VCE Biology Question Thread

[Reus]

Is it correct to say an organism with recombinant DNA is a recombinant organism or would you stick with transformed organism?

[jessica666]

Is it correct to say an organism with recombinant DNA is a recombinant organism or would you stick with transformed organism?

Transgenic organism is a good term to use i think

[Reus]

Transgenic organism is a good term to use i think

Thank you!!


Also, rDNA is short for recombinant DNA right? Or is it rtDNA?

[vox nihili]

Just to clarify a couple of things about mitochondrial DNA:

It is useful as a molecular clock because the mutation rate is known. As far as mutation rate is concerned, the rate of coding sequences is very slow. This is because the selection pressures against mutation in those genes is very strong; cells that accrue mutations in mitochondrial genes will not survive. In non-coding regions, the mutation rate is fast. Slow mutation rate is good because it can show longer term relationships. Fast mutation because it can show short term relationships.

Other bonuses include the fact that there is no crossing over and mitochondrial DNA is, for the most part, maternally inherited.

[RazzMeTazz]

One thing I'm always confused about is:

So each type of chromosome has different genes (the genes on chromosome 1 are different to the genes on chromosome 2) and each non-duplicated chromosome is made up of DNA molecule.

So does that mean that in the nucleus of a somatic cell the 46 molecules of DNA are all different to each other? since they code for different genes?

[RazzMeTazz]

Sorry this might sound silly but whenever you do a punnet square are you required to write the genotype and phenotype ratios even if the question doesn't ask for it?

Because in my checkpoints all the answers show the genotype and phenotype ratios even if the question didnt ask!

[melons]

One thing I'm always confused about is:

So each type of chromosome has different genes (the genes on chromosome 1 are different to the genes on chromosome 2) and each non-duplicated chromosome is made up of DNA molecule.

So does that mean that in the nucleus of a somatic cell the 46 molecules of DNA are all different to each other? since they code for different genes?

The 46 chromosomes are in homologous pairs. So there are two chromosome 1s, two chromosome 2s and so on. For each set, one is from the father and the other is from the mother. So those two chromosomes have the same gene loci but may have different alleles at these loci.

[Reus]

Is heat shock, in which a plasmid is taken up by a bacterial organism an example of gene delivery systems? Thanks.

[vox nihili]

Is heat shock, in which a plasmid is taken up by a bacterial organism an example of gene delivery systems? Thanks.

The gene delivery system is the plasmid and the whole shabang. Heat shock is just one of the steps involved in the gene delivery. The plasmid itself is the delivery system.

[millie96]

In the TSFX lecture I went to they went into great detail regarding neurone.. just wondering if we really need to know about neurones and neural systems besides the electrical communication process?

(I do from psych but never learnt this detail in bio classes)

[DJA]

In the TSFX lecture I went to they went into great detail regarding neurone.. just wondering if we really need to know about neurones and neural systems besides the electrical communication process?

(I do from psych but never learnt this detail in bio classes)

I believe this is no longer in the study design.

[dankfrank420]

Do DNA replication and transcription both occur in the 5' to 3' direction?

[psyxwar]

The synthesis of a new strand always occurs 5' to 3' (which means that its always read 3' to 5'). This is because of the hydroxyl group on the 3' carbon, which is necessary in joining two nucleotides together.

[grannysmith]

Examination reports are confusing me... are we required to include the stem of the question in an answer?

[Reus]

I believe this is no longer in the study design.

Wait no need to learn neurones?

Do DNA replication and transcription both occur in the 5' to 3' direction?

No, transcription occurs in a 3' to 5' creating a pre-mRNA strand of 5' to 3'