VCE Biology Question Thread

[helpme12345]

Hey there!
Can anyone help me with this question? I said person 3 had the most variation because they have two STRs that are unique in size to the rest of the individuals compared to person 1, person 2, person 4, and person 5 who share at least one STR size with another individual. However I'm not entirely sure whether person 3 has two STR fragments of the same size that are denoted by the single band. If that was the case, shouldn't the band be thicker?

Thanks!

[Billuminati]

Hey there!
Can anyone help me with this question? I said person 3 had the most variation because they have two STRs that are unique in size to the rest of the individuals compared to person 1, person 2, person 4, and person 5 who share at least one STR size with another individual. However I'm not entirely sure whether person 3 has two STR fragments of the same size that are denoted by the single band. If that was the case, shouldn't the band be thicker?

Thanks!

Indeed persons 2 and 3 are homozygotes. Also I think the question is poorly written in that there's multiple ways you can interpret "most variation", eg one can argue that homozygotes have less variation

[Chocolatepistachio]

If someone could help with this question

i don't really get this question. so for this question would it be e very accurate when you add then and divide by the number its 0.822374 but its not precise because of the 0.9043

[Rose34]

Hello,

Regarding the fossil records, are we required to memorize numbers? Eg: emergence of prokaryotes (3.8 bya), widespread of photosynthesis (2.4 bya), first eukaryotes (2 bya) etc.. would VCAA ever ask about those numbers? or would we get a better marks if we memoize them?

[yr12_vcestudent]

hey can you explain to me degenerate triplet code pls

[Billuminati]

hey can you explain to me degenerate triplet code pls

Degeneracy of the genetic code just means that multiple codons can code for the same amino acid (there are 64 codons, including 3 stop codons, but only 20 amino acids).

[gcfkn.j]

Hi! May I ask why the proteome is larger than the genome? Edrolo says it is due to post-translational modification, however, someone told me it was post-transcriptional modification as exon splicing allows the exons to be rearranged.

Thank you 

[Billuminati]

Hi! May I ask why the proteome is larger than the genome? Edrolo says it is due to post-translational modification, however, someone told me it was post-transcriptional modification as exon splicing allows the exons to be rearranged.

Thank you 

Both are correct. Post-transcriptionally, you can splice the pre-mRNA differently such that some introns become exons or vice versa (this is called alternative splicing).

Post-translationally, you can add different chemical functional groups to the amino acids of a protein to change its form and/or function eg collagen is usually hydroxylated at its proline residues to increase strength.

[yr12_vcestudent]

HEY there!
can someone explain to me what is the relationship between histone protein and DNA pls!
THANKS 

[Billuminati]

HEY there!
can someone explain to me what is the relationship between histone protein and DNA pls!
THANKS

For the purposes of VCE, histones are bead-like, basic proteins that DNA wraps around to condense itself.

In uni biochem/molecular bio, you'll learn that histones undergo chemical modifications to regulate gene expression. When histones are methylated, genes are typically off in that region, whereas the opposite is usually true when histones are acetylated. Acetylation dissociates histones from DNA, exposing the promotor for RNAP II binding

[yr12_vcestudent]

Hi
i was wondering why is DNA organised into chromosomes?
is it because DNA is tightly packaged, coiled around histones which form nucleosome which are condensed into chromatin ad packed as chromosome into the nucleus?

thanks

[kumamoe]

Hi
i was wondering why is DNA organised into chromosomes?
is it because DNA is tightly packaged, coiled around histones which form nucleosome which are condensed into chromatin ad packed as chromosome into the nucleus?

thanks

This isn't something you have to know in detail for VCE Biology, but in theory, yes. DNA is packaged into chromosomes to allow for all of an organism's genetic material to fit within the cell - since this information is necessary for protein synthesis, apoptosis, cellular functions, etc.

Hope this helps!

[Chocolatepistachio]

In humans if non disjunction led to an individual with a genotype of XO, that person would
A be male because each cell has only one x chromosome
B not survive
C be female because each cell lacks a Y chromosome
D display both male and female characteristics

Would this be c

[Billuminati]

In humans if non disjunction led to an individual with a genotype of XO, that person would
A be male because each cell has only one x chromosome
B not survive
C be female because each cell lacks a Y chromosome
D display both male and female characteristics

Would this be c

Yes, (45, XO) is Turner Syndrome and biologically patients of TS are female but infertile. In humans and other mammals, the presence of the Y-chromosome = male and its absence = female. However, in flies, the sex determination process is different. They have it such that 1X eg XO, XY, XYY = male and 2X or more eg XX, XXX, XXY = female

[Chocolatepistachio]

Which inhibitory neurotransmitter is used by neurons of the CNS to suppress the sensation of pain?
A endorphins
B acetylcholine
C Adrenalin
D serotonin

Would this be d