![The Human Cell Membrane](http://s1.studyres.com/store/data/013454859_1-8eae1ac0cfaf772fb624cf543ab90adf-300x300.png)
The Human Cell Membrane
... All cells are surrounded by a cell membrane (also called the plasma membrane). This is a biological membrane or biomembrane consisting of a double layer of lipids in which proteins are located. The cell membrane keeps the components of the cell isolated from the external environment. It also serves ...
... All cells are surrounded by a cell membrane (also called the plasma membrane). This is a biological membrane or biomembrane consisting of a double layer of lipids in which proteins are located. The cell membrane keeps the components of the cell isolated from the external environment. It also serves ...
3-20
... and the nucleus – cytosol = intracellular fluid – organelles = subcellular structures with specific functions ...
... and the nucleus – cytosol = intracellular fluid – organelles = subcellular structures with specific functions ...
Outline
... 2. Endocytosis: Movement of large particles, including large molecules or entire microorganisms, into a cell by engulfing extracellular material, as the plasma membrane forms membrane-bound sacs that enter the cytoplasm. a. Phagocytosis - “cell eating”, engulf solid materials b. Pinocytosis – “cell ...
... 2. Endocytosis: Movement of large particles, including large molecules or entire microorganisms, into a cell by engulfing extracellular material, as the plasma membrane forms membrane-bound sacs that enter the cytoplasm. a. Phagocytosis - “cell eating”, engulf solid materials b. Pinocytosis – “cell ...
Chapter 5
... a) Signal molecules convert an extracellular signal into an intracellular signal via signal transduction 5. Membrane proteins can serve as identification tags functioning in cell-tocell recognition; others form junctions between adjacent cells II. ...
... a) Signal molecules convert an extracellular signal into an intracellular signal via signal transduction 5. Membrane proteins can serve as identification tags functioning in cell-tocell recognition; others form junctions between adjacent cells II. ...
Membrane Structure & Function
... Selective permeability – only some substances can cross Amphipathic – has both hydrophobic & hydrophilic regions Singer-Nicolson: fluid mosaic model Fluid structure w/ various proteins embedded ...
... Selective permeability – only some substances can cross Amphipathic – has both hydrophobic & hydrophilic regions Singer-Nicolson: fluid mosaic model Fluid structure w/ various proteins embedded ...
MOVEMENT THROUGH THE MEMBRANE
... material into the cell by means of infoldings of the cell membrane. – Phagocytosis – extension of the cytoplasm surround and engulf the particle – Pinocytosis – similar to phagocytosis, but cells take up liquid instead of particles. ...
... material into the cell by means of infoldings of the cell membrane. – Phagocytosis – extension of the cytoplasm surround and engulf the particle – Pinocytosis – similar to phagocytosis, but cells take up liquid instead of particles. ...
Academic Cell Boundary PPT
... Membrane Proteins – PROTEIN MOLECULES are EMBEDDED in the Lipid Bilayer – HELP to MOVE Material INTO and OUT of the Cell ...
... Membrane Proteins – PROTEIN MOLECULES are EMBEDDED in the Lipid Bilayer – HELP to MOVE Material INTO and OUT of the Cell ...
Membrane structure, I
... Integral proteins - transmembrane proteins Peripheral proteins - surface of membrane Membrane carbohydrates -~ cell to cell recognition; oligosaccharides (cell markers); glycolipids; glycoproteins ...
... Integral proteins - transmembrane proteins Peripheral proteins - surface of membrane Membrane carbohydrates -~ cell to cell recognition; oligosaccharides (cell markers); glycolipids; glycoproteins ...
File academic cell boundary 2015 ppt
... Membrane Proteins – PROTEIN MOLECULES are EMBEDDED in the Lipid Bilayer – HELP to MOVE Material INTO and OUT of the Cell ...
... Membrane Proteins – PROTEIN MOLECULES are EMBEDDED in the Lipid Bilayer – HELP to MOVE Material INTO and OUT of the Cell ...
MEMBRANE PERMEABILITY ! membranes are highly impermeable
... ! rate of transport is saturable at high substrate concentrations (like enzyme catalysis) ! specific binding site(s) for substrate(s) exists ! substrate binds to site on one side of membrane, conformational change takes place, and site now opens to other side of membrane, releasing substrate ...
... ! rate of transport is saturable at high substrate concentrations (like enzyme catalysis) ! specific binding site(s) for substrate(s) exists ! substrate binds to site on one side of membrane, conformational change takes place, and site now opens to other side of membrane, releasing substrate ...
Membrane structure, I
... Integral proteins - transmembrane proteins Peripheral proteins - surface of membrane Membrane carbohydrates -~ cell to cell recognition; oligosaccharides (cell markers); glycolipids; glycoproteins ...
... Integral proteins - transmembrane proteins Peripheral proteins - surface of membrane Membrane carbohydrates -~ cell to cell recognition; oligosaccharides (cell markers); glycolipids; glycoproteins ...
The Plasma Membrane
... Resting Membrane Potential consequence of pumps, especially Na+/K+ pump, a difference in charge exists across membrane = voltage in resting state all plasma membranes have resting membrane potential of -50 to -100mV (-) sign indicates inside of cell (-) compared to outside so we say all cells ...
... Resting Membrane Potential consequence of pumps, especially Na+/K+ pump, a difference in charge exists across membrane = voltage in resting state all plasma membranes have resting membrane potential of -50 to -100mV (-) sign indicates inside of cell (-) compared to outside so we say all cells ...
Plasma membrane
... • Passive transport: The transportation of materials across a plasma membrane without using energy. ▫ Diffusion: The movement of particles from an area of high concentration to an area of low concentration; a natural result of kinetic molecular energy. ▫ Osmosis: The movement of water or another sol ...
... • Passive transport: The transportation of materials across a plasma membrane without using energy. ▫ Diffusion: The movement of particles from an area of high concentration to an area of low concentration; a natural result of kinetic molecular energy. ▫ Osmosis: The movement of water or another sol ...
Majestic Membranes
... Lipids can drift laterally but don’t “flip-flop” because their hydrophilic regions would have to cross the hydrophobic core Proteins can move, but more slowly Some proteins are held in one place by ...
... Lipids can drift laterally but don’t “flip-flop” because their hydrophilic regions would have to cross the hydrophobic core Proteins can move, but more slowly Some proteins are held in one place by ...
Document
... embedded in, and attached to, the inner (intracellular) and outer (extracellular) surfaces 2. Function a. Selectively permeable barrier: controls what enters and leaves the cell b. Phospholipids are liquid at body temperature, so proteins float around in the membrane -functions as a Fluid Mosaic ...
... embedded in, and attached to, the inner (intracellular) and outer (extracellular) surfaces 2. Function a. Selectively permeable barrier: controls what enters and leaves the cell b. Phospholipids are liquid at body temperature, so proteins float around in the membrane -functions as a Fluid Mosaic ...
Moving Cellular Materials
... concentration to a low concentration. (GASES) But what does having a high concentration mean? CLASS DEMO ...
... concentration to a low concentration. (GASES) But what does having a high concentration mean? CLASS DEMO ...
Phospholipids make up cell membranes
... solute concentration than what it is compared with. hypotonic solution- a solution with a lower solute concentration than what it is compared with. isotonic solution a solution with an equal solute concentration to what it is compared with. ...
... solute concentration than what it is compared with. hypotonic solution- a solution with a lower solute concentration than what it is compared with. isotonic solution a solution with an equal solute concentration to what it is compared with. ...
L2-Bacterial Structures v3
... •Defines the boundary of the cell •Semi-permeable; excludes all but water, gases, and some small hydrophobic molecules •Transport proteins function as selective gates (selectively permeable) •Control entrance/expulsion of antimicrobial drugs •Receptors provide a sensor system •Phospholipid bilayer, ...
... •Defines the boundary of the cell •Semi-permeable; excludes all but water, gases, and some small hydrophobic molecules •Transport proteins function as selective gates (selectively permeable) •Control entrance/expulsion of antimicrobial drugs •Receptors provide a sensor system •Phospholipid bilayer, ...
The main points that you should learn from the problems in øvelse 2
... If the protein has a ER import signal (hydrophobic stretch of amino acids at the N-terminus, page 504) the ribosome docks onto the ER membrane and the rest of the protein is synthesized into the lumen of the ER (unless a transfer stop signal is present) (page 510). Proteins with a nuclear import sig ...
... If the protein has a ER import signal (hydrophobic stretch of amino acids at the N-terminus, page 504) the ribosome docks onto the ER membrane and the rest of the protein is synthesized into the lumen of the ER (unless a transfer stop signal is present) (page 510). Proteins with a nuclear import sig ...
Cell Boundaries
... concentrated area of water to a less concentrated area of water. hypertonic (“above strength”): the more concentrated solution hypotonic (“below strength”): the more dilute solution isotonic (”same strength”): When concentrations of solutions are the same on both sides of a membrane ...
... concentrated area of water to a less concentrated area of water. hypertonic (“above strength”): the more concentrated solution hypotonic (“below strength”): the more dilute solution isotonic (”same strength”): When concentrations of solutions are the same on both sides of a membrane ...
Lipid bilayer
![](https://commons.wikimedia.org/wiki/Special:FilePath/Lipid_bilayer_section.gif?width=300)
The lipid bilayer is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells. The cell membranes of almost all living organisms and many viruses are made of a lipid bilayer, as are the membranes surrounding the cell nucleus and other sub-cellular structures. The lipid bilayer is the barrier that keeps ions, proteins and other molecules where they are needed and prevents them from diffusing into areas where they should not be. Lipid bilayers are ideally suited to this role because, even though they are only a few nanometers in width, they are impermeable to most water-soluble (hydrophilic) molecules. Bilayers are particularly impermeable to ions, which allows cells to regulate salt concentrations and pH by transporting ions across their membranes using proteins called ion pumps.Biological bilayers are usually composed of amphiphilic phospholipids that have a hydrophilic phosphate head and a hydrophobic tail consisting of two fatty acid chains. Phospholipids with certain head groups can alter the surface chemistry of a bilayer and can, for example, serve as signals as well as ""anchors"" for other molecules in the membranes of cells. Just like the heads, the tails of lipids can also affect membrane properties, for instance by determining the phase of the bilayer. The bilayer can adopt a solid gel phase state at lower temperatures but undergo phase transition to a fluid state at higher temperatures, and the chemical properties of the lipids' tails influence at which temperature this happens. The packing of lipids within the bilayer also affects its mechanical properties, including its resistance to stretching and bending. Many of these properties have been studied with the use of artificial ""model"" bilayers produced in a lab. Vesicles made by model bilayers have also been used clinically to deliver drugs.Biological membranes typically include several types of molecules other than phospholipids. A particularly important example in animal cells is cholesterol, which helps strengthen the bilayer and decrease its permeability. Cholesterol also helps regulate the activity of certain integral membrane proteins. Integral membrane proteins function when incorporated into a lipid bilayer, and they are held tightly to lipid bilayer with the help of an annular lipid shell. Because bilayers define the boundaries of the cell and its compartments, these membrane proteins are involved in many intra- and inter-cellular signaling processes. Certain kinds of membrane proteins are involved in the process of fusing two bilayers together. This fusion allows the joining of two distinct structures as in the fertilization of an egg by sperm or the entry of a virus into a cell. Because lipid bilayers are quite fragile and invisible in a traditional microscope, they are a challenge to study. Experiments on bilayers often require advanced techniques like electron microscopy and atomic force microscopy.