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      • Meaning and definition of carrier : In human genetics , an individual who is heterozygous at a given genetic locus, with one normal allele and one potentially harmful recessive allele.
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  2. Carrier | definition of Carrier by Medical dictionary › carrier

    car·ri·er. ( ka'rē-er ), 1. A person who or animal that harbors a specific infectious agent in the absence of discernible clinical disease and serves as a potential source of infection. See also: label, tracer. 2.

  3. Carrier - definition of carrier by The Free Dictionary › carrier

    carrier - (genetics) an organism that possesses a recessive gene whose effect is masked by a dominant allele; the associated trait is not apparent but can be passed on to offspring

  4. Definition of carrier in Biology. - OER2Go › biology › definition

    Another type of protein embedded in the plasma membrane is a carrier protein. Carrier proteins are typically specific for a single substance. Channel and carrier proteins transport material at different rates. Channel proteins transport much more quickly than do carrier proteins. Carrier proteins change shape as they move molecules across the membrane.

  5. Carrier - Bio-Medicine - latest biology and medical news ... › biology-definition › Carrier

    Carrier has several different meanings: in telecommunication, a carrier wave; in biology, an asymptomatic carrier; the Carrier tribe, a First Nations tribe living in British Columbia, Canada; also the name of their Athabaskan language a common carrier, a transport business (shipping or telecom) an aircraft carrier

  6. * Carrier (Biology) - Definition - Online Encyclopedia › biology › carrier

    Carrierproteins are proteinsthat carry substances from one side of a biological membraneto the other. Carrier, a video game for the Sega Dreamcast. the town of Carrier, Oklahoma. a unit in the computer game StarCraft, the Protoss Carrier. carrier.

  7. Carrier definition and meaning in biology › glossary_of_biology_terms › carrier

    Meaning and definition of carrier : In human genetics, an individual who is heterozygous at a given genetic locus, with one normal allele and one potentially harmful recessive allele. The heterozygote is phenotypically normal for the character determined by the gene but can pass on the harm

  8. Carrier protein - Definition and Examples - Biology Online ... › dictionary › carrier-protein
    • Carrier Protein Definition
    • Carriers vs. Channel-Formers
    • Types of Carrier Proteins
    • Functions of Carrier Proteins
    • Transport Mechanism
    • Examples of Carrier Proteins
    • FAQ
    • Related Terms
    • See Also
    • References

    In biology, a carrier protein is a type of protein that transports specific substance through intracellular compartments, into the extracellular fluid, or across cells as opposed to channel proteins, which is another membrane transport proteins, that are less-selective in transporting molecule. Similar to other membrane transport proteins, carrier proteins are located in lipid bilayer cell structures, such as cell membranes, mitochondria, and chloroplasts.

    Carrier proteins are membrane transport proteins along with the channel proteins. As membrane transport proteins, they are located in biological membranes and their primary function is to move molecules from one site to another. These transporters though differ in certain aspects. Channel proteins, as their name implies, form a ”channel” that serves as a passageway for molecules to pass through. They are firmly and permanently situated in the plasma membrane, with their hydrophobic domains interacting with the membrane’s lipids. Channels that remain open to both the cell’s interior and exterior are referred to as pores. Aquaporin is an example of a channel protein in the cell membrane that allows water molecules to flow through. Conversely, carrier proteins do not form channels. Rather, they have binding sites from where molecules can bind to. Then, they shuttle the molecules towards their destination, i.e. the membrane’s interior or exterior. Having binding sites indicate that carr...

    Carrier proteins that are involved in the active transport of molecules or substances may be classified based on the transport activity that they are in. Carrier proteins that are involved in carrier-mediated diffusion are those that are driven by a concentration gradient and not by ATP hydrolysis. They transport molecules from an area of high concentration to an area of low concentration. Examples are carrier proteins involved in the facilitated diffusion of sugars, amino acids, and nucleosides across cell membranes of most cells. (Ref. 1) Carrier proteins that transport molecules against the concentration gradient are those that use substantial energy. Depending on the energy source, the carrier proteins may be classified as (1) ATP-driven, (2) electrochemical potential-driven, or (3) light-driven. ATP-driven carrier proteins are those requiring ATP to transport molecules whereas electrochemical potential-driven proteins are those fueled by electrochemical potential. Light-driven...

    Carrier proteins are involved in both the passive and active types of biological transport processes. In passive transport, molecules get transported downhill, i.e. from higher to lower concentration. The difference in the concentrations between two regions creates a concentration gradient that is enough to trigger passive transport. However, because of the lipid-bilayer nature of the cell membrane, not all molecules will be able to move out or into the cell according to their concentration gradient. Polar molecules and ions cannot readily diffuse across the membrane. They need membrane transport proteins, like carriers, to facilitate their transport. If a carrier protein is utilized in the process, the molecule “takes a seat” on the carrier protein from one side of the membrane, and then carried to the other side to be released. This form of diffusion (or passive transport) that makes use of a membrane protein for transport down the concentration gradient is called facilitated diff...

    In both passive and active transport, the carrier proteins move molecules by binding to the latter and then undergo a conformational change. They change shape as they carry the molecules from one side of the membrane to the other. In an active transport though, chemical energy is required. Through ATP hydrolysis, energy is released when ATPases catalyze the decomposition of ATP to ADP. The liberation of one inorganic phosphate from the ATP causes the concomitant release of the energy as well. Not all active transport processes are fueled by direct ATP coupling. Another form of active transport makes use of an electrochemical gradient rather than ATP. For example, cations moving passivelywill generate entropy that can fuel the active transport of another group of ions.

    Glucose transporters

    ”Glucose transporters” in the cell membrane of the animal cells take up glucose molecules without utilizing ATP when the cell has less glucose than the outside. Glucose is a vital biomolecule as it serves as an energy source. In human cells, there are 14 glucose transporters. They are uniporter, binding specifically to and carrying glucose molecules. GLUT1, for example, is a glucose transporter expressed in almost all cell types. In adults, it is expressed at highest levels in red blood cells.

    Sodium-potassium pump

    Na+/K+ pump is an antiporter. It has binding sites for Na+ ions and K+ ions. Since the movement of these ions are against their concentration gradients, the pump requires an energy source. Thus, it binds to ATP to hydrolyze it to ADP, thereby, causing the release of energy. The pump uses this energy to alter its shape. After conformational change, the ions dissociate from the pump but are released in opposite directions. Na+ ions are pumped out while K+ ions are pumped into the cell. The func...

    Glucose-sodium transport proteins

    Glucose-sodium transport proteins are symport carrier proteins that transport glucose actively. When the cell has much glucose inside and yet still wants to take up more, it makes use of glucose-sodium transporter. This transporter has binding sites for glucose and two Na+ ions. Since the cell initially has less Na+ ions, the Na+ ions diffuse passively. Consequently, an electrochemical potential gradient is generated and this drives the transporter to move the glucose molecule activelyinto th...

    Is a carrier protein a transport protein? A carrier protein is a type of membrane transport protein. Another major type of membrane transport protein is a channel protein. One way to distinguish a carrier protein from a channel protein is its binding site that selects molecules to transport. When a molecule or a solute binds to this site, the carrier protein moves them to the other side of the membrane. Some carriers will need an energy source (e.g. ATP or electrochemical potential gradient) or a photon to incite the carrier to alter its shape resulting in the release of the bound molecule or a solute. What does it mean for a carrier protein to be saturated? A carrier protein is saturated when all its binding sites are occupied. Consequently, the transport rate will be maximal. Referred to as Vmax, the transport rate delineates a property of the specific carrier that reflects the rate at which it can change between its two conformational states. When the transport rate is half its m...

    Cooper, G. M. (2010). Transport of Small Molecules. Retrieved from website:
    Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2010). Carrier Proteins and Active Membrane Transport. Retrieved from website:
    BiologyOnline Editors. (2014, May 12). Sodium-potassium pump. Retrieved from Biology-Online Dictionary | Biology-Online Dictionary website:
    BiologyOnline Editors. (2014, May 12). Active transport. Retrieved from Biology-Online Dictionary | Biology-Online Dictionary website:
  9. Apr 28, 2017 · Carrier Protein Definition. Carrier proteins are proteins that carry substances from one side of a biological membrane to the other. Many carrier proteins are found in a cell ’s membrane, though they may also be found in the membranes of internal organelles such as the mitochondria, chloroplasts, nucleolus, and others.

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