Explanation: Membrane potential is the difference in charge distribution or electrical potential across the membrane of a cell.
Resting membrane potential is the membrane potential when the cell is not receiving any excitatory or inhibitory signal, it is the membrane potential when a cell is at rest. Depolarization means that the cell is less negative, that is, there is less negative ions on the inside of the cell than on the outside while hyperpolarization means that the cell is more negative or less positive, that is, there is more negative ions on the inside of the cell than on the outside of the cell.
At resting potential (absence of stimulus), the cell membrane of a neuron is said to be polarized with a net negative charge within due to more potassium (K+) ions present than sodium (Na+) ions.
However, an impressed stimuli reverses the ions content as K+ ions flows out and quickly replaced by Na+ ions, resulting in a decrease in membrane potential and a more positive cell membrane. Thus, depolarization occurs.
An increase in the membrane potential (so that it becomes more negative) is called hyperpolarization.
The student is wrong. Phosphorylation
cascade is important in cell signaling. Most cell signaling involves cyclic AMP (synthesized from
ATP). The cAMP activates Protein Kinases (PKA)
that phosphorylates protein
substrates involved in the signaling pathways
such as the GPCR. This helps in amplifying the initial signal.
The pink flower donates the r allele and produces pink flowers in 50% of the offspring. The genotype for the pink flower is Rr and the genotype for the white flower is rr. This would lead to a 50% chance of the offspring having a phenotype of pink.
