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March 28, 2024, 09:19:50 pm

Author Topic: HSC Biology Question Thread  (Read 341447 times)  Share 

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dani01

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Re: HSC Biology Question Thread
« Reply #1350 on: October 16, 2019, 09:43:09 am »
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Hi there!

This is some information on viral pathogens and the response of an Australian plant from easyhsc.com.au

Hope this helps!

Turnip Mosaic Virus

Causative pathogen:
Turnip Mosaic Virus (TuMV), a potyvirus belonging to the family Potyviridae.

Host Range:
Almost all Brassica species and other plants including:
B. oleracea
B. campestris
B. juncea
B. pekinensis
Latuca sativa
Nasturtium officinale
Raphanus sativus

Symptoms:
Chlorotic spots on inoculated leaves
Mottling followed by systemic vein clearing
Mosaic and/or necrosis
Leaf distortion
Stunting

Management:
Exclusion or avoidance – quarantine, growing crops in regions where the virus seldom occurs or during periods when the virus or its vector are at a low activity level and using virus-free seedling transplants.
Reduction in virus spreading sources – controlling weeds and other virus hosts and insect vectors, destroying old crops promptly, separating new crops from maturing crops, and avoiding overlapping crops, particularly year-round cropping.
Protection of the host plant – planting virus-resistant varieties, using barrier crops to reduce insect vector activity in the crop, using insecticides to protect plants, and using highly reflective mulches and oil sprays to deter insects.


Hey thanks for that! yeah i did see that website except I'm pretty sure we need the host response. so instead of quarantine and stuff what does the actual plant do to kill the antigen? But thankyou again for the info- it is hard to find

worldno1

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Re: HSC Biology Question Thread
« Reply #1351 on: October 16, 2019, 09:55:26 am »
+1
Hey thanks for that! yeah i did see that website except I'm pretty sure we need the host response. so instead of quarantine and stuff what does the actual plant do to kill the antigen? But thankyou again for the info- it is hard to find

Cmiiw but in the syllabus, you only need to know an Australian plant response to either a fungus or virus (that's what my teacher said). Since you already have one for fungus, should be all good. :)


annabeljxde

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Re: HSC Biology Question Thread
« Reply #1352 on: October 26, 2019, 11:12:33 pm »
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I need someone to explain to me why this pedigree chart is autosomal recessive and not sex-linked.

This is a question from Excel Success One and the answers say that for the condition to be sex-linked, the unrelated females in the second generation must be carriers. I used this reason in my justification, so I'm a bit confused. Sex-linked inheritance can occur even in non-blood-related individuals, right? Or must the inheritance of the 'disorder' be strictly between blood-related individuals?
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InnererSchweinehund

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Re: HSC Biology Question Thread
« Reply #1353 on: October 27, 2019, 08:31:06 am »
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I need someone to explain to me why this pedigree chart is autosomal recessive and not sex-linked.

This is a question from Excel Success One and the answers say that for the condition to be sex-linked, the unrelated females in the second generation must be carriers. I used this reason in my justification, so I'm a bit confused. Sex-linked inheritance can occur even in non-blood-related individuals, right? Or must the inheritance of the 'disorder' be strictly between blood-related individuals?

Hi there!

By looking at the pedigree, we immediately know that if the condition were to be sex-linked, it would have to be recessive, as the mother in the very first generation is a carrier, but is not affected herself.
By filling out the pedigree (attached), you can see that the condition can be both sex-linked recessive and autosomal recessive.

Based on the answer from Success One (which I have put below), I think they are arguing that it would be unlikely that "two of the unrelated mothers in the second generation must have independently both been carriers (as well as the daughter from the initial parents)", therefore it's more likely to be autosomal recessive.

If I had received this question in the exam and had filled out the pedigree and seen that it's possible for it to be sex-linked recessive, I definitely would've answered that, on the basis that sex-linked inheritance can occur in non-blood-related individuals. Unless the question states that the disorder is super rare and something crazy like "less than 0.000000006% of the population has it, as long as you can prove that it is sex-linked (by filling out the pedigree and giving clear evidence to how it can be sex-linked) I think you'll be fine.

Answer from success one:
The pedigree diagram indicates that only males are affected by the condition; however, as the female has to pass on the affected X chromosome to the son, two of the unrelated mothers in the second generation must have independently both been carriers (as well as the daughter from the initial parents) for this to be sex-linked inheritance. This would suggest the condition is autosomal recessive. Both of the initial parents could have been carriers, resulting in half of their offspring with the condition (ie. homozygous recessive) and their unaffected daughter and son could have been carriers (ie. heterozygous), as well as their partners.

Hawraa

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Re: HSC Biology Question Thread
« Reply #1354 on: October 27, 2019, 11:28:58 am »
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Hi everyone,
Considering the following question

("increased scientific understanding of processes of reproduction has allowed for rapid growth of the agricultural industry over the past few decades." Evaluate this statement with reference to at least specific scientific techniques.)

When we are asked to evaluate, isn't like give positives and negatives and a judgement? Because the way I structured my answer is :
Tech 1+definition+ advantages (2)
Tech 2+definition+ advantages (2)
Common disadvantage of the 2 techs
Judgement.

However, the answer only talks about the advantages without any disadvantages. So can someone please explain why? And which way is better? Thanks

InnererSchweinehund

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Re: HSC Biology Question Thread
« Reply #1355 on: October 27, 2019, 12:10:46 pm »
+1
Hi everyone,
Considering the following question

("increased scientific understanding of processes of reproduction has allowed for rapid growth of the agricultural industry over the past few decades." Evaluate this statement with reference to at least specific scientific techniques.)

When we are asked to evaluate, isn't like give positives and negatives and a judgement? Because the way I structured my answer is :
Tech 1+definition+ advantages (2)
Tech 2+definition+ advantages (2)
Common disadvantage of the 2 techs
Judgement.

However, the answer only talks about the advantages without any disadvantages. So can someone please explain why? And which way is better? Thanks

Hi Hawraa!

The way you answered the question is definitely correct. If the question asks you to evaluate, you should definitely make a judgement, but to be able to make a judgement you need to give reasons for and against!

The only reason I could think of, for why they didn't provide disadvantages, would possibly be because of the mark allocation??

To be safe in the HSC, definitely provide reasons for an against and specifically state the reasons for your judgement/decision.

Good luck tomorrow!! 
  ;D

Hawraa

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Re: HSC Biology Question Thread
« Reply #1356 on: October 27, 2019, 12:13:35 pm »
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Hi Hawraa!

The way you answered the question is definitely correct. If the question asks you to evaluate, you should definitely make a judgement, but to be able to make a judgement you need to give reasons for and against!

The only reason I could think of, for why they didn't provide disadvantages, would possibly be because of the mark allocation??

To be safe in the HSC, definitely provide reasons for an against and specifically state the reasons for your judgement/decision.

Good luck tomorrow!! 
  ;D

Thanks a lot 🌷

dani01

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Re: HSC Biology Question Thread
« Reply #1357 on: October 27, 2019, 02:14:18 pm »
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Cmiiw but in the syllabus, you only need to know an Australian plant response to either a fungus or virus (that's what my teacher said). Since you already have one for fungus, should be all good. :)

nup! the syllabus says doesn't say "or" its says for example so I think they could ask either either. your teacher may have confused it with the fact that the point says "conduct practical and/or secondary-sourced investigation."

I think they are more likely to ask about fungus since there is not much about host response for viral. but yeah doesn't say "or" so thought i would let you know :))

dani01

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Re: HSC Biology Question Thread
« Reply #1358 on: October 27, 2019, 05:04:05 pm »
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hey! just wanted to know is dolly a transgenic organism? if the question asks for transgenic organism can i talk about somatic cell nuclear transfer? thanks

Hawraa

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Re: HSC Biology Question Thread
« Reply #1359 on: October 27, 2019, 05:19:58 pm »
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Hi,
Can someone please help me with this question.

How could a change in a polypeptide effect cell activity?

Is it correct to say that since polypeptides are folded and modified to produce proteins, a change in polypeptide would result in a dysfunctional protein. This would impact cell activity such as for example if the affected polypeptide encoded for a protein functioning as an enzyme to regulate cellular processes such as DNA replication, it could prevent the process from occurring thus preventing it from copying and passing the genetic material to daughter cells, or if the polypeptide is encoding for a protein functioning as an antibody it would affect the immune system ability to recognise foreign particles and impair its ability to initiate an immune response.

Which one is a better example? (by the way, the question worths 2 marks.) thanks.
« Last Edit: October 27, 2019, 05:42:07 pm by Hawraa »

Hawraa

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Re: HSC Biology Question Thread
« Reply #1360 on: October 27, 2019, 05:26:55 pm »
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hey! just wanted to know is dolly a transgenic organism? if the question asks for transgenic organism can i talk about somatic cell nuclear transfer? thanks

Hi there,
Dolly was a clone produced by whole organism cloning, which occurs through somatic cell nuclear transfer.

With transgenic organisms or transgenesis, it does not include somatic cell nuclear transfer. It is the introduction of DNA from different organism into another organism to exhibit a particular trait and pass it to offsprings. Such as pest resistent crops. Hope this answers your question.

InnererSchweinehund

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Re: HSC Biology Question Thread
« Reply #1361 on: October 27, 2019, 06:23:14 pm »
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Hi,
Can someone please help me with this question.

How could a change in a polypeptide effect cell activity?

Is it correct to say that since polypeptides are folded and modified to produce proteins, a change in polypeptide would result in a dysfunctional protein. This would impact cell activity such as for example if the affected polypeptide encoded for a protein functioning as an enzyme to regulate cellular processes such as DNA replication, it could prevent the process from occurring thus preventing it from copying and passing the genetic material to daughter cells, or if the polypeptide is encoding for a protein functioning as an antibody it would affect the immune system ability to recognise foreign particles and impair its ability to initiate an immune response.

Which one is a better example? (by the way, the question worths 2 marks.) thanks.

Hi!

I think the best answer is to say that a change in a polypeptide chain (such as alterations to the amino acid sequence) could affect/alter/damage the protein produced, hence impacting its functional ability. You could then use your example, "This would impact cell activity, as if the polypeptide is encoding for a protein functioning as an antibody" it would affect the ability of the antibody to bind to and neutralise a specific antigen, hence compromising the immune response.immune system ability to recognise foreign particles and impair its ability to initiate an immune response.

As this question is only worth two marks, I think it's enough just to give a basic definition / overview of what would happen if a change occurred, and one solid example.

Hope this helps!
 :)

Hawraa

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Re: HSC Biology Question Thread
« Reply #1362 on: October 27, 2019, 06:31:21 pm »
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Hi!

I think the best answer is to say that a change in a polypeptide chain (such as alterations to the amino acid sequence) could affect/alter/damage the protein produced, hence impacting its functional ability. You could then use your example, "This would impact cell activity, as if the polypeptide is encoding for a protein functioning as an antibody" it would affect the ability of the antibody to bind to and neutralise a specific antigen, hence compromising the immune response.immune system ability to recognise foreign particles and impair its ability to initiate an immune response.

As this question is only worth two marks, I think it's enough just to give a basic definition / overview of what would happen if a change occurred, and one solid example.

Hope this helps!
 :)

Awesome, thanks.

dani01

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Re: HSC Biology Question Thread
« Reply #1363 on: October 27, 2019, 08:42:42 pm »
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Hi there,
Dolly was a clone produced by whole organism cloning, which occurs through somatic cell nuclear transfer.

With transgenic organisms or transgenesis, it does not include somatic cell nuclear transfer. It is the introduction of DNA from different organism into another organism to exhibit a particular trait and pass it to offsprings. Such as pest resistent crops. Hope this answers your question.

thank you so very much. best of luck for tomorrow :)

Annasimon

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Re: HSC Biology Question Thread
« Reply #1364 on: June 03, 2020, 02:18:33 pm »
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Why are white blood cells bigger and fewer in number compared to red blood cells