out of the cell through the cell membrane. They include many different ways to transport
things. Passive transport requires no expenditure of energy by the cell. However, Active
transport requires ATPs which have energy in order for it to move something through the
cell membrane. There are different types of transport to suit the sizes of molecules as well.
Passive transport includes diffusion, osmosis, and facilitated diffusion. Diffusion is a
net of movement of molecules from an area of high concentration to an area of low
concentration that doesn't require energy. It moves molecules such as oxygen into the cells
and carbon dioxide out of the cell. Osmosis is the diffusion of water across a semipermeable
membrane. It occurs because of the concentration of a solute in a solution. In a hypertonic
solution the concentration of the solute is higher and water is moved into the cell through
osmosis, but in a hypotonic solution the concentration of the solute is lower and water is
moved out of the cell. In an isotonic solution the concentration is the same in and out of the
cell, and water moves in and out evenly. In facilitated diffusion carrier proteins in the cell
membrane move substances, such as glucose, into the cell without energy.
Active transport is the transport of materials against a gradient that requires the use
of cellular energy. Active transport uses carrier proteins that act as a pump to move ions and
molecules across the membrane. The sodium-potassium pump in animals is an example of
this. It moves sodium out of the cell and potassium into it using about one third of its total
energy budget. In plants active transport allows the plant to absorb nutrients from the soil.
Active transport uses the energy that is stored un ATPs to function.
Bulk transport is the movement of large molecules across the membrane in
membrane bound sacs. Endocytosis, exocytosis, phagocytosis, and pinocytosis are examples
of bulk transport. In Endocytosis the cell surrounds and takes in material from its
surroundings. During phagocytosis the cell takes in water and during pinocytosis the cell
takes in fluid. In exocytosis the cell moves waste and cell products out of the cell.
Hormones and neurotransmitters are examples of cell products that would be sent out of the
cell by exocytosis.
Cells use active and passive transport to take in or release materials. Without it the
cells would not be able to function properly and would die. The main difference between
active and passive transport is that passive transport does not require energy, whereas active
transport does. Cells have special types of active transport to move material that os too large
through the cell membrane. The diffusion in passive transport depends on the type of
solution the cell is in. Active and passive transport play a major role in the cell's ability to
function.
You May Also Find These Documents Helpful
-
Introduction: The biological membranes are composed of phospholipid bilayers, each phospholipid with hydrophilic heads and hydrophobic tails, and proteins. This arrangement of the proteins and lipids produces a selectively permeable membrane. Many kinds of molecules surround or are contained within cells, but water is perhaps the single most important molecule in any living system (Hayden and McNeil 2012). Since water molecules are so small, they are constantly going into and out of the cell. Osmosis is a situation where more water molecules are moving across the membrane in one direction than the other (Hayden and McNeil 2012). During osmosis the net movement of water molecules will be from a solution that has a lower osmotic concentration to a solution that has a higher osmotic concentration. When a solution has a higher concentration of solute within the cell than out, it is called hypertonic. When a solution has a lower concentration of solute within the cell than out, it is called hypotonic. And when there are equal concentrations inside and out of the cell, it is called isotonic. The relative osmotic concentration can be determined by a change in mass of the tissue.…
- 840 Words
- 4 Pages
Better Essays -
Osmosis is the net diffusion of water across a membrane from a region of high concentration to low…
- 550 Words
- 3 Pages
Good Essays -
Which of the following pairs of characteristics is more likely to make a substance diffuse through the cell membrane?…
- 1246 Words
- 5 Pages
Satisfactory Essays -
All cells are surrounded by a membrane that contains the cell’s contents and acts as a semipermeable barrier to substances on either side of it. Many substances move across the membrane with the help of proteins. HINT See Infographics 3.3 and 3.7. KNOW IT j 6.…
- 7229 Words
- 29 Pages
Powerful Essays -
C. facilitated diffusion, active transport Active transport is where a cell uses energy to move molecules. Facilitated diffusion is the same as diffusion, just when they pass through integral proteins.…
- 602 Words
- 3 Pages
Good Essays -
When an ion crosses the membrane and binds to a protein to accomplish this feat, it is using active transport and facilitated diffusion.…
- 287 Words
- 2 Pages
Satisfactory Essays -
Diffusion is the process that is used in oxygen entering a cell, and carbon dioxide leaving. These molecules will move from where they are at a high concentration to where they are at a lower concentration they diffuse down a…
- 1729 Words
- 7 Pages
Powerful Essays -
a. describe the transport process and explain how the organization of cell membranes functions in the movement of specific molecules across membranes, and…
- 4263 Words
- 18 Pages
Good Essays -
The solution of salts inside the cell are hypertonic in comparison to that of the blood stream so therefore the salts move through the semipermeable membrane of the cell to the less concentrated blood stream.…
- 306 Words
- 2 Pages
Satisfactory Essays -
IV. Know the differences between active vs. passive transport and how the subtypes of each work…
- 929 Words
- 4 Pages
Good Essays -
Cells must move materials through membranes in order to maintain homeostasis. The cellular environment is aqueous, indicating that the solutes dissolve in the solvent, water. When a cell is hypertonic, or hypotonic, to its surroundings, it tries to make concentration of solution inside and outside itself equal. However, the solutes are too big to pass the cell membranes without the help of channel proteins, or transport proteins. Water may freely pass through the membrane by osmosis, which requires no energy. Thus, the cell starts to take in, or release, water until it is isotionic to its…
- 468 Words
- 2 Pages
Good Essays -
hypertonic, plasmolysis : hypertonic solution has a higher solute concentration than the cytosol of a cell. In a hypertonic solution a plant cell will lose water and shrink away from the cell wall, a process called plasmolysis.…
- 620 Words
- 3 Pages
Good Essays -
3. Active Transport- Pushing particles from low to high concentration (against the gradient), uses a carrier protein…
- 536 Words
- 3 Pages
Good Essays -
Passive Transport: Movement of molecules across the cell membrane without energy input from the cell.…
- 588 Words
- 3 Pages
Good Essays -
84. Passive transport of materials across cell membrane by carrier proteins embedded in the membrane…
- 1632 Words
- 7 Pages
Good Essays