The cell membrane's main trait is its selective permeability, which means that it allows some substances to cross it easily, but not others. Small molecules that are nonpolar (have no charge) can cross the membrane easily through diffusion, but ions (charged molecules) and larger molecules typically cannot.
Charged Ions
An ion is a molecule that is charged because it has lost or gained an electron. The cell membrane is made of a bilayer of phospholipids, with an inner and outer layer of charged,hydrophilic "heads" and a middle layer of fatty acid chains, which are hydrophobic, or uncharged. Charged ions cannot permeate the cell membrane for the same reason that oil and water don't mix: uncharged molecules repel charged molecules. Even the smallest of ions -- hydrogen ions -- are unable to permeate through the fatty acids that make up the membrane. If ions "want" to enter the cell due to a high concentration of that type of ion on one side of the cell, they can do so by entering through the protein channels that are embedded between the lipids.
Large Polar Molecules
Large uncharged molecules, such as glucose, also cannot easily permeate the cell membrane. Although they do sometimes manage to slip across the membrane through diffusion, the process is extremely slow due to the size of the molecules. In order for these molecules to cross the membrane at a normal rate of speed, they need to resort to ion channels and specific transporters, which require energy output from the cell.
The answer is survival
This is the ceasing of the existence of any particular species. ... A condition in which two populations of the same species, over time, can no longer breed with each other to produce live offspring. Survival. This is the set of skills and abilities necessary for an organism to live. If you’re looking for a one word answer, it’s survival.
Hawai'an volcanic islands
Hawai'an volcanic islands is not part of a convergent/subduction plate boundary.
<h3>What kind of plate boundary produces a sequence of volcanic islands?</h3>
- convergent boundary
- Along the convergent boundary, the new magma (molten rock) rises and may erupt violently to form volcanoes, frequently creating arcs of islands.
- Divergent plate boundaries are created when two plates are moving apart.
<h3>Why do volcanic chains and convergent borders coexist?</h3>
- Subduction causes melting that is partially molten.
- Water loss in the plate causes partial melting.
- Mantle material melts as a result and rises to the surface.
<h3>Which are the 4 types of convergent boundries?</h3>
- Divergent Plate Boundary.
- Convergent Plate Boundary.
- Transform Plate Boundary.
- Hotspot.
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<span>The cell membrane folds around the molecule.</span>
Tendons :may also attach muscles to structures such as the eyeball. A tendon serves to move the bone or structure. A ligament: is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable.
