Lesson 9 Video 1 Slide 2

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SungHoonPark97
Posts: 11
Joined: Tue May 22, 2018 12:16 pm

Lesson 9 Video 1 Slide 2

Post by SungHoonPark97 » Tue Jul 17, 2018 2:21 pm

In this lesson, Dr. Anthony explains proximal vs distal. He states that proximal is moving closer to the CNS and distal is moving further away from the CNS.
In several other sources (such as textbooks and google), it states proximal and distal was moving closer to/further away from the central part of the body (i.e. torso) unless the point of reference is stated otherwise, which isn't in the question.
Could you explain to me why the question assumed the CNS was the point of reference?

Thank you
SungHoonPark97
Posts: 11
Joined: Tue May 22, 2018 12:16 pm

Re: Lesson 9 Video 1 Slide 2

Post by SungHoonPark97 » Thu Jul 19, 2018 12:31 pm

Also on a side note, why are amino acids that are easier to ionize more likely to convert from solution to gaseous phase?
(pg. 166 of biochemistry book, chapter 7 passage practice, question 3 answer)

I thought that amino acids with lower B.P. (i.e. weaker intramolecular interactions [so not ionizable, charged amino acids]) will turn to gas first.
NS_Tutor_Alex
Posts: 36
Joined: Fri Jul 21, 2017 4:11 pm

Re: Lesson 9 Video 1 Slide 2

Post by NS_Tutor_Alex » Thu Jul 19, 2018 8:26 pm

Hi there,

Thank you for the question! The language in the question stem indicates the CNS as the point of reference because it is asking about the path a nerve impulse will take from the hand to the brain. Thus, the nerve impulses in question will be traveling from a distal location to a proximal location (i.e. the brain for appropriate sensory processing).

In regards to your second question, the key is again in the language of the question stem! The question provides key details about how amino acids are converted from solution into the gaseous phase. The detail to focus on is the ionization of amino acids in order for them to convert, thus Lysine is the logical choice as it is the only answer choice that contains an ionizable R chain.

Hope the helps!

Alex
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