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Unit 2: Cells and Systems

Unit 2: Cells and Systems. Science 8. Topic 1: Characteristics of Living Things. Structure, Function and Organization. Characteristics of Living Organisms. Living organisms need energy, they get it from food Living organisms respond and adapt to their environment

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Unit 2: Cells and Systems

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  1. Unit 2: Cells and Systems Science 8

  2. Topic 1: Characteristics of Living Things • Structure, Function and Organization

  3. Characteristics of Living Organisms • Living organisms need energy, they get it from food • Living organisms respond and adapt to their environment • Living organisms reproduce so life can continue • Living organisms grow • Living organisms produce waste like carbon dioxide

  4. Levels of Organization • Cells→ Tissue→ Organs→ Systems • The cell is the smallest, or basic, unit of every system. A cell is the smallest thing scientists consider to be alive. • Cells with the same structure and function are grouped into tissues.

  5. 4 Main Types of Tissue Found in Animals • Muscle tissue: Move the parts of the body • Nerve tissue: Carries signals between the brain and other body parts to co-ordinate activities. • Epithelial tissue: Protects the outside of the body and covers the internal structures, such as intestines. • Connective tissue: Connects and supports different parts of the body. May be solid like bone or fluid like blood.

  6. 3 Main Types of Tissue Found in Plants • Epidermal tissue: (Skin) protects the outside of the plant. Also gives structure to the plant. • Xylem tissue: Vessels transport water absorbed by the roots, throughout the plant. • Phloem tissue: Vessels transport the glucose to other parts of the plant.

  7. Organs • Organs: Distinct structures in your body that perform particular functions. • E.g. Brain, eyes, kidneys… • Other examples?? • Groups made up of different tissues form organs

  8. Systems • Organs working together form systems • Give examples of systems….

  9. Different Organisms Have Similar Functions • Plants gather food through roots and by bending; animals move around • Movement in the environment: birds have wings, whales have flippers • Food gathering structures: barnacles have tentacles, birds have bills • Breathing structures: gills vs. lungs

  10. Topic 2: The Role of Cells Within Living Things


  12. Cell • Cell: The basic unit of every system. “The building block of life, all living things are made up of cells” • It separates all forms of life from non-living things. • All living things are made up of cells! • Cells can be very specialized to suit a system in the body.

  13. Single-celled and Multi-celled organisms • Multi-cellular: Organisms made up of more than one cell or a system of cells. • Unicellular: Single celled organisms

  14. Specialized • Cells need to be specialized to meet the different needs just like a band needs to have different instruments to play a variety of songs. • Cells in multi-cellular organisms are said to be specialized for different jobs.

  15. The Advantages of being Multi-cellular • Unicellular organisms have to be able to move, eat, reproduce and respond to environments. Because they depend on cell membranes they can only live in watery, food rich environments. • Multi-cellular organisms can live in a wide variety of environments; by specializing they can be much more efficient.

  16. Topic 3: The Microscope

  17. Microscopes • Magnifying: Making something appear larger. • Early Microscopes: Anton van Leeuwenhoek invented one of the first microscopes using different glass lenses. He was able to magnify up to 300 times the size of an object. Robert Hooke was also experimenting by looking at pieces of cork under magnification. He described what he saw as cellulae “little rooms” giving us the present-day word “cell”

  18. Microscope view of cork

  19. Types of Microscopes • Light Microscope: 2,000 x magnification • Electron Microscope: 2,000,000 x magnification (must be in a vacuum therefore dead cells only)

  20. Parts of a Microscope

  21. Field of View

  22. (slide pictures)

  23. Topic 4: Plant and Animal Cells

  24. (virtual)

  25. Organelles • Organelles: Structures inside the cell. • Cytoplasm: Jelly-like material in which other parts of the cell float. • Cell membrane: Surrounds the cell and protects the cells contents. • Cell wall: Thick covering outside the cell membrane • Nucleus: Controls most of the cells activities • Vacuole: Liquid filled part for storage; smaller and more in animal cells • Chloroplast: Contains the green pigment chlorophyll. • Mitochondria: Powerhouse of the cell • Rough Endoplasmic Reticulum: Where chemical activity occurs, transportation of proteins • Smooth Endoplasmic Reticulum: Where chemical activity occurs, storage of proteins

  26. (song)

  27. Plant Cell

  28. Animal Cell

  29. Differences Between Plant and Animal Cells

  30. Movement of Gases and Liquids into and out of cells • Cell Membrane: Is like a border crossing. The membrane is selectively permeable meaning that it lets some things across but not others. • Permeable: Lets everything through • Impermeable: Lets nothing through

  31. Diffusion • Diffusion: The random movement of particles from a high concentration to a low concentration. • E.g. Popcorn smell • Diffusion in Cells: Cells burn oxygen and make carbon dioxide so there is a high concentration of CO2 inside a cell and a low concentration of O2. Diffusion in many cases will allow for a movement of particles through a membrane without a cost of energy from the cell.

  32. Diagram of Diffusion


  34. Osmosis • Osmosis: Diffusion of water through a selectively permeable membrane. Water moves from a high concentration to a low concentration. • Fluid Movement in Plants: All the water in a plant is connected from cell to cell, water taken in by roots pushes water up (through osmosis) and water evaporating off of leaves pulls water (also through osmosis)

  35. Plants Vascular tissue: like blood vessels for a plant! • Phloem tissue: Transports sugars manufactured in the leaves to the rest of the plant. • Xylem tissue: Conducts water and minerals absorbed by the roots cells to every cell in the plant. • Root hairs: Tiny hair-like roots that serve to increase the surface area in which osmosis can take place. • From the root hairs water is absorbed into the xylem tissue, to the stems, then to the leaves. Once in the leaves it is used by the chloroplasts for photosynthesis.

  36. Plants Continued… • Stoma (stomata): Are openings in the bottom of the leaves that let air in and out. Controlled by the guard cells. • Transpiration: Loss of water from a plant through evaporation from the leaves and stem.

  37. Contributing Roles of Cells, Tissues and Organs in Plant and Animal Structures • Example: Digestive System • Made up of many organs such as the intestines and the stomach. • In the stomach, muscle tissue moves to mix stomach contents. Epithelial tissue lines the stomach. Connective tissue helps hold the shape. Nerve tissue co-ordinates the activities of the stomach. • The connective tissue is made up of loose, fibrous sheets that connect and support the body.

  38. Topic 5: Systems

  39. The Body Systems • Digestive System: Used to take in food and break it down into usable energy then pass waste out of the body. • Respiratory System: Used to take in oxygen and give off carbon dioxide in the lungs. • Circulatory System: Transports nutrients and oxygen to different parts of the body and carries some waste products.

  40. More Body Systems 4. Excretory System: Filters blood and removes wastes from system 5. Sensory Awareness (Nervous) System: Responds to changes in the environment to keep your body stable.

  41. 1. The Digestive System

  42. Food Pathway • Digestive → Circulatory • Mouth→ Stomach→ Small Intestine→ Bloodstream via villi • Villi: Each villi contains a network of capillaries which absorb the digested food into the blood stream, much the same way as the alveoli. • Villi work by increasing the surface area of the small intestine, so it can absorb more nutrients • Food provides nutrients in the form of Carbohydrates, Fats, Proteins, vitamins, minerals and water that provide energy and materials for growth, development and repair.

  43. 2. The Respiratory System

  44. Air Pathway • Respiratory→ Circulatory • Bronchus tube → Bronchioles → Alveoli→ Capillaries • The respiratory system moves the air in and out of the lungs and the circulatory system picks up oxygen from the lungs while dropping off carbon dioxide. • The circulatory system carries the oxygen to the parts of the body that need it via diffusion.

  45. 3. The Circulatory System

  46. Circulatory System Cells- What is inside of blood? • Red Blood Cells: Contain hemoglobin and carry oxygen • White Blood Cells: Defend the body against sickness/disease and help blood to clot • Hemoglobin: Iron rich chemical found in the blood that attracts oxygen. Oxygen attaches to hemoglobin so that it can be transported throughout the body. • Plasma: Liquid portion of the blood. It carries food, waste, hormones and blood cells.

  47. Continued… • Platelets: Prevent blood loss • Blood Vessel: Part of a complex network of tubes/passageways that serve to bring things from the external environment to the internal environment. • Veins: Pump blood to the heart • Arteries: Pump blood away from the heart


  49. 4. Excretory System Filters waste materials from the blood. Kidneys are the key organ

  50. (intro) (advanced) (nephron/system) (virtual lab) (intro)

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