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Mediated Transport
Mediated transport refers to cellular transport mediated at the lipid bilayer through phospholipid interactions, or more frequently membrane transport proteins. Substances in the human body may be hydrophobic, electrophilic, contain a positively or negatively charge, or have another property. As such there are times when those substances may not be able to pass over the cell membrane using protein-independent movement. The cell membrane is imbedded with many membrane transport proteins that allow such molecules to travel in and out of the cell. There are three types of mediated transporters: uniport, symport, and antiport. Things that can be transported are nutrients, ions, glucose, etc, all depending on the needs of the cell. One example of a uniport mediated transport protein is GLUT1. GLUT1 is a transmembrane protein, which means it spans the entire width of the cell membrane, connecting the extracellular and intracellular region. It is a uniport system because it specifically t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid Bilayer
The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes form a continuous barrier around all cell (biology), cells. The cell membranes of almost all organisms and many viruses are made of a lipid bilayer, as are the nuclear envelope, nuclear membrane surrounding the cell nucleus, and biological membrane, membranes of the membrane-bound organelles in the cell. 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, even though they are only a few nanometers in width, because 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 transporter, ion pumps. Biological bilaye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cranio-lenticulo-sutural Dysplasia
Cranio-lenticulo-sutural dysplasia (CLSD, or Boyadjiev–Jabs syndrome) is a neonatal/infancy disease caused by a disorder in the 14th chromosome. It is an autosomal recessive disorder, meaning that both recessive genes must be inherited from each parent in order for the disease to manifest itself. The disease causes a significant dilation of the endoplasmic reticulum in fibroblasts of the host with CLSD. Due to the distension of the endoplasmic reticulum, export of proteins (such as collagen) from the Cell (biology), cell is disrupted. The production of SEC23A protein is involved in the pathway of exporting collagen (the COPII pathway), but a missense mutation causes and underproduction of SEC23A which inhibits the pathway, affecting collagen secretion. This decrease in collagen secretion can lead to the bone defects that are also characteristic of the disease, such as skeletal dysplasia and under-ossification. Decreased collagen in CLSD-affected individuals contributes to impro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteogenesis Imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that bone fracture, break easily. The range of symptoms—on the skeleton as well as on the body's other Organ (biology), organs—may be mild to severe. Symptoms found in various types of OI include sclera, whites of the eye (sclerae) that are blue instead, short stature, joint hypermobility, loose joints, hearing loss, breathing problems and problems with the teeth (dentinogenesis imperfecta). Potentially life-threatening Complication (medicine), complications, all of which become more common in more severe OI, include: tearing (Dissection (medical), dissection) of the major arteries, such as Aortic dissection, the aorta; pulmonary insufficiency, pulmonary valve insufficiency secondary to distortion of the ribcage; and basilar invagination. The underlying mechanism is usually a problem with connective tissue due to a lack of, or poorly forme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connective Tissue
Connective tissue is one of the four primary types of animal tissue, a group of cells that are similar in structure, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesoderm, the middle embryonic germ layer. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. The three meninges, membranes that envelop the brain and spinal cord, are composed of connective tissue. Most types of connective tissue consists of three main components: elastic and collagen fibers, ground substance, and cells. Blood and lymph are classed as specialized fluid connective tissues that do not contain fiber. All are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leukocytes. The term "connective tissue" (in German, ) was introduced in 1830 by Johannes Peter Müller. The tissue was already recognized as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type I Collagen
Type I collagen is the most abundant collagen of the human body, consisting of around 90% of the body's total collagen in vertebrates. Due to this, it is also the most abundant protein type found in all vertebrates. Type I forms large, eosinophilic fibers known as collagen fibers, which make up most of the rope-like dense connective tissue in the body. Collagen I itself is created by the combination of both a proalpha1 and a proalpha2 chain created by the COL1alpha1 and COL1alpha2 genes respectively. The Col I gene itself takes up a triple-helical conformation due to its Glycine-X-Y structure, x and y being any type of amino acid. Collagen can also be found in two different isoforms, either as a homotrimer or a heterotrimer, both of which can be found during different periods of development. Heterotrimers, in particular, play an important role in wound healing, and are the dominant isoform found in the body. Type I collagen can be found in a myriad of different places in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golgi Apparatus
The Golgi apparatus (), also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic Cell (biology), cells. Part of the endomembrane system in the cytoplasm, it protein targeting, packages proteins into membrane-bound Vesicle (biology and chemistry), vesicles inside the cell before the vesicles are sent to their destination. It resides at the intersection of the secretory, lysosomal, and Endocytosis, endocytic pathways. It is of particular importance in processing proteins for secretion, containing a set of glycosylation enzymes that attach various sugar monomers to proteins as the proteins move through the apparatus. The Golgi apparatus was identified in 1898 by the Italian biologist and pathologist Camillo Golgi. The organelle was later named after him in the 1910s. Discovery Because of its large size and distinctive structure, the Golgi apparatus was one of the first organelles to be discovered and observed in detail. It was d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
COPII
The coat protein complex II, or COPII, is a group of proteins that facilitate the formation of vesicles to transport proteins from the endoplasmic reticulum to the Golgi apparatus or endoplasmic-reticulum–Golgi intermediate compartment. This process is termed anterograde transport, in contrast to the retrograde transport associated with the COPI complex. COPII is assembled in two parts: first an inner layer of Sar1, Sec23, and Sec24 forms; then the inner coat is surrounded by an outer lattice of Sec13 and Sec31. Function The COPII coat is responsible for the formation of vesicles from the endoplasmic reticulum (ER). These vesicles transport cargo proteins to the Golgi apparatus (in yeast) or the endoplasmic-reticulum-Golgi intermediate compartment (ERGIC, in mammals). Coat assembly is initiated when the cytosolic Ras GTPase Sar1 is activated by its guanine nucleotide exchange factor Sec12. Activated Sar1-GTP inserts itself into the ER membrane, binding preferentially to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
COPI
COPI is a coatomer, a protein complex that coats vesicle (biology), vesicles transporting proteins from the ''cis'' end of the Golgi complex back to the rough endoplasmic reticulum (ER), where they were originally Translation (genetics), synthesized, and between Golgi compartments. This type of transport is ''retrograde transport'', in contrast to the ''anterograde transport'' associated with the COPII protein. The name "COPI" refers to the specific coat protein complex that initiates the budding process on the ''cis''-Golgi membrane. The coat consists of large protein subcomplexes that are made of seven different protein subunits, namely α, β, β', γ, Archain, δ, ε and COPZ1, ζ. Coat proteins Coat protein, or COPI, is an ADP ribosylation factor (ARF)-dependent protein involved in membrane traffic. COPI was first identified in retrograde traffic from the ''cis''-Golgi to the rough endoplasmic reticulum (ER) and is the most extensively studied of ARF-dependent adaptors. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archain 1
Archain 1 is a protein that in humans is encoded by the ARCN1 gene. Function This gene maps in a region, which include the mixed lineage leukemia and Friend leukemia virus integration 1 genes, where multiple disease-associated chromosome translocations occur. It is an intracellular protein. Archain sequences are well conserved among eukaryotes and this protein may play a fundamental role in eukaryotic cell biology. It has similarities to heat shock proteins and clathrin-associated proteins, and may be involved in vesicle structure or vesicle trafficking In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. Vesicles form naturally during the processes of secretion (exocytosis), uptake (endocytosis), and the transport of .... References Further reading * {{gene-11-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication ( translesion synthesis). Mutations may also result from substitution, insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics ( phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Transport
In cellular biology, active transport is the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: primary active transport that uses adenosine triphosphate (ATP), and secondary active transport that uses an electrochemical gradient. This process is in contrast to passive transport, which allows molecules or ions to move down their concentration gradient, from an area of high concentration to an area of low concentration, with energy. Active transport is essential for various physiological processes, such as nutrient uptake, hormone secretion, and nig impulse transmission. For example, the sodium-potassium pump uses ATP to pump sodium ions out of the cell and potassium ions into the cell, maintaining a concentration gradient essential for cellular function. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
