Answer:
Cell membrane can be described as the membrane which is present outside the cell or which separates the cell from the external environment. For an enzyme to pass through the external environment, it will have to pass through the ribosomes and the cell membrane.
Answer:
C) Release of von Willebrand factor (vWF) from the endothelium, not the epithelium.
Explanation:
Hemostasis is the physiological process of reparation and maintenance of a blood vessel to stop excess loss of blood in case of vascular injury. This process occurs in four stages:
- Vascular Injury i.e. a breach in the endothelial barrier. This results in the dislodge of endothelial cells, exposing the collagen fibers underneath.
- Vascular constriction or vasoconstriction is the constriction of the blood vessels to prevent excessive blood loss.
- Platelet plug formation involves the aggregation and adhesion of platelets to the endothelium.
- Coagulation
Platelet plug formation occurs by the adhesion of circulating platelets to the collagen fibers that have been exposed by dislodging of the endothelial cells. The endothelium, as well as the platelets release a ligand known as the von Willebrand factor (vWF). This molecule acts as a relay or bridge between the integrin receptors on the platelets and the exposed collagen fibers.
Platelets also release chemicals to attract more platelets to the wound site, resulting in more vWF release. This results in more and more platelets adhering to the endothelium, leading to platelet plug formation.
I believe 3 and 5 is the answers
