Answer:
Legionella tends to form biofilms and infect other microbial cells as intracellular pathogens.
Explanation:
The Legionella genus of the bacteria is a group of gram-negative bacteria that can cause legionnaires disease.
The<em> Legionella pneumophila</em> is a species of this genus which can cause legion pneumonia. The bacteria lives in the freshwater and is resistant to chemical treatment like chlorine and the biocide treatment.
The reason for this resistance is since this species form a polysaccharide layer around the colony of the bacteria which is resistant to these treatments and also the bacteria prove parasitic to the protozoans which feed on these bacteria.
Thus, the selected option is the correct answer.
Answer:
Homeostasis is defined as the state of body in which body maintains several chemical and physical changes inside the body affected by external factors.
Negative feedback loop includes a sensor, stimulus, control center, and effector which is used to control homeostasis.
A negative feedback loop is a reaction that reduce an excessive response and maintain the functions within the normal range. for example: if temperature and blood glucose level increases in the body, negative feedback loops control both the variables and maintain homeostasis.
Hence, negative feedback loops used to control body homeostasis.
Adhesion allows for it to be easily attracted to glass
Answer:
Helper T cells stimulate B-cells to produce antibodies and killer T cells to destroy the non-self cells. Cytotoxic T cells on the other hand are direct attack cells. They can kill the micro organisms by creating pores on the invader's cell.
Explanation:
T lymphocyte mediated immunity of cell mediated immunity do not secrete antibodies but they help stimulate the B cells to produce them. Immature T cells are produced in bone marrow from where they migrate to thymus via blood. In the thymus maturation of T cells occur and then they migrate to lymphoid tissue and get differentiated into three types:
a. Helper T cells: As the name suggests, they help in activating other immune cells, in other terms they are the regulator of virtually all functions of immune system. Protein mediator called lymphokines are produced by these helper T cells in order to regulate the immune functions. Some examples of these lymphokines are: Interleukin-2 interleukin-3, interferon gamma. T helper cells stimulate the B-cells to produce antibodies.
b. Cytotoxic cells or killer T cells: The lymphokine interleukin-2 is responsible for the growth and proliferation of both cytotoxic T cells and suppressor T cells. With the help of receptor proteins on the surface of killer T cells, they bind to the specific antigen. After binding, they secrete a pore forming protein called perforins which create pores on the invaders cell membrane for water to enter into it thereby cell swells and finally lyse.
c. Suppressor T cells: They suppress the function of above two T cells.
Active transport moves molecules across the plasma membrane of a cell with the help of transport proteins and energy (ATP).
Active transport is the means of transport of molecules across the plasma membrane with the help of energy. This method is usually used for the transport of molecule against their concentration gradient, i.e., from lower concentration to higher concentration.
Plasma membrane is the outer layer surrounding the cell. It is made up of lipid bilayer, proteins, carbohydrates and cholesterol. The lipid bilayer is amphipathic since the lipid head is hydrophilic and its tail is hydrophobic. The plasma membrane is semi-permeable in nature.
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