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Survivor39's Answer and Some Explantion to Multiple Choice Questions (1 Viewer)

Survivor39

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1. B

2. C

3. A Enviromnetal because since smoking is associated with cancer, it can be classed as environmental due to the inhalation of smoke.

4. B

5. A - Mosquito carries the protozoan Plasmodium. Hence it is responsible for the trasmission.

6. C

7. C
Yes it's C not A.. hairs and needle-like leaves don't help plant growth :D

8. B

9. NOT SURE :( Probably D

10. C

11. B

12. D

Water moves by osmosis from an area of low solute concentration to an area of high solute concentration. A and B are not correct because salt ions cannot move across the selectively permeable membrane due to their charges. Hence this leaves C and D. D is CORRECT as water moves from a low solute concentration to a high solute concentration. Low solute concentration denotes low salt ions (the solute) and high concentration of water (the solvent). Hence water moves to an area of high solute concentration (ions), and low water concentration (solvent).

13. B - RBC approx. 7 um, and WBC approx. 12 um.

14. A - Co-dominance

15. D - The two animals displays convergent evolution, evolving similar morphology due to similar environmental conditons.
 
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Survivor39

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LOL. yep. sorry for the typo :D I got confused while doing the bolding of the letters.
 

Survivor39

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Can you explain why 9 is D and not the others?

Not too much is emphasised at uni about feedback mechanisms. Only once or twice occasional mentions.
 

meLoncoLLie

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The temperature rises but is quickly counteracted (by effectors). When the temperature drops too drastically, it is pulled up again. The cycle repeats and this demonstrates a negative feedback mechanism. Homeostasis a pretty significant part of the HSC syllabus :) so this question would be quite straightforward for us
 
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peabeau

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dude i think Q 12 is c. It cant possibly be D. not biologically speaking anyway
 

SaintCait

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Survivor39- you said

"salt ions cannot move across the selectively permeable membrane due to their charges"

I think you may be wrong. What do you think the kidney is!! It's a selectively permeable membrane- hence it selects levels of h20 and salt ions to reabsorb in the accending loop of henli due to ADH and Aldosterone levels.

According to all my biology teachers who are also markers, For that question, B and D are both correct and they are having trouble determining which is more correct.
 

Bush Elephant

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peabeau said:
dude i think Q 12 is c. It cant possibly be D. not biologically speaking anyway
and quoting SaintCait

"According to all my biology teachers who are also markers, For that question, B and D are both correct and they are having trouble determining which is more correct."

ITS D

definition of osmosis from "Heinemann Biology"

'Osmosis is a special case of passive transport involving the diffusion of water molecules across a differentially permeable membrane. Water will move by diffusion from an area where there is more of it to an area where there is less of it. This results in the movement of water from a dilute (less concentrated) solution to a stronger (more concentrated) solution.'

Therefor the best suited answer has to be D but i can understand why many people were confused here as Osmosis itself involves diffusion. However i just confused myself so all u really need of this definition is the end " This results in the movement of water from a dilute (less concentrated) solution to a stronger (more concentrated) solution."

w00t 15/15 for me :D
 

helios_sun

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12 is C, osmosis is the movement from a high concentration to a low concentration. Why would the water want to go where there is lots of water. Think about using a crowded train. Lots of people in a train when the doors open people leave to where there is not a lot of people in the train. Not 15/15 for you.
 

Zali

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it didnt say it was a charged membrane plus thats getting into chemistry not bio.

i agree both B and D are correct i think its going to depend on what the biological process it represents. i thought it was kidney dyalisis but i dont no if thats biological cos its artificial so i put B thinking that it was salt diffusing from the blood into a dyalsate solution
 

Abtari

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helios_sun said:
12 is C, osmosis is the movement from a high concentration to a low concentration. Why would the water want to go where there is lots of water. Think about using a crowded train. Lots of people in a train when the doors open people leave to where there is not a lot of people in the train. Not 15/15 for you.
omg

havent we stressed this question enough in the forums already?

the D option says area of low solute concentration to high solute concentratoin, not low water concentration to high water concentration...hence D is correct
 

Survivor39

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SaintCait said:
Survivor39- you said

"salt ions cannot move across the selectively permeable membrane due to their charges"

I think you may be wrong. What do you think the kidney is!! It's a selectively permeable membrane- hence it selects levels of h20 and salt ions to reabsorb in the accending loop of henli due to ADH and Aldosterone levels.

According to all my biology teachers who are also markers, For that question, B and D are both correct and they are having trouble determining which is more correct.
The kidney is a special case. The tubules are "leaky" allowing ions to move through. A lot of the useful ions are reabosorbed by active transport. The two hormones you were talking increases the permeability of the epithelium to water (ADH) and stimulate more reabsorption for ions (aldosterone). But that's because the kidney is regulated!

The picture suggest that no such influence from hormone! Hence the ions cannot move between the membrane! (The permeability of the membrane is unchanged, and not active transport). I think they even hinted to you the "holes" are too small for the ions to get across anyway.

If you do the actual experiment with a U-tube you will find that D is more correct.
The water will move to the side with more solute. If both sides have equal volume, the side with more solute will increase in volume because more water from the side with less solute will move across to the side with more solute.\


I hope this helps! :)
 

Abtari

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Survivor39 said:
The picture suggest that no such influence from hormone! Hence the ions cannot move between the membrane! (The permeability of the membrane is unchanged, and not active transport). I think they even hinted to you the "holes" are too small for the ions to get across anyway.
[/B]\

I hope this helps! :)
i have to agree with survivor on this one...it should be D

^ love ur rationale :D
 

Abtari

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daemon22 said:
12 is D, 9 is D, and why isn't 15 B?
from the way u were building up the repetitions, i would have thought u would have said 'why isn't 15 D?' lol

ummm no it is D, its more correct than B
 

Survivor39

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daemon22 said:
why isn't 15 B?
The question already stated the two species are not closely related. Hence they are probably not evolved from the same common ancestor. :)


Thanks Abtari :cool:
 

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