ATAR Notes: Forum
National Education => General National Education Discussion => Interstate Discussion and Comparison => Topic started by: PhoenixxFire on September 07, 2017, 07:05:01 pm
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So I know there's a game thread like this and I thought it might help us revise if anyone is interested. Or just ignore me if this is a horrible idea lol. The idea is you ask a question (from any content covered this year) and the person below has to answer and ask there own question. Fell free to add things to other peoples answers too. I'll start
Name one way someone could artificially acquire passive immunity. (1 mark)
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It can be passed on from parent to offspring.
Describe how a vaccine helps to keep an individual immune to a disease. Hint: describe in terms of the immune response, and the primary and secondary response. (3)
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It can be passed on from parent to offspring.
Describe how a vaccine helps to keep an individual immune to a disease. Hint: describe in terms of the immune response, and the primary and secondary response. (3)
hey OG just a small problem. :)
Antibodies passed from parents to offspring is actually naturally occuring passive immunity.
An example of an artificially occuring type of passive immunity would be injection of antibodies.
I'll leave your question for someone to answer :)
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hey OG just a small problem. :)
Antibodies passed from parents to offspring is actually naturally occuring passive immunity.
An example of an artificially occuring type of passive immunity would be injection of antibodies.
I'll leave your question for someone to answer :)
Ah, sorry. I glimpsed through the question, sorry about that ahaha
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It can be passed on from parent to offspring.
Describe how a vaccine helps to keep an individual immune to a disease. Hint: describe in terms of the immune response, and the primary and secondary response. (3)
A vaccine contains antigens of the pathogen being vaccinated against, which trigger the clonal expansion of specific B cells with receptors for this antigen into B plasma cells and B memory cells. Memory cells are retained in the individuals, such that in the secondary exposure to the same antigen, these B memory cells quickly differentiate into more B plasma cells to produce more specific antibodies against the antigen at a faster rate than in the primary response. Hence, the individual has long term humoral immunity against the pathogen being vaccinated against.
Question: Drosophila flies must perform a courtship dance to attract their female mates. Only wild type wings allow the flies to do so. If a mutation occured, producing flies with curly wings as determined by a dominant allele, how long would it take for this trait to be wiped out of the population? (2 marks)
:)
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A vaccine contains antigens of the pathogen being vaccinated against, which trigger the clonal expansion of specific B cells with receptors for this antigen into B plasma cells and B memory cells. Memory cells are retained in the individuals, such that in the secondary exposure to the same antigen, these B memory cells quickly differentiate into more B plasma cells to produce more specific antibodies against the antigen at a faster rate than in the primary response. Hence, the individual has long term humoral immunity against the pathogen being vaccinated against.
Question: Drosophila flies must perform a courtship dance to attract their female mates. Only wild type wings allow the flies to do so. If a mutation occured, producing flies with curly wings as determined by a dominant allele, how long would it take for this trait to be wiped out of the population? (2 marks)
:)
Good answer!
I think your question is interesting (and a 1/2 question for once!) but it's unanswerable. I think you're implying that flies with curly wings absolutely can't breed. If that were the case, it would take one generation for the trait to disappear.
It's actually not the case though; lots of Drosophila have curly wings (so many that I've actually seen it myself! :)).
Describe the mechanism by which Relenza (zanamivir) slows the spread of influenza through a population [4 marks]
I want you to describe the molecular basis but also reflect on why we prescribe this drug in bulk in flu season :)
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Good answer!
I think your question is interesting (and a 1/2 question for once!) but it's unanswerable. I think you're implying that flies with curly wings absolutely can't breed. If that were the case, it would take one generation for the trait to disappear.
It's actually not the case though; lots of Drosophila have curly wings (so many that I've actually seen it myself! :)).
Describe the mechanism by which Relenza (zanamivir) slows the spread of influenza through a population [4 marks]
I want you to describe the molecular basis but also reflect on why we prescribe this drug in bulk in flu season :)
Just looking through the Bio forum and found this gem. Let's see if we can bring it back to life!
EDIT: this revival attempt probably would have been more successful about a week ago. I think most people are exhausted from bio, however I have a unabating addiction to answering bio questions (regardless of my poor skills) and need an outlet.
Relenza is a rationally designed drug with a specific conformation and charge complementary to the active site of enzyme neuraminidase on the influenza virus which functions to cleave the connection (docking protein) between a virus and host cell in the replication cycle of influenza. As such, Relenza will bind to the active site of neuraminidase and cause inhibition of its function to cleave the virus-host cell connection and thus prevent the completion of the virus replication cycle. This reduces the spread of influenza within the host organism treated with Relenza and will enable the immune system to more effectively deal with the infection. Since Relenza functions to block the active site of neuraminidase, it is thus a competitive inhibitor and as such its efficacy in preventing virus spread is improved when in greater concentration in allowing out-competition for the neuraminidase active site. Bulk use of Relenza would also not carry with it the same ethical concerns over production of resistant influenza as neuraminidase is highly conserved and unchanging (at least that is what I gather but may be wrong).
EDIT: I tried editing my answer to make it less horrendous, but alas I think I will not satisfy the 4 marks
My question:
Explain why mtDNA is commonly used over DNA for molecular clock analysis and determining evolutionary relatedness
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My question:
Explain why mtDNA is commonly used over DNA for molecular clock analysis and determining evolutionary relatedness
Mitochondrion are found in all Eukaryotes which allows the evolutionary relationship of a large number of species to be compared. The critical role mitochondrion play in sustaining complex life means that coding sequences of mtDNA are highly conserved and have the same function across species whereas sections of nuclear coding DNA may have different functions in a variety of species. The mutation rate of mtDNA is known, and the mutation rate of non-coding regions of mtDNA is high, which allows relatedness to be measured to a higher degree of accuracy than using nuclear DNA.
Question:
List four factors that can affect the rate of photosynthesis.
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Question:
List four factors that can affect the rate of photosynthesis.
1. Carbon dioxide concentration
2. light intensity
3. Temperature
4. The quantity of light harvesting pigments (e.g chlorophyll)
Question: name a element of the first line of defense (1m) and state its function (1m)
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Question: name a element of the first line of defense (1m) and state its function (1m)
An element of the first line of defence is mucous and cilia in the respiratory tract. Mucous helps trap any non-self particles and the cilia then push the mucous up the respiratory tract to allow it to be swallowed. This protects the lungs from any pathogens.
Question: Describe the process of translation.
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Question: Describe the process of translation.
Answers to this question could vary a bit depending on the number of marks allocated, however I've decided to treat it as a 3 or 4 mark question given that it is a 'describe' question about a process :)
Translation occurs when a ribosome binds to the 5' end of an mRNA molecule. When the ribosome reaches the START sequence of the mRNA, it begins synthesising a polypeptide chain made up of amino acids. These amino acids are brought to the ribosome from the cytosol by tRNA possessing an anticodon that is complementary to the mRNA's codon. The ribosome catalyses the formation of peptide bonds between amino acids, adding them to the growing polypeptide chain. This continues until a STOP codon, where the polypeptide chain is released.
Question:
Explain the structural difference between a polypeptide chain and a protein.
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Explain the structural difference between a polypeptide chain and a protein
A polypeptide chain refers merely to a sequence of amino acids.
A protein can include multiple polypeptide chains (if it has quaternary structure) and the term 'protein' also relates not just to the sequence of amino acids, but also to the secondary and tertiary configurations of the biologically-active molecule (i think)
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A polypeptide chain refers merely to a sequence of amino acids.
A protein can include multiple polypeptide chains (if it has quaternary structure) and the term 'protein' also relates not just to the sequence of amino acids, but also to the secondary and tertiary configurations of the biologically-active molecule (i think)
*psssst*
you need to come up with another question :)
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Oh lol sorry!
Question: do lipid or polar-soluble signalling molecules cause faster cellular responses? justify!
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Oh lol sorry!
Question: do lipid or polar-soluble signaling molecules cause faster cellular responses? justify!
Polar (water soluble) signaling molecules bind to membrane-bound receptor proteins and elicit the activation of many second messengers in a signal cascade to transduce the signal and bring about a cellular response. Since the precursors of the signaling molecules are usually 'ready' to be activated and the signal cascade causes the amplification of the signal, polar signaling molecules tend to bring about rapid response. Non-polar (lipid-soluble) signaling molecules bind to intracellular receptor proteins, forming a signal-receptor complex which often acts as a transcription factor and brings about a relatively slow response of altering gene expression. As such, polar signaling molecules typically cause a faster cellular response.
My question:
In forests, short plants that grow low to the ground under the shade of taller plants tend to develop leaves with much larger surface areas than plants in direct sunlight.
a) Explain the evolutionary advantage of larger leaves for these plants
b) A low growing plant species possessing small leaves was introduced to a forest environment where it receives little direct sunlight. Explain the process of natural selection that may occur to this introduced plant species to result in the development of larger leaves over time.
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In forests, short plants that grow low to the ground under the shade of taller plants tend to develop leaves with much larger surface areas than plants in direct sunlight.
a) Explain the evolutionary advantage of larger leaves for these plants
b) A low growing plant species possessing small leaves was introduced to a forest environment where it receives little direct sunlight. Explain the process of natural selection that may occur to this introduced plant species to result in the development of larger leaves over time.
a) It is advantageous for these plants to have larger leaves as they are sheltered from a lot of direct sunlight due to the shelter from other plants meaning that it is difficult for them to get the amount of sunlight that they need to successfully fuel photosynthesis and thus create energy. Larger leaves provide a larger surface area for sunlight to reach and thus larger opportunities for photosynthesis
b) The plant with small leaves receiving minimal sunlight due to its location would struggle to photosynthesis the desired amount and thus would not have sufficient energy. Over generations, plants of this species with slightly larger leaves would be more likely to survive (due to natural selection) and thus more likely to reproduce meaning that gradually this species would come to have larger leaves.
Describe the role of DNA polymerase. (2)
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Describe the role of DNA polymerase. (2)
DNA polymerase is an enzyme that plays an important role in the replication of DNA strands. Its main role is to catalyse the joining together (via condensation polymerisation) of DNA nucleotides (that are complementary to the original DNA strand) in a 3 to 5 prime direction, thereby leading to the formation of another DNA molecule.
And a question for you ;)
Alex is playing a game on a field of grass and rolls on the grass to reach the ball. He comes home with a mild rash on his legs. Throughout the month, he returns multiple times to play on the same field of grass and every time he comes home with a more severe version of the initial rash.
a) Explain how Alex first became sensitised to the grass allergen. (3)
b) Why does Alex's rash get worse each time he comes in contact with the grass? (2)
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And a question for you ;)
Alex is playing a game on a field of grass and rolls on the grass to reach the ball. He comes home with a mild rash on his legs. Throughout the month, he returns multiple times to play on the same field of grass and every time he comes home with a more severe version of the initial rash.
a) Explain how Alex first became sensitised to the grass allergen. (3)
b) Why does Alex's rash get worse each time he comes in contact with the grass? (2)
a) The grass molecules would enter Alex's body, which would recognise it as a foreign antigen and launch an adaptive immune response. Specific T-helper cells recognise the foreign grass antigen and release cytokines, which stimulate the matching naive B cell to become active and proliferate into plasma cells and memory B cells. These plasma cells will produce specific IgE antibodies that bind to the surface of mast cells, priming the mast cells to recognise the allergen the next time the same grass molecule antigens enter the body through their IgE antibody receptors. During sensitisation, Alex's body will not experience an allergic response.
b) Subsequent exposure to the same grass allergen when Alex goes to play on the same field will cause more IgE antibodies to be released and attach to mast cells. The increased number of IgE antibody receptors on mast cells mean more of them will recognise the grass allergen and release histamine. Histamine will cause vasodilation and increased blood flow to the area, as well as heat, swelling and rashes. As Alex continues to visit the same field, the allergic response will become worse each time, causing his rash to also increase in severity.
(please correct me if I'm wrong, especially for part b), as I wasn't too sure!)
Ella was completing PCR on a segment of DNA in order to use it for subsequent testing. The DNA segment she wants to amplify has the following code:
T T A C A T G A C G T C A
a) What is the complementary sequence to this code? (1 mark)
b) Explain the steps Ella will need to go through in order to successfully complete PCR. Ensure you reference the temperatures and inputs of each step. (4 marks)
c) This DNA segment is a part of a group of linked genes found in bacteria such as E. coli, and is a segment of the lac operon. Explain what occurs when lactose is abundant and glucose is not in terms of gene expression, in reference to the lac operon. (3 marks)
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Ella was completing PCR on a segment of DNA in order to use it for subsequent testing. The DNA segment she wants to amplify has the following code:
T T A C A T G A C G T C A
a) What is the complementary sequence to this code? (1 mark)
b) Explain the steps Ella will need to go through in order to successfully complete PCR. Ensure you reference the temperatures and inputs of each step. (4 marks)
c) This DNA segment is a part of a group of linked genes found in bacteria such as E. coli, and is a segment of the lac operon. Explain what occurs when lactose is abundant and glucose is not in terms of gene expression, in reference to the lac operon. (3 marks)
a) AATGTACTGCAGT
b)
- Ella would need to isolate the DNA segment from the rest of the DNA
- Heat the solution containing the DNA segment to 92ºC, denaturing DNA to separate the DNA into two single strands of DNA.
- Cool the solution to 55ºC and add primers which would attach to complementary DNA sequence.
- Heat the solution to 72ºC and add Taq Polymerase. This would result in the production of copies of the DNA segment.
- The process is repeated multiple times to amplify the DNA segment to the required amount.
c)
- The lac operon is an inducible operon. When lactose is present it binds to the allosteric site of the repressor protein.
- Resulting in a conformation change in the repressor protein, the shape of the active site is altered. Thus, it is unable to bind to the operator region.
- Hence, DNA polymerase is able to bind to the promoter region of the lac operon and transcribe the structural proteins. Therefore, gene expression occurs when lactose is present.
Here’s a few questions for you! 8)
Imagine that we are living in a pandemic, and a nasty virus that is highly virulent is spreading through the globe. You are a virologist who is trying to find a vaccine for this virus – known as coronavirus. A different strain of coronavirus has previously infected the world.
a) Why would a vaccine be effective in this situation (hint: herd immunity) and how would a vaccine against coronavirus work? (4 marks)
b) Which kind of drugs will be effective against the virus? Give an example of how a drug might work (2 marks)
c) Describe the process by which this drug can be produced? (hint: Rational Drug Design) (3 marks)
d) What are strategies (other than lockdown, wearing masks and washing your hands) can the government introduce to deal with limiting the spread of this contagious virus? (2 marks)
e) From world renowned scientists, we have heard that a vaccine that acts against this virus can be developed within a year or two. Whereas vaccines for other viruses have taken at least 6 to 10 years to develop. Suggest 2 reasons why it is predicted that a Coronavirus vaccine can be developed in a shorter time frame? (2 marks)
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b) Good answer, however it might be necessary to say that Taq polymerase catalyses the joining of complementary DNA nucleotides to the DNA segment.
c) Slight correction. RNA polymerase transcribes the 3 structural genes in the lac operon, not DNA polymerase. This is so the proteins (enzymes used to break down lactose) can be made, first by creating the mRNA strand complementary to that segment of DNA, which requires RNA polymerase.
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b) Good answer, however it might be necessary to say that Taq polymerase catalyses the joining of complementary DNA nucleotides to the DNA segment.
c) Slight correction. RNA polymerase transcribes the 3 structural genes in the lac operon, not DNA polymerase. This is so the proteins (enzymes used to break down lactose) can be made, first by creating the mRNA strand complementary to that segment of DNA, which requires RNA polymerase.
Yep, thanks whys :) Confused DNA with RNA, I hope I don't make the same mistake again haha.