Cell Structure and Function

NEED TO KNOW VOCAB Solute - the minor component in a solution, dissolved in the solvent. Solvent - able to dissolve other substances, the liquid in which a solute is dissolved to form a solution. Solution - a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent), the process or state of being dissolved in a solvent. Remind them water is the universal solvent Sugar and powder are solutes Solution is the kool aid made in the end

Vocab continued Hydrophobic – tending to repel or fail to mix with water. Hydrophilic - having a tendency to mix with, dissolve in, or be wetted by water. YOUR NOT ALLERGIC TO WATER… Remember to bath But some parts of your body do resist mixing with water more so than other parts

Plasma Membrane Contains cell contents Double layer of phospholipids & proteins Plasma membrane is double layer to protect the liquid in cells from mixing with liquids out of cells ALSO KNOWN AS CELL MEMBRANE

Phospholipids Polar Interacts with water Hydrophylic head Hydrophobic tail Interacts with water Try to expand on the concept on phospholipids having a had and tail. They pair and bond according to POLARITY Tie this back to Water and the charges it has, which causes the position of Hydrogen bonds

Movement Across the Plasma Membrane A few molecules move freely Water, Carbon dioxide, Ammonia, Oxygen Carrier proteins transport some molecules Proteins embedded in lipid bilayer Fluid mosaic model – describes fluid nature of a lipid bilayer with proteins Some things move easy. Some don’t. There are 4 types of movement

Membrane Proteins 1. Channels or transporters 2. Receptors Move molecules in one direction 2. Receptors Recognize certain chemicals Membrane- a pliable sheetlike structure acting as a boundary, lining, or partition in an organism. Protiens -any of various naturally occurring extremely complex substances that consist of amino-acid residues joined by peptide bonds, contain the elements carbon, hydrogen, nitrogen, oxygen, usually sulfur, and occasionally other elements EX (such as enzymes, hormones, or antibodies)

Membrane Proteins 3. Glycoproteins 4. Enzymes Identify cell type Catalyze production of substances

Cytoskeleton Filaments & fibers Made of 3 fiber types 3 functions: Microfilaments Microtubules Intermediate filaments 3 functions: mechanical support anchor organelles help move substances Support, movement and transport of substance in and out of cell are the basic components of the cytoskeleton. Cytoskeleton is similar to human skin. It has a mechanical feature(temperature control, keeps organs in place, and moves waste out the body and nutrients in)

Molecule Movement & Cells Passive Transport Active Transport Endocytosis (phagocytosis & pinocytosis) Exocytosis End of Day 1. Work on assignments

Passive Transport No energy required Move due to gradient differences in concentration, pressure, charge Move to equalize gradient High moves toward low

Types of Passive Transport 1. Diffusion 2. Osmosis 3. Facilitated diffusion

Diffusion Molecules move to equalize concentration

Osmosis Special form of diffusion Fluid flows from lower solute concentration Often involves movement of water Into cell Out of cell

Solution Differences & Cells solvent + solute = solution Hypotonic Solutes in cell more than outside Outside solvent will flow into cell Isotonic Solutes equal inside & out of cell Hypertonic Solutes greater outside cell Fluid will flow out of cell

Facilitated Diffusion Differentially permeable membrane Channels (are specific) help molecule or ions enter or leave the cell. Channels usually are transport proteins (aquaporins facilitate the movement of water) No energy is used

Process of Facilitated Transport Protein binds with molecule Shape of protein changes Molecule moves across membrane

Active Transport Molecular movement Requires energy (against gradient) Example is sodium-potassium pump

Endocytosis Movement of large material Movement is into cells Particles Organisms Large molecules Movement is into cells Types of endocytosis bulk-phase (nonspecific) receptor-mediated (specific)

Process of Endocytosis Plasma membrane surrounds material Edges of membrane meet Membranes fuse to form vesicle

Forms of Endocytosis Phagocytosis – cell eating Pinocytosis – cell drinking

Exocytosis Reverse of endocytosis Cell discharges material

Exocytosis Vesicle moves to cell surface Membrane of vesicle fuses Materials expelled

Exit Slip 1. Which structure regulates what enters and leaves the cell? Mitochondria Plasma membrane Chloroplast Nucleus 2. Water has a lot of properties. These properties make water essential to life. Being essential to life water is known as the universal __________? Solution Solute Solvent substance

Exit Slip 3. What are the types of Passive Transport 4. Which type of transport requires energy? 5. What is endocytosis?