VCE Biology Exam Discussion and Solutions

[LifeisaConstantStruggle]

Woah sneaky vox. He's going hard bois

[vox nihili]

11   D
12   C
13   D
14   B
15   D
16   D
17   C
18   A
19   D
20   B

[goldencale]

Regarding MC Q25 about MS and hygiene,

I ended up going with the stomach ulcers option (c) rather than D because the question said MS individuals had a 30% lower rate of infection. From that I assumed that they had a stronger specific immune response to the bacteria, resulting from previous exposure via the stomach ulcers.

Thoughts?

[Roadrunnerani]

Hey Vox are you sure question 6 is c?

My understanding is that using a greater amount of substrate would not increase the reaction rate, as there are limitied enzymes.

However increasing the concentration of catalase (option A) would lead to a greater rate of the production of oxygen?

[vox nihili]

21   C
22   B
23   B
24   C
25   D
26   A
27   A
28   D
29   C
30   C
31   A

That's all I've got at the moment. When I get the entire exam I'll finish off the results.

There's a potential that question 22 will be struck off. Macrophages are capable of producing interferon. Indeed, anyone who has ever been tested for TB will have potentially had a blood test that relies on the fact that macrophages produce interferon. This is outside the VCE course; however, someone may encourage them to revisit this question, as their answer is technically flawed.

Regarding MC Q25 about MS and hygiene,

I ended up going with the stomach ulcers option (c) rather than D because the question said MS individuals had a 30% lower rate of infection. From that I assumed that they had a stronger specific immune response to the bacteria, resulting from previous exposure via the stomach ulcers.

Thoughts?

Infection with H.pylori does not necessarily mean the development of stomach ulcers. You're right though, they should have used the word colonisation instead of infection. Many patients with H.pylori end up with gastritis instead of stomach ulcers.

[jaronmak]

1   A
2   B
3   D
4   C
5   B
6   C
7   C
8   D
9   A
10   C

Just with Q10, wouldn't the answer be D, because C implies that the electron transport chain is occurring, and Y isn't technically pointing to the proteins on the plasma membranes, where the electron transport chain occurs?

[LifeisaConstantStruggle]

Hey Vox are you sure question 6 is c?

My understanding is that using a greater amount of substrate would not increase the reaction rate, as there are limitied enzymes.

However increasing the concentration of catalase (option A) would lead to a greater rate of the production of oxygen?

The substrate level was kept constant so the volume of oxygen released would eventually reach the same point if you go far enough if you increase the amount of enzymes.
But if you change the amount of substrate the rate will go higher and you will get more oxygen.

[PhoenixxFire]

Hey Vox are you sure question 6 is c?

My understanding is that using a greater amount of substrate would not increase the reaction rate, as there are limitied enzymes.

However increasing the concentration of catalase (option A) would lead to a greater rate of the production of oxygen?

It has to be C. The graph shows the amount of O2 produced NOT the rate of the reaction, therefore when the graph levels off, all of the substrate has been used. The only way to increase this level is to add more substrate

[vox nihili]

Just with Q10, wouldn't the answer be D, because C implies that the electron transport chain is occurring, and Y isn't technically pointing to the proteins on the plasma membranes, where the electron transport chain occurs?

Unfortunately not. The proteins are located in the cristae.

It has to be C. The graph shows the amount of O2 produced NOT the rate of the reaction, therefore when the graph levels off, all of the substrate has been used. The only way to increase this level is to add more substrate

The graph does show the rate too; there's just no change (suggesting that the amount of enzyme is kept constant). You're right though

[Joseph41]

A COPY OF THE EXAM.

[LPadlan]

11   D
12   C
13   D
14   B
15   D
16   D
17   C
18   A
19   D
20   B

Hey Vox, are you sure question 13 is d? I chose c as point p is around 0.18 and s is around 0.06

[goldencale]

Infection with H.pylori does not necessarily mean the development of stomach ulcers. You're right though, they should have used the word colonisation instead of infection. Many patients with H.pylori end up with gastritis instead of stomach ulcers.

Thanks for explaining, but what information in the stem suggests that childhood infection helps protect against MS?

[Roryr99]

Why is question 12 multi choice C and not B? chloroplasts do not have a single circular chromosome, but many circular chromosomes, and they do reproduce by dividing in half?

Also why is 25 not C?

[Pandable]

Why is question 12 multi choice C and not B? chloroplasts do not have a single circular chromosome, but many circular chromosomes, and they do reproduce by dividing in half?

Also why is 25 not C?

Yes Chloroplasts do have circular chromosomes and for question 25 people with stomach ulcers have  a slight immunity to MS as 30% of the women with MS didnt have Stomach Ulcers

[Roryr99]

It says "SINGLE" circular chromosome