Biology Biology

Cells Biology: Cells Biology: Structure and HomeostasisStructure and Homeostasis

Biology - Cells

Topics• Introduction to

Microscopes

• Types of Cells

• Cell organization

• Animals vs. plant Cells

• Cell Organelles: Structure & Function

Essential QuestionsEssential Questions1.1. What is the proper order of steps when using a What is the proper order of steps when using a

light microscope? light microscope? 2.2. What are the two general types of cells? What are the two general types of cells?

Describe each.Describe each.3.3. How are cells organized?How are cells organized?4.4. What are the differences in plant and animal What are the differences in plant and animal

cells? cells? 5.5. Identify and describe the following cell Identify and describe the following cell

organelles: nucleus, plasma membrane, cell organelles: nucleus, plasma membrane, cell wall, mitochondria, vacuoles, chloroplasts, and wall, mitochondria, vacuoles, chloroplasts, and ribosomes. ribosomes.

6.6. How does structure relate to the function of a How does structure relate to the function of a cell’s organelle?cell’s organelle?

7.7. How are cells specialized?How are cells specialized?8.8. How do cells communicate with one another?How do cells communicate with one another?

Microscope Care and UseMicroscope Care and Use1.1. Always carry the microscope by holding the arm Always carry the microscope by holding the arm

of the microscope with one hand and supporting of the microscope with one hand and supporting the base with the other hand.the base with the other hand.

2.2. Place the microscope on a flat surface. The arm Place the microscope on a flat surface. The arm should be positioned toward you.should be positioned toward you.

3.3. Look through the eyepieces. Adjust the Look through the eyepieces. Adjust the diaphragm so that light comes through the diaphragm so that light comes through the opening in the stage.opening in the stage.

4.4. Place a slide on the stage so that the specimen Place a slide on the stage so that the specimen is in the field of view. Hold it firmly in place by is in the field of view. Hold it firmly in place by using the stage clips.using the stage clips.

5.5. Always focus first with the coarse adjustment Always focus first with the coarse adjustment and the low-power objective lens. Once the and the low-power objective lens. Once the object is in focus on low power, the high-power object is in focus on low power, the high-power objective can be used. Use ONLY the fine objective can be used. Use ONLY the fine adjustment to focus the high-power lens.adjustment to focus the high-power lens.

6.6. Store the microscope covered.Store the microscope covered. Microscope lab

Protein Protein constructionconstructionand energy and energy conversionconversionoccur occur without without specializedspecializedinternal internal structuresstructures

Cells: The Basic Unit of Life Cells: The Basic Unit of Life Prokaryotic Cell (bacteria)Prokaryotic Cell (bacteria)

DNADNA(information (information storage, no storage, no nucleus)nucleus)

Cell membraneCell membrane(transport of(transport ofraw materialsraw materialsand finishedand finishedproducts)products)

Eukaryotic CellEukaryotic Cell

NucleusNucleus(information(informationstorage)storage)

PackagingPackagingGolgi BodyGolgi Body

EnergyEnergyConversion Conversion MitochondriaMitochondria

ProteinProteinConstructionConstructionERER

Cell SongCell Song

Comparing Prokaryotic and Eukaryotic Comparing Prokaryotic and Eukaryotic CellsCells

Prokaryotic Eukaryotic

Generally smallerGenerally smaller

No true nucleusNo true nucleus

No membrane bound No membrane bound organellesorganelles

Have DNA in nucleoid region

Less complexLess complex

Examples: bacteria Examples: bacteria and archaebacteriaand archaebacteria

Generally largerGenerally larger

More complexMore complex

True nucleusTrue nucleus

Have DNA contained in a membrane bound nucleus

membrane bound organelles: membrane bound organelles: ER ER Mitochondria, Golgi, Chloroplasts and moreMitochondria, Golgi, Chloroplasts and more

Examples: Animals, Plants, Fungi and Examples: Animals, Plants, Fungi and ProtisitsProtisits

Cell organellesStructure / Function

The cell is like a The cell is like a factoryfactory

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 CellPlant Cell Animal CellAnimal Cell

The Nucleus – Control Center of the CellThe 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 lineEndoplasmic Reticulum – assembly line

Plant CellPlant Cell Animal CellAnimal 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 ExportThe Golgi Apparatus – Packaging and Export

Plant CellPlant Cell Animal CellAnimal Cell

Mitochondria

ChloroplastChloroplast

The powerhouse of the cell

Site of aerobic cellular respiration

The organelle responsible for The organelle responsible for photosynthesis and the photosynthesis and the production of sugar and production of sugar and oxygenoxygen

LysosomesLysosomes

GolgiGolgi

Waste disposalWaste disposal

Packaging and ExportPackaging and Export

Regulates substances in Regulates substances in and out of the celland out of the cell

Plasma membrane

Comparing Plant and Animal Cells Comparing Plant and Animal Cells

PlantPlant AnimalAnimal

Common Common StructuresStructures

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 QuestionsEssential Questions

1.1. How is homeostasis maintained? How is homeostasis maintained? How are temperature, pH, blood How are temperature, pH, blood glucose and water balanced? glucose and water balanced?

2.2. What is the difference between What is the difference between active and passive transport? active and passive transport? What is a semi permeable What is a semi permeable membrane?membrane?

3.3. What is osmotic pressure; can What is osmotic pressure; can you predict changes? (isotonic, you predict changes? (isotonic, hypotonic, and hypertonic)hypotonic, and hypertonic)

HomeostasisHomeostasisHomeostasis OverviewHomeostasis Overview

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

Dog HomeostasisDog Homeostasis

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

Figure 7-12Figure 7-12

Cell BoundariesCell Boundaries

Identification makersIdentification makers

Passive TransportPassive TransportDiffusionDiffusion describes the spread of describes the spread of particles through randomrandom motion motion from regions of higher from regions of higher concentration to regions of lower concentration.

OsmosisOsmosis is the movement of is the movement of water moleculeswater molecules through a through a selectively permeable membrane selectively permeable membrane into a region of higher solute into a region of higher solute concentration, aiming to equalize concentration, aiming to equalize the solute concentrations on the the solute concentrations on the two sides two sides

TransportTransport

Passive Transport Passive Transport OsmosisOsmosis

Virtual LabVirtual Labdiffusiondiffusion

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

TonicityTonicity is a measure of the is a measure of the osmotic pressure gradient (as defined by gradient (as defined by the water potential of the two solutions) of two solutions separated by a the water potential of the two solutions) of two solutions separated by a semipermeable membrane. It is commonly used when describing the . It is commonly used when describing the response of cells immersed in an external solution. response of cells immersed in an external solution.

Hypotonic SolutionHypotonic Solution If water molecules continue to diffuse into the cell, it If water molecules continue to diffuse into the cell, it will cause the cell to swell, up to the point that will cause the cell to swell, up to the point that cytolysis (rupture) may (rupture) may occur occur

Isotonic solutionIsotonic solution isotonic environment happens when an equal isotonic environment happens when an equal concentration exists inside and outside the cell concentration exists inside and outside the cell

Hypertonic SolutionHypertonic Solution If water molecules continue to diffuse out of the cell, If water molecules continue to diffuse out of the cell, it will cause the cell to shrink, or crenate. it will cause the cell to shrink, or crenate.

Animal cellAnimal cell Plant cellPlant cell