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Cell Biology
Metabolism/Secretion
55
Biology
Undergraduate 4
11/18/2011

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Term

catabolism

anabolism?

Definition
  • breakdown of molecules to produce energy
  • formation of macromolecules that requires an input of energy
Term
first step in glycolysis is?
Definition
  • glucose to glucose 6 phosphate with hexokinase
  • removes glucose from solute pool
  • uses ATP to prepare glucose for E extraction

 

Term
Third step in glcolysis
Definition
  • fructose 6 phosphate to fructose 1,6-biphosphate
  • phosphofructokinase
  • uses second ATP; ends E investment
Term
sixth step in glycolysis
Definition
  • glyceraldehyde 3 phosphate to 1,3-bisphosphoglycerate 
  • glyceraldehyde phosphate dehydrogenase
  • NAD+ to NADH and Pi added
  • reaction made favorable by steady state conditions
Term
seventh step in glycolysis
Definition
  • 1,3-bisphosphoglycerate to 3 phosphoglycerate
  • phosphoglycerate kinase
  • 2 ATP made for each glucose that recoups invested ATP
Term
tenth step in glycolysis
Definition
  • Phosphoenolpyruvate to pyruvate
  • pyruvate kinase 
  • 2 more ATP /glucose
Term
2 ways to make ATP and their definitions?
Definition
  • substrate-level phosphorylation - direct transfer of Phosphate from an organic molecule to ADP
  • oxidative level phosphorylation - indirect transfer of phosphate from an inorganic molecule to ADP (NADH used to make H+ gradient to make ATP)
Term
how is glycolysis thermodynamically favorable?
Definition
  • payout phase molecules have a lower affinity for the phosphate group than does ATP
  • investment phase molecules have a higher affinity for phosphate than does ATP
Term
products of glycolysis?
Definition

2 ATP 

2 NADH

2 pyruvate that can be metabolized further or anaerobically be turned to lactic acid to recycle NADH to NAD+ for further glycolysis

Term
fermentation step
Definition
pyruvate to lactic acid with lactate dehydrogenase
Term
how is glycolysis regulated?
Definition
allosteric effectors - bind somewhere other than the binding site which causes a change in binding affinity of the enzymes in glycolysis
Term

allosteric activators?

allosteric inhibitors?

examples of both?

Definition

A - increase binding affinity

ADP

AMP

I - decrease binding affinity

ATP

citrate

Term
how are the 2 membranes of the mitochondria different?
Definition
  • outer - 1:1 protein lipid ratio; permeable with porins
  • inner - 3 to 1 protein lipid ratio; highly impermeable
Term
properties of mitochondria?
Definition
  • contain some DNA (from moms)
  • double membrane
  • can replicate themselves; fusion and fission
  • powerhouse of cell
  • contain ribosomes so they can do their own protein synthesis
Term
evidence for endosymbiotic theory?
Definition
Fission is like bacterial fission
Mitochondrial DNA is circular & lacks histone proteins = like bacteria not nucleus
Size and drug sensitivity of ribosomes are similar to bacterial ribosomes not cytoplasmic
inner memb. = like original bacterial memb.
outer memb. = like host plasma memb. after endocytosis
Term
how is pyruvate entered into TCA cycle
Definition
  • pyruvate to Acetyl CoA
  • pyruvate dehydrogenase
  • NADH produced
  • CoA added; CO2 released
Term
Look over TCA cycle
Definition
Term
TCA products?
Definition

4 NADH (1 from Acetyl CoA production)

1 GTP 

1 FADH2

Term
5 types of e- carriers in the ETC?
Definition
  • carbon rings
  • ubiquinone
  • metal ions (Cu)
  • hemes
  • FE-S centers
Term
first half of the ETC. complex1 to 3
Definition
  • 2e-s are transfered from NADH to complex 1; E released used to pump 4H+ to intramembrane space
  • they join Q along with 2H+ to balance out the charge on the matrix side of the membrane and float across the membrane to the intramembrane side of complex 3.
  • they are released to complex 3 without the 2 H+ which are released outside the membrane
Term
role of complex 2
Definition
  • in the oxidation of succinate to fumarate FAD is reduced to FADH2
  • FADH2 is oxidized by complex 2 and the electrons are taken by Q along with 2H+ to balance the charge
  • Q binds to complex 3 and gives it its e-s and releases its 2H+
Term
2nd half of ETC. complex 3 to 4?
Definition
  • E released to move e-s through complex 3 releases 2H+
  • one e- at a time is acquired by cyt c at the IM side of complex 3 and moves through the intermembrane space to complex 4
  • Cu accepts one e- at a time until it gets 4e-
  • for every e- pair 2H+s move to IMS
  • then Cu moves to the matrix side and releases e-'s to oxygen and 4H+ to form 2 H20's
Term
what is the proton motive force?
Definition
  • a steep proton gradient that generates a electrochemical gradient
  • depends on impermability of inner mito membrane
Term
ATP synthase structure?
Definition
  • Fo stalk - made of 12 c subunits and A. rotates around gamma structure
  • F1 ball - 3 beta subunits that catalyze ATP synthesis; 3 alpha subunits provide structural support. stationary by s subunit held by b and a.
Term
how is the gamma subunit able to change the Beta subunits conformation?
Definition
since its assymmetrical it can interact differently with each subunit
Term
3 conformations of Beta subunit?
Definition
  • Loose - medium affinity for ADP and Pi as they bind loosely
  • Tight - high affinity for ADP and Pi as they join to form ATP
  • Open - releases ATP and low affinity for ADP and Pi as it binds very loosely
Term
3 purposes of the H+ gradient
Definition
  1. ATP synthesis
  2. exchange ATP for ADP (antiport)
  3. bring in Pi (symport)
Term
how is the ETC inhibited?
Definition
  • the H+ gradient becomes so steep that the energy to pump out H+ is too great.
Term
what specific causes the ETC to be inhibited?
Definition
  • ADP levels are low
  • H+s are blocked from the ATP synthase
  • chemicals can block e- transport in complexes
Term
what do uncouplers do?
Definition
  • allow H+ to diffuse back into mito matrix
  • therefore more glucose will have to be oxidized in order to produce a steep H+ gradient
Term
3 membranes of chloroplasts
Definition
  1. outer envelope - double membrane; permeable
  2. thylakoid membrane - impermeable
Term

2 sets of rxns taht make up photosynthesis?

products? location?

Definition
  • light dependent - converts light and water into oxygen while producing ATP and NADPH in thylakoid membrane
  • light independent - converts CO2 to carbohydrates in stroma using ATP and NADPH
Term
ETC consists of?
Definition
  1. photosystem II
  2. cytochrome b6f
  3. photosystem I
Term
where are H+s pumped to?
Definition
thylakoid lumen
Term
chlorophyll structure?
Definition
  1. P-ring - porphyrin ring 
  2. phytol tail 
  • looks like a lilly pad
Term
three ways electrons can release E?
Definition
  1. fluorescence - photon of longer wavelength emitted
  2. resonance energy transfer (RET) - energy is transfered to another molecule
  3. Electron transfer - electron is donated to another molecule
Term
PS II mechanism?
Definition
  • light E is absorbed by reaction center cholorphyll starting e- transport
  • H2O is ripped apart by oxygen evolving complex and 4e-s enter as 4H+s contribute to H+ gradient and oxygen is produced
  • e-s go through PSII and exit in plastoquinone
Term
what increases the number of photons captured?
Definition
antenna and Light harvesting complexes absorb light and transfer it randomly to other antenna and LHC's via RET until it reaches a reaction center chlorophyll (only place where e- transport can begin)
Term
mechanism thru PSI?
Definition
  • e-s leave PSII in PQ and go through cytochrome b6f pumping H+s into TK lumen
  • e-s then leave in plastocyanin (PC) to PSI
  • e-s used to reduce NADP+ to NADPH
Term
where are the ATP and NADPH used then?
Definition
calvin cycle in stroma
Term
Calvin cycle overview? key enzyme?
Definition
  • uses a lot of energy (ATP and NADPH) to convert CO2 into RuBP
  • uses RUBP carboxylase (Rubisco)
Term
which proteins are made in the cytoplasm? RER?
Definition
made in Cytoplasm
  • cytoplasmic proteins
  • imported mito proteins
  • nuclear proteins

made in RER

  • secretory proteins
  • IMPS at PM, ER, golgi, nuclear envelope, lysozymes
  • lumenal proteins of ER, golgi, lysozymes
Term
layers of the golgi?
Definition
  1. cis golgi network
  2. cis cisternae
  3. medial golgi
  4. trans cisternae
  5. trans golgi network
Term
how do we visualize RER to golgi fxn
Definition
  • attach GFP to a chimeric gene
Term
what is the signal hypothesis?
Definition
  • set of signal codons at the 5' end of mRNA
  • as singal codon is translated its signal peptide product causes the mRNA/ribosome/protein to go to the RER
  • protein is inserted into RER through pore
  • signal peptide is cleaved off once inside the RER.
Term
  1. advantages of radioactivity tracing?
Definition
  1. traceable
  2. quantifiable
  3. sensitive
Term
how is it read?
Definition
gel autoradiography - SDS-PAGE ran and film laid over gel. film is developed and bands show radioactivity
Term
when centrifuged after homogenation what are microsomes in?
Definition
pellet 2
Term
mitochondria import mechanism?
Definition
  • IMP - goes through TOM complex, then TIM 22 complex where it is integrated into the inner membrane. has internal targeting sequence
  • Matrix - has presequence at N terminus. goes through TOM complex, then through TIM 23 complex. MPP chops off presequence

 

Term
fxns of smooth ER?
Definition
  • hormone synthesis
  • detoxification (liver)
  • Ca sequestering (sarcoplasmic reticulum)
  • lipid synthesis
Term
N-linked oligosaccharides?
Definition
- are oligosaccharrides added on the Asn of the Asn-x-ser/thr
Term
how do proteins get help in folding properly in the RER?
Definition
  • chaperone proteins like BiP, calnexin and calreticulin
  • protein disulfide isomerase (PDI)
  • serve as quality control
Term
chaperone mechanism? 6 steps
Definition
  1. last 2 glucose removed from oligoscde
  2. calnexin recognizes it and binds
  3. chaperone part binds and last glucose removed by glucosidase II
  4. Glucosyltransferase looks over and if is unfolded improperly adds glucose back
  5. then binds back to calnexin for another try
  6. if no glucose added then protein goes on its designated pathway
Term
what happens if a protein takes too long to fold properly?
Definition
It is shipped back to the cytoplasm where it is targeted by a proteasome and degraded
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