The Discovery and Structure of Cells

1. Chapter 7- Cell Structure & Function

2. I. Life is CellularA-The Discovery of the Cell • It was not until the _________ that scientists began to use microscopes to observe organisms. • In 1665 ____________used an early compound microscope to see tiny chambers in cork.He called these chambers cells after the tiny rooms in monasteries….we know these not to be empty now. Robert Hooke Mid-1500’s

3. About the same time in Holland________________used a single-lens microscope to look @ pond water, Anton van Leeuwenhoek

4. Cell Theory • In 1838 Matthew Schleiden concluded plants were made of cells • 1839 Theodore Schwann said all animals were made of cells • 1855-Virchow said cells could only come from existing ones.

5. These 3 things compile_________________ Cell Theory • All living things composed of ___________ • Cells are the basic units of ___________________of living things • New cells are produced from ______________________. Existing cells cells Structure and function

6. B-Exploring the Cell • Most microscopes use lens to magnify the image of a specimen with light or electrons • _________________,which scans cells w/a laser beam can make 3-d images of cells • Video technology make it possible to watch cell growth , division and development Confocal light microscopy

7. Light makes it difficult to visualize tiny structures because it scatters/______________________allow things like proteins to be visualized (things as much as 1000 x smaller can be visualized….TEMS allow you to see specimens cut into ultra thin slices Electron microscopes

8. With light microscopes stains need to often be used since most living cells are transparent-some stains are structure specific • Some dyes show fluorescence dyes give off light of a ceratin color when viewed under specific wavelenghths • May be able to track specific molecules

9. W/ a ______________specimens do not have to be cut to see 3-D images….both must be placed into a vacuum so air molecules do not scatter electrons/TEM-shows details • 1990’s-____________________________have revolutionalized visualization of surfaces and atoms have been observed…can be used in ordinary air and can show DNA structure Scanning probe microscopes SEM pollen

10. C .Prokaryotes and Eukaryotes • Cells typically range from _________micrometers,but some bacteria are .2 and some amoeba are 1000 micrometers • All cells have 2 things in common: • cell membrane-a barrier • @ some point they contain_______ 5-50 micrometers DNA

11. 2 broad categories: • _____________________________-genetic material is NOT contained in a nucleus/generally less complicated than other cells/carry out all cell activities…present day members are ________________. • Only organelles are ribosomes and they are NOT MEMBRANE BOUND Prokaryotes bacteria

12. _____________________________-contain a nucleus w/ genetic material,generally larger,much diversity • HAVE all organelles/most membrane bound • Include all organisms EXCEPT bacteria Eukaryotes

14. Division of Labor Section 7-2 • A cell is made up of many parts with different functions that work together. Similarly, the parts of a computer work together to carry out different functions. • Working with a partner, answer the following questions. • 1. What are some of the different parts of a computer? What are the functions of these computer parts? • 2. How do the functions of these computer parts correspond to the functions of certain cell parts? Go to Section:

15. Cell Wall Chloroplasts Venn Diagrams Section 7-2 Eukaryotes Prokaryotes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell membrane Ribosomes Cell wall Animal Cells Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Vacuoles Mitochondria Cytoskeleton Lysosomes Go to Section:

16. II. EUKARYOTIC CELL STRUCTURE • Organelles • 2 major parts of eukaryotic cells nucleus cytoplasm Specialized structure that performs important functions within an eukaryotic cell. /”little organs”/ Cytoplasm is material inside membrane and outside nucleus

20. The Nucleus • Contains nearly all the cell’s DNA • Codes for instructions to make proteins and other molecules • Surrounded by nuclear envelope---has many pores to allow material in and out • Contains chromatin—has DNA bound to protein,usually spread throughout nucleus,but condenses during cell division to make CHROMOSOMES,containing genetic info • Usually contain Nucleolus—assembly of ribosomes begin here.

21. Organelles That Store , Clean-up and Support • Vacuoles • Sac like structures that store water ,salts ,proteins, and carbs • Plants may have a single large water filled vacuole • Contractile vacuoles control water in paramecium

22. VESICLES-store and move between organelles and cell surface

23. Lysosomes • Small organelles filled w/enzymes • May digest or break down lipids,carbs,and proteins into small molecules that can be used by the rest of the cell • Lysosomes remove “junk”,or used up organelles…-very important that this aspect / function occurs • May be in some/ very few plants

24. Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Michondrion Figure 7-7 Cytoskeleton Section 7-2 Go to Section:

25. Cytoskeleton • Network of protein filaments that help cell maintain shape • Also involved in movement • MICROFILAMENTS are threadlike structures made of a protein-actin….make a major network and a tough framework///allows amoebas and such to move • MICROTUBULES-hallow structures made of proteins called tubulins—important in holding a cell’s shape----form a mitotic spindle in cell division/which helps separate chromosomes • CENTRIOLES are microtubules near nucleus in animals and help organize cell division • Microtubules also help make projections like cilia or flagella • Arranged in “9+2” pattern of microtubules

26. ORGANELLES THAT BUILD PROTEINS • Ribosomes : • Proteins are assembled here • Made out of small particles of RNA and protein • Found throughout cytoplasm • Coded instructions from nucleus tell how to make proteins • Cells active in protein synthesis have a lot of ribosomes

27. ER • Endoplasmic Reticulum • ER-Site where lipid components of cell membrane are assembled ,along w/ proteins and other materials exported from cell(those proteins are made there)

28. Rough ER is involved in protein synthesis,because ribosomes are on it-finishes twisting and folding • Smooth ER involved in lipid metabolism and detoxifying poisons • Newly made proteins leave ribosomes and insert on rough ER ,where they may be modified • If cell makes a lot of protein ,there is much ER • Smooth ER may contain many specialized enzymes

29. GOLGI BODY: • proteins from rough ER go here in this stack of membranes/get “address tags” to package and export to correct place-bundled in vesicles • Golgi modifies ,sorts , packages proteins and other materials from ER for storage or release from cell

32. ORGANELLES THAT CAPTURE AND RELEASE ENERGY • ==Mitochondria and Chloroplasts • Most all eukaryotic cells contain mitochondria that convert chemical energy stored in food into compounds convenient for cell to use • Mitochondria have an outer and inner membranes • In humans,nearly all mitochondria comes from ovum(egg cell)

33. Chloroplasts • Capture energy from sunlight and convert into chemical energy in photosynthesis • Contain 2 membranes and chlorophyll

34. Organelle DNA • Organelle DNA • In chloroplasts and mitochondria • Small DNA molecules • Maybe descendants of early prokaryotes • ----Endosymbiotic theory says these prokaryotic ancestors developed a symbiotic relationship w/ early eukaryotes and resided within---evolving into mitochondria

36. All cells have a _____________________________and some have a cell wall Cell membrane

38. A. Cell Membrane • Regulates what enters and leaves the cell and also provides _____________________________. • Almost all cell membranes are made of a double layered sheet called a ___________________________-flexible,yet strong barrier • Cell membranes usually have a protein molecule imbedded in the bilayer w/ carbohydrate molecules attached • Called a _________________model • Some of the proteins form channels or pumps to move material across the membranes • Some of the carbs act as ____________________tags Fluid mosaic Phospholipid bilayer Protection and support Chemical id tags

42. B. Cell Walls • In plants,algae,fungi, and many prokaryotes • Lie _______________the cell membrane • Usually porous enough to let water,O2,CO2 and certain other substances to pass through easily • Main function is support and protection • Usually made of fibers of ____________________-produced in cell and secreted to surface • Mostly _____________________-tough carb fibers/to withstand gravity cellulose Carbohydrate and protein outside

45. C.Diffusion Through Cell Boundaries • Every cell is in a liquid environment • Cell membrane regulates the movement of cell materials from one side to the other

47. 1.Measuring concentration • Cytoplasm is a solution of various substances in water • _____________of a solution is the mass of solute in given volume of solution---ie. Mass/volume…..If you have 15 g salt in 3 mL water,what is the concentration?------_______….If you have 24 g salt in 2mL water you would have 12 g/mL salt….Which solution is more concentrated?______________ 12 g/mL 5g/mL concentration

49. Diffusion-Passive Transport-needs no energy moves WITH concentration gradient DIFFUSION • In a solution the particles move constantly,spreading out randomly….tending to move where more concentrated to an area less concentrated…This is called __________________. • ____________________= concentration of a solute is the same throughout a system • does not require energy because random movement • if equilibrium is reached,particles keep moving across the membrane,still balancing concentration isotonic