CELL TRANSPORT

How do your cells get the Nutrients they need from the food you eat? CHEW EAT DIGEST SUGAR FAT PROTEIN

Nutrients Move Through Blood Vessels FAT BLOOD VESSEL CELL SUGAR PROTEIN SMALL INTESTINE

Homeostasis Your body is constantly trying to maintain a balance of all of its systems and processes. Homeostasis: steady state of the internal operations of a living organism regardless of external changes. For your body to maintain homeostasis the internal environment of a cell needs to have the appropriate amount of everything that it needs.

Energy Your body maintains homeostasis by moving the materials required by cells throughout the body. Kinetic Energy: energy of movement. The molecules in air, liquid, and solids have constant motion and bounce off of each other RANDOMLY.

Diffusion Diffusion: The random movement of solute (a substance dissolved in a solution) from an area of HIGH concentration TO an area of LOW concentration until they reach DYNAMIC EQUILIBRIUM. This is a form of PASSIVE TRANSPORT which requires NO ENERGY! Dynamic Equilibrium: when the number of particles entering and leaving a region are equal. The movement continues but there is no net change.

Diffusion Cont… When there is a higher concentration of solute outside the cell, then the net movement of solute is to the inside of the cell until equilibrium is achieved. = solute

Diffusion Cont… When there is a higher concentration of solute inside the cell, then the net movement of solute is to the outside of the cell until equilibrium is achieved.

Cell Membrane Nutrients, water, and waste diffuse in and out of a cell through the cell membrane. Cell membrane: Is the outer boundary of the cell which encloses the cell’s contents. Serves to maintain homeostasis. Is made up of lipids and proteins. Is selectively-permeable (only allows certain substances to pass through).

Cell Membrane Cont… Folded cellular membranes increase the efficiency of the cell by increasing the surface area. Increased surface area = increased space for molecules (nutrients and wastes) to pass in and out of the cells.

                                                                                                                         Cell Membrane Anatomy

Cell Membrane Cont… Some things move freely across and some don’t. Water always diffuses freely. Many larger molecules can’t diffuse without help from: Transport Proteins: proteins in the cell membrane that help bigger molecules move across the membrane.

Facilitated Diffusion Facilitated Diffusion: Uses transport proteins to help the passage of larger molecules, like glucose, in and out of the cell across the cell membrane. A type of PASSIVE TRANSPORT which requires NO ENERGY!

Osmosis (no, you can’t watch “Osmosis Jones”) Osmosis: The diffusion of WATER. This is a type of PASSIVE TRANSPORT which requires NO ENERGY!. Water diffuses based on the concentration of water compared to other dissolved particles, like salts or sugars.

Osmosis Cont… = Water = Solute Hypotonic Solutions: Solutions in which more solute is present in the cell than outside of the cell. More water outside the cell then inside the cell, therefore, the net movement of water will be into the cell where more solute is present.

Osmosis Cont… Hypertonic Solution: A solution where there is more solute present outside of the cell than inside the cell. More water was located inside the cell then outside of the cell, therefore the net movement of water will be out of the cell to where there was more solute.

Osmosis Cont… Isotonic Solution: A solution where there is equal concentration of water inside and outside of the cell, therefore the net movement of water is equal in and out of the cell.

Turgidity/Plasmolysis Turgor pressure: When a plant is fully watered and the cell vacuoles are full. Plasmolysis: The shrinking or wilting of a cell due to water leaving the cell.

Cytolysis Cytolysis: The intake by a cell of so much water that it bursts.

Plasmolysis and cytolysis in plant and animal cells Osmosis Cont… Plasmolysis and cytolysis in plant and animal cells

Active Transport Active Transport: An ENERGY REQUIRING process in which particles are moved from an area of LOW concentration to an area of HIGH concentration.

Endocytosis Endocytosis: the process by which a cell engulfs substances that are too large to pass through the membrane. ENERGY REQUIRING process.

Exocytosis Exocytosis: The passage of large molecules such as manufactured proteins out of the cell. ENERGY REQUIRING process.

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