CELL STRUCTURE AND FUNCTION

1. CELL STRUCTURE AND FUNCTION

2. Essential questions… • What is a Cell? • Do all Cells look the same and have the same function? • Why is it important to understand the parts of a cell? • How does the tiniest cell have any relationship to our entire body? • Where do we find cells?

3. Definition of a Cell A Cell is: The smallest unit that is capable of performing life functions.

4. How do we know this? We know that scientific knowledge comes from experimentation and as scientists began developing microscopes – they quickly realized they were entering a new world of microorganisms.

5. Scientists to Remember Robert Hooke: • Invented the first compound microscope with 2 lenses. • He observed a piece of cork under the microscope and described the boxes he saw as “cells”

6. Hooke’s Discovery

7. Anton van Leeuwenhoek • Used a single lensed microscope to see living organisms in pond water.

8. van Leeuwenhoek’s contribution

9. Theodor Schwann and Matthias Schleiden 1. Schwann: all animals are composed of cells 2. Schleiden: all plants are composed of cells Jointly concluded that all living things are composed of cells

10. Rudolf Virchow Said that all cells must arise (come from) pre-existing cells.

11. The Cell Theory • All living things are composed of cells • Cells are the smallest working units of all living things • All cells come from pre-existing cells through cell division

12. The Cell Theory (cont.) Exceptions to the Cell Theory 1. Mitochondria and Chloroplasts: contain their own genetic material (DNA) and can duplicate themselves. Evidence that they are descendants of primitive bacteria (Probacteria) 2. Viruses: consist of DNA surrounded by a protein coat. 3. Where did the first cell come from…? Viruses- Can only reproduce inside a living cell but are not cells themselves

13. The Cell Theory is a unifying concept in Biology which further supports the The Theory of Evolution Which indicates that all organisms share a common ancestors.

14. It is important to realize that our bodies, our individual cell have levels of organization and function

15. Cellular and Tissue Organization • As organisms become more complex, their structures are organized in more complex ways. A. Cell: the basic unit of structure and function in organisms. 1. Unicellular: a complete living thing that is made of only one cell Example: ameba, paramecium, euglena 2. Multicellular: a complete living thing that is made up of many cells. Example: human, palm tree, dog

16. Cellular and Tissue Organization B. Tissue: a group of cells in an organism that are alike in structure and activity. Example: muscle tissue, blood, blood vessels, nerve tissue, bone, cartilage, etc. C. Organ: A group of tissues that work together to perform a specific function. -Example of an Organ: Stomach (made of nerves, muscles and blood vessels)

17. Cellular and Tissue Organization D. Organ System: A group of organs that work together to perform a specific function. -Example: Digestive System (includes mouth, esophagus, stomach, intestines, liver, etc.) E. Organism: A living thing OrganelleCellTissueOrgan Organ SystemOrganismSpecies

18. Cells have evolved two different architectures: • Prokaryote “style” Pro = primary • Eukaryote “style” Eu = true

19. Two Major Classes of Cells • PROKARYOTIC: Any cell that lacks a nucleus. Example: A bacteria

20. These are prokaryote E. coli bacteria on the head of a steel pin.

21. Prokaryote cells are simply built (example: E. coli) • capsule: slimy outer coating • cell wall: tougher middle layer • cell membrane: delicate inner skin

22. Eukaryotic: Any cell that DOES have a nucleus Example: A human body cell

23. Eukaryotes are bigger and more complicated • Haveorganelles • Examples ??? • Havechromosomes • can be multicellular • include animal and plantcells

24. Summary of differences!

25. Are all Animal Cells Alike? No! They differentiate (specialize) to perform specific functions.

26. Cell Specialization The principle of cell specialization means that the cells found in a multicellular organism are not all the same, nor do they all have the same function. Specialized cells allow multicellular organisms to efficiently carry out processes necessary for life. Although cells are specialized, they do not operate in isolation.

27. Cell Specialization and Tissues • Main advantage of multicellular organisms is cellular differentiation • Tissue: group of cells with specific function • Humans have 14 major tissue types (bones, muscles, nerves, blood, etc.) • Humans have more than 200 specialized cell types that differ in • Size (nerve cell vs. blood cells) • Lifetime (nerve cells vs. bone marrow cells) • Note: all cells have exactly the same genetic code; the difference comes from differences in gene expression

28. Examples of specialized euk. cells • liver cell: specialized to detoxify blood and store glucose as glycogen.

29. Examples of specialized euk. cells • An excitable cell specialised for the transmission of electrical signals over long distances

30. sperm cell: specialized to deliver DNA to egg cell

31. Mesophyll cell • specialized to capture as much light as possible • inside a leaf

32. Cellular Communication http

33. Multicellular organisms require specialized cells to perform the various processes of life efficiently. Specialization requires communication between cells. • Cells use a variety of different signaling molecules to communicate with one another, including proteins, fatty acid derivatives, and even gases. • To receive and interpret signals, cells have specific receptor proteins that bind signaling molecules and trigger certain chemical reactions inside the cell. • Some receptor proteins reside in the cytosol and bind to signaling molecules that pass through the plasma membrane; others reside in the plasma membrane and bind only to external signaling molecules. • One signaling molecule can induce many chemical reactions, amplifying the cell’s response to the signal. • Different signaling molecules can affect some of the same chemical reactions in the cell, resulting in the combining of different signals.

34. Components of cells are known as:CELL ORGANELLES

35. Nucleus • Directs the cell’s activities • Surrounded by a nuclear membrane • Contains the nucleolus • Life Process: Regulation

36. Nucleolus • Dense area inside nucleus • Contains DNA • Life Process: Synthesis (rRNA)

37. Cell Membrane • Separates cell from outer environment • Controls what enters and leaves the cell • “semi-permeable” • Life Process: Regulation & Transport

38. Cytoplasm • Watery substance between the cell membrane and the nucleus. • Life Process: Transport

39. Mitochondria • Produces energy through chemical reactions • Cellular Respiration takes place here! • Life Process: Respiration

40. Ribosomes • Site of protein synthesis • Found on ER or floating around the cell • Life Process: Synthesis

41. Endoplasmic Reticulum (ER) • Moves materials around the cell (the highway of the cell) • Smooth type: lacks ribosome's • Rough type: ribosome's embedded in the surface. • Life Process: Transport

42. Golgi Complex • Protein packaging plant • Process, package and stores cell products • Life Process: Regulation

43. Vacuoles • A fluid filled organelle • Storage of nutrients or wastes • Life Process: Regulation and Nutrition

44. Lysosome • Digestive Center for the cell. • Breaks down food • Life Process: Regulation

45. Centriole • ONLY IN ANIMAL CELLS • Function in cell division • Life Process: Reproduction

46. Chloroplasts • ONLY IN PLANT CELLS • Contains green chlorophyll • Where photosynthesis takes place

47. Cell Wall • ONLY IN PLANT CELLS • Supports and protects cells

48. Label the following diagrams: This is an ANIMAL CELL Cell Membrane Mitochondria Lysosome Vacuole Golgi Body Centrioles Ribosomes Nucleus Nucleolus Endoplasmic Reticulum (Smooth ER) Endoplasmic Reticulum (Rough ER)

49. Label the following diagrams: This is a PLANT CELL Cell Membrane Golgi Body Nucleolus Mitochondria Cell Wall Chloroplast Ribosomes Nucleus Vacuole Endoplasmic Reticulum (Smooth ER) Endoplasmic Reticulum (Rough ER)

50. How are Plant and Animal Cells different? Cell Wall Centrioles Vacuoles Chloroplasts