Membrane transport protein

Efflux is a method of facilitated transport carried out by protein complexes that fall into one of six currently identified classes based on their protein structure.44 These complexes are commonly able to recognize more than one substrate, making them a major cause of multidrug resistance, especially in Gram negative organisms.45 As many of these proteins are not expressed constitutively, it may be hard to predict the effect these complexes have on in-vivo treatment; many are tightly regulated to maintain cell homeostasis, and alterations to the control of these systems can cause drastic changes in resistance. The genes encoding efflux proteins can be both chromosomal and harbored on plasmids, making it possible for horizontal transmission…

Structure of Tight Junctions and their Dynamic Functions in Health and Disease Tight junction (TJ) discovery in the 1960s helped determine the nature of paracellular transport while the discovery of their constituting proteins subsequently improved understanding of TJs’ dynamic structure. Their role can be appreciated particularly in epithelial cells and when their formation is compromised; I aim to briefly explore the cause of Crohn’s disease to illustrate this. Furthermore, I will outline the…

of membranes that are grouped together and mainly amphipathic. The variation in head groups and aliphatic chains allows the presence of more than 1000 different lipid species in any eukaryotic cell. Different types of lipid include Phospholipids, Sphingolipids and Cholesterol. Lipid plays a role in many functions of the cell such as the signaling and the conversion of energy, membrane fluidity and compartmentalization of cellular organelles. The movement of lipids from their sites of synthesis…

from 60% RNA and 40% protein, and consist of two subunits, one large and one small. When produced, the subunits stay separate to exit through the nuclear pores: it is only because of their miniscule size that they can fit through. Many ribosomes then bind themselves to the RER, although some stay free in the cytoplasm. Free and bound ribosomes both create polypeptide chains, which are used to make proteins. To create a polypeptide chain the large and small subunits must join together. Between…

work of early scientists by changing the soup broth with bacteria in it to a preserved petri dish. 4. Both cells and atoms are basic building blocks. 5. This poison would not kill bacteria because bacteria do not have a nucleus. 3.2 1. The cytoskeleton provides support for the cell and helps the organelles in the cell move. 2. The nucleus is protected by a double membrane which has pores that provide a pathway to the cytoplasm. 3. The mitochondrion provides energy to the cell using its stored…

allow the cell to do the job it is assigned correctly. An example of a cell would be the animal cell, which is a eukaryotic cell or a cell that contains a plasma membrane. Inside the membrane there are parts of the cell called the organelles. (Animal Cell Structure, 2005) Organelles inside the cell have specific jobs to perform for the cell, organelles include the ribosomes, vacuoles, centrioles, lysosomes, peroxisomes, cilia, flagella, mitochondria and the endoplasmic reticulum. In addition…

In the fifth chapter of Biology, Peter Raven and George Johnson demonstrate the pedagogical functionality of metaphor by “highlighting” (Kövecses 91) the biological function of cell membranes through the underlying descriptive structural megametaphors CELL MEMBRANE IS A WALL and TRANSPORT PROTEINS ARE DOORS and the mappings between them, and by “hiding” (Kövecses 92) other aspects of this concept. Throughout this chapter, Peter Raven and George Johnson pair these main conceptual metaphors with…

Interactive Question 7.2 Cite some experimental evidence that indicates that membrane proteins drift. A good form of experimental evidence is Fluorescence Recovery After Photobleaching, aka FRAP. In the FRAP process, membrane proteins are labelled with a green fluorescent protein, and part of the plasma membrane is “bleached” with a laser, causing them to lose their fluorescence. The part that was bleached will eventually become fluorescent again, as molecules drift in by diffusion. How might…

This semi-permeable membrane works as a barrier for the cell. Since it is semi-permeable, it allows some substances/particles into the cell but denies access to others. The cytoplasm is the fluid within each individual cell that surrounds the organelles. This is the 'place' where the organelles complete their individual tasks. The Rough Endoplasmic(RER) Reticulm is a part of a series of connected 'hallways' that carry materials to various parts of the cytoplasm. The RER has many ribosomes…

oval-shaped structure bound by a double membrane called the nuclear envelope. Inside the nucleus, are organelles called nucleoli, which assemble RNA and synthesize ribosomal subunits. Throughout the inside of the nucleus, is a substance called the nucleoplasm, which suspends the nucleus’ structures. The nucleus controls the activities of the cell to maintain life and reproduce. It also regulates the synthesis of protein by sending mRNA to the ribosomes of the cell as a template for protein…