Lecture

Lipid Bilayers: Diffusion and Mechanisms

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In course

BIO-207: Cellular and molecular biology II

This course is aimed to familiarize students with the 3D organization of a eukaryotic cell, its compartmentalization, how cellular compartments communicate together and how a cell communicates with its environment. The related molecular mechanisms will be ...

Description

This lecture explores the reasons behind the diversity of lipids in biological membranes and their impact on diffusion mechanisms within lipid bilayers. Topics include the collective diffusive motions of neighboring lipids, the process of lipid flip-flop between bilayer sheets, the role of proteins like flipases and scramblases in lipid movement, membrane heterogeneity and asymmetry, and the concept of lipid rafts. Additionally, the lecture discusses the composition of liposomes with different lipid mixtures and the origin of biological phase separation. The asymmetric transverse distribution of lipids in the lipid bilayer and the action of kinases and phosphatases on phosphoinositides are also covered.

Instructors (3)

Romain Zufferey

Teaching & PhD Courses Biology for engineers MSE-212 This course consists of an introduction to biology and more particularly to biology as a multidisciplinary field, emphasizing natural examples of materials engineering. It should therefore allow engineering students to find inspiration from biology in future materials research problems. Cellular biology and biochemistry for engineers BIO-105 Basic course in biochemistry as well as cellular and molecular biology for non-life

Françoise Gisou van der Goot Grunberg

Gisou van der Goot is the Head of the Laboratory of Cell and Membrane Biology, and founding member of the Global Health Institute (GHI), School of Life Sciences, at the Swiss Federal Institute of Technology Lausanne/EPFL (Ecole Polytechnique Fédérale de Lausanne). She is currently Vice President for Responsible Transformation, in charge of reinforcing values such as inclusion and sustainability throughout the School’s campus. From 2014 to 2020, she was Dean of the School of Life Sciences. Before joining EPFL, she was Group Leader at the Faculty of Sciences of the University of Geneva (UNIGE) and subsequently Associate Professor at the Faculty of Medicine of the same university. She studied engineering at the Ecole Centrale de Paris, then did a PhD in Molecular Biophysics at the Nuclear Energy Research Center, Saclay, France, followed by a postdoc at the European Molecular Biology Laboratory (EMBL) in Heidelberg. She obtained an EMBO Young Investigator award in 2001, a Howard Hughes International Scholar award in 2005 and the Swiss Prix Marcel Benoist in 2009, the same year she was elected EMBO member (European Molecular Biology Organisation). She is a leader in the fields of molecular and cellular understanding of bacterial toxins, the organization of mammalian membranes and in organelles biology. Professor van der Goot is member of diverse scientific boards such as the Swiss National Science Foundation (SNF), the Conseil suisse de la science et de la technologie (CSST) and the European Research Council (ERC).

Wouter Richard Karthaus

Teaching & PhD PhD Students Jillian Rose Love, Estelle Deby, Ester Simkova, Turan Badalli Courses Cellular and molecular biology II BIO-207 This course is aimed to familiarize students with the 3D organization of a eukaryotic cell, its compartmentalization, how cellular compartments communicate together and how a cell communicates with its environment. The related molecular mechanisms will be discussed. Practical - Karthaus Lab BIO-616 Students will learn 1) how organoids c

Official source

Ontological neighbourhood

Biology

Cell biology: Membrane biology

Related concepts (22)

Lipid bilayer phase behavior

One property of a lipid bilayer is the relative mobility (fluidity) of the individual lipid molecules and how this mobility changes with temperature. This response is known as the phase behavior of the bilayer. Broadly, at a given temperature a lipid bilayer can exist in either a liquid or a solid phase. The solid phase is commonly referred to as a “gel” phase. All lipids have a characteristic temperature at which they undergo a transition (melt) from the gel to liquid phase.

Lipid bilayer fusion

In membrane biology, fusion is the process by which two initially distinct lipid bilayers merge their hydrophobic cores, resulting in one interconnected structure. If this fusion proceeds completely through both leaflets of both bilayers, an aqueous bridge is formed and the internal contents of the two structures can mix. Alternatively, if only one leaflet from each bilayer is involved in the fusion process, the bilayers are said to be hemifused.

Protein

Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity.

Protein folding

Protein folding is the physical process where a protein chain is translated into its native three-dimensional structure, typically a "folded" conformation, by which the protein becomes biologically functional. Via an expeditious and reproducible process, a polypeptide folds into its characteristic three-dimensional structure from a random coil. Each protein exists first as an unfolded polypeptide or random coil after being translated from a sequence of mRNA into a linear chain of amino acids.

Facilitated diffusion

Facilitated diffusion (also known as facilitated transport or passive-mediated transport) is the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins. Being passive, facilitated transport does not directly require chemical energy from ATP hydrolysis in the transport step itself; rather, molecules and ions move down their concentration gradient reflecting its diffusive nature.

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