When is facilitated diffusion necessary?

Carbon dioxide in the atmosphere traps heat. Scientists are concerned that too much carbon dioxide is being released into the ai

WITCHER [35]

Pollution control in the air

3 0

3 years ago

Explain the following Genetics Evolution Variation

NARA [144]

Answer:

genetics;the study of heredity and the variation of inherited characteristics.

evolution;evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection

variation;a change or difference in condition, amount, or level, typically with certain limits

Explanation:

7 0

4 years ago

Read 2 more answers

Correctly identify each of these definitions or examples as either depolarization or hyperpolarization of the plasma membrane. 1

natulia [17]

Answer:

hyperpolarization
depolarization
hyperpolarization
depolarization
hyperpolarization
depolarization
depolarization

Explanation:

The resting membrane potential is balanced by ion leakage and ion pumping, to get an electrical signal started the membrane potential has to lose its balance. This starts with a membrane channel opening for Na+ since Na+ concentration is higher outside the cell, ions will rush into the cell. This will change the relative voltage inside the cell. The resting potential has a voltage of -70 mV, the sodium cation entering the cell cause it to become less negative. This is known as depolarization.

The concentration gradient for Na+ will continue to enter the cell making the voltage to become positive reaching +30 mV. At the same time, this happens, other voltage-gated channels are also opening, a concentration gradient acts on K+, as well, as it leaves the cell, it takes a positive charge with it making the membrane potential to move back to its resting voltage of -70 mV. This is called repolarization.

For potassium ions to reach equilibrium the membrane voltage needs to be below -70 mV, this leads to a period of hyperpolarization that occurs while the K+ channels are open.

I annexed an image that illustrates this action potential process.

Considering the information given during depolarization there's an increase in the number of sodium leak channels (7) making the inside of the cell more positive (2) increase in the membrane potential (4), this also implies a decrease in the extracellular concentration of potassium (6)

Meanwhile, during hyperpolarization an increase in the extracellular concentration of potassium (3) decreases the membrane potential (1) making the inside of the cell more negative (5).

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