T-helper cells, also known as CD4+ cells, are a type of white blood cell that play a crucial role in the immune system by coordinating the immune response. They help activate and direct other immune cells, such as B cells and T-killer cells, to fight off infections. T-killer cells, also known as cytotoxic T cells, are another type of white blood cell that are responsible for directly killing infected cells or cancer cells in the body. Together, T-helper cells and T-killer cells work in harmony to mount an effective immune response against pathogens. **

No, T-killer cells do not arise from T-lymphocytes due to the activation of T-helper cells. T-killer cells, also known as cytotoxic T cells, are a subset of T-lymphocytes that are activated by the recognition of specific antigens presented by antigen-presenting cells. Once activated, T-killer cells can directly kill infected or abnormal cells. T-helper cells, on the other hand, play a different role in the immune response by helping to activate other immune cells, including T-killer cells, through the release of cytokines. **

Yes, plant cells can burst under certain conditions. This can happen if the plant cells take in too much water, causing them to swell and potentially burst. This process is known as osmotic lysis. Additionally, plant cells can also burst if they are exposed to extreme environmental conditions such as freezing temperatures or physical damage. Overall, while plant cells are generally more rigid and less prone to bursting than animal cells, they can still burst under specific circumstances. **

Yes, plant cells are correct. Plant cells have a cell wall, chloroplasts, and a large central vacuole, which are unique features that distinguish them from animal cells. These structures allow plant cells to carry out photosynthesis, provide structural support, and store nutrients and waste products. Overall, plant cells are essential for the growth, development, and functioning of plants. **

When T-helper cells are no longer present, the immune system's ability to coordinate an effective response to pathogens is compromised. This can lead to a weakened immune response, making the body more susceptible to infections and diseases. Without T-helper cells, other immune cells may not be properly activated, resulting in an inability to mount an appropriate immune response. This can have serious consequences for overall health and can lead to increased vulnerability to various illnesses. **

The HIV virus enters T-helper cells by binding to the CD4 receptor on the cell surface. Once inside the cell, the virus replicates and produces new viral particles, which can then infect other T-helper cells. This continuous cycle of infection and replication leads to a decline in the number of T-helper cells, weakening the immune system and making the body more susceptible to infections and diseases. Additionally, HIV can also directly cause cell death in T-helper cells, further contributing to the damage to the immune system. **

Plant cells, virus cells, and animal cells all have different components and structures. Plant cells have a cell wall, chloroplasts, and a large central vacuole, which are not present in animal cells. Virus cells are not considered living cells and are much simpler in structure, consisting of genetic material (DNA or RNA) surrounded by a protein coat. Animal cells have centrioles and lysosomes, which are not found in plant cells. Additionally, animal cells do not have a cell wall like plant cells do. Overall, each type of cell has unique components that contribute to their specific functions and characteristics. **

Plant cells have a cell wall made of cellulose, while animal cells do not. Plant cells also have chloroplasts for photosynthesis, which animal cells do not have. Additionally, plant cells often have a large central vacuole, while animal cells have smaller vacuoles. Finally, plant cells are typically rectangular or square in shape, while animal cells are more irregular in shape. **