADP + P
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ATP releases energy when a phosphate group is moved.
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ADP
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turned back into ATP during cellular respiration
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chemical process
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electrons and protons are transferred from glucose to oxygen through a series of oxidations
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Reduction
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is gained
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oxidation
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is lost
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NADH
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is used to move electrons in cellular respiration. (electron carrier)
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energy
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earobic reaction. heat is used to burn glucose in small amounts rather than all at once.
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686 kcals
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amount of heat energy needed for the oxidation of glucose
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Burning glucose
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produces 38 molecules of ATP that are 7.3 kcal + heat.
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outside the mitochondria
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glycolysis-->pyruvate (cytosol)
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glycolysis
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glucose-->2 pyruvate and 2 H2O. Uses 2 ATP. Product: 2 ATP, 2NADH, 2 pyruvate
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NADH
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is used to move electrons in cellular respiration. (electron carrier)
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pyruvate oxidation
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moves on a transport chain into the mitochondria. gives off a CO2, NADH --> Acetyl CoA
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energy
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earobic reaction. heat is used to burn glucose in small amounts rather than all at once.
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Kreb's Cycle
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acetyl coA enters the cycle and results in: 2 CO2 USED --> 3NADH, 1 ATP, 1 FADH
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686 kcals
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amount of heat energy needed for the oxidation of glucose
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ETC
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embedded in the membrane of mitochondria.
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Burning glucose
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produces 38 molecules of ATP that are 7.3 kcal + heat.
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ETC2
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NADH and FADH give their electrons to ETC which lose energy as they go. results in protons being pumped out creating a proton gradient.
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outside the mitochondria
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glycolysis-->pyruvate (cytosol)
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glycolysis
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glucose-->2 pyruvate and 2 H2O. Uses 2 ATP. Product: 2 ATP, 2NADH, 2 pyruvate
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pyruvate oxidation
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moves on a transport chain into the mitochondria. gives off a CO2, NADH --> Acetyl CoA
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Kreb's Cycle
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acetyl coA enters the cycle and results in: 2 CO2 USED --> 3NADH, 1 ATP, 1 FADH
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ETC
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embedded in the membrane of mitochondria.
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ETC2
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NADH and FADH give their electrons to ETC which lose energy as they go. results in protons being pumped out creating a proton gradient.
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ETC3
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electron is given to O2 making respiration aerobic. (passive)
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ATP synthase
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enzyme
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NADH
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electron carrier. 3 protons pumped out
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FADH
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electron carrier. 2 protons pumped out. (starts later in the ETC)
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chemiosmosis (oxidative phosphorylation)
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protons pass back through the ATP synthase protein. For each protein that comes through ADP +P --> ATP
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38 ATP
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product of cellular respiration in a perfect world. 36-30 is more common.
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reduced energy yield
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due to leaky inner membrane and use of proton gradient
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fermentation
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uses organic molecules as final electron acceptor (lactic acid) very innefficient.
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anaerobic
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lack of oxygen eliminates all steps but glycolysis. pyruvate goes directly to lactic acid
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why is respiration important?
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the products of respiration are the starting molecules for other cell parts and functions
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photosynthesis and cell. respiration
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product of one is the substrate of another. (continuous cycle)
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photosynthesis
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6CO2 + 6H2O ---(sunlight)---> C6H12O6 +6O2
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thylakoid membrane
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sacs that contains chlorophyll
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chloroplasts
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contains thylakoid membrain
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stroma
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semi liquid substance surround thylakoid
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light dependant reactions:
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capture energy from sunlight, make ATP and reduce NADP+ to NADPH in thylakoid
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carbon fixation reactions:
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(calvin cycle) use ATP and NADPH to synthesize organic molecules from CO2 in stroma
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NADPH
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NADPH: anabolic
NADH: catabolic |
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visible light
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utilized by plants--either absorbed, transmitted or reflected.
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Chlorophyll
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mainly absorbs blue and red, reflects green. organized into photosystems I and II
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accessory pigments
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increase the range of light wavelengths that can be used.
can protect the plant from excess light. |
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photon
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energy coming in from the sun. the amount of energy depends on its wavelength
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step I of light dependant:
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photosystem II absorbs photons and excites electrons
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step II of light depedant:
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electrons are transferred. transfer provides energy to pump a over membrane
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step III of light dependant:
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photosystem I absorbs photons and re-excites electrons. ultimately reduces NADP+ to NADPH
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step 4 of light dependant:
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protons flow through ATP synthase protein. ADP+P =ATP
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Light depedant reaction:
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NADP+ and ADP+P goes in. ATP and NADPH goes out
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Calvin cycle
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CO2, ATP and NADPH goes in. GLucose comes out.
-doesn't require light because ATP is already generated |
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Calvin Cycle 2
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-carbon fixation
-reduction -regeneration of Rubisco |
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Rubisco
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most abundunt enzyme in the world. 5 carbon sugar. can bind to CO2 or O2 usually CO2
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Carbon fixation:
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rubisco + CO2 --> 2 molecules PGA (sugar) NADPH
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Reduction:
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PGA is reduced to G3P
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Regeneration:
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G3P is used to regenerate RuBP (ADP+P and NADP goes back into light dependant reaction)
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alternative photosynthesis
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used in high temps and arid climates
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photorespiration
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occurs when rubisco binds w/ O2 instead of CO2
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photorespiration results in:
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-loss of energy
-inefficient photosynthesis (due to closed stromata) |
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which occurs first?
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photosynthesis has to be faster because cell. respiration uses O2 from ps.
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photorespiration 2
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use different enzyme to bind w/ CO2 (pepc)
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pepC
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-ALWAYS BIND W/ CARBON.
-uses extra energy |
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C4 metabolism
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seperate the process in space
-CO2 in mesophyll cells -calvin cycle in bundle sheath cells |
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crassulacean acid metabolism
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seperate the process in time (night and day) use malic acid to store CO2 and dont open stromata during the day.
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