exam qs Flashcards
how do ancient cave drawings provide evidence of cultural evolution
VCAA 2021 Q8a
- cave drawings show passing of information through generations
- cave drawings become more complex over time
- cave drawings show evidence of change in cultural practices
- evidence of complex thought OR evidence of symbolic representations.
what ethical response would be expected from the researchers if they discovered that recombinant human insulin was significantly more effective than insulin from cows or pigs?
VCAA 2021 Q10d
- Researchers should stop the clinical trial and people who are being given the animal insulin should be offered the more effective recombinant version of the insulin.
- Stop production of insulin from animals to protect their welfare.
- Release information to public to increase informed decision.
give one example of a type of protein within a yeast cell that may change in concentration and explain why this change is necessary
VCAA 2021 Q2a
Enzyme: If there is a change in substrate concentration, then more or less enzyme may be produced to conserve ATP
OR
Structural protein: repair or synthesis of organelles if organelles are damaged due to increased or decreased temperature
OR
Regulatory/repressor protein: more or less repressor protein is required to inhibit or promote a reaction when there is a change in substrate availability
OR
Transcription factors: more or less is required for transcription if environmental conditions result in increased or decreased need for protein synthesis.
summarise the immune response that occurs resulting in long term protection from chickenpox from vaccination
VCAA 2021 Q4a
- the vaccine is taken up by APCS and the antigen presented on the surface of the cell.
- The antigen presenting cell moves into the lymphatic system and is taken to the lymph node.
- Helper T cell stimulates naïve B cells.
- Each B cell divides to produce plasma cells, which produce specific antibodies.
- B memory and or T memory cells are produced for long-term immunity
what is the benefit of having two doses instead of one dose?
VCAA 2021 Q4b
- The first dose leads to the activation of B cells and development of a small number of memory cells.
- The second dose increases the number of memory cells for a much faster response to subsequent infection and greater antibody production.
describe the process that led to the formation of two distinct species of octopus from the distant common ancestor
VCAA 2021 Q6a
- The two groups are geographically isolated and as a consequence there is no gene flow.
- There would be different selecting pressures or environmental factors acting upon each population.
- The result of different mutations in each population and their accumulation over many generations is that they would be regarded as two different species.
reasons that may account for the lack of genetic diversity between populations
VCAA 2021 Q6b
- The populations share a relatively recent common ancestor and interbreeding can still occur between the two populations.
- There may also be similar selection pressures in the two different regions.
what is meant by recombinant DNA in the context of making recombinant human insulin
VCAA 2021 Q10a
human DNA is incorporated with bacterial DNA
the steps required for human insulin gene to be cloned and expressed in bacteria
VCAA 2021 Q4c
- Isolate human insulin gene from human or artificially synthesise human insulin gene from known sequence.
- Insulin gene inserted into plasmid using restriction enzymes to cut and ligases to join to form recombinant plasmid, which are then placed back into bacteria.
- These bacteria are then grown in culture.
How an effective vaccine can provide long-term immunity to EVD
VCAA 2015 Q4a
- vaccine contains antigens of EVD
- B cell that is activated and produces antibodies specific to EVD
- memory B cells are created
- remain i the lymphatic system to initiate a stronger and more rapid response upon reinfection
how does the production of distinct proteins in different cell types occur?
VCAA 2015 Q7c
- factors expressed by regulator genes could lead to production of the different proteins
- specifically refer to the factors that regulate gene expression
2 pieces of evidence that indicate cultural evolution within species
VCAA 2016 Q10d
Q10d: 2 pieces of evidence that indicate cultural evolution within species
- stone tools
- position of bodies to indicate burial
- fashioned bone objects
what evidence at a cellular level would confirm the processes above were successful
VCAA 2016 Q11bi
- protein is correctly produced and is functional
how does the lymphatic system streamnline the recognition of viral antigens
ACED 2022 TRIAL 2
The lymphatic system will move antigen-presenting cells from sites of
infection/entry to the lymph nodes for recognition by lymphocytes (by
both B and T cells).
measures to control and or screen disease transmission
ACED 2022 TRIAL 2
- Handwashing.
- Using sanitisers/antiseptics/disinfectants.
- Lockdowns to prevent movement.
- Quarantine to prevent transmission.
- Screening a population with routine testing.
- Screening medication sales to see trends in symptoms among
populations. - Identifying the pathogen and method of spread.
- Mask-wearing and social distancing (if the disease spread is airborne).
- Targeting and treating the cause of disease with medicine
vaccination
herd immunity
why is biofuel more environmentally friendly than fossil fuels
ACED 2022 TRIAL 2
- Biofuels are renewable, whereas fossil fuels are not renewable.
- Biofuels are (theoretically) carbon-neutral, whereas fossil fuels are not carbon-neutral.
- Biofuels recycle waste from industries such as crops, farming and forestry; fossil fuels are derived from raw materials.
why First Nations people were severely impacted by european diseases
ACED 2022 TRIAL 2
- The First Nations people would not have had natural active immunity to
the diseases. - Changing and forced living conditions led to a lack of access to clean
water. - The overall impact of colonisation on health and wellbeing would have
made the populations more vulnerable to disease. - Their medicine was not developed to deal with European diseases.
- At the time, the high population densities of First Nations peoples (in
forced camps) allowed the rapid spread of the diseases.
why does temperatuere need to be controlled in photosynthesis experiment
A+ 2022 Q3a
- photosynthesis is catalysed by enzymes which produce the highest rate of photosynthesis at its optimal temperature
- temperature hgiher than its optimal causes the enzymes to denature, changing its shape
would green wavelengths enable the greatest rate of photosynthesis
A+ 2022 Q3b
- chlorophyll reflects green light an dhence appears green
- red and blue wavelengths are absorbed at a greater rate for photosynthesis
what is meant by a repressible system
refers to the system always being functional until protein isn’t required
how can a single nucleotide change in the HBB gene alter the structure of the haemoglobin molecule in people with SCD
NHT 2017 Q1b
- changing primary structure (or a description of this)
- affects folding/secondary/tertiary structure (shape) of molecule or the quaternary structure
may be affected as haemoglobin is made up of more than one sub-unit.
why is the rate of reaction higher in location B than A of the chloroplast
NHT 2017 Q5biii
- this may be explained by B having more chlorophyll to trap light
- this may be explained by region B membranes containing a higher concentration of
enzymes, which would lead to a greater rate of reaction.
would the gene pool have been altered (the allele frequency has changed)
NHT 2017 Q9b
The gene pool of the population has not been changed.
Both alleles are still present; the gene pool would only change if a new allele appeared or one
allele disappeared.
what other evidence other than DNA sequences and protein structures could be used to classify different species
NHT 2017 Q10a
- The individuals within a species would be able to breed with each other and produce fertile
offspring. - Anatomical features and the individuals within a species would have more characteristics in
common with each other than with those of a different species.
describe at a molecular level how antibodies perform their function
VCAA 2017 Q4b
Antibodies have shape specific to the antigen, for example, so that macrophages/other immune
cells can engulf/destroy it.
what opccurs within cells of the leaves that result in the formation of the bubbles in elodea aquarium
NHT 2018 Q1a
Chlorophyll absorbs light energy, water is split to form hydrogen ions or oxygen gas, and oxygen
will diffuse out through the plasma membrane.
explain difference in photosynthesis in low light intensity compared to high light intensity
NHT 2018 Q1bii
At low light intensities the amount of ATP and NADPH produced is smaller OR there is less
energy to produce H
+
as fewer chlorophyll molecules are excited.
In the carbon fixation/light-independent stage, less glucose is produced at lower light
intensities.
production of pre-mRNA
NHT 2018 Q3a
- RNA polymerase attaches to the promoter region.
- DNA helix unwinds and one side is used as a template strand.
- RNA polymerase reads the template strand.
- RNA polymerase joins nucleotides that are complementary to the template DNA strand.
how does constant inflammation affect HIV patients
NHT 2018 Q5bii
would cause persistent pain, redness and heat, and wastes energy needed to fight HIV
infection
brings more lymphocytes and phagocytes to the inflamed area, preventing them from being
used to fight infection elsewhere.
factors that affect the migration of DNA fragments through agarose gel during gel electrophoresis
VCAA 2019 Q8c
- the size of the molecules, as the larger molecule will move more slowly
- the charge of the molecule, as the negative charge means that DNA moves towards the
positive electrode - the length of time the voltage is applied, as there may not be enough time for the DNA to
migrate through the gel - the concentration of the agarose, as denser agarose results in the molecules moving more
slowly.
why was the antibody test unable to identify the difference between antibodies produced against Zika Virus and antibodies produced against other viruses
VCAA 2019 9C
The shape of the Zika and other viruses’ antigen is similar, enabling them both to bind on to the
same antibody.
The viruses bind to the antigen-binding site of the antibody.
why would scientists choose to sequence nuclear DNA over mtDNA
Mitochondrial DNA is only inherited from the mother (and would therefore provide very similar DNA
samples to other female ancestors); however, nuclear DNA contains the whole genome.
what is herd immunity and how does it help control the number of cases of a disease
Herd immunity is where most of the community is immune and this helps to protect, for example,
babies or those few individuals who cannot be vaccinated, or due to the reduced number of
infected individuals there are fewer hosts to pass the disease to others.
what are mass extinctions
VCAA 2017 Q33 MC
are caused by eg. catastrophic eents that caused changere enrionments which results in different selection pressures which favour different groups
two ways in which CRISPR Cas9 system is similar to the human immune system
INSIGHT 2022 Q9a
- The CRISPR-Cas9 system provides bacteria with an immunological memory of specific pathogens just as the human immune system has immunological memory due to having B memory cells.
- The CRISPR-Cas9 system responds to the presence of an antigen by secreting a protein that cuts the foreign DNA. The human immune system also responds to the presence of an antigen by secreting proteins - antibodies
what is an off-target modification
INSIGHT 2022 Q9c
occurs when Cas9 cuts at unintended locations in the genome.
why was the temp reduced to 55 degrees celsius for annealing
NHT 2017 Q7d
- the temperature was lowered to 55 °C so that the DNA primers can attach to the single stranded DNA molecules
- the temperature was raised to 72 °C as at this temperature the activity of the Taq polymerase enzyme is at its highest or optimum
- complementary nucleotides would bind to the single-stranded DNA.
has the gene pool been altered by the spraying of insecticide
NHT 2017 Q9b
- The gene pool of the population has not been changed.
- Both alleles are still present; the gene pool would only change if a new allele appeared or one allele disappeared.
it is an allele frequency change not gene pool change
ATP catabolism
KILBAHA 2022 Q15 (MC)
- the breakdown of ATP into ADP +Pi
how can regualtory genes play a role in the specialisation of immune cells
KILBAHA 2022 Q2d
- Regulatory genes may activate or deactivate more than 1 structural gene
- If different combinations of structural genes are activated by a regulatory gene, the structural proteins produced may change the type of cell that cell specialises into (B or T cells)
explanations that support the hypothesis
VCAA 2018 Q11f
There may be more living algal cells trapped in the red algal balls than the green algal balls,
giving an increase in photosynthesis.
The phenol red may affect the rate of photosynthesis in green algae more than in red algae.
There may be differences in the rate of cellular respiration between the two types of algae.
how can a scientist desgin primers for a target DNA sequence that allow amplification fo that DNA sequence and no other DNA sequences
- The scientist would need the nucleotide sequence on both strands of DNA either side of the target DNA sequence.
- The target DNA sequence is unique and can be determined.
- The scientist would make a complementary strand of nucleotides that can attach just before and just after the target DNA sequence.
- Primers can attach to the ends and provide a region for Taq polymerase to join.
how can factors affect the results seen on the gel
**Factor 1: incorrect temperatures. **
Explanation: primers may not have annealed if the temperature was incorrect or DNA polymerase may have been denatured if the temperature was too high.
Factor 2: timing of each stage.
Explanation: if the time was too short for annealing, the primers would not bind or if the denaturation time was too long, the DNA may degrade. If the extension time was too short, it would be insufficient time for complete DNA replication.
- An increase in temperature would lead to decreased activity of the enzyme
- and the eventual denaturation of enzymes
- substrates no longer able to fit or bind to the active site of the enzyme.
requirements or aspects of EXPERIMENTAL DESIGN that would need to be considered when planning the trial of drug molecule
NHT 2022 Q3c
- Use a large number of HIV-positive participants.
- Have one group / experimental group given the molecule and one group given no molecule / placebo as a control group.
- Measure the effectiveness of the molecule by percentage change in T helper cell number pre- and post-trial.
- Have appropriate control variables (for example, same gender, same duration of treatment, same sample volume of thymus tested for T helper cell count).
- Repeat the trial to confirm reliability of results.
immune response after being infected after being vaccinated
NHT 2022 Q4d
- viral antigen identified as non-self
- B/T memory cells, previously produced, become active
- plasma cells produced
- antibodies rapidly produced or already present
- virus is neutralised or agglutinated and unable to infect cells.
how does plant immune defences differe from humans
STAV 2023 Q5b
- plants only have unnate responses while humans have innate and adaptive
- pants do not have memory cells where as humans do
how does trace fossils differe from traditional fossils
STAV 2023 7a
- they don’t leave any physical structure behind
how does bacteria with GFP plasmid inserted differ from production of insulin using bacteria
- insulin requires 2 plasmids and 2 bacteria
- insulin doesnt require any additional gene to be expressed
advantages of controlling flower production in tomato plants
VCAA SAMPLE 2022 Q2c
- higher yield of tomatoes for consumers
- increased profit for farmers
- fruit can be produced out of season
why were the Indigenous poplations affected to qa freater extent than the BRITISH population when exposed to smallpox
COMPARATIVE
A lack of immunity in the Indigenous population
* Smallpox was frequently contracted during childhood by the British, providing them with active natural
immunity.
* For Indigenous populations, however, many individuals encountered smallpox for the first time, and as a
consequence, experienced severe disease.
* The Indigenous Australian population had no such immunity for smallpox, meaning they were more likely
to contract and experience severe symptoms.
number of anitbody graph reasoning
- The second dose introduces the measles antigen to an already established amount of memory B cells
from the first vaccine - This creates a faster and more vigorous production of antibodies and leaves more memory B cells behind
than the first dose
why is antigenic shift more of a concern for scientists
- This generates a new human virus (H3N2) which has not been exposed to the human population before,
hence, no prior immunity (1 mark) - Scientists would need time to produce a new vaccine for the new strain (1 mark)
why si the fetus in a second pregnancy at far greater risk of HDN than the first rhesus positive fetus
- B memory cells produced during first pregnancy
- enables a larger and more rqapid response during second pregnancy
what creates the difference in variable region for an antibody
- antigenic variation
- shuffling of nucelotides that code for the varaible region creates diff combinations
- these combinationd code for varying protein structures
what is the likely impact of a nonsense mutation in the regulatory region of the trp operon
- it will cause a stop codon to form
- results in a shortened non-functional protein
- repressor cannot bind to the operator
- trp is contrinuously made (repression can’t occur)
function of ducts leading to lymph nodes and leading from lymph nodes
LEADING TO
* They carry APCs that display antigens on the MHC II molecules.
* They carry free-floating antigens.
LEADING AWAY
* They carry specific cytotoxic T cells.
* They carry specific helper T cells.
* They carry specific antibodies.
describe two evidence that would need to present in a 25 million year old fossil to support the evolution of Equus from Hyracotherium
The length of the middle bone would need to be between that of Mesohippus and Merychippus.
* The width of the middle bone would need to be between that of Mesohippus and Merychippus.
* The size of the hoof would need to be bigger than that of Mesohippus but smaller than
Merychippus.
describe the evidence of interbreeding between H.Erectus + Denisovans in the modern Southeast Aisan genome
Since the Denisovan genome has been sequenced, some Denisovan DNA should be present
in some Southeast Asian genomes. 1 mark
Since the Homo erectus genome has not been sequenced, genome material of unknown
origin should be present in some Southeast Asian genomes. These unknown segments
could come from Homo erectus.
why are vaccinations recommended yearly for influenza rather than once every few years
- Vaccines contain new antigens resulting in the production of new antibodies OR memory cells specific to the antigen
- Memory cells allow for a faster OR larger immune response
- Any existing memory cells specific to the previous antigens would no longer be effective.
why do most vaccinated individuals, if they are infected show a mild case of the disease
- virus enters and is detected
- memory cells present
- rapid antibody production / Antibodies are produced in large numbers
- virus is neutralised
how can infection cause significant impact on Aboriginal Australian population
- Childhood immunity existed in colonists due to previous exposure prior to arrival in Australia.
- No immunity existed for the Aboriginal Australian population due to no previous exposure.
- Aboriginal children became mildly ill when exposed and became immune; this led to the increase of population numbers over 30 years, from 1790–1810.
limitations to interbreeding evidence base on location
- specific locations are not given so geographic overlapping may not have occurred over migration paths
- molecular evidence not available or considered and fossil finds of humans are very scarce or incomplete.
how boosters work and why are they necessary
2013 VCAA Q4c
- to produce more memory B cells
- memory cells are short lived
what rolse do autoantibodies play in causing the symptoms of an autoimmune disease
2013 VCAA
autoantibodies attack self cells and the destruction of this tissue leads to sumptoms of the disease
advantages of having memory cells from pevious vaccinations
2012 VCAA exam 1
- antibodies produced at a greater rate
- there would be an immediate response
- more antibodies would be produced
