CELLS Structure and Function Cell = smallest unit of life

Cell Theory 1. All living things are made of cells 2.Cells are the basic unit of structure and function 3.All cells come from pre-existing cells

Two Major Cell Types Cell Type Example ProkaryoticBacteria EukaryoticProtistsFungiPlantsAnimals

Prokaryotic Cell

Eukaryotic Cell (protist, animal)

Eukaryotic Cell (plant)

Differences Between Cell Types Prokaryotic Cell Eukaryotic Cell Single circular chromosome Multiple linear chromosomes Chromosome found in a cytoplasmic region called the nucleoid. Chromosomes found in a membrane- bound nucleus. No internal membranes Some infolded plasma membrane Extensive network of internal membranes

Common Components and Cellular Organization Plasma MembranePlasma Membrane – boundary surrounding the cell Genetic material: DNAGenetic material: DNA –located in a membrane-bound nucleus for eukaryotic cells CytoplasmCytoplasm –Semi-fluid matrix containing enzymes and organelles (enzyme = biological catalyst) CytoskeletonCytoskeleton –network of filaments and tubules in cytoplasm that maintains cell shape, allows movement

Features of Prokaryotic Cells All prokaryotic cells contain StructureFunction Plasma Membrane Regulates flow of substances into and out of cell Nucleoid Cytoplasmic region containing genetic material Cytoplasm Cytosol: fluid RibosomesEnzymes

Features of Prokaryotic Cells Other possible prokaryotic structures StructureFunction Cell Wall Supports cell Maintains shape Capsule Protects from drying Protects against white blood cells Infolded Plasma Membranes Metabolism Cell division

Features of Prokaryotic Cells Other possible prokaryotic structures StructureFunction Bacterial Flagellum Movement Plasmid Plasmid Small circular DNA Replicates independently

Applying Your Knowledge In bacterial cells where is the genetic material located?where is the genetic material located? which one is used for movement?which one is used for movement? which one provides structural support for the cell?which one provides structural support for the cell? 1. Cell Wall 2. Flagellum 3. Capsule 4. Plasmid 5. Nucleoid

Thought Questions 1.What are similarities for a. eukaryotic and prokaryotic cells? b. animal and plant cells? 2. What are differences between a. eukaryotic and prokaryotic cells? b. animal and plant cells?

Functions of Eukaryotic Cell Features StructureFunction(s) Plasma Membrane 1. Regulates passage of materials into and out of cell 2. Cell-Cell Recognition

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Function of the Cell Membrane: Cell membrane separates the components of a cell from its environment—surrounds the cell “Gatekeeper” of the cell—regulates the flow of materials into and out of cell—selectively permeable Cell membrane helps cells maintain homeostasis— stable internal balance

Passive Transport A process that does not require energy to move molecules from a HIGH to LOW concentration DDiffusion FFacilitated Diffusion OOsmosis

Diffusion is the movement of small particles across a selectively permeable membrane like the cell membrane until equilibrium is reached. These particles move from an area of high concentration to an area of low concentration. outside of cell inside of cell

Osmosis is the diffusion of water through a selectively permeable membrane like the cell membrane Water diffuses across a membrane from an area of high concentration to an area of low concentration. Semi-permeable membrane is permeable to water, but not to sugar

Facilitated Diffusion is the movement of larger molecules like glucose through the cell membrane – larger molecules must be “helped” Proteins in the cell membrane form channels for large molecules to pass through Proteins that form channels (pores) are called protein channels outside of cell inside of cell Glucose molecules

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Hypertonic Solutions: contain a high concentration of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to shrivel. Hypotonic Solutions: contain a low concentration of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypotonic solution, the water diffuses into the cell, causing the cell to swell and possibly explode. Isotonic Solutions: contain the same concentration of solute as another solution (e.g. the cell's cytoplasm). When a cell is placed in an isotonic solution, the water diffuses into and out of the cell at the same rate. The fluid that surrounds the body cells is isotonic.

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Active Transport Active transport is the movement of molecules from LOW to HIGH concentration. Energy is required as molecules must be pumped against the concentration gradient. Proteins that work as pumps are called protein pumps. Ex: Body cells must pump carbon dioxide out into the surrounding blood vessels to be carried to the lungs for exhale. Blood vessels are high in carbon dioxide compared to the cells, so energy is required to move the carbon dioxide across the cell membrane from LOW to HIGH concentration. outside of cell inside of cell Carbon Dioxide molecules

NO ENERGY NEEDED: Diffusion Osmosis Facilitated Diffusion ENERGY NEEDED: Active Transport ANALOGY:

Food is moved into the cell by Endocytosis Wastes are moved out of the cell by Exocytosis Endocytosis and Exocytosis is the mechanism by which very large molecules (such as food and wastes) get into and out of the cell

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Analogy If the cell were a factory the ____________________ would be (name a cell component) (name a cell component) a _____________________________. (name a part of a factory)

Part of Cell Part of Factory Capsule Security Gate Cell Wall Outer Fence around the factory Chloroplast Solar Panel Cytoskeleton Moving Belt where items are inspected Steel Support, Interior Walls Cilia/Flagella Conveyor Belt, Elevator/Escalator Enzyme Worker; Assemblage Machinery Golgi Complex Distribution/Packaging Department Mailroom Mitochondrion Generator, Engine Room, Power Source Nucleoid Storage of pre-production material Nucleus Supervisor’s Office, Boss Corporate Office, Central Operations Plasma Membrane Loading/Unloading Dock, Inner Wall, Door Ribosomes Assembly Line Track RER Production Line SER Shipping Dock Vacuole Storage Area

Cellular Interactions  Signal Transduction: passing a signal from the cell surface to the interior  First messenger binds to Cell Surface Receptor  Receptor signals nearby Regulator Protein  Regulator activates nearby enzyme  Enzyme catalyzes formation of Second Messenger  Second Messenger initiates Cellular Response

Cellular Interactions  Cell Adhesion: joining of cells controlled by proteins called Cellular Adhesion Molecules (CAMS) important in important in  Inflammatory Response  Placenta Formation  Learning and Memory Lack of cell adhesion is implicated in cancer and arthritis. Lack of cell adhesion is implicated in cancer and arthritis.