1. A View of the Cell Chapter 7

2. The discovery of the cell  Scientists believed curses and spirits caused illness  Leeuwenhoek invented first simple microscope  was first to view organism (living things)  Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth

3. Development of Cell Theory  Robert Hooke- coined the term “cell” while observing cork under a microscope Building blocks of life Building blocks of life  Schleiden- observed that all plants were composed of cells  Schwann- observed that all animals were composed of cells  Robert Brown- discovered the nucleus

4. The Cell Theory AAAAll organisms are composed of one or more cells CCCCells are the basic unit of structure and function for all living things CCCCells come from preexisting cells

5. The modern microscopes  Compound light microscope- uses a series of lenses to magnify up to 1500x’s Light must be able to pass through object Light must be able to pass through object Greatly expanded knowledge of microorganisms Greatly expanded knowledge of microorganisms  The electron microscope was Invented in the 1940’s Uses a beam of electrons Uses a beam of electrons Magnifies up to 500,00 times Magnifies up to 500,00 times Cannot be used on live organisms Cannot be used on live organisms

6. Electron microscopes Cont.  Two general types SEM-scanning electron microscope- produces a good 3-D shape SEM-scanning electron microscope- produces a good 3-D shape TEM- transmission electron microscope- used for small structures with in the cell TEM- transmission electron microscope- used for small structures with in the cell  STM- Scanning tunneling microscope- new technology can view objects at the atomic level can view objects at the atomic level

7. Two basic cell types  Prokaryotic- cells with no nucleus or membrane bound organelles Ex: bacteria and other monerans (unicellular) Ex: bacteria and other monerans (unicellular)

8. Cell types cont. EEEEukaryotic- cells with a nucleus and other membrane bound organelles. Organelle-means “little organ”, membrane bound structures with in the cell that carry out a certain job. Ex: protista, animal, plant and fungi

9. What’s the difference?

10. The Plasma Membrane

11. Maintaining balance  Controls what enters and exits the cell  Allows glucose, O2 and other materials in  Keeps other things out  Maintains homeostasis  It is selectively permeable- only lets some things in or out

12. Fluid Mosaic Model

13. Structure of the plasma membrane DDDDouble layer of phospholipids with proteins embedded in it MMMMake-up of phospholipid bilayer Head w/ phosphate group is polar (hydrophilic) Tail w/ fatty acids is non polar (hydrophobic)

14. Structure cont.  Creates a barrier w/ a water soluble outer layer and a water insoluble inner layer  Referred to as the fluid mosaiic model because it is flexible Fluid = flexible, movable Fluid = flexible, movable Mosaic – pattern Mosaic – pattern  Phosopholipids and proteins move w/in the membrane

15. Other parts of the cell membrane CCCCholesterol – helps stabilize the phospholipids. Keeps the fatty acids from sticking together. TTTTransport proteins – Allow needed substances or waste materials to move through the plasma membrane IIIInternal proteins – Help attach the membrane to the internal support structure of the cell. CCCCarbohydrates – Stick out off the surface and help cells identify each other.

16. Fluid Mosaic Model

17. Eukaryotic cell structures

18. Cellular boundaries  Cell wall- made up of thick cellulose layer and only found in plant cells, fungi and most bacteria Gives the cell extra support Gives the cell extra support Very porous- permeable Very porous- permeable

19. Cellular boundaries cont.  Nucleus- controls all cell activities Contains DNA w/ blueprint for proteins Contains DNA w/ blueprint for proteins Chromatin is DNA in the active form and chromosomes are compact DNA Chromatin is DNA in the active form and chromosomes are compact DNA Nucleolus- w/in nucleus; makes ribosomes Nucleolus- w/in nucleus; makes ribosomes  Nuclear membrane Separates nucleus from cytoplasm Separates nucleus from cytoplasm Regulates what enters the nucleus Regulates what enters the nucleus

20. 20 The DNA- Determines which proteins are made Chromatin- DNA unwound when it is replicating Chromosome- compact so the cells can divide

22. Centrioles  Only found in animal cells  Come in pairs  Helps the cell get organized before cell division

23. Assembly, transport and Storage

24. Building and transporting proteins DDDDNA has the information for what proteins will be built RRRRibosome's Place where protein synthesis occurs EEEEndoplasmic reticulum- highly folded membranes w/ ribosomes attached to it Transports materials w/in the cell Allows for chemical reactions Smooth E.R. has no ribosomes

25. Endomembrane system

26. Golgi Apparatus  Flattened system of tubular membranes that modify sort and package proteins.  proteins are carried in secretion vessicles to other parts of the cell

28. Vacuoles  Store food and other materials needed by the cell  Store water  Are much larger in plant cells  Help create turgor pressure

29. Lysosomes  Contain digestive enzymes Break down old worn out cell parts Break down old worn out cell parts Engulf viruses and bacteria Engulf viruses and bacteria Can fuse with vacuoles to digest contents Can fuse with vacuoles to digest contents Digest cells- example tadpole’s tails Digest cells- example tadpole’s tails

30. Organelles that produce energy  Chloroplasts-plant cells only capture light energy and convert it into glucose capture light energy and convert it into glucose Place of photosynthesis Place of photosynthesis  Mitochondria-animal and plant cells Convert glucose into ATP molecules Convert glucose into ATP molecules Where cellular respiration occurs Where cellular respiration occurs Some cells have more mitochondria than others. Some cells have more mitochondria than others. Ex. Muscle cells require a lot of energyEx. Muscle cells require a lot of energy

31. Mitochondria and chloroplasts

32. Cytoplasm CCCClear jellylike material that makes up the inner part of the cell Holds organelles in place High percentage of water Provides a place for chemical reactions to occur Made-up of the cytoskeleton-rods and filaments that provide shape

33. Cilia and Flagella  Cilia- short numerous hair-like structures that move in a wavelike motion Line some tissues in multicellular organisms Line some tissues in multicellular organisms Cover some unicellular organisms and are used for locomotion Cover some unicellular organisms and are used for locomotion Ex: paramecium Ex: paramecium  Flagella- long whiplike structure used for locomotion Ex: sperm and euglena Ex: sperm and euglena

35. Typical Animal cell

36. Types of Organelles Related to cell structure and movement Related to cell structure and movement Microtubules, microfilaments, cell wall, cilia, flagella Microtubules, microfilaments, cell wall, cilia, flagella Related to production of proteins Related to production of proteins Nucleus, ribosomes Nucleus, ribosomes Related to processing and packaging of proteins Related to processing and packaging of proteins ER, Golgi body, vesicles ER, Golgi body, vesicles Related to cell’s energy needs Related to cell’s energy needs Mitochondria, plastids, chloroplasts Mitochondria, plastids, chloroplasts Related to cell replication Related to cell replication Nucleus, centrioles, microtubules Nucleus, centrioles, microtubules

37. How do plant and animal cells differ?

38. Cell Wall  All plants have a cell wall  Animal cells do not have a cell wall  The cell wall surrounds the cell membrane  It is made of cellulose – a hard material  Cell wall has 3 jobs: 1. Protects the plant cell1. Protects the plant cell 2. Gives it shape2. Gives it shape 2. Supports the cell – like a skeleton2. Supports the cell – like a skeleton

39. Vacuoles  Remember, vacuoles are used to store different materials in a cell  Plant cells have only one or two vacuoles while animals have lots of vacuoles  Vacuoles in plants are very large  The bigger they are, the more water they can store

40. Chloroplasts  Only plant cells have these organelles.  Chloroplasts are round, green structures that contain a green fluid called chlorophyll  Chlorophyll is a chemical that helps trap sunlight and turn it into food for the plants  Chlorophyll is why plants look green

41. Plant vs Animal Cell

42. Shape  Plant cells are typically square  Animal cells are typically round or oval