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:
A
Explanation:
zygote is the merged gametes of different organisms
Answer:
75years
Explanation:
Let the Father's age be represented by 2x
Let the Son's age be represented by x
Five years ago;
Man's age will be = 2x - 5
Son's age will be = x - 5
If the ratio of their ages five years ago was 9:4, then;
2x - 5/x-5 = 9/4
4(2x - 5) = 9(x - 5)
8x - 20 = 9x - 45
- Collect like terms
-20 + 45 = 9x - 8x
25 = x
Hence, the son's age = 25 years
If x = 25, the father's age (2x) will be 2 × 25 = 50years
The sum of their ages will be = 25years + 50years = 75years
Important muscle electrical signals is the movement of charged material (ions) across cellular membranes in a limited area
Answer:
Explanation:
Can you think of a solid that can flow?
You use one twice a day! Toothpaste is a solid that can flow. Is the asthenosphere made of toothpaste? Only if the
toothpaste is ultramafic in composition, and then it would only be able to flow if it were really, really hot. Still the
toothpaste analogy gives you a good image of how the asthenosphere might behave if you squeezed it!
Lithosphere
The lithosphere is composed of both the crust and the portion of the upper mantle that behaves as a brittle, rigid
solid. The lithosphere is the outermost mechanical layer, which behaves as a brittle, rigid solid. The lithosphere is
about 100 kilometers thick. How are crust and lithosphere different from each other?
