Immune System Unit Pre-assessment (Grade 7)

The answer "1,2,3,4" suggests that the person is indicating that they have knowledge about the immune system and disease across all levels, from the lowest (1) to the highest (4). This implies that they have a comprehensive understanding of the topic and are familiar with a wide range of information related to the immune system and disease.

The given answer options indicate that the question is asking the respondent to rate their level of interest in the immune system and disease on a scale of 1 to 4, with 1 being the lowest and 4 being the highest. The answer "1,2,3,4" suggests that the respondent is equally interested in all levels, from the lowest to the highest.

All of the factors listed - toxic substances, poor nutrition, inheritance, and personal behavior - can cause disease. Toxic substances, such as chemicals or pollutants, can directly harm 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. Some diseases can be inherited from parents or passed down through genes. Personal behavior, such as smoking, excessive alcohol consumption, or lack of exercise, can also increase the risk of developing diseases. Therefore, all of these factors can contribute to the occurrence of disease.

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 immune system is unable to effectively respond and fight against them.

Uncontrolled cell division causes cancer. This is the best description of the diagram because it directly states that uncontrolled cell division leads to the development of cancer. The other statements do not directly relate to the diagram or provide a clear explanation of what is depicted in the diagram.

Vaccinations use weakened microbes (or parts of them) to stimulate the immune system to react. This means that when a person is vaccinated, they are given a small amount of a weakened or inactivated form of the microbe that causes the disease. This stimulates the immune system to produce an immune response, including the production of antibodies, without causing the person to become sick from the actual disease. This prepares the immune system to recognize and fight the microbe if the person is exposed to it in the future, providing protection against the disease.

Lymphocytes are a type of white blood cell that play a crucial role in the immune system. 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 recognize specific markers on their surface called antigens. Antibodies, on the other hand, are proteins produced by lymphocytes in response to antigens. Allergies are immune responses to harmless substances, and platelets are cell fragments involved in blood clotting. Plastids are organelles found in plant cells. Therefore, the correct answer is antigens, as lymphocytes recognize antigens as foreign molecules.

The correct answer is that the human body makes 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 recognizing and killing infected or cancerous cells. The human body is capable of producing a diverse range of cytotoxic T cells, each with a unique receptor that allows it to recognize specific antigens. This diversity is essential for the immune system to effectively target and eliminate a wide variety of pathogens and abnormal cells.

Failure of negative feedback mechanisms to maintain homeostasis can lead to the development of diseases. Homeostasis refers to the body's ability to maintain a stable internal environment. Negative feedback mechanisms help regulate various physiological processes to keep them within a normal range. When these mechanisms fail, it can disrupt the balance and lead to the development of diseases or disorders. In this case, failure to regulate blood pressure during exercise can result in hypertension, which is a risk factor for various cardiovascular diseases. Therefore, failure of negative feedback mechanisms may produce disease.

The statement describes the release of histamines as a result of antibody production, which is a characteristic of allergies. Allergies occur when the immune system overreacts to harmless substances, such as pollen or certain foods, and releases histamines as part of the immune response. Histamines cause symptoms such as sneezing, itching, and inflammation. Therefore, the letter "C" best represents the given statement.

Antibiotics have been developed by biological researchers to protect humans from bacterial infections. Antibiotics are drugs that specifically target and kill bacteria or inhibit their growth, making them effective in treating bacterial infections. They work by interfering with the bacteria's ability to grow or reproduce, ultimately eliminating the infection. Antibiotics are not effective against viral infections or cancer, which are caused by different types of organisms or cells. Therefore, the correct answer is bacterial.

Viruses are composed of a core of DNA or RNA. This means that viruses do not have cells and they do not contain all the components of a typical cell, such as organelles or a cell membrane. Instead, viruses are made up of genetic material (DNA or RNA) surrounded by a protein coat called a capsid. Some viruses may also have an outer envelope made of lipids. This composition allows viruses to infect host cells and use their cellular machinery to replicate and produce more viruses.