FEW QUESTIONS from here and there

[stronghold]

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I am doing my final revision and found these points somewhat ambiguous to me, I hope you could help me:

1) when does a child draw a triangle? square?
2) template vs coding strand? I noticed that books sometimes use them interchangeably?!
3) Nucleotide excision repair means to remove the whole nucleotide, while base excision is just to remove the sugar base, right?
4) Genetic lactase deficiency: I noticed the UW- in more than a question- mentions that genetic deficiency is due to a gene NEAR to the lactase gene! Why not the lactase gene itself? If we have a question that has both lactase gene and a gene near lactase, which one to pick?
5) I noticed in a UW explanation that Cyanide INCREASES Oxygen saturation! Why?! I though that both cyanide and CO works the same by decreasing Oxygen saturation

Sorry for may questions!

 

[Myxedema]

1) It is a bit tricky, since it can be intuitively thought that a square may be harder to draw than a triangle. However, as it turns out, a child can draw a triangle at age 6 and a squre at age 5.

2) Template strand is the strand which is used to synthesize mRNA. Coding strand is the corresponding strand to the template strand, which has the same sequence as the transcribed mRNA (except T for U of course).

3) Yes, in fact, nucleotide excision removes the strand and not just a single nucleotide. This makes sense as nucleotide excision repairs thymidine dimers.

4) I don't recall a question with that explanation (do you have the question ID?), but here is the direct quote from Robbins: "Congenital lactase deficiency is an autosomal recessive disorder caused by a mutation in the gene encoding lactase."

5) Both CO and CN cause hypoxia, but how they create hypoxia is different. CO does it by impairing oxygen-carrying capacity of blood (indicated by decreased SaO2) by preventing binding of oxygen to hemoglobin (indicated by shifting O2-binding curve to the left). CN does it by preventing oxygen usage of tissues via the inhibition of complex IV of ETC. Since oxygen carrying to the tissues is normal in CN poisoning, SaO2 is normal.

 

[CaliAtenza]

I am on my final revision too, so i will try and see if i can answer some of these 🙂
1) Its a Square at age 4 and a Triangle at age 5.
2) Reading through Kaplan, the template strand is used for Transcription. So RNA polymerase moves from 3 to 5 and mRNA is synthesized from 5 to 3. The coding strand isnt used in transcription. Bassically the point is that the template strand is made from the coding strand, and then from the template, mRNA is formed.
3) i think you are right on that.

 

[Transposony]

The way I remember it is that a square has 4 sides (so 4 yrs) and if you put a triangle on top of a square it becomes a Pentagon (so 5 yrs). In reality it's a range (4-5 yrs) and (5-6 yrs) but this is a way to remember it.
Hope this helps.