Ezywhen salinity in soil increases the soil becomes hypertonic when compared to cell sap.the movement of particles from a lower concentrated solution to a higher concentrated solution is callede osmosis. in general conditions cell sap is at higher conc. than surrounding media. this allows water and minerals to enter the plant. but when soil is at higher conc. i.e., when its salinity increases the process becomes reversed can you imagine its consequenses?
Answer:
TNF-alpha is expressed as a homotrimer that exerts its activities through binding to two types of receptors: TNFR1 and TNFR2, which are transmembrane glycoproteins characterized by having an extracellular domain with 4 cysteine-rich domains (CRD 1-4) , each with 3 cysteinecysteine disulfide bonds.
Explanation:
TNF-alpha (Tumor Necrosis Factor), which has the characteristic of being a paracrine signaling ligand, is a pleiotropic cytokine that functions as a mediator of immune regulation, the inflammatory response and apoptosis in some cell types. Receptors in this family are involved, with some exceptions, in juxtacrine signaling; that is, both the ligand and the receptor are membrane proteins with extracellular domains through which signaling is established. The cellular responses promoted by TNF are initiated by its interaction with two different types of cell receptors, the type I receptor (55 kDa) and the type II receptor (75 kDa). Both types of receptors are part of the TNF receptor family, members of which include Fas antigen (apoptosis inducer, also called Apo-1 or CD95), CD27 (T-cell activation antigen), CD30 (lymphoma marker Hodgkin) and CD40 (B-cell antigen), which share the characteristic of cysteine-rich sequences in their extracellular domains. This family of cytokines generate cellular responses that include differentiation, proliferation, activation of NFκB and cell death, promoting the aggregation of receptor monomers, that is, they have a transmembrane domain that participates in the solubilization of the receptor and a domain of intracellular death that is involved in signal transduction. The binding of TNF to TNF-R1 induces a signaling cascade through its intracellular death domain, which subsequently leads to the activation of complex I (or inflammatory) of NFkB and proceeds to the transcription of anti-apoptotic genes, pro- inflammatory diseases and apoptosis complex II (caspases).
Answer:
Explanation:
La fecundación es el proceso por el cual dos gametos (masculino y femenino) se fusionan durante la reproducción sexual para crear un cigoto con un genoma derivado de ambos progenitores. Los dos fines principales de la fecundación son la combinación de genes derivados de ambos progenitores y la generación de un cigoto.
En el caso de las plantas con semillas pros, hay que diferenciar el fenómeno de la fecundación propiamente dicho (unión íntima de dos células sexuales hasta confundirse sus núcleos respectivos y, en mayor o menor grado, sus citoplasmas),1 del proceso biológico que lo antecede: la polinización, en el que los granos de polen, desarrollados en las tecas que contiene cada antera de un estambre (hoja reproductora masculina), son transportados por el viento o los insectos a los estigmas, donde germinan emitiendo un tubo polínico que crece hacia el ovario. En este caso no se trata de gametos, sino de esporas, pues cada grano de polen contiene dos gametos o células reproductoras masculinas
