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August 04, 2020, 02:47:07 pm

Author Topic: VCE Biology Question Thread  (Read 1749639 times)  Share 

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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12735 on: July 05, 2020, 12:00:57 pm »
+2
For this question
Explain why breathing in and out increases the rate of oxygen diffusion into the blood

This is the answer but I donít really understand it
As we breathe in and out we are refreshing the oxygen concentration on the lungs which makes the concentration gradient steeper and this will increase the rate of diffusion

Owlbird83

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Re: VCE Biology Question Thread
« Reply #12736 on: July 05, 2020, 12:28:32 pm »
+12
For this question
Explain why breathing in and out increases the rate of oxygen diffusion into the blood

This is the answer but I donít really understand it
As we breathe in and out we are refreshing the oxygen concentration on the lungs which makes the concentration gradient steeper and this will increase the rate of diffusion
So if you take the left side to be after someone has just taken a fresh breath of oxygen, there's a lot more oxygen in the lungs, so it will be diffuse into the blood faster. The right side still has a higher amount of oxygen on the lungs side, but since it's only a little more than the blood it's slower to move to the blood, than when there's a higher difference.

(click image to unstretch)
Hope this helps!



Thank you so much! Most of it was with was written with pentel touch, I prefer the metal tip, or fountain pens or gel pens. Muji pens are the best though.
However the pen that I used for those notes was the Pentel Energel 0.5
Ahhh I love muji pens!! We have the same taste in stationary!! (I haven't been using mine much because I'm worried they'll run out of ink haha[/size]
« Last Edit: July 05, 2020, 12:32:27 pm by Owlbird83 »
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1729

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Re: VCE Biology Question Thread
« Reply #12737 on: July 05, 2020, 12:43:37 pm »
+6
For this question
Explain why breathing in and out increases the rate of oxygen diffusion into the blood

This is the answer but I donít really understand it
As we breathe in and out we are refreshing the oxygen concentration on the lungs which makes the concentration gradient steeper and this will increase the rate of diffusion
Dissolved gases are in equilibrium of course. So having more of a certain gas increase the rate at which it dissolves into liquid. When we breathe, we inhale both CO2 and O2, but our exhaled breath is filled with more CO2 because we've depleted the oxygen supply by using it up during cellular respiration. Since we're using up the O2, we want to replenish it by inhaling more. The less O2 we have in the blood, the more it increases the rate of diffusion. If I wrote out an equilibrium, O2 + deoxygenated blood <-> oxygenated blood if you decrease the oxygen in the blood, you push O2 into the deoxygenated blood. They talk about a "concentration gradient" in the answer. It's kinda helpful to think about there being a bigger hole, so to speak. If you imagine oxygen like flowing water, the bigger the hole, the more water that falls into the hole.

So basically, because when we breathe we change the concentration of oxygen and CO2 in the lungs like, when we breathe in, there's more oxygen in our lungs relative to in the blood diffusion gradient steep so diffusion rate fast.
because in diffusion, the goal is to reach equal concentration across both sides, right
Ahhh I love muji pens!! We have the same taste in stationary!! (I haven't been using mine much because I'm worried they'll run out of ink haha
That is the exact same as me!! I don't like using my good pens because I get worried they'll run out of ink! XD
« Last Edit: July 05, 2020, 01:09:54 pm by 1729 »
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12738 on: July 05, 2020, 06:23:57 pm »
+4
Thank you 1729 and owlbird83

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12739 on: July 06, 2020, 11:08:57 am »
+1
Hello would someone be able to help me fill this out
thanks

Owlbird83

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Re: VCE Biology Question Thread
« Reply #12740 on: July 06, 2020, 11:45:59 am »
+8
Hello would someone be able to help me fill this out
thanks

Hey, I attached some feedback.

I really hope that this is something you'll learn from and not copy down passively.

Hope it helps (let me know if anything is unclear)
« Last Edit: July 06, 2020, 11:48:23 am by Owlbird83 »
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12741 on: July 06, 2020, 12:31:26 pm »
0
Thank you that was very helpful
also i'm not sure about my answers for these if someone could give feedback


Owlbird83

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Re: VCE Biology Question Thread
« Reply #12742 on: July 06, 2020, 02:19:56 pm »
+2
Thank you that was very helpful
also i'm not sure about my answers for these if someone could give feedback

1. Add something about rabbits not having natural predators in Australia to control the numbers, like they did in England, because they didn't evolve with the Australian food chains. (If you look at the question as a whole it's asking about what differs in Aus from Eng, so it would be better to make a statement of comparison, rather than just focus on Australia imo). Also, I would add about why they are pests, not only the large numbers but also that they are detrimental to agriculture/compete for the same niche with our native animals.

4. It would be incorrect to say that 'relatives in England would not have developed resistance since the virus was not introduced in England'. You should assume that there are small numbers of rabbits in England with the resistance genes, but there are no environmental selection pressures there that will cause that trait to increase in frequency because it doesn't give them any advantage. I'd write that the Australian population has a much higher frequency of virus resistant rabbits, due to this trait being advantageous to survival here, but not in England
« Last Edit: July 06, 2020, 02:24:42 pm by Owlbird83 »
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humanbeing

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Re: VCE Biology Question Thread
« Reply #12743 on: July 06, 2020, 04:10:25 pm »
+1
Hi!

1. Does the position of the centromere of a chromosome (metacentric, submetacentric, acrocentric etc) affect the cell cycle or anything else? (I feel like the telocentric centromere wouldn't hold as much DNA)
2. (this is more just out of curiousity) : why is it two "daughter" cells rather than two "son" cells? Do "son" cells even exist?

TIA :)

1729

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Re: VCE Biology Question Thread
« Reply #12744 on: July 06, 2020, 04:50:19 pm »
+3
1. Does the position of the centromere of a chromosome (metacentric, submetacentric, acrocentric etc) affect the cell cycle or anything else? (I feel like the telocentric centromere wouldn't hold as much DNA)
Hey there humanbeing! Welcome to the forum!
They typically are placed in the centre, but they can also be on like the mid-region or wherever on the chromosome. There's different names for these locations metacentric, submetacentric, acrocentric, and telocentric. Shouldn't usually affect cell split, but anomalies can be seen in cancer cells.
2. (this is more just out of curiousity) : why is it two "daughter" cells rather than two "son" cells? Do "son" cells even exist?
This just a naming convention, because it makes sense that daughter cells grow up to become mother cells to divide into more daughter cells.

Quote from: https://biology.stackexchange.com/
During the days when philosophers used to debate, they tended to regard reproduction as a feminine trait. So naturally organisms/cells capable of producing offspring are also given a feminine trait. The parent cell is often called the mother cell, and the daughter cells are so named because they eventually become mother cell themselves.

I presume there exists a similar argument for sister chromatids, in that they are identical. When they separate, they are usually termed as undivided chromosomes.
« Last Edit: July 06, 2020, 04:53:12 pm by 1729 »
What my avatar is
If you are wondering about my avatar, It was inspired by a problem I did which asked me to prove that the graphs of xy = 1 and y^2 = x^2 + 2 intersected at a 90 degree angle. The resulting figure in the middle kinda like a 8-sided square in hyperbolic space. It also resembles the conformal map of the complex square root.
Subjects: EngLang, Lit, Methods, Spesh, Chemistry, Biology, Physics.

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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12745 on: July 06, 2020, 05:58:15 pm »
+1
I'm not sure if my answers for these questions are correct if someone could give feedback
Thanks!


Owlbird83

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Re: VCE Biology Question Thread
« Reply #12746 on: July 06, 2020, 08:02:17 pm »
+6
I'm not sure if my answers for these questions are correct if someone could give feedback
Thanks!

Looks good.
In Q2, I'd add that the are in the minority, because having the resistance did not give them a survival advantage at that time.
In Q3, you are kind of giving the same answer for each part, so I think in part a, maybe add that the size of the population would dramatically decrease, as the non resistant insects are all killed off.
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12747 on: July 06, 2020, 08:21:06 pm »
+1
Ok thanks
And for this question:
Explain why some people use the experience with ddt to support the theory of evolution by natural selection.

- DDt is an example of evolution by natural selection. There is a change in the environment- ddt is introduced some insects have a genetic resistance to the virus. The insects with the gene survive and reproduce and over time the population of ddt resistant insects increases. 

Owlbird83

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Re: VCE Biology Question Thread
« Reply #12748 on: July 07, 2020, 09:37:38 am »
+6
Ok thanks
And for this question:
Explain why some people use the experience with ddt to support the theory of evolution by natural selection.

- DDt is an example of evolution by natural selection. There is a change in the environment- ddt is introduced some insects have a genetic resistance to the virus. The insects with the resistance gene are more likely to survive and reproduce and therefore over time the frequency of the resistant insects increases in the insectpopulation.
It was good I reckon, but I modified it a bit. (Mainly the part where the you said the resistant insects survive and reproduce, it would be better to write that they have a survival advantage over the others). (The last part was probably okay how you wrote it, but I would write that the frequency increases in the population because it suggests that the non resistant insects are decreasing also.)
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Bri MT

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Re: VCE Biology Question Thread
« Reply #12749 on: July 07, 2020, 11:38:09 am »
+5
Ok thanks
And for this question:
Explain why some people use the experience with ddt to support the theory of evolution by natural selection.

- DDt is an example of evolution by natural selection. There is a change in the environment- ddt is introduced some insects have a genetic resistance to the virus. The insects with the gene survive and reproduce and over time the population of ddt resistant insects increases. 

I'd modify your wording slightly to indicate that DDT itself isn't an example of evolution (the population genetically changing to become more DDT resistant is evolution) & refer to different genotypes or alleles rather than different genes. As owlbird has indicated it's also a good idea to modify some of your other language to more accurately reflect the situation.