When something needs to be transported against its concentration gradient, or a molecule is too big to simply diffuse through a membrane, active transport has to be used. So active transport requires energy (ATP).
Examples:
1. Antiport pumps: transport one substance in one direction while transporting another substance the other way. An example of this is the sodium-potassium pump.
2. Symport pumps - uses a substance that wants to move from an area of high concentration to low concentration and carries another substance against its concentration gradient. An example of this is the sodium-glucose transport protein
3. Endocytosis - large amounts of extra cellular fluid can be taken into a cell - needs ATP to bind proteins in the cell membrane and causes them to change their shape...which eventually causes the surrounding of the fluid to be brought in (a vesicle).
4.exocytosis - opposite of above
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Answer:
Habitat is a place in which organisms live, and niche is the way in which an organism fits into its habitat
A solar eclipse occurs<span> when the moon gets between Earth and the sun, and the moon casts a shadow over Earth. </span>A solar eclipse<span> can only take place at the phase of new moon, when the moon passes directly between the sun and Earth and its shadows fall upon Earth's surface.</span>
