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Cells and Their Functions

Cells and Their Functions

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Cells and Their Functions

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  1. Cells and Their Functions

  2. What is a cell?

  3. Here’s what a “cell” is! • Cell - the smallest unit of an organism that carries on the functions of life • A cell can perform all the processes of life.

  4. Comparing cells • Many Sizes: • nerve cells - up to a meter long • human egg cell - dot of an i • bacteria - 80,000 could fit in the dot of an i

  5. Comparing cells • Different shapes: • Related to their function (job)

  6. Comparing cells • Cell types: • Prokaryotic cell - very simple; no • membrane-bound structures • (ex: bacteria) • Eukaryotic cell - more advanced; has • membrane-bound structures • (ex: animal cells, plant cells)

  7. Early Cell Scientists Robert Hooke (1665) • An English scientist who looked at slices of cork under a crude compound microscope and saw “a great many little boxes” that he called “cells.” First person to see cells. • “Cell” comes from the Latin word for “little room.”

  8. Early Cell Scientists Anton van Leeuwenhoek (1673) • A Dutch shopkeeper who looked at pond water using a simple microscope and saw what he called “animalcules.” • Today, we call them single-celled organisms. An Early Simple Microscope

  9. Early Cell Scientists Matthias Schleiden (1838) • A German botanist who discovered that all plants are made up of similar units, or cells.

  10. Early Cell Scientists Theodor Schwann(around 1830) • A German scientist who stated that all plants and animals are made up of building blocks, or cells. • He also observed that there are similarities and differences between plant and animal cells.

  11. Early Cell Scientists Rudolph Virchow (1858) • This German physician also reported that every living thing is made of up vital units, known as cells. He also predicted that cells come from other cells.

  12. Cell Theory 1. All living things are made up of one or more cells. 2. Cells are the basic unit of structure and function in living things. 3. All cells come only from other living cells.

  13. Cell Structure Animal Cell Plant Cell

  14. Cell Structure • A cell is like a small town:Different parts have different and specialized jobs. • Plant cells and animal cells have many similar structures, but have several important differences.

  15. Cell Membrane • Structure: • Outer boundary of the cell • Double lipid membrane • Selectively permeable

  16. Cell Membrane • Function (job): • Protects inside • Supports/gives shape • Controls what enters/leaves - “gatekeeper” • Helps maintain homeostasis (ability to keep a stable environment) • Analogy: • Townline

  17. Cell Wall • Structure: • ONLY IN PLANTS • Made of cellulose • Strong & rigid • Dead layer

  18. Cell Wall • Function (job): • Protects/support • Gives shape • Analogy: • Castle Wall

  19. Cytoplasm • Structure: • Jelly-like substance • 80% water

  20. Cytoplasm • Function (job): • Organelles float in cytoplasm • Materials for growth are found in cytoplasm • Expels waste through cell membrane • Analogy: • Town property

  21. Nucleus • Structure: • Surrounded by nuclear membrane • Usually round/oval • Near center

  22. Nucleus • Function (job): • Control center of cell • Controls cell activities • Contains chromosomes • Analogy: • Mayor and city council

  23. Mitochondria • Structure: • Has an outer membrane and an inner folded membrane • Rod shaped

  24. Mitochondria • Function (job): • Cellular respiration • Turns food into useable energy (ATP) • Analogy: • Power house (powerplant)

  25. Ribosomes • Structure: • Tiny, round, dark • Can be free floating or attached to endoplasmic reticulum

  26. Ribosomes • Function (job): • Protein factories • Assembles proteins used in growth, repair and control • Analogy: • Factory

  27. Endoplasmic Reticulum • Structure: • Network of tubes and canals • Smooth ER - no ribosomes attached • Rough ER - ribosomes are attached

  28. Endoplasmic Reticulum • Function (job): • Transports materials “intracellular highway” • Analogy: • Roads and highways

  29. Golgi Bodies • Structure: • Series of flattened sacs

  30. Golgi Bodies • Function (job): • Processes, packages and secretes material • Materials that are transported by the ER usually stop first at the Golgi bodies where they are stored or altered before moving to other parts of the cell • Analogy: • Center for Manufacturing and shipping (UPS)

  31. Lysosomes • Structure: • ONLY IN ANIMALS • Contains powerful digestive chemicals

  32. Lysosomes • Function (job): • Contains digestive enzymes (chemicals), breaks things down • “suicide sac” • Analogy: • Garbage collectors

  33. Vacuoles • Structure: • Fluid-filled sacs that float in the cytoplasm

  34. Vacuoles • Function (job): • Stores water and food materials • Stores waste and helps the cell get rid of waste • Plant cells contain a large central vacuole - filled with water - helps give shape • Analogy: • Storage warehouse

  35. Chloroplast • Structure: • ONLY IN PLANT CELLS • Green, oval-shaped • Contains green pigment chlorophyll

  36. Chloroplast • Function (job): • Site of photosynthesis • Traps the sun’s energy to make glucose • Analogy: • Greenhouse or solar cell

  37. How are plant and animal cells different? PLANT CELLS: Have cell walls, chloroplasts, large vacuoles

  38. How are plant and animal cells different? ANIMAL CELLS: Have lysosomes

  39. How are different cells adapted to their functions? Plant Cells: Rigid cell walls allow plants to grow upright. Muscle Cells: Have large quantities of mitochondria for energy.

  40. How are different cells adapted to their functions? Red Blood Cells: Thin, flexible discs allow them to squeeze through tiny blood vessels. Nerve Cells: Have long projections through which messages are sent throughout the body.

  41. Vocabulary Permeable Diffusion Osmosis Mitosis Chromosome Centriole Centromere

  42. Organization of Living Things

  43. Organization of Living Things Five main levels of organization 1. Cell 2. Tissue 3. Organ 4. Organ System 5. Organism

  44. Tissue • Example: Muscle • Tissues are made of specialized cells.

  45. Organ • Examples: Heart, Lung, Brain • Found in both plants and animals. • Composed of tissue that is organized into groups that work together to perform special functions.

  46. Organ System • Example: Circulatory System • A group of organs that work together.

  47. 1. Circulatory 2. Digestive 3. Nervous 4. Respiratory 5. Skin 6. Skeletal 7. Muscular 8. Reproductive 9. Excretory 10.Endocrine 10 Organ Systems in complex organisms(humans, dogs, birds, etc.)

  48. Different organ systems work together to keep the organism alive. ORGANISMS

  49. Classify the following as a tissue, organ, or organ system.a. Brain, spinal cord, and nerves b. Heartc. Group of muscle cells QUESTION: