The process of diffusion occurs in and out of a cell when molecules travel from areas of higher concentration to region of lower concentration, and this variation in concentration is described as a concentration gradient. i In order for locomotion to occur, the molecules use its kinetic energy and constant motion. The barrier of the cell is its plasma membrane, which allows the passage of molecules through the pores if they are small enough. i The plasma membrane has a phospholipid bilayer which separates the inside (the cytoplasm) and the outside (extracellular fluid and lipid-soluble solutes) of the cell. The fact that the plasma membrane monitors the passage of molecules based on size and solubility constitutes it as semi-permeable.
Diffusion can be categorized as either simple diffusion or facilitated diffusion. A similarity between simple and facilitated diffusion is that they are both passive processes and travel from areas of higher concentration to region of lower concentration. Simple diffusion only takes place through a phospholipid bilayer and occurs only for non-polar and small...
... middle of paper ...
...es in the human body to fight off cancer cells and microorganisms that could potentially be harmful to the body.
Knowing that simple diffusion is a passive process, I hypothesized the larger the MWCO (Molecular Weight Cut Off), the more solutes will pass through the semi-permeable membrane. For Activity 2, I hypothesized that by accumulating more transport proteins, the rate of solute transport heightens. I speculated in Activity 3 that the concentration gradient and osmotic pressure are related; as the concentration gradient increased, so did the osmotic pressure. As for Activity 4 that pertains to filtration, I hypothesized as the pore size or pressure enlarges, the filtration rate speeds up. Due to the fact that active transport requires ATP, for Activity 5 I speculated that as the concentration of ATP rises, it will allow active transport to happen more often.
Need Writing Help?
Get feedback on grammar, clarity, concision and logic instantly.Check your paper »
- Cells are living things that requires substances to be imported into the cell for growth and repair just as a human, or animal, needs to eat for growth and repair. Unlike the human or animal that has arms, jaws, or external tools to collect and consume food, the basic cell does not have any external appendages to readily obtain the substances it needs. This does not leave the cell without any way to obtain the required substances, obviously otherwise they would all be very short lived, and the ways they obtain substances differ in the required energy and the substance being obtained.... [tags: Cell membrane, Cell, Lipid bilayer]
730 words (2.1 pages)
- The purpose of this lab is to determine which molecules can move across a semi-permeable membrane. The hypothesis for this experiment is as follows; As the smaller molecules of iodine travel through the “cell membrane” the artificial cell will gain mass. Dialysis tubing, a thin membrane that behaves in much the same way as a living cell’s actual plasma membrane, was used to test this experiment. After filling the dialysis tubing with the starch and glucose solutions, the artificial cell was then submerged in a water and iodine solution, and the results we’re recorded after 30 minutes.... [tags: Cell membrane, Cell, Semipermeable membrane]
792 words (2.3 pages)
- In this experiment we took dialysis bags and filled them with various sucrose solutions and put them in water over a period of about 90 minutes to look at the osmosis in each bag and the tonicity of each environment the bags were in. We also took potato pieces and submerged them into various sucrose solutions to determine the ideal state of tonicity for plants and the osmosis that occurred over a period of time. The final results for the first exercise was that 0.8M sucrose solution gained the most mass and that it was hypertonic to its environment.... [tags: Osmosis, Semipermeable membrane, Diffusion]
2246 words (6.4 pages)
- 5) Gated channels are used to facilitate the movement of molecules from one side of a membrane to another and are necessary for facilitated diffusion. A gated channel can be open, closed, or in an intermediate state, and are controlled by change in membrane voltage, and differs from active by not requiring additional ATP for movement like active transport. Gated channels are exactly what they sound like, a channel that is controlled by a gate or regulator that will allow the movement of specific molecules in and out of cells.... [tags: Cellular respiration, Adenosine triphosphate]
1119 words (3.2 pages)
- ... 2. Fructose will exhibit net diffusion into the cell. 3. Glucose will exhibit net diffusion out of the cell. 3. Size of the cell, concentration gradient of the cell, carrier protein of the membrane influence whether a molecule will be able to pass through a biological membrane. If the molecule is too large, it will require some kind of transport protein that is surrounded in the plasma member to allow it to pass through. Large molecules typically carry charges, so that may also affect the process.... [tags: osmosis, filtration, transport]
730 words (2.1 pages)
- Introduction Cells communicate by transferring molecules from one to another. When a molecule is transferred it creates a reaction which then causes an effect. Within multicellular organisms there is cell-to-cell communication. Direct communication between cells can occur in two ways. One way is cell-cell recognition via interaction between surface proteins. When there is contact between cell surfaces, the proteins on the surface of the cell interact and create a signal. The other way is through cell junctions between adjacent cells.... [tags: molecules, cells, plasma membrane]
1041 words (3 pages)
- The Effect of Temperature on the Permeability of Beetroot Membrane Analysis The graph shows the colorimeter readings increase as the temperature increases, they increase by the most at higher temperatures. This is shown by a smooth curve. This means that the beetroot samples release more dye at higher temperatures. This is because higher temperatures cause the membrane structure to break down. The membrane structure: Membranes have two layers of molecules called phospolipids to make up their structure.... [tags: Papers]
888 words (2.5 pages)
- 2.1 describe the structure and function of the cell membrane. The cell membrane, also known as the plasma membrane, regulates what enters and leaves the cell. The cell membrane also deals with recognition of proteins and transport that regulates the movement of water and soluble molecules throughout the membrane. The cell membrane is composed of phospholipid molecules and consists of two lipid layers in which protein molecules float; this is sometimes referred to as a “lipid sandwich” this surrounds the cell.... [tags: Mitosis, Meiosis, Chromosome, Cell cycle]
1520 words (4.3 pages)
- Transport Across Plasma Membrane The plasma membrane covers all living cells, enabling the cells’ contents to be held together and controls movement of substances into and out of the cell. Plasma membranes are made of phospholipids, proteins and carbohydrates. The phospholipids are essentially made out of two fatty acid chains and a phosphate-glycerol group. They are arranged in a bilayer with the hydrophilic phosphate head facing outwards and the hydrophobic fatty acid chains facing inwards and to each other in the middle of the bilayer.... [tags: Papers]
901 words (2.6 pages)
- The Transport of Substances Across the Plasma Membrane The plasma membrane or, the cell surface membrane, is made almost entirely of protein and lipid. The plasma membrane controls the movement of substances into and out of a cell. It is partially permeable so some substances cross more easily than others. The lipids found in the membrane are known as phospholipids. Phospholipids are fat derivatives in which one fatty acid has been replaced by a phosphate group and one of several nitrogen-containing molecules.... [tags: Papers]
840 words (2.4 pages)