mugen_edamame: (Default)
 13 (baby, baby, baby)
(baby)

1.
Glycolysis is ANAEROBIC, takes place in the cytosol, oxidation of glucose takes place, but NO MOLECULAR OXYGEN IS USED.

2
OXIDATIVE PHOSPHORYLATION generates THE MOST ATP (x28 ATP per glucose) glycolysis nets 2, starch to glucose nets nothing, citric acid cycle makes 1 GTP

3
advantage to GRADUAL OXIDATION of glucose during cellular respiration is that energy can be EXTRACTED in USABLE amounts.

4
FINAL metabolyte of GLYCOLYSIS is PYRUVATE.

5
NET!!!! number of activated carrier molecules at the end of GLYCOLYSIS is 2 ATP and 2 NADH
(NADH not converted to NAD+ here)

6
CARBON DIOXIDE is ONLY produced during the step of CONVERSION OF PYRUVATE to ACETYL CoA

7
Enzyme that catalyzes cleaving of 6-sugar carbon into 3-sugar carbon in step 4 of glycolysis is called ALDOLASE

8
If you eat ONLY PROTEIN, EXCRETION OF MORE NITROGENOUS WASTES compared to regular diet. Amino acids can generate Acetyl CoA, so it can generate energy friend.

9
Takes place in Cytosol
Glycolysis
Glycogen breakdown
Release of fatty acids from triacylglycerols


Takes place in Mitochondria matrix (open space in the middle)
Citric acid cycle
Conversion of pyruvate to activated acetyl groups
Oxidation of fatty acids to acetyl coA

Inner mitochondrial membrane
oxidative phosphorylation

10
lol we'll deal with this later

11
GLYCOGEN BREAKDOWN does NOT occur in MITOCHONDRIA

12
phosphoglucose isomerase catalyzes glucose 6 phosphate to fructose 6 phosphate  (isonerases DO NOT add phosphate groups, kinase do)

13
HEXOKINASE phosphorylates glucose to glucose 6 phosphate serves the purpose of DRIVING the UPTAKE of GLUCOSE INTO the cell

14
In OXIDATIVE PHOSPHORYLATION, MOLECULAR OXYGEN required to make ATP
in SUBSTRATE-LEVEL PHOSPHORYLATION the enzyme-catalysed oxidation of substrate releases energy that generates ATP DIRECTLY.

15
ANAEROBICALLY GROWING YEAST relies EXCLUSIVELY on glycolysis to supply them with ATP.

16
In ANAEROBIC conditions, skeletal muscles ONLY PRODUCE LACTATE

17
Anaerobically growing yeast metabolizes pyruvate to ethanol and CO2 via fermentation.
Another important reaction during this process is
NADH -> NAD+ 

Essential for growth of this anaerobic cell because it is THE ONLY means of REGENERATING NAD+ that is required for glycolysis, the main energy-generating pathway in an anaerobic cell

18
Free energy for oxidation of aldehyde group on glyceraldehyde 3-phosphate to form a carboxylic acid is more negative than the free energy for ATP hydrolysis (oxidation of glyc 3 phosphate is energetically favourable and drives synthesis of ATP from ADP

19
enzyme glyceraldehyde 3 phosphate dehydrogenase w Serine side chain instead  of cysteine WOULD OXIDIZE SUBSTRATE BUT NOT RELEASE IT

20
Final product for fermentation in yeast is ethanol and CO2
Ethanol is C2H60, 
H2 C - OH
       l 
       CH3



21
Pyruvate moves from cytosol to mitochondria, where it's oxidised to acetyl coA and CO2 by pyruvate dehydrogenase complex what has 3 enzymes, 60 polypeptides

22
Fermentation in mammalian cells result in LACTATE which has 2 Hs more than pyruvate
CH3CH(OH)COO

23
In oxidation of pyruvates, what are the advantages of 3 enzymes in one complex instead of independent enzymes???
Substrates are already bound and properly positioned for rapid enzyme catalysis, and free energy released by one reaction can be easily used for another.

24
Reaction sequence for glycolysis is linear, it's cyclical for citric acid cycle. What are the resulting differences when an excess amount of one type of intermediate is added?
CITRIC ACID CYCLE occurs more RAPIDLY, and w addition of one intermediate LEVELS OF ALL INTERMEDIATES INCREASE. 

in GLYCOLYSIS, intermediates DOWNSTREAM of the excess intermediate will be affected


25
FALSE. Glycolysis DOES NOT result in CO2 and H2O, but in 2 pyruvate. CO2 n H20 are produced in citric acid cycle, friend.

FALSE. Cleavage of fructose 1, 6 biphosphate DOES NOT yield 2 x glyceraldeyhyde 3 phosphate, but instead in dihydroxyacetone phosphate and ONE gylceraldehyde 3 phosphate. 

TRUE. Anaerobic respiration isn't the same as fermentation, because it uses electron transport chain and fermentation does not.

FALSE. under anaerobic conditions, DO NOT continue glycolysis resulting in build up of pyruvate in cytosol, they CONVERT PYRUVATE TO LACTATE and the EXCRETE it.

TRUE. Pyruvate dehydrogenase catalyzes 3 different but linked enzymatic reactions.

TRUE. Amino acids CAN be transported into mitochondria and converted into acetyl coA.


26
OXALOACETIC acid cycle IS NOT a common name for citric acid cycle

27
 Citric acid cycle uses WATER to get the oxygen it uses to make the by-product CO2.

28
Fatty acid that has more carbons and is totally saturated (NO DOUBLE BONDS) will yield the most energy. The more carbons, the more acetyl coA that can be generated, and all carbons being saturated means that an FADH2 molecule WILL BE GENERATED IN THE FIRST STEP OF THE CITRIC ACID CYCLE.


mugen_edamame: (Default)
chapter two, 17

pump that pumps heavy metals into vacuole for sake of cell. u make fake vesicle include the pump, put Zn2+ and ATP around it, K+ into in, and then you find Zn 2+ gets pumped into the vesicle. 
then you vary the contents of the insides and outsides.
then you break the vesicles down, to find out the presence of turned on (phosphorylated) pumps
u take ones that are phosphorylated but don't have Zn outside, wash it out clean of ATP and then add Zn 2+
what do you think happens?

Small amount of Zn 2+ will move into the vesicle, no K+ will come out, protein pump becomes unphophorylated. pumps were activated previously w presence of Zn 2+ so Zn2+ gets stuck in, dephosphorylates the protein and gets spat out the other side, but absence of ATP means that the pump can't make the conformational change to take on the K+ and haul it out (assuming this works like Na+ K+ pump)



18

Antibodies that recognize the extracellular domain of Ca 2+ pump in animals blocks active transport of Ca2+ out of the cell. As a result, the intracellular contents of Ca 2+??
Ca 2+ pumps in the ER membrane keeps cytosolic Ca2+ conc. low. 

19
Na+-H+ exchanger is used to maintain pH in ANIMAL cells

20
Na+ K+ transporter keeps both Na+ and Cl- out of the cell by actively pumping out Na+ and keeping the outside so electropositive Cl- does not bother to enter.

21
Ca 2+ pumps in plasma membrane and ER are important because they prevent Ca 2+ from altering activity of molecules in the cytosol. (Ca 2+ is a very powerful signal molecule.

22
For uncharged molecule, direction of diffusion decided solely by concentration gradient
For charged molecule, it's conc. plus look at the membrane potential
Net driving force has 2 components for charged molecule, it's called the electrochemical gradient
Coupled transporters use movement of a molecule flowing down its gradient to power another going against its gradient
when transporter moves both ions in one direction it's called a symport
if it moves one in, one out, it's called a antiport

23
Movement of glucose into cell against conc. gradient can be powered w co-transport of Na+ into the cell.
movement of of Na+ ions from area o high concentration of low concentration is energetically FAVOURABLE, and increases entropy. As long as conc. in and out of the cell is significant, net entropy increase w d movement even though glucose going into area of higher glucose concentration results in loss of entropy

24
Testing rate of glucose transport into cell via Na+ glucose transporter.

In a vesicle, you have the pump put in right (glucose in, Na+ in) w glucose in vesicle and Na+ in the solution around it. You change conc. of the Na+ ions in the solution, and the rate of transport increases and then plateaus because the transporters reach a maximum capacity (become saturated) at which point maximum rate of transfer occurs, and rate will not increase regardless of addition of more Na+ ions outside.

If you also add leaky Na+ channels, the channels allow rapid equilibration of Na+ conc. in and out of the vesicle, destroying the gradient required for glucose transport, and so there will be no net movement of glucose regardless of how high the conc. of Na+solution.

25.
Gated channels open more frequently in response to a given stimulus.

26.
Patch-clamp recording sons. 

How do you set it up, and what does the 'clamp' refer to?

Requires removal of portion of cell membrane by sealing microelectrode to the cell membrane. Pull the sealed portion away, place in solution of controlled medium. Voltage applied to patch o membrane can be fixed ('clamped') while varying other parameters for study.

Spikes in readings can be go either way
depending on the direction of flow of current or manipulating the ion concentrations on either side, which can result in negative readings for current when channels open.

27
- Gap Junctions ARE NOT large pores that connect cytosol to the outside. They connect the cytosols of adjacent cells. They are v large, and if they open straight up to extracellular space the permeability of cell membrane will be too high, affecting its effectiveness and selectivity


- Charged molecules / Ions  CANNOT pass through aquaporins

- Selectivity of channel depends on THREE (NOT ONE) parameters. Diameter, shape and charge of ions.

- Most ion channels ARE gated, depend on presence of stimulus to open or close and aren't jammed open allowing unregulated flow of ions.

28
Gating mechanism of auditory hair cells is STRESS GATED

29
Acetyl-choline receptor in skeletal cells is ligand-gated ion channel

Stress-gated channels in hair cells of mammalian cochlea

Voltage-gated
responds to changes in membrane potential

Receptors for neurotransmitters are mostly ligand gated

30
Voltage-gated channels are either completely open or completely closed.

31
In a resting cell, K+ leak channels keep the electrochemical gradient of K+ at zero

32
Nernst equation pls remember  V = 62 × log(Co/Ci)
when co is 16 n ci is 106
V = 62 × log(15/106) 
V = 62 × –0.849 
V = –52.7 

33
a BAD assumption when using Nernst equation is that the plasma membrane is primarily permeable to Na+. Buddy's got K+ leak channels, so it would be way more permeable to K+!!!!

34
If Na+ channels open in a previously at rest cell, membrane potential will become more POSITIVE.

35
Dendrites come out of the cell body of nerve cells, nerve terminals are the ends on the other side of axon, the long liney bit

36
Neurotransmitters ARE small molecules released into the synaptic cleft after fusion of synaptic vesicles w presynaptic membrane (the neuron sending the message)

Action potentials ARE NOT mediated by Ca 2+ channels, usually mediated by voltage-gated Na+

Voltage-gated Na+ channels ARE inactivated automatically shortly after activation so that action potential can't move backwards.

Voltage-gated K+ channels ARE NOT immediately opened in response to local depolarisation, they open when the action potential is at its peak so they can't weaken it, and instead help restore membrane potential while Ca 2+ channels are inactivated.

37
Voltage-gated Ca 2+ channels that respond to action potential are required for secretion of neurotransmitters. Depolarisation of nerve terminal causes Ca 2+ channels to open, Ca 2\; floods in, causes synaptic vesicles to fuse to plasma membrane and secrete lotsa neurotransmitters into the synaptic cleft

38
Threshold potential (-40mV) anything above me generates action potential

39
-60mV is resting membrane potential
 
40
spike of -40mv to 40mv is the action potential

41
between -60 to -40, the change from resting to threshold is the effect of the depolarising stimulus.

42
Action potential is wave of DEPOLARISATION.
Triggered when the membrane potential becomes LESS negative than resting membrane potential.
Propagated by the opening of VOLTAGE-GATED CHANNELS. 
During action potential, membrane potential changes from NEGATIVE to POSITIVE.
Travels along the AXON to nerve terminals.
Signals received at DENDRITES what are on the nerve bodies.

43
the ACETYLCHOLINE neurotransmitter is the one released in the synaptic junctions between neurons and skeletal muscles.

44
Inhibitory neurotransmitters (like glycine n gaba) work by acting as ligands to open the gate for Cl- so they rush in and neutralise the positive charge caused by influx of Na+ and kills the action potential in its tracks

45
Neurons communicate with each other through specialised sites called SYNAPSES.
Neurotransmitter receptors are ligand-gated ion channels that open transiently in POSTSYNAPTIC cell membrane in response to neurotransmitters released by PRESYNAPTIC cell. Ligand-gated ion channels convert CHEMICAL signals into ELECTRICAL signals. Neurotransmitter release stimulated by voltage-gated Ca 2+ channels in nerve terminal membrane.

46
Experiments on Squid Giant Axon

* In the cell you double the concentration of K+, plus Oac- that cannot go out that maintains the relative electrical balance within the cell. Does this make the membrane resting potential more negative or less?

MORE NEGATIVE. Increasing conc. of K+ in cell creates driving force for K+ to leave the cell, and the cell becomes more negative and the membrane potential becomes more negative.

* u double the amount of Na + outside another cell. How does this affect the action potential?

INCREASE HEIGHT of PEAK of action potential. Driving force to enter Na+ is higher than in usual circumstances, and when the Na+ channels open flux (rate) of Na+ ions moving into cells goes up.

* for yet another cell, u remove half of the Na+ natch present in that situation, and u add choline (v big cation that doesn't bother Na+ )

ACTION POTENTIAL HEIGHT will be LOWER than usual because halving the Na+ conc. reduces the driving force that pushes Na+ into the cell through the channels 










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Yu, or Mu

September 2015

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