2. Ch. 4 Cell Structure and Function Intro.-4.2 What are the 7 Characteristics of Life? Intro.-4.2 What are the 7 Characteristics of Life?

3. / Cells, organization, reproduction, energy use, response to stimuli, adaptation, growth

4. I. Cell Discovery Timeline:

5. Early 17th century Galileo Galilei -among the first to record a biological observation made with a “microscope” Galileo Galilei -among the first to record a biological observation made with a “microscope”

6. mid 17th century Robert Hooke -coined the term “cell” after observing dead cork cells Robert Hooke -coined the term “cell” after observing dead cork cells

7. Late 1600s Antony van Leeuwenhoek -observed “animalcules” =small moving creatures Antony van Leeuwenhoek -observed “animalcules” =small moving creatures

8. 1820s Robert Brown -with improvements in lenses, viewed a nucleus Robert Brown -with improvements in lenses, viewed a nucleus

9. 1838 Matthias Schleiden -hypothesized: each cell must develop independently Matthias Schleiden -hypothesized: each cell must develop independently

10. 1839 Theodor Schwann -animals and plants are made of cells which have an individual life of their own Theodor Schwann -animals and plants are made of cells which have an individual life of their own

11. mid-19th century Rudolf Virchow -every cell comes from an existing cell Rudolf Virchow -every cell comes from an existing cell

12. II. The Cell Theory 1. Every organism is composed of one or more cells. 2. The cell is the smallest unit having the properties of life. 3. The continuity of life arises directly from the growth and division of single cells. 1. Every organism is composed of one or more cells. 2. The cell is the smallest unit having the properties of life. 3. The continuity of life arises directly from the growth and division of single cells.

13. 4.1 Basic Aspects of Cell Structure Cell- the smallest unit having the properties of life

14. I. Structural Organization of Cells

15. Plasma membrane (aka cell membrane) -separates the cell from its environment, allowing substances and signals to move across in controlled ways. *Found in all cells -separates the cell from its environment, allowing substances and signals to move across in controlled ways. *Found in all cells

16. Nucleus or nucleoid -location of DNA *eukaryotic cell *prokaryotic cell

17. Cytoplasm -semi-fluid substance in the cell

18. Prokaryotic cells -lack a membrane- bound nucleus and organelles -Kingdoms: Archaebacteria Eubacteria -lack a membrane- bound nucleus and organelles -Kingdoms: Archaebacteria Eubacteria

19. Eukaryotic cells -have a membrane- bound nucleus and organelles Kingdoms: Protista, Fungi, Plantae, Animalia -have a membrane- bound nucleus and organelles Kingdoms: Protista, Fungi, Plantae, Animalia

20. What 3 parts do all cells have?

21. II. Lipid Bi-layer of Cell Membrane Includes proteins embedded in the membrane which: 1. Act as passive channels for water- soluble substances 2. Pump substances across the bi-layer 3. Act as receptors for hormones and other signaling molecules Includes proteins embedded in the membrane which: 1. Act as passive channels for water- soluble substances 2. Pump substances across the bi-layer 3. Act as receptors for hormones and other signaling molecules

23. Read pp. 46-49 in Holt Biology book (lion on cover)

24. III. Cell size and shape Cell size is limited by the surface to volume ratio. If a cell expands in diameter during growth, its volume will increase more rapidly than its surface area. Each unit of the cell’s plasma membrane will have to serve much more cytoplasm making cell transport inefficient. Also, a small cell has more efficient transport within the cell from organelle to organelle.

26. / On the next slide you will see: / Largest human cell by volume / Smallest human cell / Longest human cell / On the next slide you will see: / Largest human cell by volume / Smallest human cell / Longest human cell

28. 4.2 Microscopes Micrograph- a photographic image taken through a microscope

29. I. Light microscope A. Compound light -light must pass through the specimen -ours magnify 1,000X max. A. Compound light -light must pass through the specimen -ours magnify 1,000X max.

30. B. Stereoscope (aka dissecting microscope) - object is lit from the top and bottom, so can be opaque, 50X B. Stereoscope (aka dissecting microscope) - object is lit from the top and bottom, so can be opaque, 50X

31. II. Electron Microscopes A. Transmission electron microscope- cannot view living organisms, specimens must be sliced and stained -50- 1,000,000X A. Transmission electron microscope- cannot view living organisms, specimens must be sliced and stained -50- 1,000,000X

32. B. Scanning electron microscope- specimens coated with a thin layer of metal, cannot view living, 3-D -5-500,000X B. Scanning electron microscope- specimens coated with a thin layer of metal, cannot view living, 3-D -5-500,000X

33. C. Scanning tunneling microscope- scans the surface of the object, can view living -up to 100,000,000X C. Scanning tunneling microscope- scans the surface of the object, can view living -up to 100,000,000X

35. Why are microscopes a critical discovery?