The Cell Chapter 7

1. The Cell Chapter 7

5. Discovery of the Cell Robert Hooke: 1665-1stperson to see a cell Used a microscope to look at a piece of cork Saw small, empty “boxes”which reminded him of the small rooms monks lived in called cells. These “cells”weren’t alive. From Robert Hooke's Micrographia (1667 ed.). National Library of Medicine

6. 1st Living Cells Anton van Leeuwenhoek 1st person to see and describe living cells: 1673 Made his own microscopes Could magnify 200 times! Described the things he observed as “Animalcules” Wrote many description of his discoveries to the Royal Society in LondoMany of his drawings and descriptions are very accurate even today

7. Cell Theory Developement From the 1stobservation of the cell by Hooke and Leeuwenhoek it took 150 years to develop a theory that explained them. A lot of reasons for the length of time. Not many people had access to microscopes. Problems with making lenses. Previous knowledge/thoughts about where life came from (spontaneous generation). Development of technology to make lenses allowed for more people to study cells.

12. The Cell Theory • 1.All Living things contain a cell or cells. • 2.Cells are the basic unit of structure and function of life • Anything smaller than a cell can’t be alive • 3.Cells come only from other cells. • Disproved spontaneous generation.

13. Two Basic Types of Cells • Prokaryotes • & • Eukaryotes

14. PROKARYOTIC CELLS • Only Unicellular (Single Celled) • DO NOT have a NUCLEUS • Examples include: • The Kingdom Monera – Bacteria Only

15. PROKARYOTIC CELLS • DO NOT have a NUCLEUS • DO NOT have membrane bound organelles

16. Information about Prokaryotics • Important Facts • Evolved 4 billion years ago • No membrane bound nucleus or organelles • Some have flagella – whip like tail • Some have cilia – short, hair like extension • Pro = Before Karyon = Nucleus

17. Eukaryotic Cells • Only Unicellular or Multicellular • DO HAVE a NUCLEUS • Examples include: • The Kingdom Protista, Fungi, Plantae, and Animalia

18. Eukaryotic Cell

19. Information about Eukaryotics • Important Facts • Evolved 3 billion years later than bacteria • Have membrane bound nuclei and organelles • More complex than Prokaryotes • Some unicellular organisms can have flagella or cilia • Eu = True Karyon = Nucleus

20. There are two main types of eukaryotic cellsanimal and plant cells What is inside of animal and plant cells?

21. What is inside the eukaryotic cell? • Cell Organelles • Organelle= “little organ” • Found only inside eukaryotic cells • Everything in a cell except the nucleus is cytoplasm

22. Cell Membrane • Boundary of the cell • Made of a phospholipidbilayer • Part is hydrophobic (water fearing) and part is hydrophillic (water loving)

23. The Nucleus • Control center of the cell • Contains DNA • Surrounded by a double membrane • Usually the easiest organelle to see under a microscope • Usually one per cell

24. What is inside the nuclear envelope?

25. Inside the Nucleus • Chromatin • granular material inside nucleus • Consists of DNA bound to proteins • Chromosomes – • what chromatin condenses to form • Contains the genetic nformation • Nucleolus • Small dense region where assembly of ribosomes begins

26. Outside of the Nucleus

27. Endoplasmic Reticulum • A.k.a. “ER” • Connected to nuclear membrane • Highway of the cell • Rough ER: studded with ribosomes; it makes proteins • Smooth ER: no ribosomes; it makes lipids

28. Ribosome • Site of protein synthesis • Found attached to rough ER or floating free in cytoplasm • Produced in the nucleolus • Two parts to the ribsome • Large and small subunits that act together • “reads” messagner RNA and makes polypeptides (proteins)

29. Golgi Apparatus • Looks like a stack of plates • Acts like the post office of the cell • Modifies, stores and sorts packages (proteins)

30. Lysosomes • Garbage disposal of the cell • Contain digestive enzymes that break down wastes

31. Mitochondria • “Powerhouse of the cell” • Structure – organelle with double membranes; the inner membrane has many folds • Cellular respiration occurs here to release energy for the cell to use • Bound by a double membrane • Has its own unique strand of DNA

32. Vacuoles • Large central vacuole usually in plant cells • Many smaller vacuoles in animal cells • Storage center for the cell • container for water, food, enzymes, wastes, pigments, etc.

33. Cytoskeleton • Acts as skeleton and muscle • Provides shape and structure • Helps move organelles around the cell • Made of three types of filaments • Microtubules • Actin filaments • Intermediate filaments

34. Centriole • Aids in cell division • Usually found only in animal cells • Made of microtubules

35. There are additional organelles in plant cells not found in animal cells

36. Chloroplast • Found only in plant cells • Structure – thylakoid membranes are stacked; they contain pigments such as chlorophyll • Contains the green pigment chlorophyll • Convert solar energy into chemical energy through photosythesis (makes glucose) • Bound by a double membrane

37. CHLOROPLAST

38. Cell Wall • Found in plant and bacterial cells • Rigid, protective barrier • Located outside of the cell membrane • Made of cellulose

39. Movement of Molecules • Diffusion –movement of molecules from HIGH to LOW concentrations • Does not require energy • Osmosis – the diffusion of water

40. Movement through a membrane • Facilitated diffusion -when substances move across a membrane through specialized protein channels

41. Active transport Active transport –movement of molecules in the cell against the gradient (from LOW to HIGH) Requires energy

42. Vocabulary to Know Isotonic = same solute as water

43. Hypotonic = less solute, more wtaer Hypertonic =more solute, less water

44. Concentration Determination Molecules will move until they are equal on each side of the membrane They will continue to pass back and forth and forth across the membrane staying equal on both sides hypertonic/hypotonic solutions are determined by comparison of solute on each side of the membrane

45. Why are cells so small? The surface of a cell, its membrane, is the site of exchange between its interior and its external environment. This surface must allow sufficient exchange to support the contents of the cell. As an object increases in size its volume increases as the cube of its linear dimensions while surface area increases as the square. As these cubes illustrate the surface area to volume ratio of a small object is larger than that of a large object of similar shape. This ratio limits how large cells can be.

46. Cell Specialization • Cells develop in different ways to perform different tasks • Stem cells • Levels of organization • Cells • Tissues • Organs • Organs systems