Riddle of the day I know a word of letters three. Add two, and fewer there will be. The word “FEW”

Pop QUiz Cell Eukaryote Prokaryote Nucleus Ribosome Protein synthesis (makes proteins) No nucleus, smaller and less complex The basic unit of life The control center of the cell, where all the DNA is stored Has a nucleus, larger and more complex

Pop quiz continued 6. Golgi Apparatus 7. Mitochondria 8. Chloroplast 9. Lysosome 10. Organelle f. Cleans up the cell. Digests molecules, gets rid of waste. g. Converts sunlight to energy, makes plants green, site of photosynthesis h. Site of ATP synthesis, gives energy to the cell, powerhouse i. Modifies, sorts, packages and ships proteins. FedEx of the cell. j. Little organs responsible for certain functions in cells

Review What is the main function of the cell membrane? Control what goes in and out of the cell Protection Support All of the above

The tails of fat molecules are hydrophilic. True False

How does diffusion work? It just does, no one knows From HIGH to LOW concentrations From LOW to HIGH concentrations None of the above

Cell Boundaries

Cells Vocab Part 2 Cell Membrane Cell Wall Lipid Bilayer Concentration Diffusion Equilibrium Osmosis Isotonic Hypertonic Hypotonic 11. Facilitated Diffusion 12. Active Transport 13. Endocytosis 14. Phagocytosis 15. Pinocytosis 16. Exocytosis 17. Cell Specialization 18. Tissue 19. Organ 20. Organ System

One of the most important parts of cell is the CELL MEMBRANE One of the most important parts of cell is the CELL MEMBRANE. -A thin, flexible barrier. Many cells also have a CELL WALL. -A strong, supporting layer around the membrane.

CELL MEMBRANE The cell membrane regulates what enters and leaves the cell. Provides protection and support. Semi-permeable LIPID BILAYER- A double-layered sheet composed of two layers of lipids (fats).

Phospholipid bilayer -They have a HYDROPHILIC HEAD that attracts water. -They have a HYDROPHOBIC TAIL that avoids water.

Parts of the cell membrane Lipids (fats) Proteins Carbohydrates Channels

Cell Wall The main function of the cell wall is to provide support and protection for the cell. Outside the membrane. Made of cellulose. (Main component in wood and paper)

The substances dissolved in the solution are called solutes The substances dissolved in the solution are called solutes. The CONCENTRATION is the mass of the solutes divided by the volume of the solution. Ex: If you dissolved 12 grams of salt into 3 liters of a water solution, the concentration would be: 12/3=4 grams/liter

diffusion Particles (solutes) constantly move. They tend to move from HIGH concentration to LOW concentration. This process is called DIFFUSION. When the concentration is the same throughout a system, the system has reached EQUILIBRIUM. (Balance)

Substances will diffuse across the membrane without requiring the cell to use energy. They diffuse from HIGH to LOW concentrations through protein channels in the cell membrane. Cells want to be in equilibrium.

Types of diffusion OSMOSIS Is the diffusion of water through a selectively permeable membrance.

ISOTONIC –same throughout, no movement. HYPOTONIC –less concentrated than another solution of the same type. If a cell is in a hypotonic solution, water will flow into the cell. HYPERTONIC –more concentrated than another solution of the same type. If a cell is in a hypertonic solution, water will flow out of the cell.

Facilitated diffusion The diffusion of specific molecules through specific channels across the membrane. Like diffusion, it still goes from HIGH concentration to LOW concentration. There are many protein channels that are specific to a certain molecule, glucose for example. Glucose channels only allow for glucose to pass through from HIGH concentrations of glucose to LOW concentrations of glucose.

Active transport Movement of materials against the concentration gradient. LOW to HIGH. Requires energy- Pumps have to pump small molecules across the membrane.

ENDOCYTOSIS- occurs when a cell wraps its membrane around a particle ENDOCYTOSIS- occurs when a cell wraps its membrane around a particle. Then turns its membrane inside out to take in the particle. If the particle is very large the process is called PHAGOCYTOSIS or cell eating. PINOCYTOSIS is the same thing only with liquids. EXOCYTOSIS is the release of excess stuff from inside the cell to outside. Opposite of endocytosis.

CELL specialization Cells in multi-cellular organisms develop in different ways to perform particular functions for the organism. Red Blood Cells transport oxygen throughout the body. Muscle cells contract and relax to move parts of the body. Guard cells control what comes into the body.

Levels of organization Cells Tissues- groups of cells performing the same function. Organs- groups of tissues performing the same function. Organ Systems- groups of organs performing similar functions. Big organisms need specialization so they can work together to function. Divide and conquer.

1. A cell has a selectively permeable or semi- permeable membrane 1. A cell has a selectively permeable or semi- permeable membrane. What does this mean? 2. What was the color of the water in the large container at the beginning of the experiment? At the end? 3. What was the color of the solution in the sandwich bag at the start of the experiment? At the end? 4. To which substance is the plastic bag permeable? 5. Why did iodine enter the bag? 6. Why didn’t the starch exit the bag? 7. How is the plastic bag like the cell membrane of a cell?