yr12student22 In a silent mutation theres no change to the protein’s 3D tertiary structure as the single base substitution still codes for the same amino acid due to the degeneracy of the genetic code.
With missense although there’s a change of one amino acid- it does not entirely change the 3D tertiary protein structure due to misfolding as a result of different interactions between the variable R groups of amino acids in the polypeptide chain. This wont be as significant of an effect compared to framshifts where the protein becomes non functional
biology unit 3/4
Hey guys, i am really struggling with natural selection and selective breeding. can someone please give me a example that summaries it.
7 days later
the main difference is what is acting as the selection pressure.
For natural selection, take the example of grey and black moths in an environment, the selection pressure is the predators who may see the grey moths better when they are against darker bark on trees. This will allow for the moths to be 'fitter' since they are selected by their environment.
for artificial selection think of cows being bred to produce more meat. Humans are the selection pressure selecting more meaty cows to breed together. In the end, they aren't necessarily 'fitter'.
hi! how do i answer this question;
Smallpox was one of the deadliest human viral diseases. People who survived this disease were often badly
scarred, blinded or both. In April 1789, 15 months after the British arrival to Australia, a major smallpox
outbreak occurred. In terms of the number of infected individuals and subsequent deaths, the outbreak
affected the Indigenous population to a greater extent than the British population.
a. The British population and the Indigenous population were both exposed to the smallpox virus.
Suggest one reason why the Indigenous population was affected to a greater extent than the British
population. Explain your response.
in my answer i stated the role of the antigen presenting cells was that the only thing needed? or do i have to implement 'smallpox virus' in my answer to get the full 3 marks
Do mutations or genetic drift have a greater effect on the gene pool?
Thanks
chemistry1111 Genetic drift since it tends to have a more profound and drastic effect on the gene pool, since the bottleneck effect wipes out much of a population and the founders effect can drastically reduce the gene pool its allele frequency due to migrating populations not genetically reflecting the many alleles found in the initial population (both populations, initial and founded, are usually greatly impacted). The effect of genetic drift can be even more pronounced in small populations, causing some to become extinct. Mutations occur all the time and are often quite small or random. Since they tend to only occur in one individual, they don't suddenly change the entire gene pool. Obviously, natural selection will alter the allele frequencies in response to a mutation and its possible advantages or disadvantages will alter the gene pool. However, you'd need a lot of mutations to have a sudden and drastic impact, and changes tend to occur gradually over time. Genetic drift is usually more sudden in its impact. The level of impact of mutations simply isn't the same as genetic drift tends to be. That said, I might be wrong, but that's sort of what I've been taught.
what's the relationship between the pathogen and antigen?
yr12student22 The antigen is a "body part" of the pathogen that your immune system recognises as foreign. Antigens can be proteins expressed by the pathogen, although there can be self-antigens produced by the body of someone affected by an autoimmune disease
what is the structure of monoclonal antibodies?
what's the relationship between innate and inflammatory response?
- Edited
do naive t cells or cytotoxic t cells undergo clonal expansion?
atarwonders they consist of one big polypeptide (heavy chain) and one small polypeptide (light chain). They also have specific variable regions, which are complementary to the antigen. (the same as a normal antibody)
6 days later
- Edited
atarwonders you only need to talk about whether the Indigenous populations were able to develop immunity as well as the British (hint: British developed immunity at a younger age and thus already had antibodies, and Indigenous Australians were exposed to it for the first time)
atarwonders Hi there! For this question the main point is about prior immunity so for 3 marks I’d say :—
- The British population had been frequently exposed to the small pox virus before, whereas indigenous Australians were exposed to the small pox virus for the first time upon European arrival
- Hence the indigenous Australians did not have any prior natural active immunity, and did not produce antibodies and memory cells against the small pox virus unlike the British
- This caused the indigenous Australians to be more likely to experience severe symptoms of the viral infection causing a much greater number of deaths and infection cases than the British population
(Make sure you use comparative statements here because it’s about the immunity of indigenous Australians VS the British population)
hope this helps!
chemistry1111 Naive T cells undergo clonal expansion and selection to form cytotoxic T cells or memory T cells
What is the underlying difference between a rule based approach and consequences based approach?
Example would really be nice
spicynuggets
Consequences-based approach = Aims to maximise the positive outcomes while minimising the negative outcomes.
- Suggests that individuals should be driven by consideration for the consequences that are likely to result.
- Often emphasises the surrounding circumstances of an action, and may sometimes allow an individual to break the rules in order to achieve the greatest good for the greatest number of stakeholders.
Duty/rule-based approach = Promotes the responsibility of the agent above all else, and places importance on the duty of each individual.
- Suggests that individuals should be driven by a fundamental duty to act in a certain way.
- Aim is to follow set rules and responsibilities, with less regard for the consequences that may result.
Is rational drug design in the new study design?
Could someone please explain the function of the PAM sequence?
biology nope. That was from the last study design, so you can ignore these questions!