Quiz thread

[Cerberus]

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Answer then ask a question.

Question 1:

What type of solvent would be best for favoring Sn1?

 

[nikibean]

Good job!

If you are farsighted, your near point is too far
(too much divergence)
your lens prescription will be +, converging

If you are nearsighted, your far point is too near
(too much convergence)
your lens prescription will be -, diverging


A histone protein is basic.

Give an example of passive immunity and active immunity.

 

[UCLAstudent]

Passive immunity: receiving antibodies produced in a rabbit
Active immunity: receiving a booster shot

Of conduction, convection, and radiation, which involves the transfer of translational kinetic energy?

 

[Cerberus]

What is the product of

aniline + Br-C(CH3) AlCl3
--------->

 

[Cerberus]

Originally posted by UCLAstudent
Passive immunity: receiving antibodies produced in a rabbit
Active immunity: receiving a booster shot

Of conduction, convection, and radiation, which involves the transfer of translational kinetic energy?

Convection?

The note A has a frequency of 233Hz, what is the frequency of the next octave?

 

[UCLAstudent]

Originally posted by Cerberus
Convection?

The note A has a frequency of 233Hz, what is the frequency of the next octave?

Correct!

466 Hz

What would be the effect of demyelination of an axon?

 

[Cerberus]

Originally posted by UCLAstudent
Correct!

466 Hz

What would be the effect of demyelination of an axon?

slowed nerve impulse

A defiency in _____ would cause a decrease in neurotransmiter released at the synaptic cleft.

 

[UCLAstudent]

Calcium

What is the neurotransmitter released at the neuromuscular juntion?

 

[Cerberus]

Originally posted by UCLAstudent
Calcium

What is the neurotransmitter released at the neuromuscular juntion?

Achetylcholine

Decreasing oxygen input while increasing oxygen needed by the tissues causes what effect on blood pH?

 

[UCLAstudent]

Blood pH will decrease.

Which base-pair exhibits the most hydrogen bonding?

 

[jhk43]

GC 3
AT 2



Rank the acidities of the alpha hydrogen

ketone
amine
acid chloride
aldehyde
beta keto ester
ester

 

[LUBDUBB]

Originally posted by jhk43

Rank the acidities of the alpha hydrogen

ketone
amine
acid chloride
aldehyde
beta keto ester
ester [/B]

orgo yummmy...

beta keto ester
aldehyde
ketone
ester
(acid chlorides)
amines (no carbonyl)

as for acid chlorides...they are very reactive, that is they will lose the leaving group (Cl) very readily and leave behind an electrophile subject to nucleophillic attack. I would probably stick it right under esters.

That being said, I think you got me on this one JHK.


Next question:

Inhibiting the electron transport chain would also inhibit which of the following: glycolysis, Krebs cycle or fermentation?

 

[Persistence101]

Originally posted by LUBDUBB
orgo yummmy...

beta keto ester
aldehyde
ketone
ester
(acid chlorides)
amines (no carbonyl)

as for acid chlorides...they are very reactive, that is they will lose the leaving group (Cl) very readily and leave behind an electrophile subject to nucleophillic attack. I would probably stick it right under esters.

That being said, I think you got me on this one JHK.


Next question:

Inhibiting the electron transport chain would also inhibit which of the following: glycolysis, Krebs cycle or fermentation?

Wouldn't acid chlorides be stronger acids than aldehydes because of the electron withdrawing effect of Cl?

 

[jhk43]

Originally posted by LUBDUBB


Next question:

Inhibiting the electron transport chain would also inhibit which of the following: glycolysis, Krebs cycle or fermentation?

The cell would continue glycolysis. some pyruvates would still go into the mitochondria for krebs, but some would start the fermentation process to compensate for the lack of NAD+.

Eventually Krebs would stop (due to lack of NAD+) and all pyruvate would try to enter fermentation. Note that at a certain point, some aerobes cant live in high lactic acid or ethanol conditions and die.

Btw, cyanide is a drug that stops the ETC.

 

[babinski bob]

Here's the CORRECT answer for the fxnl group acidity question

B-ketoester > acid chloride > aldehyde > ketone > ester > amide > amine

The stronger the e- withdrawing character of the carbonyl, the more acidic the alpha-hydrogen. Acid chlorides are more acidic than aldehydes, ketones, esters, amides, amines because of the electron withdrawing character. A general trend for the acidity of alpha H's is that they parallel C=O reactivity. So acid chlorides are more reactive than aldehydes which are more reactive than ketones which are more reactive than esters which are more reactive than amides.

 

[LUBDUBB]

Originally posted by jhk43
The cell would continue glycolysis. some pyruvates would still go into the mitochondria for krebs, but some would start the fermentation process to compensate for the lack of NAD+.

Eventually Krebs would stop (due to lack of NAD+) and all pyruvate would try to enter fermentation. Note that at a certain point, some aerobes cant live in high lactic acid or ethanol conditions and die.

Btw, cyanide is a drug that stops the ETC.

I'm sittin next to you on test day..

 

[LUBDUBB]

Originally posted by babinski bob
Here's the CORRECT answer for the fxnl group acidity question

B-ketoester > acid chloride > aldehyde > ketone > ester > amide > amine

The stronger the e- withdrawing character of the carbonyl, the more acidic the alpha-hydrogen. Acid chlorides are more acidic than aldehydes, ketones, esters, amides, amines because of the electron withdrawing character. A general trend for the acidity of alpha H's is that they parallel C=O reactivity. So acid chlorides are more reactive than aldehydes which are more reactive than ketones which are more reactive than esters which are more reactive than amides.

Ok...let's consider this...alpha hydrogens are on the carbon next to the carbonyl. The more acidic the alpha hydrogen, the more readily it will get plucked off, thus forming a carbanion. Just like when an aldehyde loses its hydrogen to give an enolate ion.

Now, an acid chloride will lose its Cl very readily, leaving behind and electrophile. My problem is that I have never seen an acid chloride lose its alpha hydrogen to become a carbanion.

Someone help me out.

 

[krull]

you guys are like thinking to hard. just memorize this trend:

http://library.tedankara.k12.tr/carey/ch21-2.html

 

[Persistence101]

Originally posted by LUBDUBB
Ok...let's consider this...alpha hydrogens are on the carbon next to the carbonyl. The more acidic the alpha hydrogen, the more readily it will get plucked off, thus forming a carbanion. Just like when an aldehyde loses its hydrogen to give an enolate ion.

Now, an acid chloride will lose its Cl very readily, leaving behind and electrophile. My problem is that I have never seen an acid chloride lose its alpha hydrogen to become a carbanion.

Someone help me out.

In EK's Ochem book, they state that just like aldehydes, acid chlorides donate their alpha hydrogen. They make stronger acids than aldehydes due to the electron withdrawing Cl.

 

[krull]

Originally posted by Persistence101
In EK's Ochem book, they state that just like aldehydes, acid chlorides donate their alpha hydrogen. They make stronger acids than aldehydes due to the electron withdrawing Cl.

exactly. this makes the carbonyl carbon more electropositive, which in turn makes the donation of a proton from the alpha position more favorable.

 

[LUBDUBB]

Thanks for clearing it up guys.

 

[krull]

What is the main difference between an electrical synapse and a chemical synapse?

 

[babinski bob]

Ok...let's consider this...alpha hydrogens are on the carbon next to the carbonyl. The more acidic the alpha hydrogen, the more readily it will get plucked off, thus forming a carbanion. Just like when an aldehyde loses its hydrogen to give an enolate ion.

Now, an acid chloride will lose its Cl very readily, leaving behind and electrophile. My problem is that I have never seen an acid chloride lose its alpha hydrogen to become a carbanion.

Here's the deal.... this question has nothing to do with whether or not you've ever seen alpha-deprotonation of an acid chloride. It's purely testing your knowledge of acidity trends. An acid chloride is a much stronger "electron-withdrawing group" than an aldehyde which is in turn more electron withdrawing than a ketone, etc.... Remember, the stronger the neighboring electron-withdrawing group, the weaker the electron density at the alpha H-carbon bond = a weaker bond = more acidic. Good luck.

 

[babinski bob]

Here's a question to brush up on your organic chemistry acidity trend knowledge.

Rank the following compounds in order of decreasing acidity


4-methoxybenzoic acid
4-chlorobenzoic acid
Benzoic acid
4-nitrobenzoic acid
3-nitrobenzoic acid
3-methoxybenzoic acid
4-N,N-dimethylaminobenzoic acid

HINT.... the "acid" is at position 1 since it's not explicitly stated.

 

[redgrover]

Q: If a rocket take off at an initial velocity of 100 m/s, 75 degrees of the horizontal, and its engine stops working after 11 seconds, what is the maximum height the rocket achieves?

I know this was way back in the thread, but we need more information to solve this problem. Note that the rocket engine stops firing after 11 seconds. Yes, we have v0, but the rocket will be accelerating due to the firing of its rocket engine for another 11 seconds. We either need either the force (which will allow us to derive the acceleration) of the engine or the acceleration of the rocket engine before we can solve.

 

[jhk43]

Originally posted by redgrover
I know this was way back in the thread, but we need more information to solve this problem. Note that the rocket engine stops firing after 11 seconds. Yes, we have v0, but the rocket will be accelerating due to the firing of its rocket engine for another 11 seconds. We either need either the force (which will allow us to derive the acceleration) of the engine or the acceleration of the rocket engine before we can solve.

The question assumes constant velocity during the first 11 seconds...

 

[jhk43]

you eat a steak. stomach gets stimulated by Sympathetic or PS? Ach or NE/E?

 

[Cerberus]

you eat a steak. stomach gets stimulated by Sympathetic or PS? Ach or NE/E?

PS..."rest and digest"

I guess i'd assume Ach for the second part

*edit adding question*

Damage to which part of the eye would cause difficulty in vision in low light situations?

 

[LUBDUBB]

you eat a steak. stomach gets stimulated by Sympathetic or PS? Ach or NE/E?

Ach released by the PS nervous system to stimulate smooth muscle contractions.



Why is mitochondria only inherited maternally?

 

[Cerberus]

Ach released by the PS nervous system to stimulate smooth muscle contractions.



Why is mitochondria only inherited maternally?

The only paternal mitochondria come from the sperm cell and are far outnumbered by the mitochondria of the mothers egg.

 

[Nuel]

Ach released by the PS nervous system to stimulate smooth muscle contractions.



Why is mitochondria only inherited maternally?

If I guess right: only the nucleus of the Y chromosome fuses with the ovum.

 

[Nuel]

Let me be the first to post a question with options . . . hmmm.. now we are doing it MCAT style.

Physics:

Fluid element can undergo non-turbulent flow because:

A. irrotational flow suggests no net angular velocity.

B. eddy currents are present to oppose turbulent flow effects.

C. there are no streamlines which cross to oppose turbulent flow.

D. fluctuating fluid density always implies incompressible fluids.

 

[LUBDUBB]

If I guess right: only the nucleus of the Y chromosome fuses with the ovum.

Upon fertilization, in the cytoplam the sperm nucleus separates from the mitochondria. The mitochondria is destroyed by an unknown mechanism. It is thought that the parental mitochondra are targeted for destruction by being marked with the protein Ubiquitin.

 

[Cerberus]

Let me be the first to post a question with options . . . hmmm.. now we are doing it MCAT style.

Physics:

Fluid element can undergo non-turbulent flow because:

A. irrotational flow suggests no net angular velocity.

B. eddy currents are present to oppose turbulent flow effects.

C. there are no streamlines which cross to oppose turbulent flow.

D. fluctuating fluid density always implies incompressible fluids.

Is it answer c?

 

[Nuel]

Certain antimetabolite drugs can cause people to lose weight by uncoupling the chemiosmotic machinery thus making the mitochondrial lipid bilayer:

A. permeable to H+ because ATP synthase is deactivated in the
mitochondrial matrix by such changes and no ATP is produced.

B. permeable to H+ because the mitochondrial catalytic sites of ATP synthase
remain active but cannot produce ATP.

C. impermeable to H+ because ATP synthase is deactivated in the
mitochondrial matrix by such changes and no ATP is produced

D. impermeable to H+ because the mitochondrial catalytic sites of ATP
synthase remains active but cannot produce ATP.

 

[Nuel]

Is it answer c?

Nope Cerberus. Good try, try again

 

[LUBDUBB]

Let me be the first to post a question with options . . . hmmm.. now we are doing it MCAT style.

Physics:

Fluid element can undergo non-turbulent flow because:

A. irrotational flow suggests no net angular velocity.

B. eddy currents are present to oppose turbulent flow effects.

C. there are no streamlines which cross to oppose turbulent flow.

D. fluctuating fluid density always implies incompressible fluids.

Choice A. No angular velocity in fluid elements --> NO turbulence.


turbulence causes eddy currents
Incompressible flow means that the density of the fluid remains constant.
And finally, non-turbulent (laminar) flow is characterized by well-ordered streamlines.

 

[Nuel]

Choice A. No angular velocity in fluid elements --> NO turbulence.

Lubdubb, you are extremely smart! I give you a 40 next Saturday.

 

[LUBDUBB]

Lubdubb, you are extremely smart! I give you a 40 next Saturday.

Not at all, I've just been drilling this info in my head for a really long time.
Good Luck



The surge in LH before ovulation is caused by what?

 

[Nuel]

Not at all, I've just been drilling this info in my head for a really long time.
Good Luck
The surge in LH before ovulation is caused by what?

GnRH is responsible for the surge of LH, and FSH too.

 

[LUBDUBB]

GnRH is responsible for the surge of LH, and FSH too.

yeah... rise of estrogen --> surge in GnRh ---> surge in LH-->ovulation.


Ok one more q & a then i gotta get back...

What is the function of the RNA primer in DNA replication?

 

[jhk43]

yeah... rise of estrogen --> surge in GnRh ---> surge in LH-->ovulation.


Ok one more q & a then i gotta get back...

What is the function of the RNA primer in DNA replication?

DNA poly. needs a primer to get started. primase (RNA primer maker) does the job. RNA primer later gets replaced by DNA poly 1 (which has 5-->3 chopping ability).

 

[jhk43]

how can u separate a solution of two enantiomers?
" " diasteromers?

 

[jhk43]

GnRH is responsible for the surge of LH, and FSH too.

what causes the GnRH rise? positive feedback for estrogen? whys it positive sometimes, and negative feedback other times?

 

[Nuel]

what causes the GnRH rise? positive feedback for estrogen? whys it positive sometimes, and negative feedback other times?

When the endometrial tissue is sloughed off, estrogen and progesterone levels fall, consequently there is withdrawal of the inhibitory efffect on GnRH release. This is my summary.

 

[Nuel]

Certain antimetabolite drugs can cause people to lose weight by uncoupling the chemiosmotic machinery thus making the mitochondrial lipid bilayer:

A. permeable to H+ because ATP synthase is deactivated in the
mitochondrial matrix by such changes and no ATP is produced.

B. permeable to H+ because the mitochondrial catalytic sites of ATP synthase
remain active but cannot produce ATP.

C. impermeable to H+ because ATP synthase is deactivated in the
mitochondrial matrix by such changes and no ATP is produced

D. impermeable to H+ because the mitochondrial catalytic sites of ATP
synthase remains active but cannot produce ATP.

Nobody is trying this? Just guess, at least that is what people like me are going to do next Saturday, although we wishfully hope we know the answers to all the questions, especially touchy-feely verbal.

 

[Nuel]

i believe Radius is max at the equator, min at the N pole..

F=GMm/R^2

g~M/R^2

since g~1/R^2, g is max at smaller radius, so escape velocity max @ north pole?

I thought escape velocity was given as v = sqrt(2gR). So I guess it should be at at the equator. If I am wrong someone should correct this.

 

[Nuel]

PS..."rest and digest"

Damage to which part of the eye would cause difficulty in vision in low light situations?

The retina? Or pupil, but most likely retina.

 

[jhk43]

The retina? Or pupil, but most likely retina.

or rod cells

 

[LUBDUBB]

Certain antimetabolite drugs can cause people to lose weight by uncoupling the chemiosmotic machinery thus making the mitochondrial lipid bilayer:

A. permeable to H+ because ATP synthase is deactivated in the
mitochondrial matrix by such changes and no ATP is produced.

B. permeable to H+ because the mitochondrial catalytic sites of ATP synthase
remain active but cannot produce ATP.

C. impermeable to H+ because ATP synthase is deactivated in the
mitochondrial matrix by such changes and no ATP is produced

D. impermeable to H+ because the mitochondrial catalytic sites of ATP
synthase remains active but cannot produce ATP.

Damnn good question Nuel, let's see if i can remember this stuff...Okay..mitochondrial uncouplers, you're talking about something like DNP..which can go right through the bilayer of the mitochondria. When it goes right through it takes protons with it into the matrix, so it messes up the proton gradient. No proton gradient --> ATP synthase are deactivated. Exaclty how that works, I really dont' know, but I'm going to go with choice A. (Although it could be choice B.) You got me on this one.

 

[Cerberus]

or rod cells

That's Correct