Term
|
Definition
| 2 layers of phospholipids (called leaflets) with hydrophobic tails on the inside and hydrophillic head groups on the outside |
|
|
Term
| what is the aqueous space enclosed by a lipid bilyer called when the lipids are part of a small liposome or cellular organelle? |
|
Definition
|
|
Term
|
Definition
| a sharply curved, single layer of lipds or detergents that form a ball with polar head groups on the outside and hydrophobic groups on the inside. |
|
|
Term
|
Definition
|
|
Term
| what are triglycerides used for? |
|
Definition
|
|
Term
| what type of lipid is used for cell-cell communication? |
|
Definition
|
|
Term
| what is the difference between the secretory system and the endocytic system? |
|
Definition
the secretory system secretes proteins and other molecules out of the cell
the endocytic system brings molecules into the cell |
|
|
Term
| what are the 3 main functions of a plasma membrane? |
|
Definition
1. protection from the environment
2. transport of proteins and other molecules into and out of the cell
3. cell-cell communication |
|
|
Term
| replication, transcription and RNA processing happen in what part of the cell? |
|
Definition
|
|
Term
| energy generation and storage happen in the _________ in animal cells using ________ and ___________ in plant cells using ______________ |
|
Definition
mitochondria, respiration
chloroplasts, photosynthesis |
|
|
Term
| compartmentaliztion, selective transport, energy storage and signaling are functions of what? |
|
Definition
|
|
Term
| how does compartmentalization improve efficiency? |
|
Definition
| it concentrates molecules that function in the same processes together |
|
|
Term
| how do biological membranes store energy? |
|
Definition
by maintaining uneuqal ion concentrations inside/outside the cell (high energy situation) and then allowing ions to flow across the
membrane in a controlled manner. this releases energy which can then be used to power unfavorable reactions in the cell |
|
|
Term
| what is the chemical structure of a phospholipid? |
|
Definition
| has a glycerol "backbone" comprised of a 3-C molecule with 3-OH groups. the OH groups are covalently linked to one phosphate group (head) and two fatty acids (tails). The phosphate group is made up of a phosphate + another charged group (phosphate linked to glycerol) and the fatty acids are made up of a hydrocarbon chain |
|
|
Term
| a __________ fatty acid tail is straight and a ____________ fatty acid tail is kinked |
|
Definition
|
|
Term
| micelles are formed by ________ -shaped lipids |
|
Definition
| conical (head > tail, only 1 tail/head) |
|
|
Term
| cylindrical (head=tail) lipids form _______ |
|
Definition
|
|
Term
| when PE (phosphotidyl ethonalamine) is concentrated in the inner leaflet the bilayer is _________ and the lipids are _______-shaped |
|
Definition
| sharply curved, conical (head < tail, small head + 2 tails) |
|
|
Term
| detergents generally form what structure when put in water? |
|
Definition
|
|
Term
| the 3 most common phospholipids in cell membranes are? |
|
Definition
1. phosphotidyl ethanolamine (small, net neutral charge)
2. phosphotidyl serine (medium sized, net negtive charge)
3. phophotidyl choline (large, net neutral charge) |
|
|
Term
| the sugar coating around the outside of a cell made from glycolipids and glycoproteins is called? |
|
Definition
|
|
Term
| the function of a gycocalix is? |
|
Definition
1. to protect the cell
2. aid on cell-specific binding and recognition |
|
|
Term
| glycolipids are located on the (inner/outer) leaflet and phosphotidyl inositol lipids are are located on the (inner/outer) |
|
Definition
|
|
Term
| immune cells use which lipids as signals that a cell is dead and needs to be digested? |
|
Definition
| PI and PS because they are only present in the inner leaflet and thus would not be exposed to immune cells unless the cell is ruptured |
|
|
Term
| what is the chemical structure of a glycolipid? |
|
Definition
2 HC tails + polar head
-no phosphate group
-3-C backbone that does not contain glycerol |
|
|
Term
| what are the four types of lipid movement within the plasma membrane? |
|
Definition
1. lateral diffusion (trade places with neighbor)
2. rotation (lipid spins)
3. flexion (lipid tails splay outwards)
4. flip-flop (lipid from inner leaflet goes to outer leaflet and vice versa - rare) |
|
|
Term
| enzyme __________ catalyzes flip-flop and aids in lipid synthesis |
|
Definition
|
|
Term
| membrane fluidity is determined by? |
|
Definition
1. length of HC tails
2. number of double bonds in HC tails
3. temperature
4. inclusion/exclusion of cholesterol (animal cells) |
|
|
Term
| mammals and tropical oils have __________, _________ tails whereas fish and temperate vegetable oils have ___________, _____________ tails. |
|
Definition
long, saturated
short, unsaturated |
|
|
Term
| a cells goal is to have _________ fluidity |
|
Definition
|
|
Term
| what is the chemical structure of cholesterol? |
|
Definition
| small hydrophillic head (OH), hydrophobic steroid rings and short HC tails |
|
|
Term
| ____________ and _______________ are two methods to restrict the later movement of membrane proteins |
|
Definition
| molecular fences, anchoring |
|
|
Term
| (molecular fences/anchoring) allows membrane proteins to diffuse freely in an area between 2 barriers |
|
Definition
|
|
Term
| the three main functions of membrane proteins are |
|
Definition
1. signaling from outside to inside cell (receptors/enzymes)
2. transporters (channels/carriers)
3. anchors for cytoskeleton |
|
|
Term
| what are the four structural classes of membrane proteins? |
|
Definition
1. transmembrane proteins
2. monolayer associated proteins
3. lipid linked proteins
4. protein attached proteins |
|
|
Term
| the (hydrophilic/hydrophobic) regions of a transmembrane protein are located outside of the membrane and the (hydrophilic/hydrophobic) regions are located inside the membrane |
|
Definition
|
|
Term
| the shape of the transmembrane domain of TM proteins is ____________ |
|
Definition
| alpha helical, non-polar or amphipathic (multi-pass) side chains |
|
|
Term
| a _______________ is a transmembrane protein structure that creates a polar channel |
|
Definition
| beta barrel (rolled up beta sheet) |
|
|
Term
| a hydropathy plot is used to |
|
Definition
predict alphahelical transmembrane domains
-plot the aa sequence on the x-axis and the hdrophobicity on the y-axis
-look for 20-30 hydrophobic aa's in a row |
|
|
Term
| ______________ transmembrane proteins are located entirely in the cytosol. how are these proteins connected to the membrane? |
|
Definition
| mono-layer associated. they are connected to the inner leaflet of the bilayer through an amphipathic alpha helix. |
|
|
Term
| lipid-linked proteins are ______________ linked to a lipid in either leaflet of the lipid bilayer? |
|
Definition
|
|
Term
| __________ membrane proteins can only be removed by disrupting the bilayer with detergents |
|
Definition
| integral (transmembrane, monolayer-associated, lipid-linked) |
|
|
Term
| _________ membrane proteins are the easiest to extract from the membrane. these form ____________ bonds with other proteins. |
|
Definition
| protein attached, ionic (salt bridges) |
|
|
Term
| what do you use to extract peripheral membrane proteins? |
|
Definition
|
|
Term
| compare and contrast SDS with Triton-X 100 |
|
Definition
SDS detergent denatures proteins and solubalizes lipids.
Triton-X 100 also solubalizes lipids but DOES NOT denature proteins. TM proteins stay folded in trition micelle. this is a milder detergent than SDS. |
|
|
Term
| in a alpha helical portion of a transmembrane protein, the aa side chains are located on the (inside/outside) of the helix and are (polar/non-polar). |
|
Definition
|
|
Term
| what are the portions of membrane proteins that span the bilayer generally alpha helical? |
|
Definition
| because the polypeptide backbone of the protein is polar (hydrophilic) and thus in the absence of water (such as inside the membrane) is driven to form hydrogen bonds with itself. an alpha helix maximizes hydrogen-bonding. |
|
|
Term
| beta barrels form (wider/narrower) pores than collections of alpha helices? this makes them (more/less) versatile? |
|
Definition
|
|
Term
| what is a tight junction? |
|
Definition
| a molecular fence formed in the epithelial cells of the gut by proteins from adjacent epithelia cells binding to one another. this prevents molecules from getting in between cells and also keeps apical and basal proteins seperate |
|
|
Term
| which types of molecules can cross bilayers on their own? which require the aid of proteins? |
|
Definition
| non-polar molecules and small polar molecules can cross on their own. large polar molecules and all ions require assistance. |
|
|
Term
| _________ transport requires no energy input and moves molecules _______ their electrochemical gradient. |
|
Definition
|
|
Term
| what is active transport? does it require energy? |
|
Definition
| transport of molecules across the lipid bilayer against their electrochemical gradient. yes, requires energy. |
|
|
Term
| passive transport is associated with a (positive/negative) change in free energy? this reaction is energetically (favorable/unfavorable) |
|
Definition
|
|
Term
| how do protein transporters help molecules overcome the kinetic barrier to movement across a membrane? |
|
Definition
| they provide a polar environment for the molecule to pass through so it doesn't have to be in the hydrophobic lipid layer and thus does not ever become a high energy, unfavorable intermediate |
|
|
Term
| what are some of the main differences between channels and carriers? |
|
Definition
channels:
-open to both sides of the membrane at once
-only passive transport
-rapid transport
-weak interaction with solute
carriers:
-only open to one side of membrane at a time
-facilitate passive or active transport
-tight binding of solute
-slower transport |
|
|
Term
| both carrier and channels have two conformations but they are not the same. describe the two confirmations of each types of transporter proteins |
|
Definition
channels: open or closed
carriers: facing in or facing out |
|
|
Term
| (K+/Na+) has a greater concentration inside a cell |
|
Definition
|
|
Term
| the inside of a cell is more (positive/negative) than the outside of the cell |
|
Definition
|
|
Term
| is there a greater concentration of H+ inside or outside a cell? does this lead to a higher pH inside or outside the cell? |
|
Definition
| greater [H+] inside cell, lower pH (higher pH outside cell) |
|
|
Term
| where are the highest concentrations of Ca++? |
|
Definition
| outside the cell and in the sarcoplasmic reticulum |
|
|
Term
| what are the three types of channel-gating mechanisms? |
|
Definition
1.ligand-gated (require binding of a ligand)
2. mechanically-gated (respond to touch, located in skin and ear)
3. voltage-gated (respond to changes in charge) |
|
|
Term
| __________ is the transport of two molecules in the same direction and __________ is the transport of two molecules in opposite directions |
|
Definition
|
|
Term
| (carriers/channels) are faster. (carriers/channels) are more specific. |
|
Definition
|
|
Term
| (carriers/channels) are faster. (carriers/channels) are more specific. |
|
Definition
|
|
Term
| describe the process of K+ and Na+ transport using the Na+/K+ pump |
|
Definition
| when pump is facing cytosol Na+ binding site is exposed. After Na+ binds, pump is phosphorylated, this leads to a conformational change which expels the Na+ outside the cell. A K+ binding site is then exposed. When K+ binds the pump is dephosphorylated which enduces a second conformational change and expels the K+ into the cytosol. The process repeats. |
|
|
Term
| how are ion channels selective? |
|
Definition
| only ions of certain sizes and charge distributions are allowed through. this is regulated by interactions between ion channel wall/ion interactions |
|
|
Term
| the glucose carrier is located on the (apical/basolateral) side of the intestinal epithelial cell. the Na+-driven transporter is located on the (apical/basolateral side). |
|
Definition
|
|
Term
| what is binding cooperativeity? what is an example of this? |
|
Definition
| when the binding of one molecule increases the binding affinity of another, always bond together. an example is the Na+ and Glc in the Na+-driven glucose transporter |
|
|
Term
| what determines the flow of glucose through the glucose carrier? what type of transport is this an example of? |
|
Definition
| glucose concentration (flows down gradient). this is an example of active transport. |
|
|
Term
| what are the steps involved in cell fractionation? |
|
Definition
1. homogenization with mortar and pestle
2. fractionation of organelles by size using differential centrifugation
3. identification and further study of proteins in each fraction using SDS PAGE, Western blot, mass spec, membrane extraction experiments, etc |
|
|
Term
| true or false: ion channels are continuously open |
|
Definition
|
|
Term
| name two ways that cholesterol helps maintain membrane fluidity over a wide range of temperatures |
|
Definition
| 1. prevents movement of nearby phospholipids when temp is high due to stiffness of steroid rings 2. prevents tight packing of phospholipids when temp is low because ther shape does not fit perfectly between phospholipids |
|
|
Term
| true or false: lipid-linked proteins are covalently attached to phosphlipids in the bilayer? |
|
Definition
| false. they are attached to specialized types of lipds found only in one leaflet or the other |
|
|
Term
| what is the first step in nuclear transport? |
|
Definition
| the binding of the nuclear transport receptor to the NLS (nuclear localization signal)of a protein in the cytoplasm |
|
|
Term
| how many leaflets make up the nuclear envelope? |
|
Definition
| 4 because it has 2 bilayers with an aqueous lumen in between |
|
|
Term
| the nuclear membrane is continuous with the __________ and the aqueous space between the bilayers is continuous with the __________ |
|
Definition
|
|
Term
| nuclear pores are (always/sometimes/never) porous to small molecules like salts and mononucleotides |
|
Definition
|
|
Term
| what is a nuclear localization signal (NLS)? |
|
Definition
| a patch of positively charged amino acids on the surface of folded proteins that bind to nuclear transport receptors |
|
|
Term
| are nuclear transport signals cleaved after transport into the nucleus? |
|
Definition
|
|
Term
| what is the role of a nuclear transport receptor? how does it accomplish this goal? |
|
Definition
| to bring specific proteins into the nucleus. it does this by binding to the NLS site on the protein, then taking it to the pore where it triggers the pore to open, escorts protein through pore and releases it inside the nucleus |
|
|
Term
|
Definition
|
|
Term
| when __________ binds to the nuclear transport receptor, the protein it escorted into the nucleus is released |
|
Definition
|
|
Term
| what happens when the Ran-GTP-bound nuclear transport receptor gets back into the cytoplasm? |
|
Definition
| a cytoplasmic factor triggers Ran to hydrolyze GTP to GDP which leads to the release of the receptor |
|
|
Term
| the rough ER is covered with ribosomes that synthesize proteins destined for the ___________ or _____________ pathways |
|
Definition
|
|
Term
| what are the three different types of sequences important in ER protein import? |
|
Definition
1. N-terminal (ER) signal sequence
2. start transfer (internal ER signal) sequence
3. Stop transfer sequence |
|
|
Term
| which signal gets cleaved off after protein is imported into the ER lumen or membrane? what happens to this signal after cleavage? |
|
Definition
| the N-terminal signal sequence. it is released into the bilayer and degraded by signal pepsidase |
|
|
Term
| a __________ binds the N-terminal signal sequence of a protein as it emerges from a ribosome and brings the protein/ribosome/mRNA complex to the ER |
|
Definition
| signal recognition particle (SRP) |
|
|
Term
| SRPs (increase/decrease) the rate of translation |
|
Definition
|
|
Term
| what is the role of an SRP receptor? |
|
Definition
| to bind the SRP (associated with a Ribosome) and direct the N-terminal signal sequence of the protein being translated to a channel which it will trigger to open |
|
|
Term
| the N-terminus of a TM protein is located on the ________ side of the bilayer and the C-terminus is located on the ________ side of the bilayer |
|
Definition
|
|
Term
| in translocation of multi-pass TM proteins _________________ act like the N-terminal signal sequence but are not cleaved at the end |
|
Definition
| internal start transfer sequences |
|
|
Term
| what are three experiments used to detect translocation? |
|
Definition
1. centrifugation (translocated proteins + orgenelles they are in sediment faster than untranslocated proteins)
2. protease protection (protease degrades all proteins outside of organelle-not translocated)
3. SDS gels before and after translocation (smaller after translocation because N-terminal sequence cleaved off) |
|
|
Term
| where does covalent modification of proteins occur? what are 2 possible modifications? |
|
Definition
| the ER and golgi apparatus. in the ER disulfide bonds form and sugars are added to glycoproteins and glycolipids (glycosylation). in the golgi stacks sugar modifications occur (different modifications occur in different steps) |
|
|
Term
| what are the components of the secretory pathway? |
|
Definition
| the ER, golgi stacks, secretory vesicles and the plasma membrane |
|
|
Term
| secretion can be __________ , vesicles are are continually traveling to and fusing with the plasma membrane, or _________ , vesicles only fuse with membrane when triggered by an external signal. |
|
Definition
|
|
Term
| what is the main purpose of the golgi apparatus? |
|
Definition
| to sort proteins into vesicles destined for either an endosome (which will eventually end up in a lysosome) or to the plasma membrane. sugar modification also occurs here. |
|
|
Term
| where are lipids synthesized? |
|
Definition
|
|
Term
| what are the three possible final destinations of the endocytic pathway? (ie what 3 places do endosomes transport cargo to?) |
|
Definition
1. lysosomes
2. the plasma membrane on the opposite side of the cell
3. the plasma membrane on the same side of the cell |
|
|
Term
| which two organelles utilize ATP-driven H+ pumps to maintain an acidic internal environment? |
|
Definition
|
|
Term
| what is the difference between transcytosis and recycling? |
|
Definition
| in transcytosis the cargo receptors and cargo are transported to another portion of plasma membrane whereas in recycling they are returned to the same portion of plasma membrane by the endosome |
|
|
Term
| what occurs in a lysosome? |
|
Definition
| the degredation of extracellular molecules and old organelles using hydrolases. the building blocks of these molecules are then transported back out into the cytoplasm |
|
|
Term
| folded proteins can go through (nuclear pores/ER translocation channels |
|
Definition
|
|
Term
| what is receptor-mediated endocytosis? |
|
Definition
| a type of recycling in which a receptor binds cargo outside of the cell, brings it into the cell in a vesicle, releases it into an endosome (due to low pH in endosome receptor undergoes conformational change), and returns in vesicle to plasma membrane to pick up more cargo |
|
|
Term
| what are the two main purposes of clathrin? |
|
Definition
1. to help form vesicles by binding to cytosolic leaflet of the plasma membrane and causing it to curve
2. to ensure all cargo in a vesicle is destined for the same organelle by binding to adaptin which in turn binds cargo-specific receptors |
|
|
Term
| adaptins and clathrins are located (inside the cell/outside the cell/in the plasma membrane) |
|
Definition
|
|
Term
| _________ helps aid in the pinching off of vesicles by forming a ring around the clathrin coated pit |
|
Definition
|
|
Term
| true or false: a vesicle uncoats when it reaches its target organelle |
|
Definition
| false. a vesicle uncoats as soon as it is fully formed and is no longer part of its membrane of origin |
|
|
Term
| _________ proteins act a a signal to make sure that a vesicle transports its cargo to the correct organelle. these proteins bind to specific ___________ proteins located in the cytoplasmic leaflet of the target organelle |
|
Definition
|
|
Term
| what do SNARES do? what are the two types of SNARES? |
|
Definition
| SNARES help fuse the vesicular and organelle membranes by bringing them into extremely close proximity ot one another. the two types are v-SNARES which are located on the vesicles and t-SNARES which are located on the target organelle. |
|
|
Term
| compare and contrast secretory vesicles, transport vesicles and endocytic vesicles. |
|
Definition
all three are small spheres surrounded by a single bilayer that are involved in the transport of molecules within cells
secretory vesicles transport molecules from the inside to the outside of a cell. they fuse with the plasma membrane (can be regulated or constitutive)
transport vesicles move molecules between different organelles within the cell and bind with these organelles membranes
endocytic vesicles transport molecules from outside the cell into the cell. they fuse with the membrane of endosomes. |
|
|
Term
| where does an endosome receive cargo from? |
|
Definition
| the golgi apparatus (via transport vesicles) and outside the cell (via endocytic vesicles) |
|
|
Term
| where do secreted molecules/proteins end up? |
|
Definition
| secreted soluble molecules end up outside the cell (extra cellular space) and transmembrane proteins end up in the plasma membrane |
|
|
Term
| what does it mean to say that the ER provides quality control of synthesized proteins? |
|
Definition
| proteins cannot leave the ER if they are misfolded, they are kept in the ER lumen by chaperone proteins until they are assembled and folded correctly or else are eventually degraded in the ER lumen |
|
|
Term
| ___ ATPs are consumed in the (preparatory/payoff) stage and ___ ATPs are produced in the (preparatory/payoff phase) of glycolysis |
|
Definition
| 2, preparatory. 4, payoff |
|
|
Term
| true or false: glycolysis requires oxygen |
|
Definition
| false. molecules are oxidized but no oxygen is used |
|
|
Term
| what is substrate-level phosphorylation? |
|
Definition
| the synthesis of ATP in glycolysis because ADP is phosphorylated directly from a substrate molecule (an intermediate of sugar) |
|
|
Term
| what are the possible end products of fermentation? when are these different molecules produced? |
|
Definition
lactate-produced in muscle cells during anaerobic exercise
EtOH + CO2-produced by organisms such as yeasts that can grow anaerobically |
|
|
Term
| what is the purpose of fermentation? |
|
Definition
| to replace depleted stores of NAD+ in cells so that glycolysis can continue in the absence of oxygen |
|
|
Term
| what are 2 ways in which energy is stored in aerobic respiration? |
|
Definition
1. H+ gradients
2. phosphorylated molecules |
|
|
Term
| how is energy release from phosphorylated molecules (ie ATP to ADP + Pi) controlled? |
|
Definition
| the hydrolysis of the phosphate group must be thermodynamically favorable (unstable) but have a kinetic barrier (stable) which keeps it from hydrolyzing spontaneously |
|
|
Term
| the more (positive/negative) the reduction potential (E'), the more favorable the reaction is |
|
Definition
|
|
Term
| the more (positive/negative) the change in free energy (G) is the more favorable the reaction is |
|
Definition
|
|
Term
| (NADH/NADPH) is anabolic whereas (NADH/NADPH) is catabollic |
|
Definition
|
|
Term
| what is the the product of the preparatory phase of glycolysis? |
|
Definition
| two 3-C molecules, each with one attached phosphate group (frc 1,6 bis-P) |
|
|
Term
| oxygen is the (oxidized/reduced) form of water? |
|
Definition
|
|
Term
| photosynthesis is a/an (catabolic/anabolic) process? |
|
Definition
|
|
Term
| how can an unfavorable reaction be forced to happen? |
|
Definition
| by coupling it to a favorable reaction |
|
|
Term
| during aerobic respiration glucose is oxidized to _________ |
|
Definition
|
|
Term
| how much energy does a high energy bond release when broken? |
|
Definition
|
|
Term
| enzymes that reduce organic molecules are called _________ |
|
Definition
|
|
Term
| what do electron carriers do? |
|
Definition
| store electrons and transfer them between substrates |
|
|
Term
| cytochrome proteins, iron-sulfur proteins and coenzyme Q are all examples of what? |
|
Definition
|
|
Term
| what happens in the the unnamed step? |
|
Definition
| pyruvate is oxidized to CO2 + acetyl-CoA |
|
|
Term
| BPG and PEP are both 3-C intermediates used to make ATP in what phase of glycolysis? how many phosphates does each contain? |
|
Definition
| payoff phase. BPG contains 2 phosphates but only one high energy bond, PEP contains one phosphate attached by a high energy bond |
|
|
Term
| where do the electrons passed down the ETC come from? |
|
Definition
| NADH produced in the TCA cycle |
|
|
Term
| each carrier in the ETC has an increasingly high __________ _________, meaning an increasingly high affinity for electrons |
|
Definition
|
|
Term
| as complexes I, III and IV are (oxidized/reduced) they pick up a proton from one side of the membrane and as they are (oxidized/reduced) drop it off on the other |
|
Definition
|
|
Term
| what 3 things can the electrochemical H+ gradient across the mitochondrial membrane drive? |
|
Definition
1. import of respiration substrates (such as pyruvate, ADP and Pi) into the matrix from the cytoplasm
2. export of respiration products (such as ATP) from matrix into cytoplasm
3. ATP synthesis |
|
|
Term
|
Definition
| the process of re-forming glucose from pyruvate (which is made by conversion of lactic acid by the liver) |
|
|
Term
| what molecules act as signals to indicate whether the cell has enough energy or needs more? |
|
Definition
|
|
Term
| when high levels of ATP are present in the cell gycolysis is (activated/inhibited) |
|
Definition
|
|
Term
| when energy sources are low the cell converts ADP to ______ and _____. explain what each is used for |
|
Definition
ATP-energy source for cell
AMP-signal to cell that energy stores are low |
|
|
Term
| ____________ is a glycolysis enzyme that adds a second phosphate to fructose and is inhibited when ATP levels are high |
|
Definition
|
|
Term
| phosphofrcutokinase has an allosteric and catalytic binding site for ATP. the allosteric site has a (high/low) affinity for ATP and the catalytic site has a (high/low) affinity for ATP |
|
Definition
|
|
Term
| what reaction does the catalytic site of phosphofructokinase catalyze? |
|
Definition
| ATP + Frc 6-P --> ADP + Frc 1,6 bisP |
|
|
Term
| when ATP is bound to the allosteric site of phsophofructokinase the enzyme is in its (active/inactive) conformation? |
|
Definition
|
|
Term
|
Definition
the path of electrons in photosynthesis
H2O -> e- carriers -> photosystem II -> e-carriers (cytochrome complex)-> photosystem I -> e- carriers -> NADPH |
|
|
Term
| what is the chemical structure of chlorophyll? |
|
Definition
| organic molecule with a hydrophobic tail and large conjugated rings with electrons that can be excited by light |
|
|
Term
| a ___________ is a protein complex containing a lot of chlorophyll |
|
Definition
|
|
Term
| what are the 2 sub-complexes of photosystems and what do they do? |
|
Definition
1. antennae complex- many proteins with 100's of chlorophyll molecules that capture light energy and pass it between chlorophylls to the reaction center
2. reaction center- contains special pair chlorophylls that undergo redox reactions |
|
|
Term
| the chlorophyll molecules in photosystem I have (higher/lower) reduction potentials and thus (higher/lower) energy than photosystem II |
|
Definition
|
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Term
| true or false: energy from light can be captured by chlorophylls in both photosystem I and photosystem II |
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Definition
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Term
| in photosynthesis across which membrane is a proton gradient created? |
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Definition
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Term
| what three reactions make the thylakoid space more acidic than the stroma? |
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Definition
1. protons are released during the splitting of water which occurs in the thylakoid space
2. a cytochome complex between PSII and PSI acts as a proton pump to transport protons across thy thylakoid membrane into the thylakoid space
3. protons from the stroma are added to NADP+ when it is reduced to NADPH |
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Term
| where is ATP synthesized in plants cells? |
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Definition
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Term
| how is ATP synthesis powered in photosynthesis? |
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Definition
| energy from the proton gradient across the thylakoid membrane |
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Term
| what are the dark reactions? |
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Definition
| carbon fixation and the calvin cycle |
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Term
| what are the three phases of the calvin cycle? |
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Definition
1. carbon fixation phase- CO2 is converted into an organic molecule
2. reduction phase- electrons from NADPH are incorporated into the organic molecule with aid of ATP
3. regeneration phase- majority of G 3-P is converted to RuBp so that cycle can continue |
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Term
| what is the product of the carbon fixation stage of the calvin cycle? the reduction phase? |
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Definition
| 2 molecules of 3PG (3-phosphoglycerate) created in the carbon fixation phase and G 3-P (glceraldehyde 3-P) produced by the reduction phase |
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