Biology Unit 4 Questions Megathread

[Russ]

I have never heard that and it seems implausible (how would the ribosome differentiate between the first codon and middle codons?)

My general reference text for bio (Life by Sinaver et al) specifically states that the first aa added is always met.

[WhoTookMyUsername]

Thanks Russ, I'll talk to my teacher about it simply because neap is usually a reliable source though it is somewhat doubtful.

Is it possible for crossing over to occur in the middle segment of a chromosome only by the formation of 2 (close) chiasmata?

[epinephrine]

@Bazza16 : are you referring to the neap smartstudy guide?

[WhoTookMyUsername]

Urgent SAC help please XD:

Are X-linked traits considered "Mendelian?"
I know codominance and incomplete aren't but not sure about X


THANKS!

[pi]

I'm pretty sure they aren't, but I'm not 100% sure on this.


EDIT: I'll doubt you'd need to know much for that SAC (the computer one right?), its very straightforward.

[lexitu]

^ No they are not because each individual does not receive one factor or the other - Mendel predicted that you'll get half and half. Also, follow the rule of independent assortment (as with all linkages).

[WhoTookMyUsername]

thankyou both

another question -
can alleles be recessive / dominant?

Checkpoints said its "inaccurate to call them recessive / dominant" as only the phenotypes are dominant...
Is that true and is it even required knowledge for U4?

[pi]

another question -
can alleles be recessive / dominant?

Checkpoints said its "inaccurate to call them recessive / dominant" as only the phenotypes are dominant...
Is that true and is it even required knowledge for U4?

Definitely DON'T call them recessive/dominant alleles. It's completely wrong.

Alleles can code for the recessive/dominant trait/phenotype, but are not recessive/dominant in themselves.

[HERculina]

yea i think you should say the allele coding for dominant/recessive trait instead of dominant/recessive allele.

Are trinucleotide repeat expansions the same as duplication mutations?
what happens in duplication mutations; does a section of a chromosome replicates and joins onto that same chromosome OR is it a segment is lost from one chromosome and is added to its homologue?

[Kaille]

is gene cloning a branch of gene tranformation or are they the same thing?

[Kaille]

what happens in duplication mutations; does a section of a chromosome replicates and joins onto that same chromosome OR is it a segment is lost from one chromosome and is added to its homologue?

A segment is lost from one chromosome and is added to its homologue. duplication come under block mutations. The chromosome with the "extra" segment or duplication will be incorporated into a gamate which ma later be constributed to an embryo.

[HERculina]

what happens in duplication mutations; does a section of a chromosome replicates and joins onto that same chromosome OR is it a segment is lost from one chromosome and is added to its homologue?

A segment is lost from one chromosome and is added to its homologue. duplication come under block mutations. The chromosome with the "extra" segment or duplication will be incorporated into a gamate which ma later be constributed to an embryo.

ah, thanks kaille.

[WhoTookMyUsername]

pi

how would  you phrase something like

. This is because the protein produced by the dominant allele


then?

Would you say,
the allele responsible for the dominant phenotype codes for a more efficient protein ?

Moderator action: removed real name, sorry for the inconvenience

[pi]

Would you say,
the allele responsible for the dominant phenotype codes for a more efficient protein ?

I think that's fine. Examiners get really mad when students use 'dom/rec' for alleles, so what you have written should be completely fine

[Russ]

Bear in mind that just because it's dominant, doesn't mean it's more efficient or beneficial