Biology Cells Biology: Structure and Homeostasis

Biology - Cells Topics Introduction to Microscopes Types of Cells Cell organization Animals vs. plant Cells Cell Organelles: Structure & Function Essential Questions 1.What is the proper order of steps when using a light microscope? 2.What are the two general types of cells? Describe each. 3.How are cells organized? 4.What are the differences in plant and animal cells? 5.Identify and describe the following cell organelles: nucleus, plasma membrane, cell wall, mitochondria, vacuoles, chloroplasts, and ribosomes. 6.How does structure relate to the function of a cell’s organelle? 7.How are cells specialized? 8.How do cells communicate with one another?

Microscope Care and Use 1.Always carry the microscope by holding the arm of the microscope with one hand and supporting the base with the other hand. 2.Place the microscope on a flat surface. The arm should be positioned toward you. 3.Look through the eyepieces. Adjust the diaphragm so that light comes through the opening in the stage. 4.Place a slide on the stage so that the specimen is in the field of view. Hold it firmly in place by using the stage clips. 5.Always focus first with the coarse adjustment and the low-power objective lens. Once the object is in focus on low power, the high-power objective can be used. Use ONLY the fine adjustment to focus the high-power lens. 6.Store the microscope covered. Microscope lab

Protein construction and energy conversion occur without specialized internal structures Cells: The Basic Unit of Life * * Prokaryotic Cell (bacteria) DNA (information storage, no nucleus) Cell membrane (transport of raw materials and finished products) Eukaryotic Cell Nucleus (information storage) Packaging Golgi Body EnergyConversionMitochondria ProteinConstructionER Cell Song Cell Song

Comparing Prokaryotic and Eukaryotic Cells ProkaryoticEukaryotic Generally smaller No true nucleus No membrane bound organelles Have DNA in nucleoid region Less complex Examples: bacteria and archaebacteria Generally larger More complex True nucleus Have DNA contained in a membrane bound nucleus membrane bound organelles: ER Mitochondria, Golgi, Chloroplasts and more Examples: Animals, Plants, Fungi and Protisits

Cell organelles Structure / Function The cell is like a factory The cell is like a factory

The nucleus controls most cell processes and contains the hereditary information of DNA. The DNA combines with protein to form chromatin, which is found throughout the nucleus. The small, dense region in the nucleus is the nucleolus. Plant Cell Animal Cell The Nucleus – Control Center of the Cell

endoplasmic reticulum synthesizes proteins for export from the cell. The rough endoplasmic reticulum, shown here, gets its name from the "rough" appearance of the ribosomes on its surface. Endoplasmic Reticulum – assembly line Plant Cell Animal Cell

The Golgi apparatus modifies, sorts, and packages proteins. Notice the stacklike membranes that make up the Golgi apparatus in this transmission electron micrograph. The Golgi Apparatus – Packaging and Export Plant Cell Animal Cell

Mitochondria Chloroplast The powerhouse of the cell Site of aerobic cellular respiration The organelle responsible for photosynthesis and the production of sugar and oxygen

LysosomesGolgi Waste disposal Packaging and Export Regulates substances in and out of the cell Plasma membrane

Comparing Plant and Animal Cells * * PlantAnimal Common Structures

Biology – Homeostasis Topics Investigate and analyze the cell as a living system including: Maintenance of homeostasis. Movement of materials into and out of cells. Essential Questions 1.How is homeostasis maintained? How are temperature, pH, blood glucose and water balanced? 2.What is the difference between active and passive transport? What is a semi permeable membrane? 3.What is osmotic pressure; can you predict changes? (isotonic, hypotonic, and hypertonic)

Homeostasis Homeostasis Overview Homeostasis Overview Homeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature, water balance or pH. Dog Homeostasis Dog Homeostasis

The cell membrane regulates what enters and leaves the cell and also provides protection and support. The composition of nearly all cell membranes is a double-layered sheet called a lipid bilayer. As you can see in Figure 7-12, there are two layers of lipids, hence the name bilayer. The lipid bilayer gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings. Figure 7-12 Cell Boundaries Identification makers

Passive Transport Diffusion describes the spread of particles through random motion from regions of higher concentration to regions of lower concentration. particles concentration particles concentration Osmosis is the movement of water molecules through a selectively permeable membrane into a region of higher solute concentration, aiming to equalize the solute concentrations on the two sides Transport

Passive Transport Osmosis Virtual Lab diffusion

Active Transport is the movement of a substance against its concentration gradient (from low to high concentration).

Tonicity is a measure of the osmotic pressure gradient (as defined by the water potential of the two solutions) of two solutions separated by a semipermeable membrane. It is commonly used when describing the response of cells immersed in an external solution. osmotic pressure semipermeable membraneosmotic pressure semipermeable membrane Hypotonic Solution If water molecules continue to diffuse into the cell, it will cause the cell to swell, up to the point that cytolysis (rupture) may occur cytolysis Isotonic solution isotonic environment happens when an equal concentration exists inside and outside the cell Hypertonic Solution If water molecules continue to diffuse out of the cell, it will cause the cell to shrink, or crenate. Animal cell Plant cell