VCE Biology Question Thread

[Reus]

I've just come across some of them in the practice VCAA exams..
Thanks for that. I'll take your word for it

What exam and question?

[soNasty]

You're misreading the question.

You are correct when you say a quarter would have no hair/white flesh, but that isn't what B is saying. B is sort of a conditional probability question - it's saying "given the fruit has no hair, what is the probability that it has white flesh".

sorry man but im still confused...
There is a 3/16 possibility that there will be a fruit with no hair and yellow, and 1/16 probability that its white with no hair.
only 1 of the 4 WITHOUT hair, have a white colour

[flares]

What exam and question?

Unit 3 exam, 2011 question 18 (that one didn't really require the knowledge of knowing the functions of the immunogobulins actually)
and Unit 3 exam, 2010 question 8b. When i did that in exam like conditions, i didn't really know how to respond to it..

Alright, now that i look back at them, the Ig G/A/M/E/D were thrown into the exam probably to just confuse the heck out of us (well it did for me) ...

Ps: only done 4 vcaa past exams and came across Ig in the ones stated above
also, would u like me to attach a pic of the question or...?

thanks

[dankfrank420]

sorry man but im still confused...
There is a 3/16 possibility that there will be a fruit with no hair and yellow, and 1/16 probability that its white with no hair.
only 1 of the 4 WITHOUT hair, have a white colour

Nah man that's what the thread is for.

But the question states that it is a test cross - HhWw x hhww. It's not a 9:3:3:1 ratio produced, but a 1:1:1:1.

[soNasty]

Nah man that's what the thread is for.

But the question states that it is a test cross - HhWw x hhww. It's not a 9:3:3:1 ratio produced, but a 1:1:1:1.

oh my god, a test cross. I thought it was a cross between two heterozygous... lol!! Didn't even read the question properly, thank you!

[dankfrank420]

oh my god, a test cross. I thought it was a cross between two heterozygous... lol!! Didn't even read the question properly, thank you!

Yeah I thought that too at first - poorly written question. Is this from a VCAA or a company exam?

[RazzMeTazz]

Why is the effect of steroid based hormones have a greater duration/ is more long-lived, than the effect of amino acid/peptide hormones?

[soNasty]

Yeah I thought that too at first - poorly written question. Is this from a VCAA or a company exam?

vcaa 2001!

[vox nihili]

It's a tricky question that did really require you to think, but I don't think it was unreasonable.

[anat0my]

I've read that auxin is produced in the meristematic tissue, but I thought that it was always present? Or is it 'dormant' until stimulated by light? Thanks!

[dankfrank420]

For signal transduction questions, is mentioning how cellular processes are altered needed, or we just have to state that they are altered? Eg: (3 marks)

- polypeptide hormone binds to receptor on cell surface
- secondary messenger molecules are activated, relaying message to nucleus of cell
- cellular processes altered
or
- messenger molecules alter nuclear DNA, hence eliciting a new response from the cell

[Sense]

Embryonic stem cells, unlike adult stem cells, ______

A)can be stimulated to become a particular type
B)Can be divided Indefinitely
C)Are difficult to obtain
D)Pose no ethical issue when used in the laboratory

[Reus]

Embryonic stem cells, unlike adult stem cells, ______

A)can be stimulated to become a particular type
B)Can be divided Indefinitely
C)Are difficult to obtain
D)Pose no ethical issue when used in the laboratory

Certainly not D, I'm thinking it's A only because embryonic stem cells mature into adult cells which then can become specific cells to replace dead cells. (I haven't really studied stem cells yet, nor has my class gone through it :/) So don't mark my word for it.

[melons]

Embryonic stem cells, unlike adult stem cells, ______

A)can be stimulated to become a particular type
B)Can be divided Indefinitely
C)Are difficult to obtain
D)Pose no ethical issue when used in the laboratory

B.
Both adult stem cells and embryonic can be stimulated to become a particular type.
Embryonic aren't that difficult to obtain
Heaps of ethical issues regarding the destruction of an embryo.

[shivaji]

Can someone betteer explain the difference in terms of structure and function of:
-alpha helices and beta-pleated chains?

i have "that alpha helices are more  flexible than beta-pleated sheets, so are involved more in regulatory proteins etc., whilst beta-pleated sheets are stronger and less flexible than alpha helices, so are a component of structural proteins."

Also, in terms of the actual physical difference in strucutres, is saying that alpha helices are helical in shape and beta pleated sheets are more like a layer in top of another ok?

thanks!