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biology unit 4 - Coggle Diagram
biology unit 4
Vesicular transport.
Some molecules or particles are just too large to pass through the plasma membrane or to move through a transport protein. So cells use two other active transport processes to move these macromolecules (large molecules) into or out of the cell. Vesicles or other bodies in the cytoplasm move macromolecules or large particles across the plasma membrane. There are two types of vesicle transport, endocytosis and exocytosis. Both are active transports which use energy.
Endocytosis:Endocytosis is the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane. The membrane folds over the substance and it becomes completely enclosed by the membrane. At this point a membrane-bound sac, or vesicle, pinches off and moves the substance into the cytosol.
Exocytosis: excytosis captures stuff inside the cell and brings it out the cell. It does the opposite.
solutions.
The salt salutions attract water which means that the water will want to go near the salt. The water will leave other places like the egg if there is enough salt.
Concentration gradients.
Difference in concentration of a substance in two areas. The movement between the different concentrations is what determines what type of movement it is.
active transports.
Passive transport is from high to low concentration. It goes along the concentration gradient. There is no chemical energy required. Its like rolling a ball from the top of the hill down the hill.
Active transport is froma low to high concentration. It goes against the concentration gradient. It requires chemical energy such as ATP. its like pushing a big ball up the hill.
osmosis.
Osmosis is a pasive transport. Its moving substances from high to low concentration. During osmosis, only water is moving. It happens when there is a semi permeable membrane which allows only certian things to pass through. If there are two sides, one with a high water concentration and less salts and one with a low water concentration and more salts, the water will move from the side with a less salts to the side with more salts becuase water likes to move where salts are.
Egg lab: when we put an egg into water with 5% salt, the water is jammed together so when we put the egg in the water goes into the egg so there is more space and the egg gains mass. When there is 10% the water wants to stay with the salt so it doesnt gain as much and with 15% water the water in the egg actaully leaves the egg to go into the cup because there is so much salt.
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Hypotonic: when the water goes into the cell faster than it goes out the cell which makes the cell swell and get bigger.
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cell membrane structure.
A phospholipid is a lipid made of glycerol, two fatty acid tails, and a phosphate-linked head group. membranes usually involve two layers of phospholipids with their tails pointing inward, an arrangement called a phospholipid bilayer. The head is polar hydrophilic and the tail is nonpolar hydrophobic. Inside the head there is a negative charge.
In a cell membrane, The components of the cell membrane are constantly moving. Cells are mainly composed of phospholipids, with proteins embedded within them .
Bread model: in the model the bread represents the hydrophilic heads while the butter represents the hydrophobic tails.
On the side with no butter the water would make it all the way through because the water in polar and the bread is polar so they went well together but when there was the part with butter it stopped the water from going to the other side of the bread because there was a nonpolar part stopping it which would be the tail.
How molecules move:
If a molecule is small, and has no charge, it can move through a cell membrane easily. Some examples are oxygen, and carbon dioxide.
If a molecule is large, like glucose, it will need a protein to get it across the membrane.
If a molecule is charged, like a Na+ ion (sodium), it will need a protein to get it across the membrane.
Transporters use energy and transport specific molecules against the concentration gradient while channel proteins move them with the concentration gradient and use no energy.
cellular transport.
One of the four ways molecules get across the cell membrane. Its the movement of materials into or out of the cell by crossing the cell membrane. Nutriens like oxygen and glucose need to be brought into the cell while waste like carbon dioxide need to be removed. Only certain things can get into the cell membrane. How easy it gets in is by the size and if its polar or not. Small nonpolar molecules easily move through the membrane while big nonpolar materials dont. When a material is too big there will be a protien that makes a hole to let it through.
Cell transport involves moving materials in and out of the cell. How easy it is to get in is depending on the size and polarity of the material. The cells need transport to stay stable and small and nonpolar materials move easily into the cell.
Its hard for big polar molecules to get into the cell and not all cells are allowed in.
simple diffusion.
In simple diffusion, the molecule that passes through is usually very small, and nonpolar (no charge on them). Some examples of molecules that can get through the membrane are oxygen (O2) and carbon dioxide (CO2).
faciliated diffusion.
During facilitated diffusion, there are big materials that cannot fit so they need a helper or they are charged. This helper is a carrier protein/protien channel. It moves from high to low concentration with no chemicals needed. Glucose is too big so it uses a carryier protien to go from a high to a low concentration.
channel mediated and carrier mediated. Mediated just means that there is a protein that will “mediate” the way the molecule gets into the cell.
Channel mediated means that a channel protein is required to transport that molecule. Glucose is transported this way (more on this later).
Carrier mediated means that the protein transports a specific molecule once it has received the proper signal.