Question 6

[anon3543]

6. Both copies of intron 1 of the amelogenin gene on the 2 sex chromosomes can be referred to as:

1. homologous chromosomes. [x]
2. recessive traits. [x]
3. alleles. [x]
4. spliced RNA. [x]

INCORRECT:
Your Answer: C
Correct Answer: D

I was just confused because I thought "intron" referred to the DNA (not RNA) that corresponds to mRNA that will be spliced. I guess intron/exon can refer to either DNA or RNA counterparts?

[admin]

No, you had it right the first time: "I was just confused because I thought "intron" referred to the DNA (not RNA) that corresponds to mRNA that will be spliced."

The key word in the question is "copies" which, in the context of the passage, is the same as "transcription" into mRNA.

[Nirfoochil2984]

[quote="admin"]No, you had it right the first time: "I was just confused because I thought "intron" referred to the DNA (not RNA) that corresponds to mRNA that will be spliced."

The key word in the question is "copies" which, in the context of the passage, is the same as "transcription" into mRNA.[/quote]

I had the the same issue. The entire passage speaks of PCR which has nothing to do with transcription. PCR just creates a bunch of "copies" of the original strand. How am I supposed to know that copies means transcription? I thought this one was a trick question, which is why I didn't put D.

[jellywing_2058]

The definition of transcription is:
“The copying of a DNA strand nucleotide by nucleotide, following the base-pairing rules, by an RNA polymerase to produce a complementary RNA copy.” (P. 668 Henderson’s dictionary of Biology)

[quadalpha]

[mcat_premed3832]

PCR does not come into play for this question. This question is about introns.

[GraemeMatt8033]

Agree with above, based off the passage and question you would think DNA. It says copies, but by that it just means more than one of the same gene. Ie. if i had two pieces of paper with the periodic table, I would have two copies of it, not that I photocopied the first table to get the second.
So it is true that it will be spliced eventually, but without specifying transcription, you can't say that that would be the answer. A closer answer would be alleles, because an allele is just one copy of many, of a particular gene. So yes you could say that those are both a form of the gene on intron 1, at any time, but unless specified that it is after transcription, you can't say indefinitely that they are "spliced RNA".

Sure you could reach, but its always supposed to be the least wrong answer. Allele would be the least wrong answer, because in any instance it is correct, whereas spliced RNA takes a specific situation, that was not referred to.
Unless I'm getting some part of the process wrong, which if I do please enlighten me.

Edit: it also says on the chromosome, which alludes to DNA, not RNA. RNA is never on a chromosome, unless to temporarily alter a process, like iRNA. I dno I just think the wording and set up of the question is poor. Might want to make clear in the question, or atleast put in some safeguards, to have the person believe its RNA and not DNA.

Thanks

[jsfkt78927]

Got this one right!

The question seems to be testing your knowledge of what is an intron. Well if you crack open your books, you'd notice its a piece of non-translated mrna, or a 'garbage' sequence of dna found btwn coding sequences.

In the passage their usage of the word intron is exactly what you guys are saying, the 'junk' dna that wont be encoded. in my opinion you have to realize that they're using the word intron as a sort of short cut rather than putting, '...which requires amplification of the dna sequence that would be intron 1 of the pre-processed rna molecule of the amelogenin gene.'

If you dont buy that, and think that the usage of the word intron is the same in the question as it is in the passage then ask yourself this question...

Also ask yourself this, can an allele really be an intron???

Refer to the definition of an allele boys and girls - genes CODING for alternative forms of a given trait...blah blah. alleles describe the coding part, not the excised junk dna.