D. a protective membrane, because they surround<span> the cell
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Answer:
C. Antibodies directly destroy antigen-bearing invaders by releasing potent toxins.
Explanation:
An antibody is part of the host cell defense and it’s made by B-cells (white blood cell). The structure of the antibody consists of two light chains and two heavy chains, and at the very tip of the antibody is a hyper variable region, which is the antigen binding site that recognizes lots of different types of antigens. An antigen is anything that is foreign to the human body (the body does not recognize it as self), it can be a virus, bacteria, fungi, some foods and particles like dust that cause allergies and in some cases your own body will appear as foreign.
Antibodies act like small keys looking for the perfect lock, once they find their target they alert the immune system to mount a full immune response. Using this binding mechanism, an antibody can tag a microbe or an infected cell for attack by the immune system or it can neutralize its target directly for example, by blocking a part of a microbe needed for entering and invading a cell. Depending on the antigen the antibody binding may impede the biological process causing the disease or may activate macrophages to destroy the foreign substance, it does not release potent toxins. Antibody binding can cause the clumping (agglutination) of large particles (viruses, bacteria etc.) making it a large complex, making phagocytosis more efficient (as they eliminate lots of clumped up viruses or bacteria in one go, and not one by one).
Answer:
c. Prevent crystal violet from leaving the cells
Explanation:
Gram Staining:
- Gram staining is a staining techniques used for the identification of bacteria in microbiological studies.
- Gram staining uses crystal violet as the primary stain. It complexes with the peptidoglycan cell wall of Gram positive bacteria giving them a purple color.
- An iodine mordant is also used that forms a crystal violet-iodine complex that fixes the crystal violet dye to the cell wall. This prevents the Gram positive cell walls from being decolorized by the application of alcohol.
- A counter stain, safranin is then applied that stains Gram negative bacteria pink.
Answer:
Fault
Explanation:
A break or crack in earth's lithosphere along with rocks move. Earth is made up of 4 basic layers a crust,mantle,outer core,inner core and lithosphere. A solid crust and hard layers of mantle make up a region name the lithosphere. The lithosphere is made up of pieces of tectonic plates. These plates are constantly changing and move towards the mantle. Non-stop movement of tectonic plates causes stress on the earth's outermost layer i.e,the crust. When these stresses extends it leads to cause cracks called faults.
