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March 28, 2024, 10:15:17 pm

Author Topic: VCE Biology Question Thread  (Read 3570429 times)  Share 

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Sine

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Re: VCE Biology Question Thread
« Reply #13260 on: December 15, 2020, 02:53:52 pm »
+8
Thanks

For this question how many marks would i get if i wrote this
1. calcium ions cannot pass through the phospholipid bilayer as they are polar charged ions only hydrophobic non polar substances can easily diffuse through the bilayer as most of the bilayer is non polar.

2. calcium pumps transport calcium ions across the membrane using energy obtained from the hydrolysis of ATP
I probably wouldn't add "most of the bilayer is non-polar" given an importnat feature of phospholipids are the fact they have polar heads and non-polar tails.

Also for question 2, you do mention ATP is used but you could improve the answer by stating it is an active process. You could also state it is against a concentration gradient.

Corey King

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Re: VCE Biology Question Thread
« Reply #13261 on: December 16, 2020, 12:24:49 pm »
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Hey guys,
How does the water molecule break the O bond in hydrolysis? They mention this happens but I don't understand the chemistry behind it. Does the O molecule joining the monomers have more attraction to the H2O's hydrogens than the waters H does to it's own O? I don't see how :P
Many thanks,
Corey

rozmaaate

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Re: VCE Biology Question Thread
« Reply #13262 on: December 17, 2020, 05:37:45 pm »
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Anyone able to explain why the circled answers are correct for the given questions ?


Bri MT

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Re: VCE Biology Question Thread
« Reply #13263 on: December 17, 2020, 06:14:19 pm »
+7
Hey guys,
How does the water molecule break the O bond in hydrolysis? They mention this happens but I don't understand the chemistry behind it. Does the O molecule joining the monomers have more attraction to the H2O's hydrogens than the waters H does to it's own O? I don't see how :P
Many thanks,
Corey

This is well and truly more in the realm of chem than bio, and even then the specifics are something you'd generally learn about in 1st year uni. That being said, if you are super keen look up a video on hydrolysis mechanisms. Basically, the oxygen in the water is attracted to the relevant carbon atom in the polymer, and carbon doesn't like having more than 4 bonds so a bond connecting it to the polymer goes away, splitting the polymer into two.


Anyone able to explain why the circled answers are correct for the given questions ?



In design 1, all 12 ducks are in the same condition. This means that any random changes (e.g. because one duck has a different personality) is likely to be "balanced out" by the other ducks. In design 2, there are only 3 ducks in each condition, so random changes are less likely to be "balanced out"

In design 1, maybe some of what you measure as the weeks go on is because they've been in the experiment for a long time, or delayed reactions to the previous environmental conditions. This could cause issues from you thinking those impacts are due to different saltiness when it's not. In design 2 you don't have that impact because in each week all 4 conditions are being tested at the same time

Corey King

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Re: VCE Biology Question Thread
« Reply #13264 on: December 19, 2020, 10:26:08 pm »
0
This is well and truly more in the realm of chem than bio, and even then the specifics are something you'd generally learn about in 1st year uni. That being said, if you are super keen look up a video on hydrolysis mechanisms. Basically, the oxygen in the water is attracted to the relevant carbon atom in the polymer, and carbon doesn't like having more than 4 bonds so a bond connecting it to the polymer goes away, splitting the polymer into two.


In design 1, all 12 ducks are in the same condition. This means that any random changes (e.g. because one duck has a different personality) is likely to be "balanced out" by the other ducks. In design 2, there are only 3 ducks in each condition, so random changes are less likely to be "balanced out"

In design 1, maybe some of what you measure as the weeks go on is because they've been in the experiment for a long time, or delayed reactions to the previous environmental conditions. This could cause issues from you thinking those impacts are due to different saltiness when it's not. In design 2 you don't have that impact because in each week all 4 conditions are being tested at the same time

Will do, thanks Brie :)

quintonishere

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Re: VCE Biology Question Thread
« Reply #13265 on: December 21, 2020, 04:21:09 pm »
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i'm looking through some notes an see there are 3 types of transport proteins:
Quote
1. Transport Proteins (passive transport)
Allows some substances, such as ions, to move through the membrane by facilitated diffusion. There are 2 types of transport proteins for this purpose: channel proteins & carrier proteins. Can become saturated, that is, there is a maximum rate at which the molecules can be transported.
2. Transport Proteins
A gated protein channel that opens to transport a specific molecule in response to contact with another molecule, such as a hormone.
3. Transport Proteins (active transport)
Protein pump is involved in active transport and requires the input of ATP. These proteins sometimes are referred as carrier proteins.
can someone please explain the classification of membrane transport proteins in reference to this info?
« Last Edit: December 21, 2020, 04:38:49 pm by quintonishere »

homeworkisapotato

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Re: VCE Biology Question Thread
« Reply #13266 on: December 21, 2020, 06:03:42 pm »
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If you mean just transmembrane protein channels then I'd say 1 and 3 :)
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quintonishere

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Re: VCE Biology Question Thread
« Reply #13267 on: December 21, 2020, 06:51:33 pm »
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If you mean just transmembrane protein channels then I'd say 1 and 3 :)
so what kind of protein is 2?

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #13268 on: December 21, 2020, 09:14:40 pm »
0
For this question would it be b
What is the most important factor influencing resistance to flow of gases in a tube?
A the length of the tube
B the radius of the tube
C  the pressure of the gas
D the type of gas

-Lilac-

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Re: VCE Biology Question Thread
« Reply #13269 on: December 22, 2020, 12:55:09 am »
+4
so what kind of protein is 2?

They are transmembrane proteins like the other two. Here ligand binding (or voltage changes) will cause a conformational change that opens the channel, allowing the ion/molecule to pass through.

For this question would it be b
What is the most important factor influencing resistance to flow of gases in a tube?
A the length of the tube
B the radius of the tube
C  the pressure of the gas
D the type of gas

Yep! Hence, why it gets harder to breathe with bronchoconstriction. 
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vox nihili

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Re: VCE Biology Question Thread
« Reply #13270 on: December 22, 2020, 01:41:49 pm »
+6
For this question would it be b
What is the most important factor influencing resistance to flow of gases in a tube?
A the length of the tube
B the radius of the tube
C  the pressure of the gas
D the type of gas

The answer you have chosen is correct but I suspect this question is very unlikely to show up on a VCE exam, as it sits outside of what you're expected to know in VCE biology.

Each of the factors in the question, with the exception of the pressure of the gas, has an influence on the resistance. A gas at higher pressure will flow more quickly; however, it does not change the resistance to that flow.
Longer tubes are more resistant to flow (that's why those long bendy straws are such a pain to use), and more viscous gasses flow more slowly. The radius of the tube is the correct answer here because resistance increases exponentially with a decrease in radius (this is why thinner straws can be harder to suck from), whereas resistance increases linearly with an increase in length.
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Oynx

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Re: VCE Biology Question Thread
« Reply #13271 on: December 22, 2020, 11:43:13 pm »
0
Hi, 

Do we need to know about the effects of high and low temperatures on the plasma membrane?

Or how cholesterol helps maintain the fluidity of the plasma membrane in high and low temps?

If someone could give a slight description of how cholesterol plays a part in maintaining fluidity that'd be appreciated.

Thanks
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #13272 on: December 23, 2020, 10:19:46 pm »
+3
In very cold temperatures cholesterol prevents the phospholipids from clustering together and solidifying ensuring they do not get too close to each other.
If it is too hot cholesterol helps maintain the integrity of the membrane by preventing the phospholipids from separating entirely.

vox nihili

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Re: VCE Biology Question Thread
« Reply #13273 on: December 23, 2020, 10:29:16 pm »
+4
In very cold temperatures cholesterol prevents the phospholipids from clustering together and solidifying ensuring they do not get too close to each other.
If it is too hot cholesterol helps maintain the integrity of the membrane by preventing the phospholipids from separating entirely.

This answer really is the extent to which you need to understand this for VCE bio, and even that's a push! Good answer :)
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Oynx

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Re: VCE Biology Question Thread
« Reply #13274 on: December 23, 2020, 10:32:48 pm »
0
This answer really is the extent to which you need to understand this for VCE bio, and even that's a push! Good answer :)
In very cold temperatures cholesterol prevents the phospholipids from clustering together and solidifying ensuring they do not get too close to each other.
If it is too hot cholesterol helps maintain the integrity of the membrane by preventing the phospholipids from separating entirely.

Thanks so much, Chocolatepistachio, had something very similar to this description. Just wasn't sure if we need to know extra detail/depth.

Thanks for the clarification vox nihili.
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