Question

passive and active transport
active transport
active transport is a vital process that helps cells move substances across their outer membranes, against a natural concentration gradient, which means from areas of lower concentration to areas of higher concentration. think of it as pushing a boulder uphill - it requires energy. in this case, the cell has to use energy, usually in the form of atp (adenosine triphosphate), to power the transport.
one common example of active transport is the sodium - potassium pump, found in our nerve and muscle cells. this pump actively moves sodium ions out of the cell and potassium ions in, maintaining the right balance for proper cell function.
endocytosis
endocytosis and exocytosis are two more examples of active transport. endocytosis is when a cell engulfs substances by wrapping its cell membrane around them. its like the cell giving a big hug to stuff outside, bringing it inside. this helps the cell take in food or other important molecules.
exocytosis is the opposite, where a cell releases substances by pushing them out through its membrane. its like the cell packing a gift into a bubble and sending it out. this is how cells get rid of waste or send out important signals.
think about it...

1. active transport means substances move from an area of ____________ to an area of ____________.
2. briefly explain the difference in the three types of active transport. ______________
3. active transport requires the cell to use ______________

a. energy
b. light
c. photosynthesis
d. water

Explanation:

1. Active transport moves substances against the concentration gradient, from lower to higher concentration.
2. The sodium - potassium pump moves ions to maintain cell function. Endocytosis is when a cell engulfs substances, and exocytosis is when a cell releases substances.
3. Active transport requires energy (ATP) to power the movement of substances against the concentration gradient.

Answer:

1. lower concentration; higher concentration
2. The sodium - potassium pump maintains ion balance in nerve and muscle cells. Endocytosis is the engulfing of substances by the cell membrane for intake, and exocytosis is the release of substances from the cell through the membrane for waste - removal or signaling.
3. a. energy