Immune System Unit Post-assessment (Grade 7)

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3. A person who has HIV/AIDS and a comprised immune system will not be able to (Standard 5.2a, 5.2f)

Produce antigens

Produce red blood cells

Fight infections

Digest food properly

Produce hormones

A person who has HIV/AIDS and a compromised immune system will not be able to fight infections. HIV/AIDS weakens the immune system by attacking and destroying CD4 cells, which are crucial for fighting off infections. As a result, the person becomes more susceptible to various infections and illnesses as their body's ability to defend against them is impaired. This is why fighting infections is not possible for someone with HIV/AIDS and a compromised immune system.

Explanation

A person who has HIV/AIDS and a compromised immune system will not be able to fight infections. HIV/AIDS weakens the immune system by attacking and destroying CD4 cells, which are crucial for fighting off infections. As a result, the person becomes more susceptible to various infections and illnesses as their body's ability to defend against them is impaired. This is why fighting infections is not possible for someone with HIV/AIDS and a compromised immune system.

4. Which statement best describes the diagram below (Standard 5.2i)?

Cancer is an example of dynamic equilibrium.

Cell division accelerates to maintain homeostasis

When skin cells die, they are quickly replaced.

Tumors result when cells divide at an acclerated rate

All of the above

The diagram below (Standard 5.2i) represents the statement that tumors result when cells divide at an accelerated rate. This means that when cells divide at a faster pace than normal, it can lead to the formation of tumors. The other statements mentioned in the options do not accurately describe the diagram or the concept of dynamic equilibrium.

Explanation

The diagram below (Standard 5.2i) represents the statement that tumors result when cells divide at an accelerated rate. This means that when cells divide at a faster pace than normal, it can lead to the formation of tumors. The other statements mentioned in the options do not accurately describe the diagram or the concept of dynamic equilibrium.

5. Which disease can be treated by antibiotics (Standard 5.2j)?

Cancer

Flu Virus

West Nile Virus

Bacterial Meningitis

Both B and C

Bacterial meningitis can be treated by antibiotics. This is because bacterial meningitis is caused by a bacterial infection, and antibiotics are effective in killing bacteria. Cancer, flu virus, and West Nile virus are caused by different factors and cannot be treated with antibiotics. Therefore, the correct answer is Bacterial Meningitis.

Explanation

Bacterial meningitis can be treated by antibiotics. This is because bacterial meningitis is caused by a bacterial infection, and antibiotics are effective in killing bacteria. Cancer, flu virus, and West Nile virus are caused by different factors and cannot be treated with antibiotics. Therefore, the correct answer is Bacterial Meningitis.

6. The human body (Standard 5.2d):

Does not make antibodies.

Makes only one type of antibody.

Makes one hundred different types of antibodies.

Makes billions of different types of antibodies.

Only makes cytotoxic T cell antibodies.

The human body is capable of producing billions of different types of antibodies. Antibodies are proteins produced by the immune system in response to the presence of foreign substances, such as bacteria or viruses. Each antibody is designed to recognize and bind to a specific target, known as an antigen. The diversity of antibodies is achieved through a process called somatic recombination, where different gene segments are combined to create unique antibody genes. This allows the immune system to effectively recognize and neutralize a wide range of pathogens.

Explanation

The human body is capable of producing billions of different types of antibodies. Antibodies are proteins produced by the immune system in response to the presence of foreign substances, such as bacteria or viruses. Each antibody is designed to recognize and bind to a specific target, known as an antigen. The diversity of antibodies is achieved through a process called somatic recombination, where different gene segments are combined to create unique antibody genes. This allows the immune system to effectively recognize and neutralize a wide range of pathogens.

7. Subtances released by the human body in response to allergens are called: (Standard 5.2g)

Allergies

Cytotoxic T cells

Histamines

Hormones

Neurotransmitters

Histamines are substances released by the human body in response to allergens. When an allergen enters the body, histamines are released by immune cells called mast cells. Histamines cause inflammation, itching, and other symptoms associated with allergic reactions. They are responsible for the dilation of blood vessels, increased mucus production, and smooth muscle contraction. Antihistamines are commonly used to block the effects of histamines and alleviate allergic symptoms.

Explanation

Histamines are substances released by the human body in response to allergens. When an allergen enters the body, histamines are released by immune cells called mast cells. Histamines cause inflammation, itching, and other symptoms associated with allergic reactions. They are responsible for the dilation of blood vessels, increased mucus production, and smooth muscle contraction. Antihistamines are commonly used to block the effects of histamines and alleviate allergic symptoms.

8. Which statement about diseases is NOT true (Standard 5.2h)?

Diseases can be caused by poor nutrition

Disease can be caused by personal behavior

Diseases can be inherited

Diseases can be caused by antibodies

Disease can be caused by toxic substances

Antibodies are proteins produced by the immune system in response to foreign substances (antigens) such as bacteria or viruses. Antibodies themselves do not cause diseases; they help to fight against them. Therefore, the statement "Diseases can be caused by antibodies" is not true.

Explanation

Antibodies are proteins produced by the immune system in response to foreign substances (antigens) such as bacteria or viruses. Antibodies themselves do not cause diseases; they help to fight against them. Therefore, the statement "Diseases can be caused by antibodies" is not true.

9. Helper T cells present a processed ____________ to B cells to activate them so they can begin a specific immune response. (Standard 5.2c)

Antibody

Allergen

Cytokine

Antigen

Lymphocyte

Helper T cells present a processed antigen to B cells to activate them so they can begin a specific immune response. Antigens are substances that can trigger an immune response in the body. Helper T cells recognize antigens that have been processed and presented by antigen-presenting cells, such as macrophages, and then they interact with B cells to stimulate the production of antibodies. This interaction between helper T cells and B cells is crucial for the adaptive immune response to effectively target and eliminate pathogens.

Explanation

Helper T cells present a processed antigen to B cells to activate them so they can begin a specific immune response. Antigens are substances that can trigger an immune response in the body. Helper T cells recognize antigens that have been processed and presented by antigen-presenting cells, such as macrophages, and then they interact with B cells to stimulate the production of antibodies. This interaction between helper T cells and B cells is crucial for the adaptive immune response to effectively target and eliminate pathogens.

10. Failure of negative feedback mechanisms to maintain homeostasis (Standard 5.2 a):

Occurs when blood pressure increases during exercise

Cannot be corrected by medical therapy

Can be corrected by stimulating positive-feedback mechanisms

Prevents disease

May upset dynamic equilibrium.

The given correct answer suggests that failure of negative feedback mechanisms to maintain homeostasis may upset dynamic equilibrium. This means that when the body's negative feedback mechanisms, which are responsible for maintaining stability and balance, are unable to regulate a certain physiological parameter, it can lead to a disruption in the overall equilibrium of the body. In this case, the failure of negative feedback mechanisms to control blood pressure during exercise can potentially upset the dynamic equilibrium of the body.

Explanation

The given correct answer suggests that failure of negative feedback mechanisms to maintain homeostasis may upset dynamic equilibrium. This means that when the body's negative feedback mechanisms, which are responsible for maintaining stability and balance, are unable to regulate a certain physiological parameter, it can lead to a disruption in the overall equilibrium of the body. In this case, the failure of negative feedback mechanisms to control blood pressure during exercise can potentially upset the dynamic equilibrium of the body.

11. Which of the following is true about viruses? (Standard 5.2b)

All viruses contain DNA.

The building blocks of viruses are white blood cells.

A virus is made up of one or more cells.

A virus needs a host in order to reproduce.

All of the above.

A virus needs a host in order to reproduce. This is true because viruses are not considered living organisms and therefore cannot replicate on their own. They require a host cell to invade and use the host's cellular machinery to replicate and produce more viruses. Without a host, viruses are unable to reproduce and survive.

Explanation

A virus needs a host in order to reproduce. This is true because viruses are not considered living organisms and therefore cannot replicate on their own. They require a host cell to invade and use the host's cellular machinery to replicate and produce more viruses. Without a host, viruses are unable to reproduce and survive.

12. Which of the following statements is true about vaccinations (Standard 5.2e)?

Vaccinations use weakened antibodies to stimulate the immune system to react.

Vaccinations utilize hormones in the blood to inhibit reproduction of the virus.

Vaccinations release enzymes from platelets that hydrolyze the virus.

Vaccinations use weakened microbes to stimulate the immune system to react.

None of these statements are true.

Vaccinations use weakened microbes to stimulate the immune system to react. This is true because vaccines contain small amounts of weakened or inactivated microbes, such as viruses or bacteria. When these microbes are introduced into the body through vaccination, they stimulate the immune system to produce an immune response. This immune response helps the body recognize and fight off the actual disease-causing microbes in the future, providing immunity against the disease.

Explanation

Vaccinations use weakened microbes to stimulate the immune system to react. This is true because vaccines contain small amounts of weakened or inactivated microbes, such as viruses or bacteria. When these microbes are introduced into the body through vaccination, they stimulate the immune system to produce an immune response. This immune response helps the body recognize and fight off the actual disease-causing microbes in the future, providing immunity against the disease.