VCE Biology Question Thread

[lasagne]

(These questions are all from the BIOL EXAM 2) Unit 4

CHAPTER 9/10: (EXAM: 2)
MULTIPLE CHOICE:
Q7 (2009)
Q6 (2012) (Would the 1st child ALSO be a 1 in 4 chance?)
Q26, Q27 (2013)

SHORT-ANSWER:
Q8 c (iii) (2015)

2009 MC, Q7    C
Meisham sows must be mated with British males in order to have enough teats to account for all piglets, ie, up to 18; If it were the other way around, there would only be 12 teats between 11-16 piglets. Without a teat, some piglets would die :/
+ The British already have the smaller sized litters and the Chinese already have the larger sized litters.

2012 MC, Q6       A
Each parent is phenotypically normal, yet together they have a child with phenylketonuria. Thus, they're both heterozygous for the trait. Going by the normal cross ratios, the genotypes would be 1 PP: 2Pp: 1 pp. Since the trait is autosomal recessive, the chance is 1/4 of a child with the trait.
The first child's chance is 1, he/she already has it.

2013 MC, Q26        C
MM RR SS × M’M’ R’R’ S’S’ automatically makes a child MM' RR' SS'. So add the height contributions for all alleles, 5+2+5+2+5+2= 21cm.

2013 MC, Q27         D
The stem tells you that there can only ever be one active X chromosome in each somatic cell. The rest become Barr bodies. In A, there would be 1 Barr body. In B, 3. In C, 0. In D (XXXY), there would be 2 Barr bodies, leaving an X and Y chromosome active. therefore, the answer is D.

2015 SA, Q8ciii
I don't believe this question existssssss + haven't done this exam yet.

Hope this helps!

[lasagne]

Can someone explain to how the structure of glycogen,starch and cellulose reflects their function?

Glycogen and Starch are branched polysaccharides as this allows more energy to be stored in the greater amount of chemical bonds. (glycogen more than starch). They're both used for energy storage.

Cellulose, however, is a structural component of plant cell walls, therefore they don't have branching and are basically just chains. (think of comparing globular proteins to fibrous, not the same, but same sorta gist)

[HasibA]

what are our thoughts on the 2015 vcaa bio exam- if anyones done it? legit, a bitch of an exam.
reading the assessors reports and seeing only <5% gettin full marks on some questions... hopefully we get a similarly difficult exam this year [i like difficult ones xD]

[purplegiraffe]

Hey guys
Can anyone help to explain what DNA profiling is for?

Thanks x

[HasibA]

Hey guys
Can anyone help to explain what DNA profiling is for?

Thanks x

legit what the name implies. essentially creating profiles for individuals based on their DNA, useful for forensics etc.
holla if you neeed a bit more elaboration!

[sweetcheeks]

what are our thoughts on the 2015 vcaa bio exam- if anyones done it? legit, a bitch of an exam.
reading the assessors reports and seeing only <5% gettin full marks on some questions... hopefully we get a similarly difficult exam this year [i like difficult ones xD]

I quite liked it. I was challenged by some questions and those that I got wrong I was able to learn a lot from. I felt that some questions were a bit too vague but none the less I enjoyed completing it. I definitely preferred completing it over other exams, as it was difficult so a lot could be learnt from it, unlike some other exams (2014 VCAA).

[HasibA]

I quite liked it. I was challenged by some questions and those that I got wrong I was able to learn a lot from. I felt that some questions were a bit too vague but none the less I enjoyed completing it. I definitely preferred completing it over other exams, as it was difficult so a lot could be learnt from it, unlike some other exams (2014 VCAA).

yeah defs man. some questions could've been written better, but very nice exam indeed, in many aspects. 2014 VCAA is relatively straightforward- i found it alright, didn't learn much except for where some gaps in knowledge are.
have you done the 2013 VCAA one/ the sample exam? im yet to do 2013 or the sample- but i hope i can learn a lot from them.

has anyone done any STAV exams? i find them particularly specific, and erring on the side of difficulty higher than VCAAs, nonetheless, a solid exam company for bio :')

[The Usual Student]

Glycogen and Starch are branched polysaccharides as this allows more energy to be stored in the greater amount of chemical bonds. (glycogen more than starch). They're both used for energy storage.

Cellulose, however, is a structural component of plant cell walls, therefore they don't have branching and are basically just chains. (think of comparing globular proteins to fibrous, not the same, but same sorta gist)

the tsfx notes states some bonds are hydrophili? ..... aren't whole molecules hydrophilic not just individual bonds?
P.S GOT A SELFIE WITH ANDREW DOUCH BWAHH

[HasibA]

the tsfx notes states some bonds are hydrophili? ..... aren't whole molecules hydrophilic not just individual bonds?
P.S GOT A SELFIE WITH ANDREW DOUCH BWAHH

did you by any chance go to an access education lecture that douchy presented? XD

[The Usual Student]

did you by any chance go to an access education lecture that douchy presented? XD

yeah hahahaha, the 8:45 one. Got a pic with the man himself. That was the most entertaining and actually engaging bio lecture I ever had.

[hodang]

Thanks so much lasagne!!! Legend!!

Btw guys, can someone tell me:

• Is selective breeding and artificial selecting the same?

• Can someone also tell me what is everything we need to know about Barr Bodies? Are they reused? Like what happens to them after inactivation? 

+ Anyone know any similar examples to Q10 in the 2015 vcaa paper


Thanks!

[The Usual Student]

Thanks so much lasagne!!! Legend!!

Btw guys, can someone tell me:

• Is selective breeding and artificial selecting the same?

• Can someone also tell me what is everything we need to know about Barr Bodies? Are they reused? Like what happens to them after inactivation? 

+ Anyone know any similar examples to Q10 in the 2015 vcaa paper


Thanks!

someone correct me if i am wrong, i think selective breeding is an example of artificial selection.
With Barr Bodies, just know what they are and why they are turned off, because we have an X chromosome already
I don't think they are reused. When they are turned off, they don't affect the phenotype of the organism.

[HasibA]

yeah hahahaha, the 8:45 one. Got a pic with the man himself. That was the most entertaining and actually engaging bio lecture I ever had.

i went to the same one! hahah was the dude in a black beanie, and brown tracksuit pants up the back of the lecture hall with glasses haha.
yeah it was pretty good haahah! so much passion about bio

question-> how do you guys recommend filling in gaps in knowledge? getting a few questions inccorrect b/c i dont fully rmbr the correct terms etc. Just read over notes? i find i forget things really quickly i.e i cram quite a lot thanks!

[K888]

i went to the same one! hahah was the dude in a black beanie, and brown tracksuit pants up the back of the lecture hall with glasses haha.
yeah it was pretty good haahah! so much passion about bio

question-> how do you guys recommend filling in gaps in knowledge? getting a few questions inccorrect b/c i dont fully rmbr the correct terms etc. Just read over notes? i find i forget things really quickly i.e i cram quite a lot thanks!

I find going back and watching videos, looking at diagrams, reading the powerpoint for the topic and what I wrote for it and trying to write/summarise it in a few dot points to be good, and then I'll apply it by doing some questions until I become confident that I can answer it.
I think it's a matter of trial and error, really

[vox nihili]

Was anyone here at the SWOT Biol lectures by the way? On Tuesday





Salbutamol is a drug very commonly used to treat asthma. It is given in an inhaler to relieve acute symptoms of asthma, such as wheeze and shortness of breath. The drug works by making bronchi (the tubes that take air into the lungs) dilate.

If, however, salbutamol is injected, it can cause an increase in heart rate and blood pressure. It can also make some blood vessels constrict, and others dilate.

In some instances, salbutamol has been used by athletes as a means of doping. This is because, if given over a long period, salbutamol can encourage the production of muscle tissue.

Give two reasons why salbutamol can have these different effects.

Why do patients with asthma typically not experience an increase in heart rate after using their puffer (with salbutamol)?