Biological interphases membranes

In the following section, the role of the various types of complexes mentioned above will be discussed with regard to various mechanisms of interactions at biological interphases. It is clear that metal ions and hydrophilic complexes cannot distribute into the membrane lipid bilayer or cross it. The role of hydrophilic ligands has thus to be discussed in relation to binding of metals by biological ligands. In contrast, hydrophobic complexes may partition into the lipid bilayer of membranes (see below, Section 6). 

Every living cell, whether it be a unicellular organism on its own or a part of a multicellular organisation, is encircled by a biological membrane. In this context, the terms cell membrane , plasma membrane , and cytoplasmic membrane are used synonymously. Generally, the interphase between an organism and its environment encompasses the elements outlined in Figure 1. The scheme shows that the cell membrane, with its hydrophobic lipid core, has the most... 

Ion pairs are outer-sphere association complexes, which have to be clearly distinguished from the organometallic complexes discussed in Section 6. Ion pair formation appears to be much less important in biological membranes as compared with octanol, because the charge of the ions at the membrane interphase can be balanced by counter charge in the electrolyte in the adjacent aqueous phase. The reactions involved in ion pair formation are depicted in Figures 5b for acids and 5c for bases, and the equilibrium constant K ix is defined as follows ... 

A. 19.3 While the best model depends on the question being investigated, the Stern model would provide a more accurate model of the interphase because it considers molecular size and non-electrostatic molecular absorption, both of which are very important to biological systems. For example, proteins control the flow of ions through membranes based on size, so if size isn t considered, the interactions leading to flow control would be missing an essential component. Hydrophobic and hydrophilic interactions are also an important part of interphase interactions. 

Functional analyses have suggested that lamins are involved in a number of biological processes, including DNA replication, chromatin organization, cellular differentiation during development, nuclear envelope reassembly following mitosis, and the structural stabilization of the nuclear membrane during interphase (for review, see Moir et al., 1995). Here we describe two methods that we have successfully applied in our laboratories and that have allowed us to analyze functional and dynamic properties of lamins in vivo by the microinjection of cultured cells with either affinity-purified lamin antibodies or with fluorescently labeled lamins. 

According to Wikipedia [1], a membrane is a thin, typically planar structure or material that separates two enviromnents or phases and has a finite volume. It can be referred to as an interphase rather than an interface. Membranes selectively control mass transport between phases or environments. Again, according to Wikipedia, membranes can be divided into three groups (1) biological membranes, (2) artificial membranes, and (3) theoretical membranes. 

Biological membranes, called biomembranes for short, are nature s most abundant interfaces. Or, more precisely, as their matrix is made of a self-assembled bilayer of phospholipids (see Section 11.6), biomanbranes rather form interphases with interfaces at both sides of the bilayer. This is clearly pictured in the classical, generalized presentation of the membrane structure, proposed by Singer and Nicolson in the 1970s and shown in Fignre 19.1. 

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