Which of the following is an important factor in predicting the nuclear stability of an isotope?
- Atomic radius
- Nuclear radius
- The ratio of neutrons to protons
- The ratio of electrons to protons
Aussie Maths & Science Teachers: Save your time with SmarterEd
Which of the following is an important factor in predicting the nuclear stability of an isotope?
→ Nuclear stability refers to the stability of the nucleus within the atom.
→ As the nucleus is made up of protons and neutrons, it is the ratio of these particles which are an important factor in predicting nuclear stability.
What flame colour do copper ions produce when heated?
→ Copper ions produce a blue-green colour during a flame test.
A representation of the Periodic Table is shown. The positions of six different elements,
Which row of the following table shows the correct acid and base reactivities of the oxides of these elements?
→ Acidic Oxides: are often the oxides of non-metals and form acidic solutions
→ Basic Oxides: are usually formed by reacting oxygen with metals, they participate with acids in neutralisation rections
→ Neutral Oxides: react with neither acids or bases and do not lead to either acidic or basic solutions
→ Amphoteric Oxides: exhibit both acidic and basic properties, they can chemically react as either an acid or base
When placed in the Periodic Table, the recently discovered element 116 would be found in the same group as
→ Elements in the same column are in the same Periodic Table groups.
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i. → The position of centromeres.
→ The banding patterns present.
ii.
i. → The position of centromeres
→ The banding patterns present.
ii.
A virus was used to kill rabbits in Australia. After first release of the virus nearly all rabbits were killed, but over time the numbers recovered.
Outline how Darwin/Wallace's theory of evolution could be used to explain the recovery of rabbit numbers. (3 marks)
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→ Darwin/Wallace’s theory of evolution suggests variation in a population and the fittest survive to pass on their characteristics.
→ When the virus emerged, it killed most of the rabbits, however, some rabbits would be resistant and survive.
→ The survivors reproduced and passed this characteristic (resistance) on to their offspring and as the population increased, most rabbits were then resistant to the virus.
→ Darwin/Wallace’s theory of evolution suggests variation in a population and the fittest survive to pass on their characteristics.
→ When the virus emerged, it killed most of the rabbits, however, some rabbits would be resistant and survive.
→ The survivors reproduced and passed this characteristic (resistance) on to their offspring and as the population increased, most rabbits were then resistant to the virus.
Name an Australian ectotherm and describe its response to a decrease in ambient temperature. (2 marks)
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Answers can include:
→ The Eastern Brown Snake will bask in the sun when the ambient temperature falls.
→ Goannas can rapidly move their gular (throat) pouch which acts as a cooling mechanism.
Answers can include:
→ The Eastern Brown Snake will bask in the sun when the ambient temperature falls.
→ Goannas can rapidly move their gular (throat) pouch which acts as a cooling mechanism.
Data can be provided by a pulse oximeter pegged to a person's finger, as shown in the diagram.
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a. 97%
b. Answers could include:
→ Data requires context (eg. is the user exercising or resting).
→ There are many other parameters of physical health: disease status, blood levels of toxic environmental substances, presence of cancers etc…
→ There are other aspects of non-physical health (eg. mental health).
→ The pulse oximeter could read faulty i.e. if not properly calibrated, so comparing with results from another form of test such as a blood pressure monitor would give a better indication of cardiorespiratory health.
c. Answers could include:
→ The pulse oximeter can give you immediate and continuous data. This makes it better than arterial blood gas determination from a blood sample that requires the sample to be analysed in a laboratory with a delayed and one-off reading.
→ The pulse oximeter is very portable being compact and battery operated.
→ The pulse oximeter is better for an ambulance where fast and continuous data delivery in an emergency setting is required.
a. 97%
b. Answers could include:
→ Data requires context (eg. is the user exercising or resting).
→ There are many other parameters of physical health: disease status, blood levels of toxic environmental substances, presence of cancers etc…
→ There are other aspects of non-physical health (eg. mental health).
→ The pulse oximeter could read faulty i.e. if not properly calibrated, so comparing with results from another form of test such as a blood pressure monitor would give a better indication of cardiorespiratory health.
c. Answers could include:
→ The pulse oximeter can give you immediate and continuous data. This makes it better than arterial blood gas determination from a blood sample that requires the sample to be analysed in a laboratory with a delayed and one-off reading.
→ The pulse oximeter is very portable being compact and battery operated.
→ The pulse oximeter is better for an ambulance where fast and continuous data delivery in an emergency setting is required.
The diagram shows a vascular bundle from a flowering plant.
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a.
b. → Leaves wilt when they lose water.
→ As xylem tissue is responsible for water transport from roots to leaves, plants with the adaptation will wilt easier as the xylem vessels are more likely to collapse with thinner walls.
a.
b. → Leaves wilt when they lose water.
→ As xylem tissue is responsible for water transport from roots to leaves, plants with the adaptation will wilt easier as the xylem vessels are more likely to collapse with thinner walls.
Give TWO potential benefits of artificial blood. (2 marks)
Answers can include:
→ It does not need to be refrigerated.
→ It does not require blood-type matching.
→ Can be a valid substitute for certain ethnic/cultural groups which have concerns surrounding blood products.
→ Does not require a donor.
Answers can include:
→ It does not need to be refrigerated.
→ It does not require blood-type matching.
→ Can be a valid substitute for certain ethnic/cultural groups which have concerns surrounding blood products.
→ Does not require a donor.
Potassium chloride readily dissolves in water. With the use of a labelled diagram, describe the changes in bonding and entropy that occurs during this process. (4 marks)
→ Potassium chloride has a high tendency to dissociate into
→ Water is a dipolar molecule because each atom has a partial charge, as shown in the diagram.
→ The oxygen dipole in water has a partial negative charge and is attracted to the potassium ion. The hydrogen dipoles have a partial negative charge and are attracted to the chloride ion.
→ This attraction breaks the ionic bonds and forms ion-dipole bonds.
→ The entropy of the system is increased as the ionic bonds of the
→ Potassium chloride has a high tendency to dissociate into
→ Water is a dipolar molecule because each atom has a partial charge, as shown in the diagram.
→ The oxygen dipole in water has a partial negative charge and is attracted to the potassium ion. The hydrogen dipoles have a partial negative charge and are attracted to the chloride ion.
→ This attraction breaks the ionic bonds and forms ion-dipole bonds.
→ The entropy of the system is increased as the ionic bonds of the
The structure of an organic compound is shown.
Which row of the table correctly shows how this compound reacts with bromine water and with blue litmus?
→ Organic compound is sorbic acid.
→ Bromine water changes from a bright yellow to a colourless solution when it reacts with sorbic acid.
→ The acidic nature of the organic compound will turn blue litmus red.
Hydrogen gas reacts with iodine gas to form hydrogen iodide according to the following equation.
At equilibrium, the concentrations for
What is the value of the equilibrium constant for this reaction? (2 marks)
53.7
Consider the following reaction.
What is the equilibrium expression for this reaction?
→ All elements in the reaction are included in the
Three gases
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a. At time
→ The concentration of all species decreases by an amount proportional to their initial concentration.
→ This could be due to an increase in the volume of the container.
b. Chemical reaction:
→ After the system change, equilibrium re-establishes by favouring the conversion of
→ As change in concentration of all species is equal, they react in a 1:1:1 molar ratio.
→ Therefore the chemical reaction is:
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a. Methodology:
STEP 1: Reflux equipment using a hot plate heating source.
STEP 2: Pour 10 mL of ethanol into a round bottom flask. Add 20 mL of glacial (water-free) acetic acid.
STEP 3: Add 1 mL of concentrated
STEP 4: Allow the solution to cool. The contents should then be transferred to a separating funnel.
STEP 5: Distilled water should be used to wash the contents which will remove excess alcohol and acetic acid. The ester layer has a density less than 1 g/mL and will therefore form a layer above the aqueous solution.
STEP 5: Remove the aqueous solution using the separating funnel.
STEP 6: By adding a solution of 1 mol L ¯1
b. → Ethanol presents a danger due to its combustibility.
→ A safety precaution that reduces the fire threat is through the use of a hot plate for heating rather than a naked flame.
a. Methodology:
STEP 1: Reflux equipment using a hot plate heating source.
STEP 2: Pour 10 mL of ethanol into a round bottom flask. Add 20 mL of glacial (water-free) acetic acid.
STEP 3: Add 1 mL of concentrated
STEP 4: Allow the solution to cool. The contents should then be transferred to a separating funnel.
STEP 5: Distilled water should be used to wash the contents which will remove excess alcohol and acetic acid. The ester layer has a density less than 1 g/mL and will therefore form a layer above the aqueous solution.
STEP 5: Remove the aqueous solution using the separating funnel.
STEP 6: By adding a solution of 1 mol L ¯1
b. → Ethanol presents a danger due to its combustibility.
→ A safety precaution that reduces the fire threat is through the use of a hot plate for heating rather than a naked flame.
Explain how infrared spectroscopy is used in the analysis and identification of organic substances. (3 marks)
→ When analysing organic substances, IR radiation of specific wavelengths will be absorbed by certain atoms of the organic molecules. The absorption is dependent on the length of the compound’s atomic bonds.
→ By utilising the complete IR spectrum, the particular bonds in a molecule can be identified. The degree of the absorption can be used to calculate the relative number of each specific bond.
→ The resulting absorption data can be used to create an absorption spectrum of the organic material. This spectrum can then be compared to published data and used to identify the organic material.
→ When analysing organic substances, IR radiation of specific wavelengths will be absorbed by certain atoms of the organic molecules. The absorption is dependent on the length of the compound’s atomic bonds.
→ By utilising the complete IR spectrum, the particular bonds in a molecule can be identified. The degree of the absorption can be used to calculate the relative number of each specific bond.
→ The resulting absorption data can be used to create an absorption spectrum of the organic material. This spectrum can then be compared to published data and used to identify the organic material.
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a. →
→ It bends the charged particles that are accelerated through an electric field and directed through it.
→ The amount of bending can then be used to distinguish between and identify the particles/ions.
b. Advantages of mass spectrometry
→ The mass spectrometer can identify the mass/charge ratio of ions that pass through it. This data can then be used to identify components of a mixture or components in a compound.
→ Different isotopes of elements in a compound can be identified by mass spectrometers. This allows the compound to be matched to a sample.
→ Mass spectrometry can provide both qualitative and quantitative data on a compound.
→ Finally, mass spectrometers only require a small quantity of a compound to perform detailed analysis, as well as being fast and sensitive.
a. →
→ It bends the charged particles that are accelerated through an electric field and directed through it.
→ The amount of bending can then be used to distinguish between and identify the particles/ions.
b. Advantages of mass spectrometry
→ The mass spectrometer can identify the mass/charge ratio of ions that pass through it. This data can then be used to identify components of a mixture or components in a compound.
→ Different isotopes of elements in a compound can be identified by mass spectrometers. This allows the compound to be matched to a sample.
→ Mass spectrometry can provide both qualitative and quantitative data on a compound.
→ Mass spectrometers only require a small quantity of a compound to perform detailed analysis, as well as being fast and sensitive.
The diagram shows the deflection paths of different ions through a mass spectrometer.
Account for the different deflection paths. (3 marks)
→ Mass spectrometers use an electric field to accelerate positively charged ions before passing them through a magnetic field.
→ Once in the magnetic field, the ions travel in a curved path, the direction of which depends on whether the ion is positively or negatively charged.
→ The amount of curvature is dependent on the speed at which the ion is travelling and its mass to charge ratio.
→ Lighter ions have less momentum and are deflected more strongly than heavier ions.
→ Mass spectrometers use an electric field to accelerate positively charged ions before passing them through a magnetic field.
→ Once in the magnetic field, the ions travel in a curved path, the direction of which depends on whether the ion is positively or negatively charged.
→ The amount of curvature is dependent on the speed at which the ion is travelling and its mass to charge ratio.
→ Lighter ions have less momentum and are deflected more strongly than heavier ions.
Particle reacts with particle
to form the molecule
. The system comes to an equilibrium.
The diagram shows the initial reactants.
Which combination of diagrams best represents the molecule in a dynamic equilibrium and a static equilibrium?
→ In dynamic state, some particles have not yet combined to form a molecule.
→ In static state, all particles that could react have formed molecules.
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a. Procedure steps:
→ Secure the smartphone so it can rotate at a measured and fixed distance from the computer screen.
→ Set the computer to emit a constant intensity of light.
→ Find the position of the smartphone at which light of maximum intensity is obtained. Set this position to be 0° and record the intensity.
→ Rotate the smartphone through 360° and record the intensity at regular intervals of 10°.
→ Plot obtained results on a graph.
b. → Malus’ Law gives the equation
→ The graph shape that is produced by the experimental data is consistent with the equation.
→ The experiment uses a sufficient range of data to show a relationship and uses a sufficient number of data points.
→ However, the equipment used must have been incorrectly calibrated, or the measurements were not taken correctly. Measurements appear to be offset by 30° as the maximum intensity of light should occur at 0° rather than 30°.
a. Procedure steps:
→ Secure the smartphone so it can rotate at a measured and fixed distance from the computer screen.
→ Set the computer to emit a constant intensity of light.
→ Find the position of the smartphone at which light of maximum intensity is obtained. Set this position to be 0° and record the intensity.
→ Rotate the smartphone through 360° and record the intensity at regular intervals of 10°.
→ Plot obtained results on a graph.
b. → Malus’ Law gives the equation
→ The graph shape that is produced by the experimental data is consistent with the equation.
→ The experiment uses a sufficient range of data to show a relationship and uses a sufficient number of data points.
→ However, the equipment used must have been incorrectly calibrated, or the measurements were not taken correctly. Measurements appear to be offset by 30° as the maximum intensity of light should occur at 0° rather than 30°.
A spaceship sitting on its launch pad is measured to have a length
Which observations of the length of the spaceship are correct?
→ An observer in the frame of reference of the spaceship will measure the proper length of the spaceship.
→ An observer on the planet will observe relativistic length contraction and will observe the length to be shorter than
In which of the following areas of physics did James Clerk Maxwell NOT contribute to our understanding?
→ Maxwell’s contributions to our understanding of electromagnetism were only theoretical.
→ Maxwell used equations to predict the existence and properties of electromagnetic waves, however, never experimentally validated their existence.
A current of 4.0 A flows in a wire that is placed in a magnetic field of 0.75 T. The wire is 0.80 m long and is at an angle of 45° to the field.
Calculate the force on the wire. (2 marks)
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Negatively charged particles were accelerated from rest between a pair of parallel metal plates. The potential difference between the plates was varied, and the final velocity of the particles was measured for each variation.
The data in the table show the potential difference between the plates and the square of the corresponding final velocity of the particles.
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a.
b. → The gradient of the line =
→ Calculate the gradient using two points on the line of best fit (choose values close to limits):
→ The change in kinetic energy is equal to the work done by the electric field on the charged particles:
→ Calculate the charge to mass ratio of the particles:
→ Calculate the charge to mass ratio of an electron:
→ Therefore, the charged particles are not electrons.
a.
b. → The gradient of the line =
→ Calculate the gradient using two points on the line of best fit (choose values close to limits):
→ The change in kinetic energy is equal to the work done by the electric field on the charged particles:
→ Calculate the charge to mass ratio of the particles:
→ Calculate the charge to mass ratio of an electron:
→ Therefore, the charged particles are not electrons.
An 'electron gun' like that used by JJ Thomson is shown.
Electrons leave the cathode and are accelerated towards the anode.
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a. The force on the electrons is given by
The electric field strength is given by
Calculate the acceleration:
b. Using kinematic equations:
What is the role of a transformer at a power station?
→ At a power station, heating is reduced to decrease power loss.
→ This is done by stepping up the voltage, which decreases transmission current and lowers heating loss consistent with
A student performed an experiment using two identical, current-carrying metal rods connected to a power supply. Rod
What is the dependent variable in this experiment?
→ The dependent variable is the variable which is being measured.
→ In this experiment, the mass recorded on the balance is measured.
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a. Polycystic kidney disease
→ A disease in which cysts grow in the kidney.
→ This interferes with filtration and overtime, adversely affects the overall function of the kidney.
Other disorders/disease can include
→ Astigmatism, myopia or hyperopia.
→ Single sided deafness, hearing loss.
b. Use of technology in treating polycystic kidney disease
→ Polycystic kidney disease will often progress in patients until kidney failure has occurred.
→ When 80% of kidney function is lost and a transplant cannot be found, dialysis is often the only viable option.
→ There are two types of dialysis, both of which replace the function of the kidney and clean the blood.
→ Both forms of dialysis are extremely effective in replacing kidney function. Despite being time consuming and uncomfortable, they allow patients suffering from polycystic kidney disease to survive for extended periods, during which a transplant may become available.
Other technologies can include
→ Glasses.
→ Any form of hearing aid dependent on the ear disease/disorder, including standard hearing aids, bone conduction implants or cochlear implant.
a. Polycystic kidney disease
→ A disease in which cysts grow in the kidney.
→ This interferes with filtration and overtime, adversely affects the overall function of the kidney.
Other disorders/disease can include
→ Astigmatism, myopia or hyperopia.
→ Single sided deafness, hearing loss.
b. Use of technology in treating polycystic kidney disease
→ Polycystic kidney disease will often progress in patients until kidney failure has occurred.
→ When 80% of kidney function is lost and a transplant cannot be found, dialysis is often the only viable option.
→ There are two types of dialysis, both of which replace the function of the kidney and clean the blood.
→ Both forms of dialysis are extremely effective in replacing kidney function. Despite being time consuming and uncomfortable, they allow patients suffering from polycystic kidney disease to survive for extended periods, during which a transplant may become available.
Other technologies can include
→ Glasses.
→ Any form of hearing aid dependent on the ear disease/disorder, including standard hearing aids, bone conduction implants or cochlear implant.
The diagram shows the immune response after primary exposure to a pathogen.
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a. & b.
a. & b.
Which of the following is an example of an educational program to reduce the incidence of skin cancer?
By Elimination
→ Options C and D primarily increase the chances of diagnosing skin cancer rather than constituting an educational program.
→ Making sunscreen freely available will reduce the risk of skin cancer but is not an educational campaign.
→ The advertising campaign promotes safe lifestyle decisions surrounding sun safety (e.g. the benefits of using sunscreen, wearing a hat) that will reduce the likelihood of individuals getting skin cancer when following the advice.
An investigation was undertaken to examine the cause of lactose intolerance, a non-infectious condition found in some humans who cannot digest milk. The investigation found variation in the occurrence of lactose intolerance in human populations from different parts of the world.
What is this investigation an example of?
→ An epidemiological study is one which studies diseases which affect many people by gathering and analysing a large collection of data related to incidence and mortality, while comparing it to varying factors, such as location and age.
What is the main focus of the study of epidemiology?
→ The nature of an epidemiological study reveals evidence for factors involved in disease incidence and mortality.
The diagram shows a homeostatic mechanism in a mammal.
Which row of the table describes what happens to the muscles and the arteriole walls in the skin when the core body temperature is below normal?
→ When the body is cold, it contracts to raise epidermal hairs (also known as goosebumps) which generates heat, closes skin pores and traps a layer of heat close to the skin.
→ The contraction of arteries (also known as vasoconstriction) helps conserve heat by minimising heat loss from the skin.
A practical investigation is to be carried out to test for the microbes found in food.
Complete the table to show how to minimise risks that are likely to arise in carrying out this investigation. (3 marks)
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The runny nose and coughing that is symptomatic of having a cold is an example of the body's response to a pathogen.
How does this response protect the body?
→ These symptoms are the body’s response to many illnesses and are methods to remove the virus from airways.
The flow chart illustrates the effect of a point mutation on an organism.
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a. → Stage 2: A mutagen causes a point mutation in the DNA.
→ Stage 3: The mutated DNA transcription into mRNA.
→ Stage 4: The translation of the mRNA into a polypeptide chain which is not functional due to the mutation.
b. Possible causes of Stage 2 observed changes:
→ High frequency photons including gamma and X-rays are regarded as ionising radiation due to their extremely high energy.
→ They can interfere with DNA undergoing replication causing misalignment and a possible substation change.
→ High energy gamma radiation may also cause mutation when directly striking a nitrogenous base.
Answers could also include
→ Chemical mutagens (alkylating, delaminating and structurally similar chemicals).
→ Carcinogenic metals/elements (radon, cadmium)
c. Effects of Stage 4 mutation
→ When considering the above sequence as 2 codons, the chart shows us that this mutation results in an arginine amino becoming a stop codon.
→ This mutation will hence cause a premature termination of the polypeptide and result in a non-functional polypeptide/protein it forms a part of.
→ Due to the severity of this type of mutation it usually results in extensive health complications for affected individuals.
a. → Stage 2: A mutagen causes a point mutation in the DNA.
→ Stage 3: The mutated DNA transcription into mRNA.
→ Stage 4: The translation of the mRNA into a polypeptide chain which is not functional due to the mutation.
b. Possible causes of Stage 2 observed changes:
→ High frequency photons including gamma and X-rays are regarded as ionising radiation due to their extremely high energy.
→ They can interfere with DNA undergoing replication causing misalignment and a possible substation change.
→ High energy gamma radiation may also cause mutation when directly striking a nitrogenous base.
Answers could also include
→ Chemical mutagens (alkylating, delaminating and structurally similar chemicals).
→ Carcinogenic metals/elements (radon, cadmium)
c. Effects of Stage 4 mutation
→ When considering the above sequence as 2 codons, the chart shows us that this mutation results in an arginine amino becoming a stop codon.
→ This mutation will hence cause a premature termination of the polypeptide and result in a non-functional polypeptide/protein it forms a part of.
→ Due to the severity of this type of mutation it usually results in extensive health complications for affected individuals.
A New Zealand research team inserted a single gene into an onion to reduce the activity of the enzyme that makes your eyes water, resulting in an onion that you can cut without crying.
Which term best describes this team's process?
→ Manually altering an organisms genome (such as in transgenic organisms) is referred to as genetic engineering.
A student was doing a literature review on biotechnology and wanted to see how biotechnology research could positively benefit people who suffered from Type 1 diabetes. He found several potential measures that were being explored to help people with diabetes.
Which of the following measures does NOT use biotechnology?
By Elimination
→ Gene therapy, auto monitoring insulin and screening and all examples of biotechnology. Option D is an epidemiological study (Eliminate A, B and C).
A non-infectious disease was observed in a mother and her four sons who live with her. She has no daughters. The father of these children does not have the disease and does not live with them. The woman's parents and her two sisters who live overseas do not have the disease.
A geneticist suspects that the disease is inherited.
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a.
b. Evidence disease is recessive and not sex-linked:
→ Generation 1 parents do not have the disease but it is present in their daughter, meaning it must be recessive.
→ If the disease was sex-linked, the same daughter who has the disease must have a father with the disease, however this is not the case.
a.
b. Evidence disease is recessive and not sex-linked:
→ Generation 1 parents do not have the disease but it is present in their daughter, meaning it must be recessive.
→ If the disease was sex-linked, the same daughter who has the disease must have a father with the disease, however this is not the case.
There are some significant differences in the form that DNA has in prokaryotic and eukaryotic cells.
In the space provided draw a labelled diagram demonstrating the difference in the form of DNA between prokaryotic and eukaryotic cells. (3 marks)
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Points to note on images:
→ Prokaryotic DNA is in the form of a loop
→ Eukaryotic DNA has two loose ends and is tightly coiled in the body
Students conducted preliminary experiments to analyse the DNA base composition of five different individuals.
The table shows the experimental data collected.
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a.
b. Relationship: As the % of Adenine increases, the % of Guanine decreases.
c. Adenine/Guanine relationship
→ Because Adenine pairs with Thymine and Cytosine pairs with Guanine occurring to DNA base pairing rules, each should directly correlate to each other and account for the same % within the DNA composition of any species.
→ There are the only 4 components that make up all DNA composition. This also means that when comparing % of bases that do not pair, such as Adenine and Guanine, they must combine to form 50% of all DNA. This is evident when looking at individuals A and B, as well as C, D and E which are only off by 1-2%, most likely due to human error.
→ This always explains the relationship where an increase in Adenine (and Thymine) % will result in a decrease in Guanine (and Cytosine) % as the A and T pairs now occupy more space in the genome.
a.
b. Relationship: As the % of Adenine increases, the % of Guanine decreases.
c. Adenine/Guanine relationship
→ Because Adenine pairs with Thymine and Cytosine pairs with Guanine occurring to DNA base pairing rules, each should directly correlate to each other and account for the same % within the DNA composition of any species.
→ There are the only 4 components that make up all DNA composition. This also means that when comparing % of bases that do not pair, such as Adenine and Guanine, they must combine to form 50% of all DNA. This is evident when looking at individuals A and B, as well as C, D and E which are only off by 1-2%, most likely due to human error.
→ This always explains the relationship where an increase in Adenine (and Thymine) % will result in a decrease in Guanine (and Cytosine) % as the A and T pairs now occupy more space in the genome.
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a.
b. The role and changes in levels of hormones in pregnancy.
→ Progesterone is a sex hormone which is initially secreted by the corpus leuteum after ovulation to thicken the endometrium for implantation.
→ Once the placenta has developed, it then increases the progesterone levels which maintain the pregnancy.
→ Progesterone levels eventually drop in the last stage of pregnancy to facilitate delivery.
Answers could also include information about other hormones including
→ Oestrogen
→ hCG
a.
b. The role and changes in levels of hormones in pregnancy.
→ Progesterone is a sex hormone which is initially secreted by the corpus leuteum after ovulation to thicken the endometrium for implantation.
→ Once the placenta has developed, it then increases the progesterone levels which maintain the pregnancy.
→ Progesterone levels eventually drop in the last stage of pregnancy to facilitate delivery.
Answers could also include information about other hormones including
→ Oestrogen
→ hCG
A student completed a genetics exercise by preparing a Punnett square.
What were the likely genotypes of these parents?
→ Genotype ratio
A student constructed a model of meiosis as shown. However, there is an error in the model.
Which aspect of this model does NOT fit with observations of meiosis?
→ Stage 4 and 5 have to switch to fix the error. All other aspects are correct.
Einstein's equation
Justify this statement. (7 marks)
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Its importance is due to its critical role in explaining and analysing a broad range of ideas, processes and phenomena. These include:
→ The energy sourced from the processes of nuclear fission and fusion, including the energy associated with radioactive decay.
→ The relationship between the binding energy of atoms and their mass defect.
→ Mass dilation of objects approaching the speed of light.
→ The fundamental principles and technology upon which nuclear bombs and nuclear reactors operate.
→ Processes which source energy in stars through the conversion of mass into energy.
→ Processes which allow for particle accelerators to operate, allowing us to investigate into the fundamental structure and properties of matter.
Other equations, such as Newton’s Universal Law of Gravity, do not have the same myriad of applications in fields that make up our current understanding of physics.
It is therefore justified in being called one of the most important equations in the history of physics
Its importance is due to its critical role in explaining and analysing a broad range of ideas, processes and phenomena. These include:
→ The energy sourced from the processes of nuclear fission and fusion, including the energy associated with radioactive decay.
→ The relationship between the binding energy of atoms and their mass defect.
→ Mass dilation of objects approaching the speed of light.
→ The fundamental principles and technology upon which nuclear bombs and nuclear reactors operate.
→ Processes which source energy in stars through the conversion of mass into energy.
→ Processes which allow for particle accelerators to operate, allowing us to investigate into the fundamental structure and properties of matter.
Other equations, such as Newton’s Universal Law of Gravity, do not have the same myriad of applications in fields that make up our current understanding of physics.
It is therefore justified in being called one of the most important equations in the history of physics
A 5-gram sample of radioactive strontium-90 decayed over time. The graph shows the mass of strontium-90 remaining from the initial sample as a function of time.
What is the approximate value of the decay constant, in
→ From the graph, the half life (mass = 2.5 g) is approximately 29 years.
Which of the following is true in relation to Millikan's oil drop experiment?
→ Millikan’s experiment involved levitating oil drops in an electric field in order to measure the charge on an electron.
After DC voltage was applied to an apparatus containing hydrogen gas, the hydrogen separated into streams of oppositely charged particles.
What could be concluded from this observation?
→ The separation shows that hydrogen atoms contain both positive (protons) and negative (electrons) components.
A Hertzsprung-Russell diagram is shown.
In which region would a star have the same surface temperature as a star on the main sequence?
→ Using the
A torque is applied to a nut, using a wrench.
Which change will increase the magnitude of applied torque?
→
→ Increasing the distance (
A sequence is given by the recursive formula
Using mathematical induction to show the formula for the general term of the sequence is
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Solve
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A researcher estimates the number of brumbies in a National Park after
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ii.
iii.
iv.
The population of Myna birds in a national park is decreasing at a rate proportional to the population at that time.
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ii. | ||
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ii.
iii.
Use vector methods to find the coordinates of the point that divides the interval joining the points
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Two planes are flying in directions given by the vectors
A person in the flight control centre is plotting their paths on a map.
Calculate the acute angle between their projected flight paths, giving your answer correct to one decimal place. (2 marks)
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A parallelogram is formed by joining the points
Use vector methods to find
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