Biology Unit 4 Questions Megathread

[Kaille]

do germ cells undergo meiosis to produce become gametes?

[vexx]

do germ cells undergo meiosis to produce become gametes?

yep.

[HERculina]

What's more common in living organisms: complete or partial dominance? And does anyone know a good book to use for mono/dihibrid crosses and pedigree questions. Thanks

[lexitu]

I'm almost certain it's complete dominance. Hmm, I think Biozone is pretty good for that sort of stuff if I remember correctly.

[HERculina]

does DNA sequencing involve single or double stranded DNA when being loaded into the gel?

[HERculina]

do we ahve to know about multi & single locus probes

[scar]

Do all polypeptides have methionine as the first amino acid since it is coded by AUG?

EDIT: Why am I so dumb? Haha of course they do but I forgot to realize that post-transcriptional modification of the primary transcript or pre-mRNA would simply remove this amino acid if it is not vital for the polypeptide's primary structure

Careful -  The polypeptides do start with a methionine since this is what triggers the ribosome to start its first ORF.  If the amino acids are not structurally important they will get taken off post TRANSLATION.  (ignoring all the exceptions to the 'universal' code.)  You can't just take off the AUG from the RNA otherwise the ribosome doesn't know where to start!

[WhoTookMyUsername]

Diseases such as Hungtinton's Disease or Fragiile X syndrome are caused by excessive repeats.
e.g. huntingtons is caused by 61 + repeats of a certain segment

do people with say, 150 repeats have more sever Huntington's then those with 62 or 61? and why? (if not, why does 1 repeat have SO much affect (60 - 61))

[Russ]

Depends on the disease.
As for why 1 repeat difference is so significant, it's because at the molecular level it can be a big deal

[WhoTookMyUsername]

Does tac only code for methionine in body of dna?

[Russ]

What do you mean "body of DNA"?

[WhoTookMyUsername]

as in, the start codon is TAC - so what is between that and the end

sorry, shoudl have said, body of gene

[WhoTookMyUsername]

would you happen to know the answer Russ ?

[Russ]

as in, the start codon is TAC - so what is between that and the end

Still not 100% sure what you're asking, have 3 different answers. Between the start codon and the termination codon are just regular codons/bases? Technically if we're talking about codons then it's mRNA so it should be UAC, but I'm not sure that's what you mean? AUG always codes for methionine regardless of where it appears, but the original methionine may be spliced out post-translationally if necessary,

[WhoTookMyUsername]

Say you have a gene

Starts off with

TAC - AGA - ATA - etc....

In Neap it says that the TAC will NOT code for an amino acid (meth) in this case because its at the start of a gene, TAC will only code for meth if its AFTER the start codon (the first TAC) is this correct?
I haven't been able to verify this through any other sources.

Thanks russ