Biology Exam: Answers and Discussion!

[katiesaliba]

I don't get why 270 is wrong, if you were to count the start and stop codons (bases that  code for a acids  which aren't actually part of the polymer) then why stop there? Why exclude the promoter sequence, and the other bases that get added to it (adenine tail, methylated cap?) I reckon it was 270, only because it used the word 'coding'.

"Stop codons signal the termination of this process by binding release factors, which cause the ribosomal subunits to disassociate, releasing the amino acid chain. While start codons need nearby sequences or initiation factors to start translation, stop codon alone is sufficient to initiate termination." - wiki

Stop and Start aren't translated 

The start codon is translated and codes for the amino acid met.
Promotor and terminator regions are not transcribed into mRNA (at least, I don't think they are)
The question asked for the number of nucleotides that allowed for the coding of the polypeptide (paraphrasing here). Therefore, stop codons are necessary for the translation process.

[katiesaliba]

For the glucose question, I said something like

glucose is unable to pass directly through the phospholipid bilayer, so it must pass through the membrane through specific protein channels embedded in the membrane.This process does not require energy.


I wrote:

90 amino acids, and 3 nucleotides per amino acid hence 90*3=270
However, add 3 nucleotides for STOP codon
Therefore 270+3=273 bases needed

Same, however I said that it goes with its concentration gradient instead of not requiring energy. 

[dankfrank420]

Same, however I said that it goes with its concentration gradient instead of not requiring energy.

I think that's implicit anyway, but yeah should have wrote that.

[katiesaliba]

I think that's implicit anyway, but yeah should have wrote that.

Exactly! I feel like I should have written that it doesn't require energy :') ahaha

[Aman476]

Yeah, logically i would say 270 - but a vcaa exam, too easy for 1 mark just to multiply by 3 and i really dont remember the specific wording, if it said allowed then defs have to add the extra stuff (still dont get why we have to dismiss the other added bases but...)

Oh yeah you're completely right, start codon is translated - but wouldn't that just be one of the 90 monomer subunits?

[dankfrank420]

Exactly! I feel like I should have written that it doesn't require energy :') ahaha

No I meant I should have written your answer, that the process goes with conc. gradient

[Sup]

Would it be sufficient to write specific protein channel in regards to the facilitated diffusion question?

[Reus]

I wrote about the concentration gradient however did not make mention of no requiring energy... I thought that was self explanatory since it was 'facilitated diffusion' haha pls suffice

[vcestudent123]

37/40 .. errr I guess I did okay... tbh I really shouldn't have lost any of these, hopefully I did alright on short answer.

I probably got something like 35/70 for S.A :/

[davomac]

can anyone remember their phenotype and genotype ratios for those two questions???   

[dankfrank420]

can anyone remember their phenotype and genotype ratios for those two questions???   

For the ZZ x ZW question, pretty sure phenotypic was just 1 of each
For the Bb^1b question, I think phenotypic was 2 purple: 1 lilal: 1 white

[Reus]

For the ZZ x ZW question, pretty sure phenotypic was just 1 of each
For the Bb^1b question, I think phenotypic was 2 purple: 1 lilal: 1 white

Woooooo!!
Do you make mention of the gender too in the phenotype?

[davomac]

For the ZZ x ZW question, pretty sure phenotypic was just 1 of each
For the Bb^1b question, I think phenotypic was 2 purple: 1 lilal: 1 white

Yeah thats what I thought!

[Idolift]

DAMNNN!!

On the double checking of MC i changed 3 answers and they were all wrong, so i got 37/40
That sucks...

[dankfrank420]

Woooooo!!
Do you make mention of the gender too in the phenotype?

Yes, only in the ZZ ZW question though
The b question was autosomal

Hoping these questions where the answers are pretty straightforward can drag me over the line. I think I might get marked down alot due to the ambiguity of questions/VCAA's strict answers.