Presentation on theme: "Ch. 8 Cell Structure & Function Lesson 1: What Do Cells Do?"— Presentation transcript:
1 Ch. 8 Cell Structure & Function Lesson 1: What Do Cells Do?
2 CellsMain Idea: All living things are made of cells. To stay alive and healthy, cells need food and water. They also need a way to get rid of waste.Plant Cells and Animal CellsA single cell is the smallest structure that carries out activities necessary for life.A cell is like a tiny factory: different parts of the factory produce or control different things.1. gets food or water2. keeps cell clean3. in charge of reproduction
3 Like parts of a factory, all parts must work together to run smoothly. An organism can’t survive without cells doing their work.Animal and plant cells look different, but sharemany similar features.Common features:1. cell membrane2. nucleus3. cytoplasmCell membraneOuter covering of cellWater and food enter through itWastes leave through it
4 Plant cells have extra structure called cell wall which adds more support to plant cell. NucleusControl center of cellCarries information forreproductionDirects all cell activitiesCytoplasmGel-like material that surrounds all parts of cell within membraneContains nucleus and cells’ organelles
5 Cell Transportation Organelle-small structure that has certain job 1. mitochondria2. vacuoles3. nucleus4. cell membrane5. golgi bodies and endoplasmicreticulumChloroplast-special organelle that uses energy of sunlight combined with water and carbon dioxide to make food for cellCell TransportationCell membrane holds cell matter inside, but allows water, gasses, and wastes to pass through.
6 In passive transport, matter moves into or out of cell without cell using any energySimplest kind of passive transport-diffusionDiffusion:Spreads substances through gas or liquid (can smell dinner across room b/c food molecules diffuse through air)Transports many gases into and out of cellsSubstances diffuse from areas of high concentration to areas of low concentrationSpecial form of diffusion-osmosis
7 Osmosis:Diffusion of water across membraneMembrane stops many substances that aredissolvedOften keeps water inside cellsSometimes a cell needs to move materials opposite to the way diffusion would move them.In active transport, substances move from areas with less matter to areas with more matterCell must use energy to do this.Large proteins in cell membrane help move materials in and out.Protein acts as tunnels that allow certain materials to pass.
8 Using Energy Scientists study these proteins for clues to how cells operate.Using EnergyAll living things need energy to survive.Plants use chloroplasts to make foodby using energy of sunlight, water, andcarbon dioxideProcess takes place in chloroplasts and depends ongreen pigment called chlorophyll.Chlorophyll captures energy from sunlight.Photosynthesis:1. series of chemical reactions join water fromground with carbon dioxide from air.
9 2. By products are oxygen, which plant releases into air, and a molecule called glucose.Glucose1. High energy material that is classified as sugar2. Plants and animals use sugar for food.3. Plant and animal cells have organelles calledmitochondria.4. Mitochondria-break down sugars so cells canuse sugars as energyMitochondria1. perform cell respiration(reverse reaction to photosynthesis)2. Break down sugars to make energy
10 Cell Division 3. process combines glucose with oxygen to form water and carbon dioxide4. lot of energy released in process5. store energy in molecule called ATP which isreleased during cell respiration6. ATP acts like battery-cell can draw fromATP whenever it needs to useenergyCell DivisionBody is made of trillions of cellsBegan as one single cellCells copy themselves in process known as celldivisionNew organisms begin when cells from two parentscombine to form fertilized egg.Soon the single cell divides into 2 cells.
11 Two cells divide into 4 cells Four cells divide into 8 cellsSometimes cells divide within hoursallowing organism to grow very quickly.As cells divide, they differentiate(become different from one another)Early on, cells organize themselves into 3 groups calledgerm layers:1. form the skin and nerves2. becomes the lining of the digestive tract3. produces all other body partsBacteria and other single-celled organisms can copythemselves which results in new individuals.When conditions favor division, a bacteria colony candouble very quickly.