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BIOLOGY, M7 2021 VCE 4c

Outline similarities and/or differences in active and passive ways of acquiring immunity.   (3 marks)

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→ Active immunity leads to the body producing its own antibodies and memory cells, resulting in long-lasting protection.

→ Passive immunity provides immediate protection by transferring pre-existing antibodies, but this protection is temporary and short-term.

→ Both active and passive immunity involve the presence of antibodies that can neutralize or eliminate the target pathogen.

→ The key difference is that active immunity develops the immune system’s own capacity to respond, while passive immunity borrows antibodies from an external source.

Show Worked Solution

→ Active immunity leads to the body producing its own antibodies and memory cells, resulting in long-lasting protection.

→ Passive immunity provides immediate protection by transferring pre-existing antibodies, but this protection is temporary and short-term.

→ Both active and passive immunity involve the presence of antibodies that can neutralize or eliminate the target pathogen.

→ The key difference is that active immunity develops the immune system’s own capacity to respond, while passive immunity borrows antibodies from an external source.

BIOLOGY, M7 2023 HSC 6 MC

Liver fluke is a disease caused by parasites that infect grazing animals, including sheep. The life cycle of the liver fluke is shown.
 

   

How could the transmission of this disease to humans be prevented?

  1. Eradicating the snails
  2. Administering antibiotics to sheep
  3. Wearing gloves when handling sheep
  4. Regularly spraying fields with herbicides
Show Answers Only

\(A\)

Show Worked Solution

→ Option \(A\) will serve as an effective option which will interrupt the lifecycle of liver fluke and hence prevent it’s transmission to humans.

\(\Rightarrow A\)

♦♦♦ Mean mark 26%.

BIOLOGY, M7 EQ-Bank 24

Scientific advances have resulted in new methods of managing plant diseases and insect pests.

Describe how TWO of these methods have changed the management of plant diseases and/or insect pests.   (5 marks)

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Transgenic Organisms

→ The development transgenic organisms has lead to the creation of GMO’s with ‘built-in’ pesticides. 

→ The modified plant contains a gene from another genus which allows it to be partially or fully resistant to a pest or disease.

→ For example, Bt Cotton is a type of transgenic cotton which has been modified with a gene which makes it almost immune to Bollworm, the number one burden of cotton plant death globally. This means that pesticides for Bollworm do not have to be used, saving time and expense.

Quarantine

→ The knowledge behind the transmission of specific disease has allowed societies to take adequate measures which will have the best chance for reducing the spread of said disease.

→ Quarantine is the process of isolating any imported crops for a certain amount of time dependent on the infection period of a given disease. This significantly reduces the chances of international diseases spreading into Australia.

Show Worked Solution

Transgenic Organisms

→ The development transgenic organisms has lead to the creation of GMO’s with ‘built-in’ pesticides. 

→ The modified plant contains a gene from another genus which allows it to be partially or fully resistant to a pest or disease.

→ For example, Bt Cotton is a type of transgenic cotton which has been modified with a gene which makes it almost immune to Bollworm, the number one burden of cotton plant death globally. This means that pesticides for Bollworm do not have to be used, saving time and expense.

Quarantine

→ The knowledge behind the transmission of specific disease has allowed societies to take adequate measures which will have the best chance for reducing the spread of said disease.

→ Quarantine is the process of isolating any imported crops for a certain amount of time dependent on the infection period of a given disease. This significantly reduces the chances of international diseases spreading into Australia.

BIOLOGY, M7 2014 HSC 22a

Explain how TWO specific personal hygiene practices reduce the risk of infection.   (4 marks)

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“

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Answers can include any TWO of the following:

→ Washing hands after handling garbage to remove any pathogens from the skin.

→ Covering your mouth when coughing to reduce the chance of pathogens spreading via water droplets.

→ Covering cuts and sores with bandaids or bandages to reduce the chance of infecting others through the transfer of blood and puss which, as well as covering up potential portals of entry for pathogens, will also protect the individual.

→ Daily showers with body wash and shampoo to remove pathogens from skin and scalp.

BIOLOGY, M7 2017 HSC 22b

Explain how TWO different methods used to treat drinking water reduce the risk of infection.   (4 marks)

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→ Filtration and chlorination are two effective methods that materially reduce the risk associated with drinking water contaminants.

→ Filtration removes pathogens which reduces the risk of infection by preventing them from passing through the filter.

→ Chlorine kills pathogens before the water reaches humans thereby reducing the risk  of disease and infection.

BIOLOGY, M8 2018 HSC 30

The graph shows the expected life span (the age to which people are expected to live in years) for people of different ages during the 20th century in one country.
 

There have been many biological developments that have contributed to our understanding of the identification, treatment and prevention of disease.

Evaluate the impact of these developments on the expected life span. In your answer, include reference to trends in the data provided.  (8 marks)

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→ For all ages listed in the graph, life expectancy increased during the 20th century.

→ The lifespan from birth has increased more significantly than other ages ~ 48 to 74 years.

→ The smallest increase being for 60 year olds at ~ 5 years.

→ The ability to understand pathogens and the causes of infectious disease (Koch and Pasteur) has led to early identification and treatment of childhood illnesses such as rubella, polio and whooping cough.

→ Koch and Pasteur established germ theory, culture techniques and a set of postulates to follow in order to create the link between a particular pathogen and disease.

→ Vaccines to combat childhood illnesses were developed through a knowledge of germ theory.

→ The infant/childhood mortality rate has improved significantly, and hence life expectancy, due to the immunity provided by vaccines.

→ An understanding of inherited disorders has also improved lifespans with early diagnosis and prenatal genetic screening for genetic disorders and illnesses.

→ Antibiotic remedies were developed to combat bacterial diseases such as Staphylococcus aureus, due to an understanding of the difference between prokaryotic and eukaryotic cells.

→ With the use of antibiotics many diseases were then no longer life threatening, leading to improved mortality rates across all ages.

→ However, bacterial resistance has resulted with the overuse of antibiotics, so some diseases are now unresponsive to antibiotic treatment.

→ Epidemiology studies involving intricate planning and design, control groups and large scale analysis of data have lead to improvements in the treatment of non-infectious diseases such as cancer.

→ For example the discovery of links between smoking and lung cancer, sun exposure and melanoma, obesity and type II diabetes, has lead to widespread public health campaigns to inform people of the health risks and lowered the associated mortality rates.

→ Improved hygiene, food storage and preservation, and water filtration also occurred in the 20th century leading to fewer preventable diseases and hence increased life spans for all age groups.

→ Improved quarantine requirements have helped prevent the spread of plant, animal and human diseases via international travel.

→In conclusion, developments in biology have lead to increased life expectancy across all age groups, with the biggest improvements for babies and children.

→ These benefits are not necessarily a worldwide phenomenon as poor living conditions and access to medical treatment is not available in many poor socioeconomic communities.

Show Worked Solution

→ For all ages listed in the graph, life expectancy increased during the 20th century.

→ The lifespan from birth has increased more significantly than other ages ~ 48 to 74 years.

→ The smallest increase being for 60 year olds at ~ 5 years.

→ The ability to understand pathogens and the causes of infectious disease (Koch and Pasteur) has led to early identification and treatment of childhood illnesses such as rubella, polio and whooping cough.

→ Koch and Pasteur established germ theory, culture techniques and a set of postulates to follow in order to create the link between a particular pathogen and disease.

→ Vaccines to combat childhood illnesses were developed through a knowledge of germ theory.

→ The infant/childhood mortality rate has improved significantly, and hence life expectancy, due to the immunity provided by vaccines.

→ An understanding of inherited disorders has also improved lifespans with early diagnosis and prenatal genetic screening for genetic disorders and illnesses.

→ Antibiotic remedies were developed to combat bacterial diseases such as Staphylococcus aureus, due to an understanding of the difference between prokaryotic and eukaryotic cells.

→ With the use of antibiotics many diseases were then no longer life threatening, leading to improved mortality rates across all ages.

→ However, bacterial resistance has resulted with the overuse of antibiotics, so some diseases are now unresponsive to antibiotic treatment.

→ Epidemiology studies involving intricate planning and design, control groups and large scale analysis of data have lead to improvements in the treatment of non-infectious diseases such as cancer.

→ For example the discovery of links between smoking and lung cancer, sun exposure and melanoma, obesity and type II diabetes, has lead to widespread public health campaigns to inform people of the health risks and lowered the associated mortality rates.

→ Improved hygiene, food storage and preservation, and water filtration also occurred in the 20th century leading to fewer preventable diseases and hence increased life spans for all age groups.

→ Improved quarantine requirements have helped prevent the spread of plant, animal and human diseases via international travel.

→In conclusion, developments in biology have lead to increased life expectancy across all age groups, with the biggest improvements for babies and children.

→ These benefits are not necessarily a worldwide phenomenon as poor living conditions and access to medical treatment is not available in many poor socioeconomic communities.


♦♦ Mean mark 35%.

BIOLOGY, M7 2018 HSC 17 MC

The diagram shows the life cycle of the malaria parasite, Plasmodium sp. Five stages in this life cycle are numbered on the diagram.
 


 

To prevent malaria, the following four strategies have been used:

    • taking anti-malarial drugs
    • spraying swamps with insecticides
    • using mosquito nets over beds
    • administering a malaria vaccine.

Which row in the table shows the stage in the life cycle in which each of these strategies would be most effective?
 

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`D`

Show Worked Solution

→ Vaccines are most effective when administered before the parasite enters the cell (1).

→ Mosquito nets are only useful if utilised prior to the injection of the parasite into a human (5).

→ Insecticides help prevent the vectors from breeding (3).

→ Anti-malarial drugs may be useful once the disease is present (2).

`=>D`

BIOLOGY, M7 2016 HSC 30

Explain why the combined use of quarantine and vaccination programs is a more effective way of controlling disease than using only one of these strategies.  (5 marks)

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→ Quarantine alone does not provide any immunity from disease, so outbreaks can still occur if exposure occurs.

→ Vaccination can prevent infection, however, immunity takes time to build up, so infection can occur before the vaccine takes effect.

→ Effective vaccination programs can create herd immunity.

→ If this is backed up with isolation of containable outbreaks of the disease, a combined approach can be more effective.

Show Worked Solution

→ Quarantine alone does not provide any immunity from disease, so outbreaks can still occur if exposure occurs.

→ Vaccination can prevent infection, however, immunity takes time to build up, so infection can occur before the vaccine takes effect.

→ Effective vaccination programs can create herd immunity.

→ If this is backed up with isolation of containable outbreaks of the disease, a combined approach can be more effective.


♦ Mean mark 50%.

BIOLOGY, M7 2018 HSC 11 MC

The following plants were presented to a quarantine office in Australia as part of a shipment of plants entering Australia for the plant nursery trade.


 

Which of the following is a decision that the quarantine office is likely to make?

  1. Plant `W` can enter Australia as it looks like it has 'black spot' which already occurs in Australia.
  2. Plant `X` can enter Australia as it is unlikely the disease it has will transfer to Australian species.
  3. Plant `Y` cannot enter Australia as it has a disease caused by shortage of soil magnesium.
  4. Plant `Z` cannot enter Australia because its appearance suggests it may be carrying live insects.
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`D`

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→ The aim of quarantine is to prevent any pathogens from entering the country.

→ Any plant that appears to contain live insects has a chance of carrying international diseases, and will therefore be quarantined.

`=>D`

BIOLOGY, M7 2015 HSC 12-13 MC

Refer to the following information to answer Questions 12 and 13.

Question 12

Which reason best explains why the corresponding control measure reduces this problem?
 

 
Question 13

The following measures could be used to prevent the spread of this fruit fly across Australia.

    1. Australia-wide release of infertile fruit flies
    2. Aerial spraying of orchards throughout the country
    3. Spot spraying of newly affected orchards in Western Australia
    4. Stopping the transport of fruit from Western Australia to other states

To prevent the spread of this fruit fly across Australia, which combination of measures would be most practical to use?

  1. 1 and 2
  2. 1 and 4
  3. 2 and 3
  4. 3 and 4
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Q12.  `B`

Q13.  `D`

Show Worked Solution

Q12.

→ Future generations of flies will eventually be reduced in numbers and may even be wiped out altogether.

`=>B`
 

Q13.

→ It may be possible to contain the outbreak to local areas by restricting the movement of affected fruit to other states and countries, thus making it easier to manage.

`=>D`


♦ Mean mark (Q13) 49%.

BIOLOGY, M7 2019 HSC 10 MC

A group of islands are separated from each other by large stretches of water. Each island has its own policy on quarantine.

A nearby country is experiencing an outbreak of an infectious disease in its cattle.

An investigation is to be designed to find which of the quarantine policies operating on the islands is the most effective.

Which of the following would be a suitable design feature of the investigation?

  1. The control is the smallest island.
  2. The control is the number of infected cattle.
  3. The independent variable is quarantine policy.
  4. The independent variable is the number of infected cattle.
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`C`

Show Worked Solution

To measure effectiveness of quarantine policies:

→ The independent variable must be the different quarantine policies being investigated

`=>C`

BIOLOGY, M7 2022 HSC 30

Malaria is a disease transmitted by a mosquito vector. There has been no effective vaccine developed.

Refer to the maps below to answer Question 30.
 

   

   

Discuss possible reasons for the differences in the distribution of malaria and its vector. Include detailed reference to Map 1 and Map 2.  (7 marks)

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→ Malaria is a disease which is transmitted via a female mosquito.

→ The plasmodium responsible for the disease can multiply inside a mosquito.

→ When it bites an individual, it enters the bloodstream via the mosquito’s saliva.

→ The presence of infected individuals and the malaria vector (mosquito) in the same regional area is an obvious overlap between the two maps.

 
Regions with mosquito vector but no infected individuals

→ Areas such as Japan, Western Europe and North America have the mosquito vector responsible for malaria but no infected individuals.

This can be due to:

→ Accessibility to medical treatment such as pharmaceuticals which can treat infected individuals.

→ Better mosquito control eg effective repellent.

→ Better quarantine of infected individuals.

 
Regions with no mosquito vector but infected individuals

→ Areas such as China, sections of Northern and Southern Africa and areas of the North-Western coast of South America have cases of malaria but no mosquito vectors in the area.

This can be due to:

→ Migration of infected individuals to the areas stated above from surrounding areas where both the vector and disease are present.

Show Worked Solution

→ Malaria is a disease which is transmitted via a female mosquito.

→ The plasmodium responsible for the disease can multiply inside a mosquito.

→ When it bites an individual, it enters the bloodstream via the mosquito’s saliva.

→ The presence of infected individuals and the malaria vector (mosquito) in the same regional area is an obvious overlap between the two maps.

 
Regions with mosquito vector but no infected individuals

→ Areas such as Japan, Western Europe and North America have the mosquito vector responsible for malaria but no infected individuals.

This can be due to:

→ Accessibility to medical treatment such as pharmaceuticals which can treat infected individuals.

→ Better mosquito control eg effective repellent.

→ Better quarantine of infected individuals.

 
Regions with no mosquito vector but infected individuals

→ Areas such as China, sections of Northern and Southern Africa and areas of the North-Western coast of South America have cases of malaria but no mosquito vectors in the area.

This can be due to:

→ Migration of infected individuals to the areas stated above from surrounding areas where both the vector and disease are present.


Mean mark 56%.

BIOLOGY, M7 2020 HSC 21

Cholera is an acute diarrhoeal infection caused by the bacterium Vibrio cholerae. Humans are infected when they consume food or water that is contaminated with the bacterium.

Outline THREE strategies that could prevent the spread of cholera.   (3 marks)

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Successful answers should include three of the following:

→ Washing yours hands with soapy water after going to the toilet removes bacteria from skin.

→ The filtration and purification of drinking water will help kill and remove bacteria.

→ Proper disposal of sewerage would stop exposure to bacteria present.

→ Thoroughly cooking food, such as vegetables, to eliminate bacteria residing within.

→ Public health campaigns to encourage proper hygiene, cooking, purifying your own water while camping will improve sanitation and safety around bacterial exposure for individuals.

Show Worked Solution

Successful answers should include three of the following:

→ Washing yours hands with soapy water after going to the toilet removes bacteria from skin.

→ The filtration and purification of drinking water will help kill and remove bacteria.

→ Proper disposal of sewerage would stop exposure to bacteria present.

→ Thoroughly cooking food, such as vegetables, to eliminate bacteria residing within.

→ Public health campaigns to encourage proper hygiene, cooking, purifying your own water while camping will improve sanitation and safety around bacterial exposure for individuals.

BIOLOGY, M7 2020 HSC 6 MC

Citrus canker is a bacterial disease that originates in south-east Asia and affects citrus fruit.

What would be the most effective way to prevent the disease from spreading into or across Australia?

  1. Monitor citrus trees and fruit continuously.
  2. Certify orchards before fruit is transported.
  3. Keep citrus trees and fruit entering Australia in quarantine stations until the incubation period has passed.
  4. Inspect citrus trees and fruit entering Australia in quarantine stations before transportation across Australia.
Show Answers Only

`C`

Show Worked Solution

→ Bacterial infections may not be apparent or detected on initial arrival inspection (eliminate D).

→ Options A and B would be difficult to execute and too costly.

→ Quarantining the citrus for the duration of the incubation period should enable the detection of the disease.

`=>C`

♦ Mean mark 46%.

BIOLOGY, M7 2021 HSC 21

  1. Label TWO features on the diagram below that would help to classify this pathogen as a bacterium.   (2 marks)
     
     

     
  2. A scientist followed Koch's postulates to confirm that this bacterium was causing diarrhoea in pigs on a local farm. 
  3. Complete the boxes in the flowchart provided to show the steps taken by the scientist.    (2 marks)
     
     

  4.  
  5. Two pig farmers on neighbouring farms noticed that their pigs were suffering from diarrhoea and gradually losing weight. The farmers each adopted a different strategy to deal with this disease, as shown in the table.  
     
     

    Outline ONE benefit and ONE limitation of the strategies used on each farm.   (3 marks)

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a.    Include two of the following labels:
 
       

b.   Box 2: Bacteria grown in pure culture and identified.

Box 4: Healthy pig became ill with diarrhoea.
 

c.   Benefits and Limitations of the strategies used on each farm.

→ The use of antibiotics on farm 1 has resulted in a rapid elimination of diarrhoea cases, however may induce antibiotic resistance in the
future, rendering the strategy less effective.

→ The removal of rats and mice from pig sheds to increase hygiene on farm 2 is slow to eliminate diarrhoea cases, however provides reassurance to prevent future outbreaks.
 

Other correct answers:

→ Proper hygiene practices can reduce incidence of other diseases, not just diarrhoea.

Show Worked Solution

a.    Include two of the following labels:
 
       
 

b.   Box 2: Bacteria grown in pure culture and identified.

Box 4: Healthy pig became ill with diarrhoea.
 

c.   Benefits and Limitations of the strategies used on each farm.

The use of antibiotics on farm 1 has resulted in a rapid elimination of diarrhoea cases, however may induce antibiotic resistance in the
future, rendering the strategy less effective.

The removal of rats and mice from pig sheds to increase hygiene on farm 2 is slow to eliminate diarrhoea cases, however provides reassurance to prevent future outbreaks.
 

Other correct answers:

  • Proper hygiene practices can reduce incidence of other diseases, not just diarrhoea.