Otago HSFY chat - archive

[SeeKay]

Oh yes, forgot about that!

Thanks a bunch.

EDIT: Actually having thought about it, the sensory pathway for proprioception is also the medial lemniscal pathway and the 1a neuron is the fastest conducting neuron in the body = must be myelinated?
Argh, oh well, at least I know other people have it down as dorsal horn as well...

 

[Proshot]

Hey guys, could anyone possibly explain the process of bacterial artificial chromosome cloning and also when the past papers ask for shotgun sequencing do they mean after using the BACs or Craig Ventors method? thanks

 

[brin]

Serves me right for leaving study until the last minute I guess - all the HUBS slides on blackboard appear to be blank.

 

[Nimbus2000]

yikes @brin , have you tried saving a local copy and then opening it?

Goiseee, i have a question - you know during mid stance, how the gluteus maximus works to extend the hip? How is it working eccentrically though? (This is what I've written down during the lecture) - Isn't it technically shortening in length from the early stance phase? So wouldn't it be working concentric, agonistic?

PLEASE HELP D:

EDIT: [MENTION=13401]Proshot[/MENTION], I'm sorry, I have absolutely no idea.

I just realised how royally screwed I am for CELS on monday :/

 

[Ruth]

yikes @brin , have you tried saving a local copy and then opening it?

Goiseee, i have a question - you know during mid stance, how the gluteus maximus works to extend the hip? How is it working eccentrically though? (This is what I've written down during the lecture) - Isn't it technically shortening in length from the early stance phase? So wouldn't it be working concentric, agonistic?

PLEASE HELP D:

EDIT: @Proshot , I'm sorry, I have absolutely no idea.

I just realised how royally screwed I am for CELS on monday :/

Yeah [MENTION=8682]brin[/MENTION] if you try saving it then it might work? I just tried then and it did.

I've got 'agonist gluteus maximus and hamstrings act concentrically' so yeah, not eccentric.

 

[Nimbus2000]

@rurururuth , LOL ok then, clearly i just copied it down wrong (and learnt it all wrong for the first terms test D: ). Thanks Do you mind sharing, what you have down for the 3 groups in late swing?

 

[Ruth]

@rurururuth , LOL ok then, clearly i just copied it down wrong (and learnt it all wrong for the first terms test D. Thanks Do you mind sharing, what you have down for the 3 groups in late swing?

haha lucky it didn't come up in the terms test then

• Hip = more flexed - agonist iliopsoas acts concentrically (antagonist gluteus maximus and hamstrings act a little to stop flexing too much - gives stability)

• Knee = fully flexed - agonist quadriceps femoris act concentrically (and hamstrings to control rate of extension), ready for heel strike
• Ankle = dorsiflexion - agonist tibialis anterior acts concentrically

 

[Sam]

Hey guys, could anyone possibly explain the process of bacterial artificial chromosome cloning and also when the past papers ask for shotgun sequencing do they mean after using the BACs or Craig Ventors method? thanks

If they ask for hierarchical shotgun sequencing then it's that of the human genome project (BAC -> Plasmid -> Sequence -> Compare). Otherwise you're safe with Craig Ventors method I think

 

[keypadlocked]

Hi
STRESS!!!
Could someone please explain Delayed Type Hypersensitivity? It just seems like a regular Chronic cell-mediated response- apart from necrosis of the cells and such... Could someone please clarify what exactly happens and why there's necrosis of the cells?
Cheers!!!

 

[Nimbus2000]

Hey guys,

Can someone please explain why most types of snake venom are unable to enter the CNS from the bloodstream due to the anatomical protection mechanism that the CNS has. The only thing that I can think of is the layers of meninges - but don't blood vessels still course through to get to the brain and stuff? I don't see how snake venom is unable to enter, when the blood stream literally goes everywhere?

EDIT: @rawry , hey i don't think we need to know why necrosis occurs... but its something about a highly inflammatory environment causing the cells to eventually die (according to bb)... sorry I couldn't be of much help, those last few lectures... err, i'm a tad worried about, especially looking at past year questions :S

 

[Bluerock]

My guess? Blood Brain Barrier - the Astrocytes surrounding the capillaries prevent large molecules flowing through. Allows diffusion of small molecules but venom would be too large to pass through?

 

[Nimbus2000]

[MENTION=11852]Shaunasaur[/MENTION], omg, totally forgot about that haha, thank you!

 

[Wongtong]

Hey guys, could anyone possibly explain the process of bacterial artificial chromosome cloning and also when the past papers ask for shotgun sequencing do they mean after using the BACs or Craig Ventors method? thanks

Thought this video was helpful (hierarchical shot gun sequencing / human genome project)
Human Genome Project animation - YouTube

 

[DrakeRamoray]

Hey guys. Looking at the 2009 Chem paper, question 3a, in the answers it shows a protonation of OH step before the SN2 reaction. I thought with SN2 reactions it did not depend on the quality of the leaving group, and so the protonation would not be necessary?

 

[Wongtong]

Hey guys. Looking at the 2009 Chem paper, question 3a, in the answers it shows a protonation of OH step before the SN2 reaction. I thought with SN2 reactions it did not depend on the quality of the leaving group, and so the protonation would not be necessary?

Me and a couple of friends thought this as well :bored:

 

[Proshot]

Hey guys. Looking at the 2009 Chem paper, question 3a, in the answers it shows a protonation of OH step before the SN2 reaction. I thought with SN2 reactions it did not depend on the quality of the leaving group, and so the protonation would not be necessary?

I think its because the C-O bond of the -OH group is fairly strong and stable thus hard to remove without protonation.

oh and thanks wongtong and lulwut <3

 

[Sam]

Hey guys. Looking at the 2009 Chem paper, question 3a, in the answers it shows a protonation of OH step before the SN2 reaction. I thought with SN2 reactions it did not depend on the quality of the leaving group, and so the protonation would not be necessary?

I thought protonation was always necessary with a OH group, as it is not (or it is, i can't remember hnngh) very electron withdrawing and thus won't leave even if a decent nucleophile is attacking..

 

[SeeKay]

I think the OH group is quite electron withdrawing which is why you get partial charges.
What I thought was that disassociation of HBr leads to formation of H+ which could either bond to either the Br- thats formed or the OH, and since protonating the OH will produce a better leaving group hence faster reaction, we would see that reaction more - just a guess :S

[OFFTOPIC]ARGH hubs 2011 paper essay question 2...don't know anything about it...did the lecturer go into enough details about the light reflex to answer that essay question?[/OFFTOPIC]

 

[DrakeRamoray]

Thanks guys, I wasn't sure if protonation applied to SN2 reactions.

 

[Sam]

ARGH hubs 2011 paper essay question 2...don't know anything about it...did the lecturer go into enough details about the light reflex to answer that essay question?

I think they are more or less just using the iris as an example of sympathetic innervation. Just explain how it works, the receptor types and what the iris does when it is stimulated by sympathetic processes (pupil dilation).

From what I am gathering, they present an example then ask a very broad question and you have to just use the given example to explain the question.