Cell Transport, Osmosis and Diffusion

Cell Transport Cells regulate what enters and leaves the cell based on its environment. Homeostasis is the maintenance of the cells internal conditions. Cells need to regulate the themselves to be able to survive in their ever changing environments and to reach equilibrium 1. Be able to obtain and use energy through photosynthesis (plants) or cellular respiration (animals)

4 ways to maintain homeostasis 1. Be able to obtain and use energy through photosynthesis (plants) or cellular respiration (animals) 2. Make new cells/reproduce (mitosis or meiosis)

3. Exchange materials through active or passive transport 3. Exchange materials through active or passive transport. ACTIVE transport is the movement of materials that requires energy. PASSIVE transport is the movement of materials that does not require energy.

Active Transport Example. a. Cells can also use endocytosis to take in materials, or exocytosis to remove materials from the cell. This only happens if the molecule is too large to fit through membrane proteins 4. Remove waste through excretion.

- Cell membranes are semipermeable, which means they allow things to enter and leave the cell. The cell membrane is also called a phospholipid bilayer . This means it has two layers of phospholipids to regulate water concentration inside and outside of the cell. Hydrophilic: water loving Hydrophobic: dislike water

Diffusion Diffusion is a form of passive transport. Passive transport is a form of movement across the cell membrane that does not require the use of energy. Diffusion is the movement of molecules from high concentration to low concentration.

When molecules are evenly distributed, the cell has reached equilibrium.

Active Transport Sometimes, molecules need to move from areas of low concentration to high concentration. This is called active transport, and requires the use of cellular energy called ATP Could be glucose, other sugars, potassium, calcium, iron or other elements/minerals the cell needs.

Osmosis Diffusion of water through a cell membrane. Movement of water across a membrane. Osmosis is specifically the movement of water from high concentration to low concentration. This form of passive transport only deals with the movement of water. OSMOSIS = DIFFUSION OF WATER

Three types of osmotic solutions Hypotonic Solution: too much water enters the cell, causes it to swell and could burst. HYPO HIPPO Isotonic Solution: The right balance of water inside and outside the cell. Cell functions normally Hypertonic Solution: Losing too much water, can cause cells to shrivel and die. HYPER SKINNY