SCIENCE HOMEWORK HELp?

Question

(white blood cells) what is pahgocytosis? it needn't be much detail

what is phagocytosis? it needn't be too detalied., jsut a sentence

Answer 1

The engulfing and ingestion of bacteria or other foreign bodies by phagocytes

Answer 2

There are several stages of phagocytosis:
1. Chemotaxis
This is the movement of cells up a gradient of chemotactic factors. It may be directly induced by a substance such as C5a, produced as a result of complement activation. It can also be indirectly induced as a consequence of release of preformed mediators within mast cells by the action of C3a or C5a e.g. eosinophil chemotactic factor, or neutrophil chemotactic factor. Leukotrienes, produced by the metabolism of mast cell arachidonic acid, are also chemotactic.
2. Adherence
This works reasonably well for whole bacteria or viruses, but less so for proteins or encapsulated bacteria. In order to deal more effectively with encapsulateed bacteria, antibodies directed against the capsule enable the phagocytic cells to ingest the organisms, using their Fc receptors (see below).
3. Pseudopodium formation
This is the protrusion of membranes to flow round the "prey".
4. Phagosome formation
Fusion of the pseudopodium with a membrane enclosing the "prey" leads to the formation of a structure termed a phagosome.
5. Phago-lysosome formation
The phagosome moves deeper into the cell, and fuses with a lysosome, forming a phago-lysosome. These contain hydrogen peroxide, active oxygen species (free radicals), peroxidase, lysozyme and hydrolytic enzymes. This is known as the oxidative burst, and leads to digestion of the phagolysosomal contents, after which they are eliminated by exocytosis. Some peptides however, undergo a very important separate process at this stage. Instead of being eliminated, they attach to a host molecule called MHC class II and end up being expressed on the surface of the cell within a groove on the MHC molecule (antigen presentation).
The speed of phagocytosis can be increased markedly by bringing into action two attachment devices present on the surface of phagocytic cells:


Fc receptor: which binds the Fc portion of antibody molecules, chiefly IgG. The IgG will have attached the organism via its Fab site.
Complement receptor: the third component of complement (C3) also binds to organisms and then attaches to the complement receptor.
This coating of the organisms by molecules that speed up phagocytosis, is termed 'opsonization', and the Fc portion of antibody, and C3 are termed 'opsonins'.

i hope this helps.

Answer 3

Phagocytosis (literally "cell-eating") is a form of endocytosis wherein large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a phagosome, or "food vacuole."

Answer 4

phagocytosis means "cell eating." The cell engulfs surrounding particles by extending parts of the cytoplasm and packaging it in vacuoles. It is a type of active transport.

Answer 5

Phagocytes 'gobble up' bacteria and other particles that shouldn't be there by engulfing (enveloping) them and then digesting them. The process is phagocytosis which literally means 'cell eating'.

Answer 6

Find information on Phagocytosis here (at least you can claim you did the research):

http://en.wikipedia.org/wiki/Phagocytosis
http://www.cellsalive.com/mac.htm

Okay do the rest and study hard.

Answer 7

we have 2 blood cells....red blood cells and white blood cells ..,red blood cell carry oxygen around the body,white blood cell is fighting with bacteria,virus inside our body........u know white blood cell got two parts first one (PHAGOCYTES) second one is (LYMPHOCYTES) phagocytes this type of blood cell kills germs by ingesting the bacteria, but the lymphocytes this is type of white blood cell sends out antibodies which kill germs......OK? is that clear now?

Answer 8

google it,your bound to find something!
good luck.
ooh, hang on...geeky b.f has a book out.......
nope no joy.
all the best!

Answer 9

if you have a computer , why not google it?. i have and it gives plenty of info on the condition.