LD 50 FRQ Grading

LD 50 & Disease on the Rise FRQ Grading

Lets see if this actually works!!

LD 50 Grading

(b) Explain the meaning of the term LD50 (ED50). What is the LD50 concentration of CuSO4 for brine shrimp? (2 points)

• Explanation of LD50 (ED50) (1 point)

  LD50 is the amount or dose of a chemical (toxic substance) that kills half the test population (test organisms/specimens).

• If the word “test” is omitted from the definition, students must clearly indicate that the population has been experimentally exposed to a toxin.

• No credit is earned for “kills half the 1) species population, or 2) population of a particular species, or 3) population leading to extinction of the species.”

Multiple Choice

(b)

LD50 is the does of a substance that causes the death of 50% of a group of test subjects.

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Multiple Choice

(b)

LD50, or "lethal dose 50," is the dose of a toxic substance that kills 50% of all tested organisms.

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Multiple Choice

(b)

LD50 means the toxicity of a chemical

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Multiple Choice

(b)

the amount of a substance given of which that deals 50% of deaths

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(c) Explain the meaning of the term “threshold level of toxicity”.

• Explanation of threshold level of toxicity (1 point)

• The dose (level) below which no toxic (lethal) effects are observed and/or above which the toxic (lethal) effects are apparent.

  
  

Multiple Choice

(c)

It mean how much on the toxin someone can handle

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Multiple Choice

(c)

Threshold level of toxicity is the largest amount of the dose before it is fatal or kills any of the test subjects.

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Multiple Choice

(c)

Threshold level is the dosage amount needed to make any impact on the number of killed individuals. Anything below the threshold level and nothing dies.

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(d) Provide one argument for extending these toxicity results to humans and one argument against doing so. (2 points)

One argument FOR extending these toxicity results to humans (1 point)

• Since the copper sulfate (metal ion) was toxic to brine shrimp, it is reasonable to assume that it might be toxic to humans.

• Copper sulfate is a water soluble toxin and humans are susceptible/exposed to water-soluble compounds.

• Since there is evidence of a dose effect in the brine shrimp, there may be a dose effect in humans.

• Since it may be unethical and/or illegal to test on humans or it might result in injury, harm or death to humans, testing must be done on other organisms.

• These dose-response results can be mathematically extrapolated/estimated and applied to humans.

• This was an experiment conducted under laboratory conditions, therefore the results are verifiable.

• No credit is earned for “Brine shrimp and humans are living organisms”.

Multiple Choice

There can be the same dose that can have the same effect on a different species to humans.

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Multiple Choice

An argument for extending these toxicity results to humans are if something is harmful to animals, plants, marine life, etc; then this would be harmful for humans too.

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Multiple Choice

An argument for extending these toxicity results to humans would be that it helps avoid people from getting sick from a toxic substance

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One argument AGAINST extending these toxicity results to humans ( 1 point)

• Test animals and humans differ in anatomy, body size, physiology, metabolism, genetics and/or sensitivity, and exposure to toxins.

• Many factors affect the dose-response results — species, sex and age of organism, temperature, synergistic effects, diet, and number of organisms in a cage or container.

• Laboratory conditions do not necessarily reflect actual conditions.

• It is difficult to mathematically predict/estimate these effects on humans. 

• Brine shrimp are aquatic organisms and humans are terrestrial. 

• A mammalian test population (such as mice or rats) might be more appropriate.

• Dose-response testing only provides data on acute effects and does not address chronic effects.

• The experimental results may not be accurate — sample size too small, only one trial, no control group, error in measurements. 

• Dose-response studies should be conducted on several species before they are applied to humans. 

• Just because CuSO4 is toxic to brine shrimp does not necessarily mean it is toxic to humans. 

• Documented historic data/incidences on human exposure to CuSO4 might provide more reliable information.

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Multiple Choice

There is always a chance that there cannot be the same effects or not an effect.

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Multiple Choice

An argument against this would be animals, plants, marine life, etc have different structures, are different types of species, have different reactions, genes, etc; so humans and these organisms might have different reactions from one another so humans can possibly get different results compared to animals, plants, marine life, etc.

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Multiple Choice

An argument against extending these toxicity results to humans would be that these experiments would be done on rats, mice or other animals (not humans), so using those results from the other animals would not be accurate. Sometimes a substance that is toxic for an animal (that's not human) isn't toxic for a human, and vice versa.

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Disease on the Rise FRQ

 (a)  For one new disease and one old disease named in the article above, explain how the disease is transmitted through the human population and describe an effective method for controlling the spread of the disease.

• (4 points possible)For each disease, 1 point is earned for how the disease is transmitted to humans, and 1 point is earned for the method of controlling its spread.

• Note: Students may receive a point for the method for controlling the spread of the disease without receiving the point for how the disease is transmitted.

Consult the rubric (a) for details about this Question

Multiple Choice

(a)

West Nile River Fever is spread through the water systems present in the area. Waterways such as wells and pluming. This can be controlled by the donation and usage of clean purified water. Also, a closing of the river areas that are infected.Malaria is spread through mosquitos, when a person is bite by them they are exposed to the disease. It can be prevented through covering ones skin and usage of mosquito nets.

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Multiple Choice

(a)

SARS was a new disease, transmitted directly from animals to humans. An effective method for controlling the spread of the disease is to not have humans and animals in close proximity. Malaria was the old disease, transmitted by bite of infected mosquito. An effective method for controlling the spread of the disease is to spray mosquito habitat with pesticides.

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That one was identical to the rubric, so you know they cheated...

Multiple Choice

(a)

The new disease, SARS, is transmitted through the human population from close human contact in which the virus starts spreading. Quarantining is a method to prevent the spread of the new disease. For old diseases, malaria is caused by mosquito bites which is transmitted through the human population. A method to prevent mosquito bites could be limiting being outside when mosquitos are present.

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(b)  For one of the two diseases you chose in part (a), identify one environmental factor that contributed to the emergence or reemergence of the disease and explain how that factor influenced the increased incidence of the disease. 

(2 points possible)

One point is earned for the environmental factor, and 1 point is earned for how that factor influenced increased incidence.

Note: The factor and the explanation must be causally linked.

Consult the rubric (b) for details about this Question

Multiple Choice

(b)

One environment factor that has contributed to the emergence of the Tuberculosis is the coming of winter. This causes larger amounts of peoples to be forced inside rather than outside during large gatherings. This increases the incidence of Tuberculosis because the greater number of people the lower the air quality and Tuberculosis is contracted within low air quality areas.

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Multiple Choice

(b)

Poverty plays an important role in the reemergence of diseases, like tuberculosis. Most commonly, tuberculosis has reemerged in less developed countries where poverty levels are very high. People in poverty often do not have access to sanitation or practice good hygiene therefore, it is easier for diseases to spread, as good hygiene is a key component of prevention.

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Multiple Choice

(b)

Malaria is spread through mosquitos, and mosquitos are present in very warm weather. The hot environment allows for mosquitos to live, therefore, infecting people of the disease.

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(d)    The graphs above show the mortality from infectious diseases in the United States since 1900. Identify an infectious disease that made an important contribution to the trend of increasing mortality rates that began in about 1980 and explain one major cause of the increased rate of mortality from that disease.

(2 points possible)One point is earned for the disease, and 1 point is earned for the cause of the increased rate of mortality.

Disease:    HIV/AIDS

• Cause: · infected blood transfusions/organ transplants

  · sharing syringes

  · having unprotected/unsafe sex and/or having multiple sex partners

  · lack of education about how the disease is spread, leading to high risk behaviors

  · transmission from mother to child

  · lack of ability to develop effective treatments/vaccine/no permanent cure

  · increased progression of disease in individuals/long incubation period

  · opportunistic infections due to compromised immune systems

  
  

Disease:   Influenza or pneumonia

Cause: · increased mortality rate due to aging population

·  drug-resistant strains of pneumonia

Multiple Choice

(d)

An infectious disease that made an important contribution to the trend of increasing mortality rates in 1980 was AIDS. One major cause of this was how quickly AIDS spread between people and how many didn't treat it which caused it to affect the mortality rate.

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Multiple Choice

(d)

An infectious disease that made an important contribution to the trend of mortality rates that began in about the 1980 was the AIDS epidemic. The most critical impact toward the increase of this epidemic was the societal shift that happened during this time period. There was a huge shift for the LGBTQ+ community, and the epidemic initially spread inside of these bathhouses.

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Multiple Choice

(d)

HIV was an infectious disease that made an important contribution to the trend of increasing mortality rates that began in about 1980. Having unprotected sex was a major cause of the increased rate of mortality of HIV.

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