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January 21, 2021, 01:24:14 pm

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#### Oynx

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##### Re: VCE Biology Question Thread
« Reply #13260 on: December 02, 2020, 02:41:47 pm »
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Hey Oynx!
No, they are not the same thing and thus they are not interchangeable.

They are both similar in that H20 (water) is released. However, with condensation polymerisation, repeating sub units (monomers) are bonded together to form polymers. This is seen when amino acids (the monomers) form peptide bonds with each other to form a polypeptide (the polymer).
Condensation is simply water being released.

Hope this helps!

Thanks for the reply much appreciated, so I would use condensation polymerisation when monomers form polymers?

So I would be marked wrong if I say "polypeptide chains are formed through condensation reactions"?

« Last Edit: December 10, 2020, 08:58:55 pm by Oynx »

#### Evolio

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##### Re: VCE Biology Question Thread
« Reply #13261 on: December 02, 2020, 03:15:31 pm »
+5
Thanks for the reply much appreciated, so I would use condensation polymerisation when monomers form polymers?
Yes, I think so.

Quote
So I would I be marked wrong if I say "amino acid polymers are formed through condensation reactions"?
It's not wrong necessarily but it's better to say 'condensation polymerisation' as there is that extra detail of monomers (amino acids) forming polymers. So, it would be better to say 'condensation polymerisation' in responses when talking about this process.Also, be careful: it's amino acid monomers not amino acid polymers. The polypeptide is the polymer.

#### Oynx

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##### Re: VCE Biology Question Thread
« Reply #13262 on: December 02, 2020, 04:27:49 pm »
+1
Yes, I think so.
It's not wrong necessarily but it's better to say 'condensation polymerisation' as there is that extra detail of monomers (amino acids) forming polymers. So, it would be better to say 'condensation polymerisation' in responses when talking about this process.Also, be careful: it's amino acid monomers not amino acid polymers. The polypeptide is the polymer.

Ah yes, fixed it the monomer, polymer stuff up. Thanks for the help!

#### Chocolatepistachio

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##### Re: VCE Biology Question Thread
« Reply #13263 on: December 10, 2020, 08:22:09 pm »
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If someone could help with this question I don’t understand would it be c

Why do solutions for intravenous injections into people with low blood volume (perhaps due to dehydration) normally contain 0.9% NaCl ?
A this is a hypotonic solution which will cause water to move into dehydrated blood cells
B this is an isotonic solution, and the water in IV fluid will follow Na+ and Cl- into the intracellular fluid compartment
C this is an isotonic solution, and Na+ and Cl- are non penetrating solutes. Na+ and Cl- will keep the water in iv fluid in the extracellular fluid compartment
D Na+ and Cl- are penetrating solutes which will get these more quickly into blood cells to increase their volume

#### darkz

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##### Re: VCE Biology Question Thread
« Reply #13264 on: December 10, 2020, 11:06:47 pm »
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If someone could help with this question I don’t understand would it be c

Why do solutions for intravenous injections into people with low blood volume (perhaps due to dehydration) normally contain 0.9% NaCl ?
A this is a hypotonic solution which will cause water to move into dehydrated blood cells
B this is an isotonic solution, and the water in IV fluid will follow Na+ and Cl- into the intracellular fluid compartment
C this is an isotonic solution, and Na+ and Cl- are non penetrating solutes. Na+ and Cl- will keep the water in iv fluid in the extracellular fluid compartment
D Na+ and Cl- are penetrating solutes which will get these more quickly into blood cells to increase their volume

For this question, what we're looking for is something that will increase the extracellular fluid level. That is, the question tells us that we give people 0.9% NaCl for those with low blood volume, thereby increasing their blood volume (extracellular fluid level). Knowing this, we can eliminate the other answer options as follows:

A. If it were hypotonic and water moved into the RBCs, they'd likely lyse. Also, we want to increase blood volume, not move water into RBCs.
B. Isotonic refers to the same solute concentration on either side and therefore there should be no net movement of water. Also, there should be no significant flux of $Na^+$ or $Cl^-$ into a cell, since they're both charged ions and hence cannot freely diffuse.
C. Yes, isotonic means no net movement of water, allowing the NaCl solution to remain the extracellular fluid.
D. Again, we don't want to increase the fluid within RBCs, and don't think they're penetrating solutes either
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#### Chocolatepistachio

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##### Re: VCE Biology Question Thread
« Reply #13265 on: December 11, 2020, 04:27:08 pm »
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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

#### Sine

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##### Re: VCE Biology Question Thread
« Reply #13266 on: December 15, 2020, 02:53:52 pm »
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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 #13267 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
Many thanks,
Corey

#### rozmaaate

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##### Re: VCE Biology Question Thread
« Reply #13268 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 #13269 on: December 17, 2020, 06:14:19 pm »
+6
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
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 #13270 on: December 19, 2020, 10:26:08 pm »
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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 #13271 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 #13272 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 #13273 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 #13274 on: December 21, 2020, 09:14:40 pm »
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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