Chemistry and Bio: Random Questions?

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lotus0618
Posts: 182
Joined: Sun Dec 29, 2019 5:47 pm

Chemistry and Bio: Random Questions?

Post by lotus0618 » Sat Jul 11, 2020 10:35 pm

1) why are transitional metals in metal complexes considered to be lewis acid? Basically, why do they accept electrons, but metals donate electrons?

2) "The sky appears blue (490 nm) due to the scattering..." Whenever I come across these similar words "appear blue," I interpret them as the actual color of the sky is yellow, but what we see is its complementary color blue. Is that correct?

3) "The strength of the dipole moment generated in a polar-covalent molecule can be calculated using which 2 variables?
a. charge and atomic size (atomic size can inform us about the stability of the molecule, but is unrelated to the dipole moment)
b. electronegativity and atomic size (i picked this one; it's wrong)
c. charge and distance (correct answer)
d. electronegativity and atomic number (eliminated because the atomic number is unrelated to the dipole moment)
Question:
a) why is electronegativity wrong?
b) without knowing the equation of dipole moment, can you please explain why is C the correct answer?


4)"In order for plasmids to produce proteins in cells, the plasmid must be localized to the:
a) nucleus
b) cytoplasm"
Why is the correct answer nucleus? I thought plasmids are independent of DNA chromosomes and they stay in the cytoplasm of cells. They can also replicate independently, so I thought they can transcribe and translate in the cytoplasm as well.

Thank you
NS_Tutor_Yuqi
Posts: 57
Joined: Fri May 29, 2020 11:43 pm

Re: Chemistry and Bio: Random Questions?

Post by NS_Tutor_Yuqi » Sun Jul 12, 2020 3:22 pm

1. Lewis acids are anything that have vacant orbitals to accept electrons. For example, H+ is a Lewis acid that can accept electrons from OH-, a Lewis base. Since transition metals can do so, they are considered Lewis acids.

2. The sky is blue due to an effect called Rayleigh scattering, where blue light is scattered by particles in the atmosphere. It's not true that the sky is actually yellow, but rather that all colors other than blue are scattered less since blue light has the shortest wavelength, which is why the sky often appears blue to us.

3. It seems like this question is asking you which combination of variables is the best for determining dipole movement. Although a greater electronegativity difference indicates a greater dipole movement, atomic size and number aren't relevant for finding dipole movement. Even if you don't know the equation for dipole movement, the definition of a dipole is a separation of charge between two atoms. Therefore, you can infer that charge, and the distance that the two charges are separated by, are relevant for calculating dipole movement.

4. Although the genetic material carried by plasmids is separate from the host genome, plasmids must still use the host machinery to undergo transcription and translation. In other words, they replicate on their own, but need other structures in order to create proteins. Since transcription normally occurs in the nucleus, the plasmid must also localize to the nucleus to take advantage of host transcription mechanisms. This question is interesting because plasmids are usually inserted into bacteria through transformation. As bacteria do not have nuclei, this question would not be relevant for those situations.
lotus0618
Posts: 182
Joined: Sun Dec 29, 2019 5:47 pm

Re: Chemistry and Bio: Random Questions?

Post by lotus0618 » Sun Jul 12, 2020 5:11 pm

1. So i understand what lewis base and lewis acid are. Out of curiosity, I want to understand why transitional metals want to accept electrons instead of donating electrons like metals. After all, they are 'metals' right?

2. Here is my confusion: under what scenarios do we use complementary colors? I remember getting some questions wrong because I didn't use complementary colors. Sorry if this question seems so silly

3. So I relooked at the question and you are right. It's very interesting in the sense that this is an eukaryotic plasmid. The question indicates the presence of a nucleus. I have a couple questions regarding this topic?
-Your explanation about independent replication but dependent transcription and translation applies to BOTH eukaryotic and prokaryotic plasmids?
NS_Tutor_Nancy
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Joined: Wed May 27, 2020 7:25 pm

Re: Chemistry and Bio: Random Questions?

Post by NS_Tutor_Nancy » Thu Jul 16, 2020 10:10 am

Hey!

1) The transition metals are a tricky group as far as accepting vs. donating electrons. Because of where they are on the periodic table, forming transition metal ions often involves rearrangement of s and d orbital electrons and this makes them more of a special case compared to metals.

2) Thinking of complementary colors is important for absorbing vs. reflecting light. If something appears purple it means that it is absorbing the complementary color (yellow) really well and reflecting violet light, which is why it appears purple.

3) Yes, this applies to both eukaryotic and prokaryotic plasmids. The difference is that a eukaryotic plasmid would have to localize to the nucleus to take advantage of the cell machinery, whereas this is not necessary in prokaryotes that do not have a nucleus.

I hope this helps!
lotus0618
Posts: 182
Joined: Sun Dec 29, 2019 5:47 pm

Re: Chemistry and Bio: Random Questions?

Post by lotus0618 » Thu Jul 16, 2020 11:14 am

2. This is a very silly question, but I need to ask you to get it out of my head hahaha. So the lens doesn't absorb the color?
3. Okay one final time regarding the differences to make sure I have everything down: both eukaryotic and prokaryotic plasmids replicate independently. While the prokaryotic plasmids transcirbe and translate in the cytoplasm since they don't have a nucleus, the eukaryotic plasmids go to the nucleus to transcribe and translate later in the cytoplasm. DOes that sound good to you? thanks
NS_Tutor_Yuqi
Posts: 57
Joined: Fri May 29, 2020 11:43 pm

Re: Chemistry and Bio: Random Questions?

Post by NS_Tutor_Yuqi » Sun Jul 19, 2020 1:45 pm

2. I'm not sure which lens you're talking about. Are you referring to the eye?
3. Yes! You got it!
lotus0618
Posts: 182
Joined: Sun Dec 29, 2019 5:47 pm

Re: Chemistry and Bio: Random Questions?

Post by lotus0618 » Sun Jul 19, 2020 2:24 pm

Hi!
I don't remember what I asked you. So basically complementary color has to do with absorbing and reflecting light. Human lens or any lens or mirrors can absorb and reflect light. That means we can apply the complementary colors to all of those things?
Also, the blue sky due to Rayleigh scattering has nothing to do with complementary colors here.
NS_Tutor_Yuqi
Posts: 57
Joined: Fri May 29, 2020 11:43 pm

Re: Chemistry and Bio: Random Questions?

Post by NS_Tutor_Yuqi » Sun Jul 26, 2020 2:49 pm

Hi! Hopefully this website can help clarify some of your questions about complementary colors. https://www.chem.purdue.edu/jmol/cchem/color.html
I don't believe the lens of our eyes absorbs color since its primary role is to focus light onto our retinas
Here is a website that further explains Rayleigh scattering! http://hyperphysics.phy-astr.gsu.edu/hb ... lusky.html
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