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Unlike xylem (which is composed primarily of dead cells), the phloem is composed of still-living cells that transport sap. The sap is a water-based solution, but rich in sugars made by photosynthesis. These sugars are transported to non-photosynthetic parts of the plant, such as the roots, or into storage structures, such as tubers or bulbs. [14]
Plasma cells, also called plasma B cells or effector B cells, are white blood cells that originate in the lymphoid organs as B cells [1] [2] and secrete large quantities of proteins called antibodies in response to being presented specific substances called antigens.
B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. [1] They function in the humoral immunity component of the adaptive immune system. [1] B cells produce antibody molecules which may be either secreted or inserted into the plasma membrane where they serve as a part of B-cell receptors. [2]
Primarily, phloem carries dissolved food substances throughout the plant. This conduction system is composed of sieve-tube member and companion cells, that are without secondary walls. The parent cells of the vascular cambium produce both xylem and phloem. This usually also includes fibers, parenchyma and ray cells.
When the memory cells get stimulated by the antigen to produce plasma cells (just like in the clone's primary response), and leave even more memory cells in the process, this is known as a secondary immune response, [21] which translates into greater numbers of plasma cells and faster rate of antibody production lasting for longer periods. The ...
A blood cell (also called a hematopoietic cell, hemocyte, or hematocyte) is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).
Contrary to popular belief, haemoglobin is not a blood protein, as it is carried within red blood cells, rather than in the blood serum. Serum albumin accounts for 55% of blood proteins, [ 1 ] is a major contributor to maintaining the oncotic pressure of plasma and assists, as a carrier, in the transport of lipids and steroid hormones .
The most common simplified overview description of the B cell differentiation pathway involves the following steps: an antigen interacts with the corresponding surface membrane immunoglobulin after which the B cell begins expressing receptors for growth factors secreted by T cells (BCGFs and IL-2), after these factors bind, the lymphocytes ...