Simple diffusion is the process by which a substance moves across a cell membrane from an area of high concentration to an area of low concentration. Substances that move by simple diffusion are able to diffuse directly across the phospholipid bilayer of the cell membrane. These substances are generally small and neutral, as large or charged particles cannot cross the phospholipid bilayer. Some examples of molecules that move by simple diffusion are carbon dioxide and oxygen.
Facilitated diffusion is the process by which a substance moves across a cell membrane from an area of high concentration to an area of low concentration with the aid of a membrane protein. Substances that move by facilitated diffusion are not able to diffuse directly across the phospholipid bilayer of the cell membrane. These substances are generally large and/or charged. They therefore travel through a protein channel in the cell membrane along their concentration gradient. Some examples of substances that can move by facilitated diffusion are glucose, sodium ions and chloride ions.
The similarities between facilitated diffusion and simple diffusion are:
They both involve the movement of a substance across a cell membrane along its concentration gradient (from an area of high concentration to an area of low concentration).
They are both examples of passive transport, as neither requires energy from the cell to move the substance across the membrane.
Answer:
"It is the enzyme that breaks down acetylcholine in the synaptic cleft, ending stimulation of the muscle fiber. -It is the type of receptor found in the motor end plate that binds acetylcholine, initiating an electrical impulse."
Explanation:
Answer:
On the face (In the middle)
Explanation:
The human nose is the most protruding part of the face. It bears the nostrils and ... reconstructive surgery. Elective procedures to change a nose shape are a type of cosmetic surgery.
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(d) chemosynthetic forms
Explanation:
Autotrophs are characterized by their ability to produce their own food; parasites, saprophytes, and pathogenic (disease-causing) organisms do not have this ability. Chemosynthetic ones, however, can through the conversion of one or more carbon-containing molecules into organic matter.
