Immune System Unit Post-assessment (Grade 8)

not-available-via-ai

not-available-via-ai

All of the factors listed in the options - toxic substances, poor nutrition, inheritance, and personal behavior - can contribute to the development of diseases. Exposure to toxic substances such as chemicals or pollutants can have harmful effects on the body and lead to various diseases. Poor nutrition, including a lack of essential nutrients or an unhealthy diet, can weaken the immune system and make individuals more susceptible to diseases. Certain genetic factors inherited from parents can increase the risk of developing specific diseases. Personal behavior, such as smoking, excessive alcohol consumption, or lack of exercise, can also increase the likelihood of developing diseases. Therefore, all of these factors can cause diseases.

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 the CD4 cells, which are responsible for fighting off infections. As a result, the person becomes more susceptible to various infections and diseases, as their body is unable to effectively defend itself against pathogens. This is why individuals with HIV/AIDS often experience frequent and severe infections, as their compromised immune system is unable to fight them off.

Vaccinations use weakened microbes (or parts of them) to stimulate the immune system to react. This means that a small amount of the microbe is introduced into the body, which triggers the immune system to produce an immune response. This response includes the production of antibodies that can recognize and neutralize the microbe in the future. By using weakened microbes, vaccines can safely train the immune system without causing severe illness. This statement accurately describes the process of vaccination.

Antibiotics have been developed by biological researchers to protect humans from bacterial infections. Antibiotics are specifically designed to target and kill bacteria, making them effective in treating bacterial diseases. They work by either directly killing the bacteria or inhibiting their growth and reproduction. Antibiotics are not effective against viral infections or cancer, as these are caused by different types of organisms or cells. Therefore, the correct answer is bacterial.

Uncontrolled cell division causes cancer. This statement accurately describes the diagram. Cancer is characterized by the uncontrolled growth and division of cells, leading to the formation of tumors. This can occur due to various factors, such as genetic mutations or exposure to carcinogens. Understanding the role of uncontrolled cell division in cancer is crucial for developing effective treatments and prevention strategies.

Viruses are composed of a core of DNA or RNA. This is the correct answer because viruses are not cells and do not contain cells. Instead, they are made up of genetic material (DNA or RNA) surrounded by a protein coat. Additionally, viruses are not composed of nerve tissue. Therefore, the correct statement is that a virus is composed of a core of DNA or RNA.

Lymphocytes are a type of white blood cell that plays a crucial role in the immune response. They are responsible for recognizing and attacking foreign substances in the body, such as bacteria or viruses. In order to identify these foreign molecules, lymphocytes specifically recognize antigens. Antigens are molecules that can stimulate an immune response and are typically found on the surface of pathogens or other foreign substances. Therefore, the correct answer is antigens.

The statement mentions that chemicals known as histamines are released as a result of antibody production. Histamines are commonly associated with allergic reactions, where the body's immune system overreacts to harmless substances. This aligns with the concept of allergies, as they involve an immune response triggered by the release of histamines. Therefore, the letter "C" best represents the given statement.

Failure of negative feedback mechanisms to maintain homeostasis can lead to a disruption in the body's normal functioning, which may result in the development of diseases. In this context, if the negative feedback mechanisms responsible for regulating blood pressure fail during exercise and allow it to increase excessively, it can have detrimental effects on the cardiovascular system and potentially lead to the development of conditions such as hypertension or heart disease. Therefore, the failure of negative feedback mechanisms to maintain homeostasis may produce disease.

The human body is capable of producing millions of different types of cytotoxic T cells. Cytotoxic T cells are a type of white blood cell that play a crucial role in the immune response by identifying and destroying infected or abnormal cells. The diversity in cytotoxic T cells is due to the presence of a large number of different T cell receptors, which allow them to recognize a wide range of antigens. This diversity ensures that the immune system can effectively respond to a variety of pathogens and adapt to new threats.