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
Answer:
A number of tiny hair like bristlez are present on the lower surface pf an earthworm's body. These bristles help it to get a good grip on the surface of q ground.However these bristles donot provide good grip on plain glass tiles.
It probably needs to dig in the ground for worms and grub. So it's an adaptation for finding food.
Answer:
Gene pool stays the same.
Scientific law.
A scientific law describes something in nature and predicts how it will behave without explaining.
This is because before a scientific law has been made, numerous observation has been done under different situations. The scientific law is established when a natural event invariable occur given a set of circumstances.
