VCE Biology Question Thread

[soNasty]

thank you all

[walkec]

(Image removed from quote.)

how is it A? I had C. Confused, help 

I would say it is A. A recessive trait means that an affected individual has to have two unaffected parents (as is the case in A). Sex linked traits are more common in males than females, and affected individuals in A are males.

[grannysmith]

A recessive trait means that an affected individual has to have two unaffected parents

I think you mean: if an affected individual has two unaffected parents, then it must be recessive inheritance.

[dankfrank420]

C shows dominant sex linked.

Remember that squares are males and circles are females. The mnemonic that I use is that men are square shouldered and women have curves.

That's a good way of remembering it, the mnemonic I have for women is... *ahem* unsuitable for the rules of this forum.

How much of mutations do we need to know?

[katiesaliba]

Crossing over can create new alleles, right?

If translocation can happen between two homologous chromosomes, how does it differ from crossing over?

[nerdmmb]

Crossing over can create new alleles, right?

If translocation can happen between two homologous chromosomes, how does it differ from crossing over?

Crossing over creates new combinations of alleles. New alleles are made by mutation, if I'm not mistaken.

Translocation can happen between any two chromosomes, not just a homologous pair.
It occurs when a segment of one chromosome breaks off and joins another chromosome.
Crossing over is really specific and occurs between homologous pair of chromosomes. It involves the exchange of genetic material at specific gene loci between non-sister chromatids of a homologous pair of chromosomes.

Hope that helps

[Scooby]

Crossing over can create new alleles, right?

If translocation can happen between two homologous chromosomes, how does it differ from crossing over?

If it occurs properly, no new alleles should arise from recombination

Translocation occurs between non-homologous chromosomes

[katiesaliba]

If it occurs properly, no new alleles should arise from recombination

Translocation occurs between non-homologous chromosomes

Why won't new alleles arise?

Thanks!

[nerdmmb]

Why won't new alleles arise?

Aren't the chromosomes homologous in the attached VCAA question from the 2010 exam?

Because you'll always have two alleles for a certain gene, they may be the same (e.g. AA) or different (e.g. Aa)

When crossing over occurs, alleles are being exchanged. None are being produced

[katiesaliba]

Thanks!

During metaphase, do chromosomes (or in the case of meiosis, tetrads) always line up in the same vertical order (as in homologous chromosomes 1-23) along the equator? I understand that the homologous pairs change orientation during metaphase I, so I'm not referring to them

[Stressedyear11here]

Currently doing biotechnology in biology, now this may seem like a dumb question...but these restriction enzymes that are used to cut DNA, is that done by the organism itself or in a laboratory? And similar idea with transporting DNA, laboratory right?

Thank you

[Reus]

Currently doing biotechnology in biology, now this may seem like a dumb question...but these restriction enzymes that are used to cut DNA, is that done by the organism itself or in a laboratory? And similar idea with transporting DNA, laboratory right?

Thank you

Yes, restriction enzymes are derived from bacteria and used to manipulate DNA, henceforth done is a laboratory. What do you mean by transporting DNA?

[Reus]

Got a question myself, are Simple Sequence Repeats (SSR's) Short Tandem Repeats (STR's) and microsatellites all interchangeable terms?
And could someone clarify how population numbers remain stable despite the lack of genetic variation?
Thank you!!

Edit: Found the answer for both

Yes they are interchangeable.
Despite the lack of genetic variation, the population may be extremely adaptive to their surroundings.

[Stressedyear11here]

Yes, restriction enzymes are derived from bacteria and used to manipulate DNA, henceforth done is a laboratory. What do you mean by transporting DNA?

Transporting DNA; where plasmids are used as vectors to transport DNA from one organism to another (?) so you have the DNA fragment (the one we want) which is sticky ends, and then you have the second DNA fragment, which is from the plasmid, which is also sticky ends. And then they rejoin (ligation).

[Reus]

Transporting DNA; where plasmids are used as vectors to transport DNA from one organism to another (?) so you have the DNA fragment (the one we want) which is sticky ends, and then you have the second DNA fragment, which is from the plasmid, which is also sticky ends. And then they rejoin (ligation).

I think you've answered yourself there! Human influence of course, lab.