They exert a wide range of functions in neuronal/glial proliferation, differentiation and apoptosis, as well as in maintaining the membrane permeability to ions and in the stabilization of synaptic transporters and receptors, the latest processes relevant to the generation and propagation of the nervous impulse and synaptic transmission.20,39,40 Moreover, cell and animal models underscore the key function of sphingolipids in the neurite growth and myelination of the cerebellum and forebrain, among other brain regions.41,42 Deficiency of ceramide synthase-2 that generates sphingolipids with C22-C24 fatty acyl chains results in 50% loss of compacted myelin and 80% loss of CNS myelin basic protein.42 Similarly, a 60% reduction of myelin-associated glycoprotein in the cerebellum and forebrain characterizes mice deficient in ceramide synthase-1, the enzyme that generates C18:0 sphingolipids.41 Interestingly, mice deficient of ceramide synthase -6, which generates C16:0 sphingolipids, as well as mice deficient of GM3 synthase that is responsible for one of the first steps in the production of gangliosides, both present hyperactive behavior and have been postulated as suitable animal models for
The resting potential is generated by the specific changes in membrane permeability for of potassium (K+) and sodium (Na+) ions, which in turn result from concentrated changes in functional activity of ion channels. Cell membranes are made up of a phospholipid bilayer- consisting of two layers of linked fatty molecule. Various specialized proteins, such as ion channels, float in this bilayer. Ion channel are membrane-spanning proteins that allows the passage of certain ions through the membrane. The cell membrane of a neuron is selectively permeable to potassium ions, meaning that ion channels that will only allow potassium ions to exit or enter the cell freely.
This is called integration. Stimuli are compared with, other stimuli, memories of previous stimuli, or the state of a person at a particular time. This leads to the specific response that will be generated. Describe the components of the membrane that establish the resting membrane potential Most cells in the body make use of charged particles, ions, to build up a charge across the cell membrane. Cells make use of the cell membrane to regulate ion movement between the extracellular fluid and Cell Body.
The different amount energies released results in different color. This reason is the same reason that different elements have different line spectra. The quantum theory says that a certain amount of energy has be released or absorbed and Bohr 's said the same but with restrictions. The quantum theory would explain the vast differences in energy in color. The reason atoms need heat is because heat gives the atoms energy which causes them to move to an excited and then back to ground state.
Substrate concentration basically means the amount used for the substrate. The substrate in our experiment was 0.1% hydrogen peroxide. The 0.1% is the concentration amount. Just like temperature and pH, substrate concentration can speed the reaction only up to a certain limit. When we mixed pH 3 enzyme tube with substrate tube, we used 0.3 mL of hydrogen peroxide, but if we were to increase the amount, then the experiment would have been faster.
At a chemical synapse, an electrical signal (AP) is transformed into a chemical signal (neurotransmitter) and thereafter is (re)turned back into an electrical one (AP). Thus the signal can move across the synaptic cleft via or as a neurotransmitter before it is turned back into an electrical signal (AP) at the receptor cell. This conversion process not only assures the inter-neural conduction of signals, but also their modulation (change). Depending on what kind of neurotransmitter is released and then docks at its postsynaptic receptors, either an excitation or an inhibition will be produced. An inhibition results in a hyperpolarization.
The regulation of metabolism may be from within the cell or outside. The metabolic flux can be regulated by non-equilibrium reactions. The intracellular regulatory strategies include allosteric enzymes, substrate cycles, enzyme interconversion cycles etc. the cyclic AMP and phosphoinositide systems are major mechanisms of signal transduction. Metabolism is also regulated by hydrophobic hormones which enter their target cells and are able to interact with intracellular receptor molecules.
It is a more often observed biotransformation pathway for small endogenous compounds, but also plays a role in the metabolism of macromolecules like nucleic acids. Compounds can undergo N-, O-, S- and arsenic methylation catalyzed by enzymes called methyltransferases, employing S-adenosylmethionine as the methyl donor.95,98 Amino acid conjugation reactions are a route of metabolism of xenobiotic carboxylic acids. The enzymes of conjugation reside in mitochondria. Mechanistically, it differs from the other conjugation reactions. It involves initial activation of the carboxylic acid moiety with ATP, generating an acyl adenylate and pyrophosphate.
An important function of the dendrite is the integration of various input signals. Synapses are the gaps between the axons of transmitting neurons and the dendrites of receptor neurons. Electrochemical signals are carried across the gap by neurotransmitter molecules. These end up at the receptor proteins located in the ends of dendrites. There are various neurotransmitter chemicals.
In the lac operon of E.coli, lactose induces the synthesis of the enzyme, beta-galactosidase. This enzyme codes for the Lac Z gene and thus, when synthesized properly with no other affecting factors, would break down ONPG. If lactose is not present in the enzyme, then the Lac I gene would continue to block transcription of the genes are also not synthesized. The primary regulator of the lac operon is a negative control element known as the lac regulatory protein which acts as a repressor when binded to a gene, turning the expression of the gene off. The repressor is a regulatory protein that binds to the operator and blocks transcription of the genes of an operon.