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August 15, 2020, 05:35:48 pm

Author Topic: VCE Biology Question Thread  (Read 1758660 times)  Share 

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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12750 on: July 07, 2020, 03:56:15 pm »
+1
Hello
For this question:
Penicillin is an antibiotic that either slows the growth or kills dangerous bacteria such as staphylococcus aureus. In the pre antibiotic era more than 80%of patients suffering from staphylococcus aureus bacteraemia (blood poisoning) died. In the early 1940s few of these bacteria were resistant to penicillin and many lives were saved. By 1950 50% of the bacteria had developed resistance and this increased to 60% by the 1960s
Explain in terms of natural selection how this happened.

- Before penicillin was introduced not many bacteria had the resistant gene. After Penicillin was introduced the number of bacteria with the resistance increased and reproduce and pass on the trait

Sine

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Re: VCE Biology Question Thread
« Reply #12751 on: July 07, 2020, 04:33:03 pm »
+5
Hello
For this question:
Penicillin is an antibiotic that either slows the growth or kills dangerous bacteria such as staphylococcus aureus. In the pre antibiotic era more than 80%of patients suffering from staphylococcus aureus bacteraemia (blood poisoning) died. In the early 1940s few of these bacteria were resistant to penicillin and many lives were saved. By 1950 50% of the bacteria had developed resistance and this increased to 60% by the 1960s
Explain in terms of natural selection how this happened.

- Before penicillin was introduced not many bacteria had the resistant gene. After Penicillin was introduced the number of bacteria with the resistance increased and reproduce and pass on the trait
Good start but could elaborate a bit further. Maybe talk about why the introduction fo penicillin increased the number of bacteria with the resistance?

1729

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Re: VCE Biology Question Thread
« Reply #12752 on: July 07, 2020, 04:36:01 pm »
+4
Hello
For this question:
Penicillin is an antibiotic that either slows the growth or kills dangerous bacteria such as staphylococcus aureus. In the pre antibiotic era more than 80%of patients suffering from staphylococcus aureus bacteraemia (blood poisoning) died. In the early 1940s few of these bacteria were resistant to penicillin and many lives were saved. By 1950 50% of the bacteria had developed resistance and this increased to 60% by the 1960s
Explain in terms of natural selection how this happened.

- Before penicillin was introduced not many bacteria had the resistant gene. After Penicillin was introduced the number of bacteria with the resistance increased and reproduce and pass on the trait
I don't know how many marks this question is, but I feel like you need to expand a little more. After your first sentence, mention that penicillin kills other bacteria that did not contain or possess the resistant gene, thus leaving the resistant bacteria with no competition. This allowed them to flourish and reproduce passing on the resistant trait with less competition (due to less bacteria being present). This increases resisistant to penicillin within a bacterial population as they reproduce and pass on the trait. ALSO antibiotic resistant bacteria can transfer this resistance by transferring plasmids through bacterial conjugation and this can further increase resistance in a population and as this bacteria thrives and other ones die, the resistant bacteria reproduce and pass on trait.
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12753 on: July 07, 2020, 07:13:25 pm »
+1
Thanks also
For this question:
How do mutation and sexual reproduction contribute to natural variation within a species.

- Sexual reproduction increases genetic variation in offspring which contributes to variation within a species. Crossing over which is the exchange of alleles between homologous chromosomes and Independent assortment result in genetic variability in the offspring. Mutation contributes to variation within a species by altering the base sequence of DNA resulting in new alleles of a particular trait.

1729

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Re: VCE Biology Question Thread
« Reply #12754 on: July 07, 2020, 07:48:44 pm »
+7
Sexual reproduction increases genetic variation in offspring which contributes to variation within a species. Crossing over which is the exchange of alleles between homologous chromosomes and Independent assortment result in genetic variability in the offspring. Mutation contributes to variation within a species by altering the base sequence of DNA resulting in new alleles of a particular trait.
Maybe you can say that sexual reproduction contributes to genetic variation as the gametes are haploid, meaning only half the genes from each parent are inherited. Always always start defining natural selection, because that is one point in majority of cases as the question is explain. So explain that natural selection is something something,  therefore, penincilin will remove bacterias who dont have the resistance gene. Survival of the fittest and the better adapt survives develops resistance to penincilin, etc.
Also for future reference, write in bullet points, it will help a lot, trust me.
« Last Edit: July 08, 2020, 09:10:56 am by 1729 »
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Coolmate

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Re: VCE Biology Question Thread
« Reply #12755 on: July 07, 2020, 07:56:20 pm »
+7
Thanks also
For this question:
How do mutation and sexual reproduction contribute to natural variation within a species.

- Sexual reproduction increases genetic variation in offspring which contributes to variation within a species. Crossing over which is the exchange of alleles between homologous chromosomes and Independent assortment result in genetic variability in the offspring. Mutation contributes to variation within a species by altering the base sequence of DNA resulting in new alleles of a particular trait.

Hey Chocolatepistachio!

This is a good response so far, but just adding onto 1729's suggestion:

"Sexual reproduction (can) increases genetic variation in offspring a genus by granting natural which contributes to variation within an offspring and ultimately its species. Crossing over which is the exchange of alleles between homologous chromosomes and independent assortment (Define 'independent assortment'). Both processes occur in Meiosis resulting in genetic variability as different combinations of genes are formed in the gametes, prompting variance in an offspring. Mutation contributes to variation within a species by altering the base sequence of DNA resulting in new alleles of a particular trait." (In the next sentence explain what the effect of this new trait has for a species)

I hope this helps!
Coolmate 8)
« Last Edit: July 07, 2020, 08:02:15 pm by Coolmate »
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12756 on: July 07, 2020, 11:22:56 pm »
+4
Thank you!

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12757 on: July 08, 2020, 04:04:54 pm »
0
Hello what do you guys think for this question
Plants perform the light reactions of photosynthesis during the day. However plants also carry out cellular respiration
It was once proposed that large tanks of photosynthetic algae could supply astronauts in spacecraft with oxygen and remove carbon. Do you think this would work why or why not?

This is what I was thinking
- this would not work because there would not be much sunlight , the algae needs to be in water and you would need to be able to get the oxygen out of the tank . The tanks would be quite heavy

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Re: VCE Biology Question Thread
« Reply #12758 on: July 08, 2020, 05:54:09 pm »
+4
Hello what do you guys think for this question
Plants perform the light reactions of photosynthesis during the day. However plants also carry out cellular respiration
It was once proposed that large tanks of photosynthetic algae could supply astronauts in spacecraft with oxygen and remove carbon. Do you think this would work why or why not?

This is what I was thinking
- this would not work because there would not be much sunlight , the algae needs to be in water and you would need to be able to get the oxygen out of the tank . The tanks would be quite heavy
That's a cool question. I'm not completely sure to be honest, but I'll try my best, (but don't take what I say as correct).
I would say, yes, this could work, the algae would use the astronauts CO2 in photosynthesis and release O2 as a waste product. Types of algae can be much more efficient than plants for photosynthesis. Algae is able to photosynthesise in low light intensity conditions.
(Maybe it's one of those questions where you are right either way if you back it up?) I think what you've said about the weight/ space it could take up are good arguments against it.
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12759 on: July 09, 2020, 04:15:20 pm »
0
What is the function of the pericycle and cortex in the root

Coolmate

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Re: VCE Biology Question Thread
« Reply #12760 on: July 09, 2020, 05:33:45 pm »
+6
What is the function of the pericycle and cortex in the root

Hey Chocolatepistachio!

The Pericycle is a vascular bundle composed of parenchyma (non-vascular cells for the Pericycle only) and sclerenchyma cells whereas the Cortex is the outer layer of a stem composed of large parenchyma cells.

🌱Pericycle Function = Provide support, protection and helps with the creation of new roots. The Pericycle also helps hold the plant upright for allowing for optimal growth

🌴Cortex Function = Responsible for storing and the transportation of nutrients (e.g. Carbohydrates) and water throughout a plant, via diffusion.

I hope this helps!
Coolmate 8)
« Last Edit: July 09, 2020, 05:39:10 pm by Coolmate »
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Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12761 on: July 10, 2020, 11:03:12 am »
+1
Thank you!!
Also for this question
How is it thought that eukaryotic cells obtained mitochondria and chloroplasts.

Is this right
- Mitochondria and chloroplasts used to be free living prokaryotes until they were engulfed by eukaryotes. Mitochondria and chloroplasts evolved from engulfed prokaryotes that once lived as an independent organism

SockInfinite

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Re: VCE Biology Question Thread
« Reply #12762 on: July 10, 2020, 11:09:29 am »
+7
Thank you!!
Also for this question
How is it thought that eukaryotic cells obtained mitochondria and chloroplasts.

Is this right
- Mitochondria and chloroplasts used to be free living prokaryotes until they were engulfed by eukaryotes. Mitochondria and chloroplasts evolved from engulfed prokaryotes that once lived as an independent organism
Looks good to me. You should also include the mutualistic relationship between the eukaryotes and mitochondria + chloroplasts - pretty much how one benefited the other and vise versa

Chocolatepistachio

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Re: VCE Biology Question Thread
« Reply #12763 on: July 10, 2020, 12:58:50 pm »
+1
For this question
Different cells in an organism and cells from different organisms require different types of food. Does this mean that these cells are chemically different explain
Is this right
- these cells are not chemically different because all cells contain DNA which is composed of a nucleotide which contains a phosphate, sugar and a base

1729

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Re: VCE Biology Question Thread
« Reply #12764 on: July 10, 2020, 01:52:41 pm »
+3
For this question
Different cells in an organism and cells from different organisms require different types of food. Does this mean that these cells are chemically different explain
Is this right
- these cells are not chemically different because all cells contain DNA which is composed of a nucleotide which contains a phosphate, sugar and a base
I think maybe you should add evidence of other organelles that are common within many cells. Talk about more macromolecules
And how their compositon for specific things are the same across species. They are essential for life, lipids are responsible for the cell membrane nucleic acids are important within DNA and also provides evidence for common ancestry, proteins are composed of amino acids which living organisms produce through protein synthesis.
« Last Edit: July 10, 2020, 03:22:27 pm by 1729 »
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