Gravitational.....................
Phagocytosis is the ingestion and destruction of particle matter by the amoeba
HIV directly attacks CD4 helper lymphocytes directly. (D)
Answer:
The plant cell wall is strengthened by the molecular structure of cellulose. Cellulose is made up of ß-glucose arranged upside down, this arrangement aided hydrogen bonds between the hydrogen ions of the hydroxyl group and oxygen of the of the ring of same betta -glucose.
The aggregation of the hydrogen bonds give bundles of strong tensile strength of cellulose called the microfibrils (of 60-70 celluose molecules).They are held together in bundled called fibers.T<u>hese is the source of plant cell walls strength.
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Collagen is the main extracellur matrix (EM) in animal cells.It is a glycoprotein made up of 25%of body protein of animals.Each collagen molecule is made of helix shaped ,three polypeptide chains, wound around each other to form<u> triple helix.</u>The bonds holding helix together are hydrogen and covalent bonds.
Each triple helix is attached to adjacent collagen molecule, parallel to it. The covalent bonds formed a cross link which held the collagen molecules together forming FIBRILS. This gives flexibility to collagen, while maitaing strong tensile strength. This is what is responsible for the structural strength of cell membrane
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.The EM,is futher reinforced with carbohydrate molecules(proteoglycans) which<u> aided in water movements by osmosis following sodium movements into the matrix.</u>
