1.3 Quantitative effect of non-constant time constant Say that a particular neuron, X, has a set of synapses that fire when either stimulus A or stimulus B is present. The sequence of events is this: 1. X's resting membrane potential is -62mV. 2. Stimulus A occurs and raises the voltage to -55mV. Then, it stops, and the voltage begins to fall. 3. 20ms after stimulus A ends, stimulus B immediately adds an additional 8mV. (It's not actually immediately, but for the purposes of this question, please treat it that way.) X's threshold is -50mV. As you can see, stimulus A by itself is not enough to increase the membrane potential to threshold. However, let's see if the additional 8mV provided by stimulus B is enough to get the membrane to threshold. In other words, please calculate the final membrane potential in the following two scenarios, and say whether it hits threshold:
Enzyme kinetics
In biochemistry, enzymes are proteins that act as biological catalysts. Catalysis is the addition of a catalyst to a chemical reaction to speed up the pace of the reaction. Catalysis can be categorized as either homogeneous or heterogeneous, depending on whether the catalysts are distributed in the same phase as that of the reactants. Enzymes are an essential part of the cell because, without them, many organic processes would slow down and thus will affect the processes that are important for cell survival and sustenance.
Regulation of Enzymes
A substance that acts as a catalyst to regulate the reaction rate in the living organism's metabolic pathways without itself getting altered is an enzyme. Most of the biological reactions and metabolic pathways in the living systems are carried out by enzymes. They are specific for their works and work in particular conditions. It maintains the best possible rate of reaction in the most stable state. The enzymes have distinct properties as they can proceed with the reaction in any direction, their particular binding sites, pH specificity, temperature specificity required in very few amounts.
The time constant of a membrane is a measure of how quickly it responds to a stimulus. A longer time constant means that the membrane will take longer to reach its final state. A shorter time constant means that the membrane will reach its final state more quickly.
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