Upon fertilization, the eggs of many species undergo a rapid change in potential difference across their outer membrane. This change affects the physiological development of the eggs. The potential difference across the membrane is called the membrane potential, Vm, which is the potential inside the membrane minus the potential outside it. The membrane potential arises when enzymes use the energy available in ATP to expel three sodium ions (Na+) actively and accumulate two potassium ions (K+) inside the membranemaking the interior less positively charged than the exterior. The egg membrane behaves as a capacitor with a capacitance of about 1 μF/cm2. The concentration of Na+ is about 30 mmol/L in the eggs interior but 450 mmol/L in the surrounding seawater. The K+ concentration is about 200 mmol/L inside but 10 mmol/L outside. A useful constant that connects electrical and chemical units is the Faraday number, which has a value of approximately 105 C/mol; that is, Avogadros number (a mole) of monovalent ions, such as Na+ or K+, carries a charge of 105 C.

How many moles of Na+ must move per unit area of membrane to change Vm from -70 mV to +30 mV , if we assume that the membrane behaves purely as a capacitor?

10−4 mol/cm2
10−9 mol/cm2
10−12 mol/cm2
10−14 mol/cm2

the correct option is 3 = 10−12 mol/cm2 moles of Na+ must move per unit area of membrane.

Explanation:

The capacitance is given by ;

the specific capacitance ;

it is said that the potential changes from -70 mV to +30 mV

= 100mV

The charge moving per unit area;

= 100mV X 10^-3V/1mV X 1microF X 10^-6F/1microF

= 1 X 10^-7C/m^2

= 10^-12mol/cm^2

As such, the correct option is 3 = 10−12 mol/cm2  moles of Na+ must move per unit area of membrane.

explanation:

the largest database of organic compounds lists about 10 million substances, which include compounds originating from living organisms and those synthesized by chemists. the number of potential organic compounds has been estimated at 1060—an astronomically high number. the existence of so many organic molecules is a consequence of the ability of carbon atoms to form up to four strong bonds to other carbon atoms, resulting in chains and rings of many different sizes, shapes, and complexities. the simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons. even though they are composed of only two types of atoms, there is a wide variety of hydrocarbons because they may consist of varying lengths of chains, branched chains, and rings of carbon atoms, or combinations of these structures. in addition, hydrocarbons may differ in the types of carbon-carbon bonds present in their molecules. many hydrocarbons are found in plants, animals, and their fossils; other hydrocarbons have been prepared in the laboratory. we use hydrocarbons every day, mainly as fuels, such as natural gas, acetylene, propane, butane, and the principal components of gasoline, diesel fuel, and heating oil. the familiar plastics polyethylene, polypropylene, and polystyrene are also hydrocarbons. we can distinguish several types of hydrocarbons by differences in the bonding between carbon atoms. this leads to differences in geometries and in the hybridization of the carbon orbitals.

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).