Objective: Today we will describe how materials move into and out of the cell through the cell membrane Materials Pen/Pencil Notebook Packet Book pg 48 Agenda Daily question Chapter 2 Packet Notes Daily Question: what is photosynthesis? 01/09/15- No gum Please!

Plant Vs. Animal Cell Lab  Obtain materials from teacher  Set magnification to 10x first (low power)  Put Elodea slide under microscope observe what it looks like on low power –draw a picture  Put Elodea slide on high power, observe and identify organelles-draw scientific picture in notebook  Have one student come up to Ms. Mildebrath and swab cheek cell, Ms. Mildebrath will put dye on slide, return with animal cell to group  Put animal cell under low power microscope, observe organelles and structures- draw scientific drawing in notebook  Put animal cell under high power and observe changes, identify organelles and draw observations in notebook

Scientific Drawing Example Cork cell 100x Cork cell Cell membrane

Photosynthesis

Cellular Respiration

Materials move across the cell’s membranes  Diffusion  Osmosis  Active Transport Vs. Passive Transport  Endocytosis (in)  Exocytosis (out)

Diffusion Diffusion is the process by which molecules spread out or move from areas where there are many of them to areas where there are fewer of them. Diffusion helps cells maintain conditions that are necessary for life. During cellular respiration oxygen enters your cells by the process of diffusion. Also, carbon dioxide leaves cells by diffusion

The concentration of a substance is the number of particles of that substance in a specific volume. The greater the difference in concentration between two areas, the more rapidly diffusion occurs. Concentration and Diffusion Ex. When you add salt to water, although you may be able to see salt sitting at the bottom of the cup, you are able to taste the salt mixed in with the water. This is because the concentration of salt has become the same throughout the cup.

This is how water moves into and out of the cells in our bodies. If the concentration of water is higher outside of the cell, then the water moves into the cell until it has reached equilibrium. Ex: Watering plants – if you forget to water a plant, it wilts. The soil dries out, and the plant’s roots have no water to absorb. Water leaves the plant cells by osmosis and they shrink. If you water the plant, the leaves return to normal as water moves back into the cells. Osmosis Osmosis -is the diffusion of water through a membrane.

Active transport is the process of using energy to move materials through a membrane. Endocytosis and exocytosis are examples of this. Ex. Our kidneys filter wastes from our blood by active transport. The cells in the kidneys remove the excess salt from the blood. Active Transport and Passive Transport Passive transport is the process of moving materials without using the cell’s energy. Diffusion and osmosis are examples of this. Ex. Glucose is able to move into out of cells to give it the food energy it needs.

Endocytosis and Exocytosis Endocytosis is the process in which a portion of the cell membrane folds and absorbs a particle in order to move it into a cell. Cells in the body use this process to fight bacteria and viruses. Exocytosis is the process in which a membrane within a cell encloses the material that needs to be removed. This membrane then joins with the cell membrane. Cells use exocytosis to get rid of waste materials, proteins, or hormones.