Answer:
C) Through genomic imprinting, methylation regulates expression of the paternal copy of the gene in the brain.
Explanation:
The pattern of gene expression wherein either paternal or maternal gene is expressed in specific cells while the other one is prevented from expression is known as genomic imprinting.
In the given example, the maternal copy of the gene on chromosome 15 is expressed in brain cells while its paternal copy is not expressed in these cells. Hence, the pattern of expression of this gene is regulated through genome imprinting. One of the mechanism is methylation of cytidine residues of CpG islands of the DNA that are more frequently present within promoters of the genes.
When the cytidine residues of these sequences are methylated into 5-methylcytidine, the transcription factors do not bind to these promoters preventing the expression of these genes.
Hence, methylation of cytidine residue in CpG islands of the promoters of the gene present on chromosome 15 could have silenced its expression in brain cells.
limbic system
Explanation:
center of emotional processing is the amygdala
Answer:
If an inhibitory synapse fires at the same time and at the same distance from the initial segment as an excitatory synapse of the same intensity there will be no changes in the potential in the firing zone.
Explanation:
Under normal conditions, the transmembrane potential depends on the ionic charges present in the intracellular and extracellular spaces. The extracellular space load is usually positive and in the cytoplasm is negative.
- <u>Depolarization</u> occurs by opening ion channels that allow sodium to enter the cell, making the intracellular space more positive.
- An opening of potassium channels releases this ion to the extracellular space, leading to <u>hyperpolarization</u>.
An excitatory synapse is one capable of depolarizing a cell and boosting the production of action potential, provided it is capable of reaching the threshold of said potential.
On the other hand, an inhibitory synapse is able to hyperpolarize the cell membrane and prevent an action potential from originating, so that they can inhibit the action of an excitatory synapse.
The interaction between two synapses, one excitatory and one inhibitory, -called synapse summation- will depend on the strength that each of them possesses. In this case, the intensity of both synapses being the same, there will be no changes in the membrane potential in the firing zone.
Learn more:
Excitatory and inhibitory postsynaptic potentials brainly.com/question/3521553
The Pentagon is the headquarters of the <span>United States Department of Defense
And is a symbol of the US military </span>
Answer: Positive feedback loop
Explanation:
Even before the food reaches the stomach (before ingesting it), the glands of the stomach mucosa begin to release its gastric secretion. The main characteristic of this secretion is acidity, as measured by pH (one of the physiological variables).
This acidity is a result of the presence of hydrochloric acid, which is part of the secretion composition. In addition to it, water, pepsinogen (which will give rise to the enzyme pepsin) and the intrinsic factor. The acid has a function of the protection of the entire system by eliminating microorganisms. It is also responsible for the activation of pepsin (which only occurs with acid pH), the enzyme that digests proteins containing the amino acids leucine or phenylalanine or tryptophan or tyrosine.
The concept of Positive feedback loop states that the body tries to increase the value of a variable (acidity, in the case of pepsinogen) when it is below its optimal value (called a point adjustment) and decreases this value when it is above optimal.
