Answer: Increasing its membrane's permeability to Na
Explanation:
Depolarisation is a decrease in the absolute value of the membrane potential in a neuron. The membrane potential of a neuron at rest is normally negative in the intracellular area (-70 mV). This negative potential is generated by the presence on the membrane of:
- Sodium/potassium pumps, which actively extract 3 Na+ (sodium) ions from the inside to the outside of the cell and introduce 2 K+ (potassium) ions, consuming 1 molecule of ATP.
- Potassium channels which allow free exchange of K+ ions.
- Cl- pumps, which actively extract chlorine.
<u>As a result, the outside of the cell is richer in Na+ and Cl- than the inside</u>, <u>while K+ ions accumulate on the inside with respect to the outside</u>. The net charge balance is negative because 3 Na+ ions are released for every 2 K+ ions and also, because of the presence of negatively charged molecules in the interior of the cell such as ATP and proteins.
When a neuron receives a stimulus, the sodium channels present in the membrane are opened, and therefore Na+ enters the cell in favour of the concentration gradient, so that the membrane potential changes to positive by means of ion exchange, producing depolarisation. <u>If the depolarization reaches a certain threshold value, an action potential is generated.</u> The next step is the opening of the potassium channels and the inactivation of the sodium channels, so that the repolarization of the membrane takes place. The sodium channels, will return to the closed state in the hyperpolarization to continue in this state during all the rest potential; until the arrival of a new action potential which produces the activation and opening of the sodium channels, repeating the cycle again and generating a new depolarizing action. This process is part of the synaptic transmission.
Answer:
it depends on birth rate and population history of the city or country
Explanation:
In exponential growth, a population's per capita (per individual) growth rate stays the same regardless of population size, making the population grow faster and faster as it gets larger. In nature, populations may grow exponentially for some period, but they will ultimately be limited by resource availability.
Answer: Gametophytes
The female gametophyte is also commonly called the embryo sac or megagametophyte. The male gametophyte, also called the pollen grain or microgametophyte, develops within the anther and consists of two sperm cells encased within a vegetative cell
Answer:
Solution
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Correct option is
A
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
Prokaryotic cells have a cell wall surrounding the cell membrane. The fluid matrix filling the cell is the cytoplasm. There is no well-defined nucleus. The genetic material is basically naked in the cytoplasm, not enveloped by a nuclear membrane. The nuclear membrane is found in eukaryotes. The prokaryotic cells lack mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, microtubules, microfilaments, and centrioles.
Cytoplasmic streaming, also called cyclosis, is the directed flow of cytosol (the liquid component of the cytoplasm) and organelles that aids in the delivery of organelles, nutrients, metabolites, genetic information, and other materials to all parts of the cell. In prokaryotes, cytoplasm does not show cyclosis or streaming movements.
So, the answer is A.
Answer:
The cell cycle is the replication and reproduction of cells, whether in eukaryotes or prokaryotes. It is important to organisms in different ways, but overall it allows them to survive.
Explanation:
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