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Membrane in Biological Definition

Biological membrane

A biological membrane or biomembrane is a membrane which acts as a barrier within or around a cell . It is a lipid bilayer , being composed of a double layer of lipid -class molecules , specifically phospholipids , with occasional proteins intertwined, some of which function as chan...

Chloroplast membrane

Chloroplasts contain several important membranes , vital for their function. Like mitochondria , chlorplasts have a double-membrane envelope, called the chloroplast envelope . Each membrane is a phospholipid bilayer , between 6 and 8 nm thick, and the two are separated by a gap of 10-20...

Cell membrane

A component of every biological cell , the selectively permeable cell membrane (or plasma membrane or plasmalemma ) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell . It separates a cell's interior from its surroundings and controls what...

Cell membrane

A component of every biological cell , the selectively permeable cell membrane (or plasma membrane or plasmalemma ) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell . It separates a cell's interior from its surroundings and controls what...

Actin

...st case, one end of myosin is bound to the plasma membrane while the other end walks towards the plus end of the actin filament. This pulls the membrane into a different shape relative to the cell cortex..., form the cells cortex. This underlies the plasma membrane and is responsible for the shape of the cell. ...

Acrosome

...ucida, this reaction takes place, during which actin polymerizes to form the acrosomal process ; also, the acrosomal vesicle fuses with the plasma membrane of the egg cell, and digestive enzymes are released from the sperm to digest the zona pellucida and give access to the egg. See also Capaci...

Acrosome

...ucida, this reaction takes place, during which actin polymerizes to form the acrosomal process ; also, the acrosomal vesicle fuses with the plasma membrane of the egg cell, and digestive enzymes are released from the sperm to digest the zona pellucida and give access to the egg. See also Capaci...

Active transport

... movement of desired substance across a membrane, independent of any other species. Secondary transport concerns the diffusion of one species across a membrane to drive the transport of another. Primary Primary active transport directly uses energy to transport molecules across a membrane. Most of th...

Albumin

...d for proper distribution of body fluids between intravascular compartments and body tissues. Albumin is negatively charged. The glomerular basement membrane is also negatively charged, this prevents the filtration of albumin in the urine. In nephrotic syndrome, this property is lost, and there is more albu...

Anatomy

...s (not classified): Artery Coelom Diaphragm Gastrointestinal tract Hair Exoskeleton Lip Nerve Peritoneum Serous membrane Skeleton Skull Spinal cord Vein See also List of anatomical topics List of human anatomical features Important p...

Antibiotic

...etronidazole, quinolones, novobiocin Drugs which interfere with RNA synthesis Rifampin (rifampicin) Drugs which interfere with cell membrane function Polymyxin B, gramicidin Antibiotics can also be classified by the organisms against which they are effective, and by the type of ...

Antibody

...0 kD. It can be found on the surface of the plasma membrane of basophils and mast cells of connective tis... This complex is moved to the outside of the cell membrane , where it can be recognized by a T lymphocyte , ...hich compares it to similar structures on the cell membrane of a B lymphocyte . If it finds a matching pair, ...

Apoptosis

... the nuclear envelope . At this stage, the double membrane that surrounds the nucleus still appears complete;... due to the degradation of DNA [4] . Plasma membrane blebbings. The cell is phagocytosed , or , ...he major extrinsic mediator of apoptosis. The cell membrane has two specialized receptors for TNF: TNF-R1 and ...

Archaea

...also set the Archaea apart. Unlike most bacteria, they have a single cell membrane that lacks a peptidoglycan wall. Further, both bacteria and eukaryotes ...lace eukaryotes closer to Eurarchaeota than Crenarchaeota are, although the membrane chemistry suggests otherwise. However, the discovery of archaean-like gene...

ATP synthase

...is fashion is termed oxidative phosphorylation . Same process takes place in mitochondria , were ATP synthase is located in the inner mitochondrial membrane (so that F 1 -part sticks into mitochondrial matrix, were ATP synthesis takes place). Plant ATP synthase In plants ATP synthase is also present...

ATPase

...widely used in all known forms of life . Some such enzymes are integral membrane proteins (anchored within biological membranes ), and move solutes acro...ically preferred direction of movement—that is, from the side of the membrane where they are in low concentration to the side where they are in high conc...

B cell

...e produced in all other vertebrates. The human body makes hundreds of different types of B cells, and each type has a unique receptor protein on its membrane that will bind to one particular antigen; at any one time in the human body millions of B cells are circulating in the blood and lymph, but are not ...

Bacterium

... Gracilicutes - bacteria with a second cell membrane containing lipids , giving them Gram-negative stains Firmicutes - bacteria with a single membrane and thick peptidoglycan wall, giving them Gram-... stains Mollicutes - bacteria with no second membrane or wall, giving them Gram-negative stains Th...

Biochemistry

...of cell metabolism has been extensively described. Other areas of biochemistry include the genetic code ( DNA , RNA ), protein synthesis , cell membrane transport, and signal transduction . Contents showTocToggle("show","hide") 1 Development of biochemistry 2 Subdisciplines ...

Biophysics

...tical analysis . Medicine and neuroscience - tackling neural networks experimentally (brain slicing) as well as theoretically (computer models), membrane permitivity, gene therapy, understanding tumors. Pharmacology and physiology - channel biology, biomolecular interactions, cellular membranes, p...

Brain

... are caused by germs. Viral or bacterial infection of the meninges, the membrane that covers the brain, can lead to meningitis . Bovine spongiform encepha...he development of research in bioelectricity and to the discovery of the membrane potential , action potential , etc., by researchers such as Emil du Bois-...

Cell biology

...s, such as those to be incorporated in membranes ( membrane proteins ), are transported into the ER during s...ocessed in the Golgi apparatus . From the Golgi, membrane proteins can move to the plasma membrane , to other subcellular comparments or they can be ...

Cell nucleus

...0 to 20 micrometres . It is enclosed by a double membrane called the nuclear envelope . The inner and outer membrane fuse at regular intervals, forming nuclear pores ... reactions happening within the nucleus. The outer membrane is continuous with the rough endoplasmic reticulu...

Cell growth

...rily for nutrient storage can have a smooth surface membrane, but metabolically active large cells often have some sort of folding of the cell surface membrane in order to increase the surface area available for transport functions. Yeast cell size regulation The relationship between cell size and c...

Cellular respiration

...lized due to such losses as the cost of moving pyruvate into mitochondria. This takes place in the mitochondria in eukaryotic cells , and at the cell membrane in prokaryotic cells . Anaerobic respiration (Fermentation) " Anaerobic respiration" It does not require oxygen. True anaerobic respiration ...

Cell metabolism

... Protein catabolism is the breakdown of proteins into amino acids and simple derivative compounds, for transport into the cell through the plasma membrane and ultimately for the polymerisation into new proteins via the use of ribonucleic acids ( RNA ) and ribosomes . See also Biochemistry ...

Chemiosmotic hypothesis

...unctioned as a kind of electrochemical capacitor , using the energy of NADH and FADH 2 to create a proton gradient across the mitochondrial membrane and that this energy was used by a reversible proton pump , the ATP synthase , to create ATP . This was a radical proposal at the time, and not we...

Chloroplast

...plants. Both organelles are surrounded by a double membrane with an intermembrane space; both have their own D...ining chloroplasts, forming chloroplasts with four membrane layers. The fluid within the chloroplast is cal... thylakoid. The photosynthetic proteins in the membrane bind chlorophyll , which is present with various ...

Cilium

...d scientists to re-evaluate its physiological role(s) in the cell signaling and the control of cell growth and development. A cilium has an outer membrane that surrounds a core called an axoneme , which contains nine pairs of microtubule doublets and other associated proteins. Motile cilia have a c...

Cisterna

...terna, Italy . A cisterna (plural cisternae ) comprises a flattened membrane disk which makes up the Golgi apparatus . A typical Golgi has anywhere fro...also carry structural proteins important for its maintenance as a flattened membrane and its stacking upon each other. The earliest cisternae are called the...

Ion gradient

...is fashion is termed oxidative phosphorylation . Same process takes place in mitochondria , were ATP synthase is located in the inner mitochondrial membrane (so that F 1 -part sticks into mitochondrial matrix, were ATP synthesis takes place). See also Transmembrane potential difference ...

Crista

... Cristae are the infoldings of the inner membrane of a mitochondrion . They are studded with proteins, including ATP synthase and a variety of cytochromes , and function in cellular respiration ...

Cytoplasm

...is the colloidal , semi-fluid matter contained within the cell 's plasma membrane , in which organelles are suspended. In contrast to the protoplasm , the...mes , ribosomes ), several vacuoles , cytoskeletons as well as complex membrane structures (e.g. endoplasmic reticulums or the golgi apparatus ). ...

Cytoskeleton

...enance of cell shape. All non-spherical bacteria have genes encoding actin-like proteins, and these proteins form a helical network beneath the cell membrane that guides the proteins involved in cell wall biosynthesis . Some plasmids encode a partitioning system that involves an actin-like protein ParM...

Cytotoxic T cell

...d tumor cells. Once activated by a MHC-antigen complex, T C cells release the protein perforin , which forms pores in the target cell's plasma membrane ; this causes ions and water to flow into the target cell, making it expand and eventually lyse . T C also release granzyme , a serine protease ,...

Cytosol

...rd the outside of the cell. Water flows into the cell, making the cell larger. To prevent the cell from bursting apart, molecular pumps in the plasma membrane , the cytoskeleton, the tonoplast or the cell wall (if present), are used to counteract the osmotic pressure. Details The cytosol is 20% to 3...

Developmental biology

...ula , blastulation , chorion , chrysalis , cleavage , ectoderm , embryo , embryogenesis , embryogeny , embryology , endoderm , extra-embryonic membrane , fetus (or foetus ), gastrula , gastrulation , germ layer , germ plasm , germination , induction , juvenile , larva , maternal effect , m...

Depolarization

... refers to the event a cell undergoes when its membrane potential grows more positive with respect to the... Compare to hyperpolarization . Depolarization of membrane potentials is important for other cell types, part...icularly muscle cells. Related topics membrane potential action potential ...

Dialysis

...erent. It works by having the blood flow along one side of a semipermeable membrane , with the dialysis solution flowing along the other side. Due to the difference in osmolarity between the two liquids, water traverses the membrane in order to dilute the dialysis liquid, carrying along the unwanted blood c...

Diffusion

...ons depends on the concentration gradient, and the membrane potential. The net flux of ions can be altered by ...sion of a solute across a selectively permeable membrane . Photon diffusion When photons travel ...r junction transistor Brownian motion Cell membrane Circulatory system Diffusion equation ...
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