Unit One- Chapter 3 Cell Structure

1. Unit One- Chapter 3Cell Structure Mrs. Cook Biology

2. History of the Microscope • Robert Hooke- • 1665- used an early light microscope to look at slice of cork from an oak tree. • What he saw looked like little boxes that he called “cells” • He noticed that the cells of trees, roots and stems looked similar.

3. Anton Van Leeuwenhoek 1673- Dutch scientist observed first living cells- “microorganisms”. Invented the microscope. observed cells from algae called spirogyra and bell-shaped cells on stalks of protists called vorticella. called these organisms “beasties” and then formally “Animacules” we now call them Protists.

5. The Cell Theory • 1838, German Botanist- Matthais Schleiden said that allplants were made of cells. • 1839, German Zoologist, Theodor Schwann said the same thing for animals. • The German Physician, Rudolf Virchow(1821-1902), said that all cells come from other cells.

6. The Cell Theory • These ideas were combined to form a basic theory about the cellular nature of life called The Cell Theory. • All living things are made of one or more cells. • Cells are the basic units of structure and function of organisms. • All cells arise from existing cells. Note: somatic cells = body cells gametes = sex cells (sperm and eggs)

8. All living things include the following characteristics • ORGANIZATION • METABOLISM • CHANGE WITH TIME • RESPOND TO STIMULI • REPRODUCTION • MAINTAIN HOMEOSTASIS • GROWTH & DEVELOPMENT

9. Microscopes • The continuous development of microscopes has helped scientists to clarify our definition of life. Compound Microscope Scanning electron Microscope

10. Microsopes cont. • Light microscope: light passes through one or more lenses to produce an enlarged image. • Electron microscope: forms an image using a beam of electrons rather than light. • Parts of a microscope: • Magnification- is the quality of making an image appear larger than the objects actual size. • Resolution- is a measure of the clarity of an image

12. Compound Light microscope

13. Cell Features • We have trillions of cells that range from 5 nanometers in size to 20 nanometers. • So, Why do we have trillions of little cells instead of fewer larger cells? • This has to do with surface area to volume ratio. • Smaller the cell, the quicker it can get substances into the cell and to the area that needs them. The larger the cell, the longer it would take for the substances to travel through the cell.

14. http://youtu.be/wuXSEOKNxN8

15. Cell Features cont. http://youtu.be/o1GQyciJaTA • All cells share 3 common features: • Cell Membrane (aka plasma cell membrane)- - the cells outer boundary -acts as a barrier between the inside and the outside of the cell - All materials must enter or exit through this • castle walls • Gates to Turnpike

16. Cell Features Cont. • 2nd feature common to all cells: 2. Cytoplasm- - the region inside the cell membrane that includes all fluids (Cytosol), organelles(tiny organs), and the nucleus.

17. Cell features cont. • 3rd feature common to all cells: 3. DNA -all cells have DNA for regulating function and reproduction. - DNA in some cells floats freely - Other cells have a membrane bound organelle, that contains the cells DNA, called the Nucleus.

18. Two Basic Types of Cells Prokaryotes • Smallest and simplest cells • Single celled organisms (bacteria, amoebas) • Lacks a nucleus, has circular DNA • No organelles • Has a protective cell wall surrounding its cell membrane. Gives the cell structure, stability, and shape. • Most haveflagella- long threadlike structures that protrude from the cell’s surface for movement.

20. Second Type of Cell Eukaryotic Cells • cells that have a nucleus - Nucleus -internal compartment that holds the cell’s DNA - Control center for the cell • Has specialized structures called organelles. - Organelles- well defined structures that carry out specific functions within the cell. - located inside the cell membrane and outside the nucleus • Cilia- some single celled Eukaryotes contain them to move around- short hair like flagella.

23. Cell Structures • Cytosol-(watery part of the cytoplasm). - fluid surrounding the cytoplasm’s organelles, internal membranes, and cytoskeleton fibers. • Cytoskeleton- -holds the cell together and keeps the cell’s membranes from collapsing. - made up of thin tubes and filaments - also acts as a system of tracks for things to move around the cell

24. Cell Structure Cont. • 3 types of Cytoskeleton: 1. Actin Fibers- form a network just beneath the cell membrane. Contracts and expanding to help keep the cell’s shape. 2. Microtubles- act as a highway system for the transportation of information from the nucleus to organelles in the cell. 3. Intermediate Fibers- provide a framework to keep organelles in a particular region of the cell.

25. Cell Structure Cont. • Cell Membrane - primarily made of lipids - makes a barrier that separates the outside of the cell from the inside of the cell - it allows only certain substances in the environment to pass through, “selectively permeable” Lipid Bi-layer -phosolipids are arranged in a double layer -non-polar tails make up the interior of the bi-layer. - “Hydrophobic” -polar heads make up the outside of the bilayer. - “Hydrophilic”

26. Cell Structure cont. • Phospholipid bi-layer contains several types of Membrane Proteins 1. Marker Proteins- attached to carbohydrate on cell surface and advertise cell type- heart cell, liver cell, etc. 2. Receptor Proteins- recognize and bind to substances outside the cell. Ex: hormones 3. Enzyme- assist in chemical reactions inside the cell. 4. Transport Proteins- move substances into and out of the cell.

27. Figure 12, Pg 61

30. Cell Organelles • Nucleus- - Control center of the cell. Houses and protects the cells genetic information, DNA. - when the cell is not dividing DNA is in the form of Chromatin. - when the cell is dividing, DNA is in the form of chromosomes. • Contains its own protective cover called the Nuclear Envelope. • Contains small channels called nuclear pores. • RNA, made in the nucleus, moves out of the nucleus through these pores.

31. Cell Organelles cont. • Nucleus cont. - Nucleolus- location of the assembly of Ribsomes.

32. Nucleus

33. Cell Organelles cont. • Ribosome - Organelle made of Protein and RNA, and directs Protein Synthesis in the cytoplasm. (They make proteins). - round in shape - some are free in the cytosol and some are attached to another organelle called the Rough Endoplasmic Reticulum.

34. Ribosomes

35. Cell Organelles cont. • Endoplasmic Reticulum (ER)- - system of tubes and sacs that function as a intercellular highway to move molecules through the cell. -Two Type of ER- - Rough ER- - covered in Ribosomes -makes phospholipids and proteins - little sacs or vesicles can pinch off from the end of the ends of the rough ER and store products until the are released from the cell.

36. Cell Organelles cont. • 2nd type of ER - Smooth ER- - does not have Ribosomes - most cells contain very little smooth ER - build lipids such as Cholesterol - produces estrogen and testosterone in the ovaries and testes; makes calcium in the skeletal and heart muscles.

37. Endoplasmic Reticulum

38. Cell Organelles cont. • Golgi apparatus- • Set of flattened, membrane bound sacs that serves as the packaging and distribution center of the cell. • Vesicles, containing proteins, that leave the ER move to the Golgi apparatus. • Enzymes with in the Golgi apparatus modify the proteins from the ER. • They repackage the proteins in new vesicles which then leave the Golgi apparatus. • The vesicles then move to the cell membrane, where they release their contents outside the cell.

40. Golgi Apparatus

41. Cell Organelles cont. • Lysosomes - bud from the Golgi apparatus and contain digestive enzymes. - break down larger molecules - digest old or worn out organelles - breaks down the cell when it is time to die

42. Lysosomes

43. Cell Organelles cont. • Mitochondria - makes energy for the cell by changing organic molecules to ATP. “Power House” of the cell. - The more active a cell is the more mitochondria it will have (like a muscle or heart cell). - Has two membranes; outer membrane is smooth & the inner membrane is folded. - has its own DNA that it uses to make some proteins. http://youtu.be/4DWaAIVlW3k

44. Mitochondria

45. Tour of the Cell

46. Cell Organelles and their Functions

47. Cell Organelles cont. • Cilia -HAIR-LIKE STRUCTURES THAT EXTEND FROM THE SURFACE OF THE CELL - ARE USED FOR MOVEMENT -ARE SHORT AND ARE PRESENT IN LARGE NUMBERS

48. Cell Organelles cont. Flagella • HAIR-LIKE STRUCTURES THAT EXTEND FROM THE SURFACE OF THE CELL • ARE USED FOR MOVEMENT • ARE LONG & FAR LESS NUMEROUS IN CELLS • WORK IN A WHIP-LIKE MOTION PROPELLING CELLS

49. Cell Organelles cont. • Centrioles • CONSIST OF TWO SHORT CYLINDERS OF MICROTUBULES AT RIGHT ANGLES TO EACH OTHER • ARE SITUATED IN THE CYTOPLASM NEAR THE NUCLEAR ENVELOPE • OCCUR IN ANIMAL CELLS WHERE THEY ORGANIZE MICROTUBULES FOR CELL DIVISION

50. Structures of Plant Cells • ***(Add into Notes) Plants have every organelle that animals cells do with the exception of Centrioles. • Plant cells have 3 additional structures than the animal cell structures we discussed. • Cell Wall- - rigid layer found outside the cell membrane - made of cellulose - helps support and maintain the shape of the cell, protects it from damage, and connects it with adjacent cells.