Receptor Protein – Protein that binds to a specific single molecule, enabling the cell to respond to the signal molecule.
i.e. – The muscles of a person exercising can not contract without receptor proteins and signal molecules that tell the muscles when to contract and when to relax.
Second Messenger – Signal molecule produced in response to the binding of a chemical signal. Acts as a signal molecule in the cytoplasm.
Signal Molecule – Carries information throughout the body and to other cells.
Ion Channel – A large protein in the cell membrane that transports a specific ion.
Enzyme Action – Speeds up chemical reactions in the cell
Beta Blocker – A drug that interferes with the binding of signal molecules to receptor proteins and heart muscles.
Changes in permeability – Occur when a receptor protein is coupled with an ion channel.
Functions of receptor proteins
The signal molecule binds to the receptor protein that’s specialized to fit the molecule.
Binding of a signal molecule to the matching receptor protein causes a change in the activity of the receiving cell in three ways:
1. Changes in permeability of receiving cell
2. Triggering the formation of second messengers inside the cell
3. Activating the enzymes inside the cell
1. Changes in Permeability
An Ion Channel may be coupled with the receptor protein, is in Figure 4-8 on Pg. 84. The binding of the second messenger and the receptor protein causes the Ion Channel to open. This allows specific ions to cross the cell membrane.
2. Second Messengers
Receptor protein can cause a second messenger to form inside of the cell. Some second messengers activate enzymes, triggering a series of biochemical reactions in the cell.
The pump exchanges three sodium molecules for two potassium molecules. In doing so an electrical gradient is formed across the basolateral membrane of the cell due to the imbalance of charge generated. The interior of the cell is negative by about 80mV in relation to the outside...
For muscles to contract then there must be a presence of calcium within the fibers as it connects with troponin protein and orders tropomyosin to clear the binding sites to allow myosin to attach to these sites, which allows the muscle to contract and produces movement. Without all of these elements working in sync then the function of skeletal muscle would no longer work or even exist.
...s to interfere with bonding to the receptors. The final possibility uses CNP, which downregulates the activation in MAP kinase pathways in the chondrocytes (4).
There are a series of nodes along the axon where there is a high concentration of sodium (Na+) and K+ channels. There is a high concentration of Na+ outside the cell and a high concentration of K+ inside the cell. As the nodes sen...
When something changes in the inner environment it sends information to the receptor. The receptor sends information to the control center and then the control center sends instructions to the effector once the information is received from the control center it proceeds to either oppose or increase the stimulus. This process is designed to repeatedly work at restoring or maintaining homeostasis.
This occurs when special carrier proteins carry solutes dissolved in the water across the membrane by using active transport. When the concentration gradient can not allow travel from one side of the membrane to the other fast enough for the cell’s nutritional needs, then facilitated diffusion is used. The transport protein is specialized for the solute it is carrying, just as enzymes are specialized for their substrate. The transport protein can be
glutamate receptors using antibodies, that tag on to the receptor itself. The proteins that make up the
The entire process starts off when an agonist involved is bound to receptors specific to it, expressed on the endothelial cell surface, activating enzymes like phospholipase C (PLC) directly through vascular endothelial growth factor receptors (VEGFR) or by thrombin or histamine through G protein coupled receptors (GPCR).
An analogy that fits very well with the study of the endocrine system is that of a message in a bottle. We can think of the body as a river, and a specific hormone may be a bottle containing a message. The organs or glands mentioned above would manufacture the “bottles'; (hormones) that would be released into the river (blood stream). If there were no receptor sites for the hormones in the body, then they would continue to flow along the river and probably not make their destination. However, there are systems of receptor sites that enable specific hormones to bind in specific places. Structure also plays a major role in determining which hormones are able to bind to which receptors.
The direction of osmosis depends on the relative concentration of the solutes on the two sides. In osmosis, water can travel in three different ways. If the molecules outside the cell are lower than the concentration in the cytosol, the solution is said to be hypotonic to the cytosol, in this process, water diffuses into the cell until equilibrium is established. If the molecules outside the cell are higher than the concentration in the cytosol, the solution is said to be hypertonic to the cytosol, in this process, water diffuses out of the cell until equilibrium exists. If the molecules outside and inside the cell are equal, the solution is said to be isotonic to the cytosol, in this process, water diffuses into and out of the cell at equal rates, causing no net movement of water. In osmosis the cell is selectively permeable, meaning that it only allows certain substances to be transferred into and out of the cell. In osmosis, the proteins only on the surface are called peripheral proteins, which form carbohydrate chains whose purpose is used like antennae for communication. Embedded in the peripheral proteins are integral
Neurotransmitters can also produce their effects by modulating the production of other signal-transducing molecules ("second messengers"messengers") in the post-synaptic cells (Cooper, Bloom and Roth 1996). Nine compounds -- belonging to three chemical families -- are generally believed to function as neurotransmitters somewhere in the central nervous system (CNS) or periphery. In addition, certain other body chemicals, for example adenosine, histamine, enkephalins, endorphins, and epinephrine, have neurotransmitter-like properties, and many additional true neurotransmitters may await discovery.
8. Becker W. M, Hardin J, Kleinsmith L.J an Bertoni G (2010) Becker’s World of the Cell, 8th edition, San Francisco, Pearson Education Inc- Accessed 23/11/2013.
= == In relative terms enzymes are biological catalysts; control the rate of chemical reaction, different temperatures and pH’s affect their optimum rate of reaction in living organisms. In detail; enzymes are globular proteins, which catalyse chemical reactions in living organisms, they are produced by living cells – each cell has hundreds of enzymes. Cells can never run out of enzymes as they or used up in a reaction.
Enzymes are types of proteins that work as a substance to help speed up a chemical reaction (Madar & Windelspecht, 104). There are three factors that help enzyme activity increase in speed. The three factors that speed up the activity of enzymes are concentration, an increase in temperature, and a preferred pH environment. Whether or not the reaction continues to move forward is not up to the enzyme, instead the reaction is dependent on a reaction’s free energy. These enzymatic reactions have reactants referred to as substrates. Enzymes do much more than create substrates; enzymes actually work with the substrate in a reaction (Madar &Windelspecht, 106). For reactions in a cell it is important that a specific enzyme is present during the process. For example, lactase must be able to collaborate with lactose in order to break it down (Madar & Windelspecht, 105).
Protein is configured to detect a specific analyte and ensuing signal is read by detection instrument for example fluorometer or luminometer.