Cells and their_functions1


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Cells and their_functions1

  1. 1. Cells and Their Functions
  2. 2. What is a cell?
  3. 3. Here’s what a “cell” is! <ul><li>Cell - the smallest unit of an organism that carries on the functions of life </li></ul><ul><li>A cell can perform all the processes of life . </li></ul>
  4. 4. Comparing cells <ul><li>Many Sizes: </li></ul><ul><ul><ul><li>nerve cells - up to a meter long </li></ul></ul></ul><ul><ul><ul><li>human egg cell - dot of an i </li></ul></ul></ul><ul><ul><ul><li>bacteria - 80,000 could fit in the dot of an i </li></ul></ul></ul>
  5. 5. Comparing cells <ul><li>Different shapes: </li></ul><ul><ul><ul><li>Related to their function (job) </li></ul></ul></ul>
  6. 6. Comparing cells <ul><li>Cell types: </li></ul><ul><ul><ul><li>Prokaryotic cell – </li></ul></ul></ul><ul><ul><ul><li>very simple; no membrane-bound structures </li></ul></ul></ul><ul><ul><ul><li>(ex: bacteria ) </li></ul></ul></ul><ul><ul><ul><li>Eukaryotic cell – </li></ul></ul></ul><ul><ul><ul><li>more advanced; has membrane- bound structures </li></ul></ul></ul><ul><ul><ul><li>(ex: animal cells, plant cells) </li></ul></ul></ul>
  7. 7. Early Cell Scientists <ul><li>Robert Hooke (1665) </li></ul><ul><li>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. </li></ul><ul><li>“ Cell” comes from the Latin word for “ little room .” </li></ul>
  8. 8. Early Cell Scientists <ul><li>Anton van Leeuwenhoek (1673) </li></ul><ul><li>A Dutch shopkeeper who looked at pond water using a simple microscope and saw what he called “ animalcules .” </li></ul><ul><li>Today, we call them single-celled organisms . </li></ul>An Early Simple Microscope
  9. 9. Early Cell Scientists <ul><li>Matthias Schleiden (1838) </li></ul><ul><li>A German botanist who discovered that all plants are made up of similar units , or cells. </li></ul>
  10. 10. Early Cell Scientists <ul><li>Theodor Schwann (around 1830) </li></ul><ul><li>A German scientist who stated that all plants and animals are made up of building blocks , or cells. </li></ul><ul><li>He also observed that there are similarities and differences between plant and animal cells. </li></ul>
  11. 11. Early Cell Scientists <ul><li>Rudolph Virchow (1858) </li></ul><ul><li>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 . </li></ul>
  12. 12. Cell Theory <ul><li>1. All living things are made up of one or more cells . </li></ul><ul><li>2. Cells are the basic unit of structure and function in living things. </li></ul><ul><li>3. All cells come only from other living cells. </li></ul>
  13. 13. Cell Structure Animal Cell Plant Cell
  14. 14. Cell Structure <ul><li>A cell is like a small town : Different parts have different and specialized jobs . </li></ul><ul><li>Plant cells and animal cells have many similar structures, but have several important differences . </li></ul>
  15. 15. Cell Membrane <ul><li>Structure : </li></ul><ul><li>Outer boundary of the cell </li></ul><ul><li>Phospholipid bilayer membrane </li></ul><ul><li>Selectively permeable </li></ul>
  16. 16. Cell Membrane <ul><li>Function (job) : </li></ul><ul><li>Protects inside </li></ul><ul><li>Supports/gives shape </li></ul><ul><li>Controls what enters/leaves - “gatekeeper” </li></ul><ul><li>Helps maintain homeostasis (ability to keep a stable environment) </li></ul>
  17. 17. Cell Wall <ul><li>Structure : </li></ul><ul><li>ONLY IN PLANTS </li></ul><ul><li>Made of cellulose </li></ul><ul><li>Strong & rigid </li></ul><ul><li>Dead layer </li></ul>
  18. 18. Cell Wall <ul><li>Function (job) : </li></ul><ul><li>Protects/ supports </li></ul><ul><li>Gives shape </li></ul>
  19. 19. Cytoplasm <ul><li>Structure : </li></ul><ul><li>Jelly-like substance </li></ul><ul><li>80 % water </li></ul>
  20. 20. Cytoplasm <ul><li>Function (job) : </li></ul><ul><li>Organelles float in cytoplasm </li></ul><ul><li>Materials for growth are found in cytoplasm </li></ul><ul><li>Expels waste through cell membrane </li></ul>
  21. 21. Nucleus <ul><li>Structure : </li></ul><ul><li>Surrounded by nuclear membrane </li></ul><ul><li>Usually round/oval </li></ul><ul><li>Near center </li></ul>
  22. 22. Nucleus <ul><li>Function (job) : </li></ul><ul><li>Control center of cell </li></ul><ul><li>Controls cell activities </li></ul><ul><li>Contains chromosomes </li></ul>
  23. 23. Mitochondria <ul><li>Structure : </li></ul><ul><li>Has an outer membrane and an inner folded membrane </li></ul><ul><li>Rod shaped </li></ul>
  24. 24. Mitochondria <ul><li>Function (job) : </li></ul><ul><li>Cellular respiration </li></ul><ul><li>Turns food into useable energy (ATP) </li></ul>
  25. 25. Ribosomes <ul><li>Structure : </li></ul><ul><li>Tiny, round, dark </li></ul><ul><li>Can be free floating or attached to endoplasmic reticulum </li></ul>
  26. 26. Ribosomes <ul><li>Function (job) : </li></ul><ul><li>Protein factories </li></ul><ul><li>Assembles proteins used in growth, repair and control </li></ul>
  27. 27. Endoplasmic Reticulum <ul><li>Structure : </li></ul><ul><li>Network of tubes and canals </li></ul><ul><li>Smooth ER - no ribosomes attached </li></ul><ul><li>Rough ER - ribosomes are attached </li></ul>
  28. 28. Endoplasmic Reticulum <ul><li>Function (job) : </li></ul><ul><li>Transports materials “intracellular highway” </li></ul>
  29. 29. Golgi Bodies <ul><li>Structure : </li></ul><ul><li>Series of flattened sacs </li></ul>
  30. 30. Golgi Bodies <ul><li>Function (job) : </li></ul><ul><li>Processes, packages and secretes material </li></ul><ul><li>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 </li></ul>
  31. 31. Lysosomes <ul><li>Structure : </li></ul><ul><li>ONLY IN ANIMAL CELLS </li></ul><ul><li>Contains powerful digestive chemicals </li></ul>
  32. 32. Lysosomes <ul><li>Function (job) : </li></ul><ul><li>Contains digestive enzymes (chemicals), breaks things down </li></ul><ul><li>“ suicide sac” </li></ul>
  33. 33. Vacuoles <ul><li>Structure : </li></ul><ul><li>Fluid -filled sacs that float in the cytoplasm </li></ul>
  34. 34. Vacuoles <ul><li>Function (job) : </li></ul><ul><li>Stores water and food materials </li></ul><ul><li>Stores waste and helps the cell get rid of waste </li></ul><ul><li>Plant cells contain a large central vacuole - filled with water - helps give shape </li></ul>
  35. 35. Chloroplast <ul><li>Structure : </li></ul><ul><li>ONLY IN PLANT CELLS </li></ul><ul><li>Green, oval-shaped </li></ul><ul><li>Contains green pigment chlorophyll </li></ul>
  36. 36. Chloroplast <ul><li>Function (job) : </li></ul><ul><li>Site of photosynthesis </li></ul><ul><li>Traps the sun’s energy to make glucose </li></ul>
  37. 38. How are plant and animal cells different? PLANT CELLS: Have cell walls , chloroplasts , large vacuoles
  38. 39. How are plant and animal cells different? ANIMAL CELLS: Have lysosomes
  39. 40. How are different cells adapted to their functions? Muscle Cells: Have large quantities of mitochondria for energy. Plant Cells: Rigid cell walls allow plants to grow upright .
  40. 41. 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 message s are sent throughout the body.
  41. 42. Vocabulary <ul><li>Permeable </li></ul><ul><li>Diffusion </li></ul><ul><li>Osmosis </li></ul><ul><li>Mitosis </li></ul><ul><li>Chromosome </li></ul><ul><li>Centriole </li></ul><ul><li>Centromere </li></ul>
  42. 43. Organization of Living Things
  43. 44. Organization of Living Things <ul><li>Five main levels of organization </li></ul><ul><li>1. Cell </li></ul><ul><li>2. Tissue </li></ul><ul><li>3. Organ </li></ul><ul><li>4. Organ System </li></ul><ul><li>5. Organism </li></ul>
  44. 45. Tissue <ul><li>Example: Muscle </li></ul><ul><li>Tissues are made of specialized cells. </li></ul>
  45. 46. Organ <ul><li>Examples: Heart, Lung, Brain </li></ul><ul><li>Found in both plants and animals. </li></ul><ul><li>Composed of tissue that is organized into groups that work together to perform special functions. </li></ul>
  46. 47. Organ System <ul><li>Example: Circulatory System </li></ul><ul><li>A group of organs that work together. </li></ul>
  47. 48. 10 Organ Systems in complex organisms (humans, dogs, birds, etc.) <ul><li>1. Circulatory </li></ul><ul><li>2. Digestive </li></ul><ul><li>3. Nervous </li></ul><ul><li>4. Respiratory </li></ul><ul><li>5. Skin </li></ul><ul><li>6. Skeletal </li></ul><ul><li>7. Muscular </li></ul><ul><li>8. Reproductive </li></ul><ul><li>9. Excretory </li></ul><ul><li>10. Endocrine </li></ul>
  48. 49. ORGANISMS <ul><li>Different organ systems work together to keep the organism alive. </li></ul>
  49. 50. QUESTION: <ul><li>Classify the following as a tissue, organ, or organ system. a. Brain, spinal cord, and nerves b. Heart c. Group of muscle cells </li></ul>
  50. 51. QUESTION: <ul><li>Can a single-celled organism contain tissue? Explain. </li></ul>
  51. 52. QUESTION: <ul><li>Give one example of each: a. Cell c. Tissue b. Organ d. Organism </li></ul>