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December 09, 2019, 10:21:34 am

Author Topic: HSC challenge questions!  (Read 1179 times)  Share 

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stella_atarnotes

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HSC challenge questions!
« on: May 26, 2019, 11:18:30 am »
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Hey guys!

Thought I'd start a topic where you guys can post and answer any challenging questions. I'll start off with a question from Module 7 and will post the answer to the question, along with feedback to any answers you guys have!

So here's the question!

"Patient 1 is sick with the flu and has been prescribed 1 course of antibiotics by his doctor. He is asked to take 2 pills a day for 10 days. After taking the antibiotics for 5 days, Patient 1 feels much better and ceases to take his prescribed antibiotics. Discuss the issues associated with this scenario." (5 marks)
« Last Edit: May 26, 2019, 11:21:02 am by stella_atarnotes »

InnererSchweinehund

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Re: HSC challenge questions!
« Reply #1 on: May 26, 2019, 05:13:30 pm »
+4

"Patient 1 is sick with the flu and has been prescribed 1 course of antibiotics by his doctor. He is asked to take 2 pills a day for 10 days. After taking the antibiotics for 5 days, Patient 1 feels much better and ceases to take his prescribed antibiotics. Discuss the issues associated with this scenario." (5 marks)

Hey! I don't think the way I've worded my response is the best but hopefully my answer is along the right line...

Influenza, also known as the flu, is a viral infection commonly obtained in the winter months. The influenza virus is considered non-living, as it requires host cells in order to inject its DNA and spread infection. Due to this, the virus (like all viruses) is non-responsive to antibiotics, as it does not have a specific shape to which the antibiotics can bind. Antibiotics are specific medications that inhibit the growth of specific bacterium through killing the bacteria by blocking their vital processes, and preventing them from multiplying.

The main issue with this scenario is that the person was prescribed antibiotics for a viral infection, by their doctor. The doctor should not have prescribed antibiotics for a virus, as when a person overuses, or uses antibiotics inappropriately (such as for a virus), it builds up their antibiotic resistance. This means that antibiotics are less likely to work effectively on bacteria, as they are able to develop mutations to overcome the antibiotic. This is furthered by the fact that the person did not finish the full course of the prescribed antibiotics. Even though the person felt better, it does not mean their infection had been cured. Through doing this, if the person did have any disease causing bacteria in their system, they would have survived and be able to begin re-dividing, causing more serious infection. Thus, whilst the person should have never been prescribed antibiotics for a virus, it is important that they follow all doctors instructions and complete the course of medication in order to decrease the risk of bacteria developing antibiotic resistance. 

Also, just a quick question, how do you know how much to write, per mark, in bio. For example, I know for english it is commonly thought that you should put 1 example less than the number of prescribed marks. Is this the same for bio??

Thanks!!

Ps. I am really excited for more questions!!

stella_atarnotes

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Re: HSC challenge questions!
« Reply #2 on: June 01, 2019, 11:33:21 am »
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Hey! I don't think the way I've worded my response is the best but hopefully my answer is along the right line...

Influenza, also known as the flu, is a viral infection commonly obtained in the winter months. The influenza virus is considered non-living, as it requires host cells in order to inject its DNA and spread infection. Due to this, the virus (like all viruses) is non-responsive to antibiotics, as it does not have a specific shape to which the antibiotics can bind. Antibiotics are specific medications that inhibit the growth of specific bacterium through killing the bacteria by blocking their vital processes, and preventing them from multiplying.

The main issue with this scenario is that the person was prescribed antibiotics for a viral infection, by their doctor. The doctor should not have prescribed antibiotics for a virus, as when a person overuses, or uses antibiotics inappropriately (such as for a virus), it builds up their antibiotic resistance. This means that antibiotics are less likely to work effectively on bacteria, as they are able to develop mutations to overcome the antibiotic. This is furthered by the fact that the person did not finish the full course of the prescribed antibiotics. Even though the person felt better, it does not mean their infection had been cured. Through doing this, if the person did have any disease causing bacteria in their system, they would have survived and be able to begin re-dividing, causing more serious infection. Thus, whilst the person should have never been prescribed antibiotics for a virus, it is important that they follow all doctors instructions and complete the course of medication in order to decrease the risk of bacteria developing antibiotic resistance. 

Also, just a quick question, how do you know how much to write, per mark, in bio. For example, I know for english it is commonly thought that you should put 1 example less than the number of prescribed marks. Is this the same for bio??

Thanks!!

Ps. I am really excited for more questions!!

Hey! Great response. Overall I would give you 3/5 for this response. Your explanation for how viruses work was great, but if you find yourself running out of time, this wasn't entirely necessary. You have correctly identified the problem with the scenario and explained it very well. One thing I would point out is that you could have related it back to the patient more, in regards how he affected his future with the antibiotics (might not be effective if he actually has a bacterial infection).  Another good thing to note was how it would disrupt John's natural bacterial environment which could allow some bacteria to thrive over others (leading to thrush etc)

With long response questions, the best guide is actually the number of marks. It's also good to think about where exactly the marks would be allocated. So with 5 marks, the marks would be for identifying if it helped John, identifying antibiotic resistance and relating that to John not taking the full course. Other marks would be for identifying how it could lead to thrush/candidiasis and similar issues, and how the drug might be ineffective for future bacteria infections.

1 mark- stating antibiotic resistance would occur
1 mark- stating antibiotics won't help viral infection
1 mark- stating antibiotic resistance can develop from not taking full course of drugs

stella_atarnotes

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Re: HSC challenge questions!
« Reply #3 on: June 01, 2019, 11:42:28 am »
+2
Great response from 0102megan!

Here are things that were good to include with your response.

- Antibiotics will have no effect on influenza virus as these drugs are only effective on bacteria
- The patient is feeling better, but this is most likely not due to the action of the prescribed antibiotics. Antibiotics use would not only destroy pathogenic bacteria, but potentially also destroy bacterial already present in his digestive tract
- Ceasing the use of antibiotics mid-course could lead to bacteria resistance within the existing population of bacteria in the body, which are not responsible for his cold.
- Under normal conditions, gut bacteria exist in a balance with the body, however they may become opportunistic pathogens when this balance is disrupted, particularly under antibiotic use.
- Misuse of the antibiotic can allow any bacteria that was resistant to the antibiotic time to develop and spread. In future, this could limit the effectiveness of antibiotics on John's treatment, if used to treat a bacterial infection.

Good responses would include all of these points. With Biology, your long response questions should be filling up the majority of the lines given in an exam paper. Ideally you should be writing about a few words under the line given for a good substantial answer. If you are writing less, you might need to beef up your response with more explanation and points. If you are writing more, you might be writing unnecessary information. This also applies if you have filled up all the lines but aren't getting all the marks.

Here the next question!

Explain why sex-linked conditions such as red-green colour blindness do not display Mendelian ratios.    (5 marks)

neverknow

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Re: HSC challenge questions!
« Reply #4 on: June 03, 2019, 11:31:29 pm »
+2
Great response from 0102megan!

Here are things that were good to include with your response.

- Antibiotics will have no effect on influenza virus as these drugs are only effective on bacteria
- The patient is feeling better, but this is most likely not due to the action of the prescribed antibiotics. Antibiotics use would not only destroy pathogenic bacteria, but potentially also destroy bacterial already present in his digestive tract
- Ceasing the use of antibiotics mid-course could lead to bacteria resistance within the existing population of bacteria in the body, which are not responsible for his cold.
- Under normal conditions, gut bacteria exist in a balance with the body, however they may become opportunistic pathogens when this balance is disrupted, particularly under antibiotic use.
- Misuse of the antibiotic can allow any bacteria that was resistant to the antibiotic time to develop and spread. In future, this could limit the effectiveness of antibiotics on John's treatment, if used to treat a bacterial infection.

Good responses would include all of these points. With Biology, your long response questions should be filling up the majority of the lines given in an exam paper. Ideally you should be writing about a few words under the line given for a good substantial answer. If you are writing less, you might need to beef up your response with more explanation and points. If you are writing more, you might be writing unnecessary information. This also applies if you have filled up all the lines but aren't getting all the marks.

Here the next question!

Explain why sex-linked conditions such as red-green colour blindness do not display Mendelian ratios.    (5 marks)

Hey, the part where it says "The patient is feeling better, but this is most likely not due to the action of the prescribed antibiotics" --> Would it be ok to call the antibiotic a placebo. Idk if it is appropriate for the context.
AND
for this part, "gut bacteria exist in a balance with the body" --> can we just say - gut flora (microbiota) exists in a balance...

Thanks.
« Last Edit: June 03, 2019, 11:37:02 pm by neverknow »

InnererSchweinehund

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Re: HSC challenge questions!
« Reply #5 on: June 04, 2019, 05:18:33 pm »
+3
Hey, the part where it says "The patient is feeling better, but this is most likely not due to the action of the prescribed antibiotics" --> Would it be ok to call the antibiotic a placebo. Idk if it is appropriate for the context.

Thanks.

Hey!

I wouldn't call the antibiotics placebo because that gives the impression that you are saying that antibiotics are prescribed for the psychological benefit to the patient, rather than for any physiological effect ( and this impression might not sit well with an examiner).
In this case, the antibiotic would work if the disease was caused by a bacteria, but as it was caused by a virus, it is ineffective.
The patient is more than likely feeling better, not due to the antibiotic, but because of the stage of the virus and the immune system's response.
 8)


stella_atarnotes

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Re: HSC challenge questions!
« Reply #6 on: June 05, 2019, 10:04:57 pm »
+1
Hey, the part where it says "The patient is feeling better, but this is most likely not due to the action of the prescribed antibiotics" --> Would it be ok to call the antibiotic a placebo. Idk if it is appropriate for the context.
AND
for this part, "gut bacteria exist in a balance with the body" --> can we just say - gut flora (microbiota) exists in a balance...

Thanks.

What InnererSchweinehund mentioned about the antibiotics is spot on. It's not very accurate to relate the antibiotics to any psychological impact since this was not the point of the prescription.

You probably won't be marked down by calling it gut flora, but just be aware that this includes all microorganisms, not just bacteria. So if you go on to say things like "antibiotics destroys gut flora" this would be an incorrect statement since microorganisms such as protists or viruses won't actually be destroyed.

elena.newlyn

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Re: HSC challenge questions!
« Reply #7 on: June 08, 2019, 10:14:15 am »
0
Could you please give an answer to the Medelian ration question

stella_atarnotes

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Re: HSC challenge questions!
« Reply #8 on: June 09, 2019, 11:40:09 am »
+5
Here's the answer to last weeks question "Explain why sex-linked conditions such as red-green colour blindness do not display Mendelian ratios." Its always good to give the question a go even if your unsure if your answer is correct, hope to see some responses next week!

Things to include in your response:
- Human females have 2 copies of the X chromosome, while males have one X and one Y, the latter being much smaller and carrying very few genes.
- Males have only one copy of X chromosome genes, all which are expressed in the phenotype.
- For X-linked recessive traits such as colourblindness, this means that a male only needs to inherit a single copy of the associated allele to be affected (hemizygous).
- Meanwhile females would need to inherit two copies of the same allele to be colourblind (homozygous recessive), to prevent the recessive alleles masked by a dominant allele. - As a result, X-linked recessive traits are more common in the male population.
- Therefore, genes carried on the sex chromosome do not display Mendelian ratios because such ratios are generally only present for traits where two copies of the genes are present for both sexes.

Onto the next question!

The attached pedigree is hereditary and not sex-linked. The pedigree represents a family in which some members have a disease. Explain why it is difficult to determine whether the disease is dominant or recessive. (4 marks)

Kombmail

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Re: HSC challenge questions!
« Reply #9 on: July 02, 2019, 08:04:50 pm »
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The pedigree given shows an affected female and unaffected male in generation two. Since only the female is affected here , it could have been stated for a sex linked but it stated not it the question. The possible genotypes here are either rr and Rr or rr and RR. If rr and RR generations two and three should have shown evidence of this through the diagram however this is not true. This cancels out the homozygous dominant mother and homozygous recessive father option. Rr and rr is now a possibility with fifty percent offspring being homozygous recessive and fifty percent heterozygous to the disease. However second generation couple affected female and non affected male produce 100 percent affected offspring. It now becomes difficult to determine the link as the children according to the pedigree diagram must be fifty percent affected and fifty percent unaffected.
-KgkG-

InnererSchweinehund

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Re: HSC challenge questions!
« Reply #10 on: July 23, 2019, 02:45:07 pm »
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Hi all!

This is quite late but here is my answer to this question.
I am looking forward to more challenging questions!! Hope everyone's prep for trials (and HSC) is going well  ;D

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
It is difficult to determine whether the disease is dominant or recessive due to the patterns of inheritance demonstrated in the pedigree.

In a normal pattern of inheritance for a dominant disease, most of the offspring of the first generation of parents would have the disease. This is especially true for second generation males, if their mother has the disease, as they must inherit an X chromosome from her, and it is therefore a 50/50 chance of them also inheriting the disease if it was dominant.

It is also difficult to assume if the disease is dominant or recessive because generation 2, with an affected mother and unaffected father, produced an affected son and daughter. This means that either the disease is recessive and the father was carrier, meaning that the generation 3 son inherited an affected X chromosome from his mother, and the generation 3 daughter inherited an affected X chromosome from both her mother and father (fig 1), or the disease is dominant and both the son and daughter inherited a dominant disease affected X chromosome from their mother (fig 2).

As we do not know the genetic makeup of the female partner of the other male unaffected offspring in generation 2, we can not determine the reasons behind their children being unaffected and therefore if the disease is dominant or recessive. For example, if the female was or wasn’t a carrier for the recessive gene, as this would impact the children’s (generation 3’s) likelihood of inheriting the disease.

Therefore, without further information, it is difficult to determine whether the disease is dominant or recessive. 

Kombmail

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Re: HSC challenge questions!
« Reply #11 on: August 05, 2019, 06:58:22 pm »
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Hi all!

This is quite late but here is my answer to this question.
I am looking forward to more challenging questions!! Hope everyone's prep for trials (and HSC) is going well  ;D

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
It is difficult to determine whether the disease is dominant or recessive due to the patterns of inheritance demonstrated in the pedigree.

Wait a sec so... did I do it right?

In a normal pattern of inheritance for a dominant disease, most of the offspring of the first generation of parents would have the disease. This is especially true for second generation males, if their mother has the disease, as they must inherit an X chromosome from her, and it is therefore a 50/50 chance of them also inheriting the disease if it was dominant.

It is also difficult to assume if the disease is dominant or recessive because generation 2, with an affected mother and unaffected father, produced an affected son and daughter. This means that either the disease is recessive and the father was carrier, meaning that the generation 3 son inherited an affected X chromosome from his mother, and the generation 3 daughter inherited an affected X chromosome from both her mother and father (fig 1), or the disease is dominant and both the son and daughter inherited a dominant disease affected X chromosome from their mother (fig 2).

As we do not know the genetic makeup of the female partner of the other male unaffected offspring in generation 2, we can not determine the reasons behind their children being unaffected and therefore if the disease is dominant or recessive. For example, if the female was or wasn’t a carrier for the recessive gene, as this would impact the children’s (generation 3’s) likelihood of inheriting the disease.

Therefore, without further information, it is difficult to determine whether the disease is dominant or recessive.
-KgkG-