Basic Structure of a Cell

Size: px

Start display at page:

Download "Basic Structure of a Cell"

Virgil Watts
6 years ago
Views:

1 Basic Structure of a Cell 1

2 Nonliving Levels ATOMS MOLECULES ORGANELLES 2

3 Living Levels CELLS life starts here TISSUES Similar cells working together 3

4 More Living Levels ORGANS ORGAN SYSTEMS ORGANISM Different tissues working together Different organs working together 4

5 CELL THEORY 1.Cells are the basic unit of structure and function in an organism (basic unit of life) 2. Plants and animals are made of cells 3. Cells come from the reproduction of existing cells (cell division) 5

6 History of Cells & the Cell Theory Cell Specialization 6

7 Scanning Electron Microscope 7

8 Scanning Electron Microscope-scans the surface detail or organisms 8

9 Transmission Electron Microscope 9

10 10

11 11

12 Number of Cells Although ALL living things are made of cells, organisms may be: Unicellular composed of one cell Multicellular- composed of many cells that may organize into tissues, etc. 12

13 Cell Size and Types Cells, the basic units of organisms, can only be observed under microscope Three Basic types of cells include: Animal Cell Plant Cell Bacterial Cell 13

14 CELL SIZE Typical cells range from 5 50 micrometers (microns) in diameter 14

15 Which Cell Type is Larger? Plant cell > Animal cell > Bacteria 15

16 Multicellular Organisms Cells in multicellular organisms often specialize (take on different shapes & functions) 16

17 Cell Specialization Cells in a multi-cellular organisms become specialized by turning different genes on and off This is known as DIFFERENTIATION 17

18 Specialized Animal Cells Muscle cells Red blood cells Cheek cells 18

19 Specialized Plant cells Guard Cells Pollen Xylem cells 19

20 20

21 Prokaryotes The first Cells Cells that lack a nucleus or membranebound organelles DNA in a region of the cell (nucleoid region) Plasmid circular chromosome found in some bacteria Surrounded by cell memb, cell wall, and sometimes a capsule Include bacteria super simple cells 21

22 Prokaryotes 22

23 Eukaryotes Cells that HAVE -a nucleus -membrane-bound organelles - larger in size Includes protists, fungi, plants, and animals More complex type of cells 23

24 Two Main Types of Eukaryotic Cells Plant Cell Animal Cell 24

25 Organelles 25

26 Organelles Very small (Microscopic) Perform various functions for a cell Found in the cytoplasm May or may not be membrane-bound (surrounded by a membrane) 26

27 Animal Cell Organelles Nucleolus Nucleus Nuclear envelope Rough endoplasmic reticulum Ribosome (attached) Ribosome (free) Cell Membrane Mitochondrion Smooth endoplasmic reticulum Golgi apparatus Centrioles 27

28 Plant Cell Organelles 28

29 Bacterial Cell 29

30 Plant vs. Animal vs. Bacteria Cells Plant Animal Bacteria Eukaryotic (nucleus) Eukaryotic(nucleus) Prokaryotic (no nucleus) nucleoid region Has a cell wall made of cellulose Have chloroplasts No centrioles Contain large central vacuole No cell wall No chloroplasts Has centrioles for cell division No major vacuole Has a cell wall made of peptidoglycan No chloroplasts No centrioles No membrane bound organelles No vacuoles 30

31 Cell Wall Cell wall Nonliving layer Found in plants, fungi, & bacteria Made of cellulose in plants Made of peptidoglycan in bacteria Made of chitin in fungi 31

or leaves the cell Outside of cell Cell membrane Proteins

32 Cell or Plasma Membrane Composed of double layer of phospholipids and proteins Surrounds outside of ALL cells Controls what enters or leaves the cell Outside of cell Cell membrane Proteins Carbohydrate chains Inside of cell (cytoplasm) Protein channel Lipid bilayer 32

33 Cell Membrane in Plants Lies immediately against the cell wall in plant cells Pushes out against the cell wall to maintain cell shape Cell membrane 33

34 Cytoplasm of a Cell cytoplasm Jelly-like substance enclosed by cell membrane Provides a medium for chemical reactions to take place Contains organelles to carry out specific jobs Found in ALL cells 34

35 The Nucleus Controls the normal activities of the cell b/c It contains DNA in the form of chromosomes 35

36 More on the Nucleus Nucleus AND genes control what proteins are made in the cell 36

37 Nuclear Envelope Double membrane surrounding nucleus Also called nuclear membrane Contains nuclear pores for materials to enter & leave nucleus Connected to the rough ER Nuclear pores 37

38 Inside the Nucleus - The genetic material (DNA) is found DNA is spread out And appears as CHROMATIN in non-dividing cells DNA is condensed & wrapped around proteins forming CHROMOSOMES in dividing cells 38

39 39

40 What Does DNA do? DNA is the hereditary material of the cell DNA made of many genes Each gene codes for a specific protein 40

41 Inside nucleus Makes ribosomes Nucleolus 41

42 Ribosomes Made of PROTEINS and ribosomal RNA (rrna) Where protein synthesis occurs (the making of proteins) 42

43 43

44 Ribosomes Can be attached to Rough ER OR Be free (unattached) in the cytoplasm 44

45 Cytoskeleton Helps cell maintain cell shape Also help move organelles around Made of proteins (microtubules & microfilaments) 45

46 Cytoskeleton MICROTUBULES MICROFILAMENTS 46

47 Centrioles Found only in animal cells Paired structures near nucleus Made of bundle of microtubules Appear during cell division Help to pull chromosome pairs apart to opposite ends of the cell during cell division 47

48 Centrioles & the Mitotic Spindle Made of MICROTUBULES (Tubulin) 48

49 Mitochondrion (plural = mitochondria) Powerhouse of the cell Where cellular respiration occurs (where sugar is broken down to make ATP) More active cells like muscle cells have MORE mitochondria Both plants & animal cells have mitochondria Mitochondria have their own DNA 49

50 MITOCHONDRIA Surrounded by a DOUBLE membrane Folded inner membrane called CRISTAE (increases surface area for more chemical reactions) Interior called MATRIX 50

51 Endoplasmic Reticulum - ER Network of hollow membrane tubules Helps with the production of proteins and transports materials through the cell. Connects to nuclear envelope & cell membrane Two kinds of ER ---ROUGH & SMOOTH 51

52 Rough Endoplasmic Reticulum (Rough ER) Has ribosomes on its surface 52

53 Rough Endoplasmic Reticulum (Rough ER) Proteins are made by ribosomes on ER surface They are then threaded into the interior of the Rough ER to be modified and transported 53

54 Smooth Endoplasmic Reticulum Smooth ER lacks ribosomes on its surface Is attached to the ends of rough ER 54

55 Functions of the Smooth ER Carbohydrate metabolism Makes membrane lipids (steroids) Regulates calcium (muscle cells) Destroys toxic substances (Liver) 55

56 Endomembrane System Includes nuclear membrane connected to ER connected to cell membrane (transport) 56

Modify, sort, & package molecules from ER for storage

57 Stacks of flattened sacs Have a shipping side and receiving side Golgi Bodies Receive proteins made by ER Modify, sort, & package molecules from ER for storage within the cell OR for transport out of cell Transport vesicle 57

58 Golgi Bodies 58

59 Golgi Animation Materials are transported from Rough ER to Golgi to the cell membrane by VESICLES 59

60 Lysosomes-digesting machines Contain digestive enzymes. Break down food, bacteria, and worn out cell parts for cells 60

61 Cells take in food by phagocytosis Lysosomes digest the food & get rid of wastes Lysosome Digestion h.edu/content/begin/cell s/insideacell/ 61

of their breakdown is Hydrogen peroxide (H2O2) which

62 Similar to lysosomes Membrane bound and have enzymes that break down toxic materials in the cell By-product of their breakdown is Hydrogen peroxide (H2O2) which they then break down into water and oxygen. Peroxisomes 62

63 Function in moving cells, in moving fluids, or small particles across the cell surface Cilia & Flagella Cilia are shorter and more numerous on cells Flagella are longer and fewer (usually 1-3) on cells 63

64 Cell Movement with Cilia & Flagella 64

65 Cilia Moving Away Dust Particles from the Lungs Respiratory System 65

66 Vacuoles Plant cells have a large central vacuole Includes storage of sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes 66

67 Contractile Vacuole Found in unicellular protists like paramecia Regulate water intake by pumping out excess (homeostasis) Keeps the cell from lysing (bursting) Contractile vacuole animation 67

sacs calledthylakoids Thylakoids in stacks are called Grana

68 Use energy from sunlight to make own food (glucose) - photosynthesis Chloroplasts Inner membrane modified into sacs calledthylakoids Thylakoids in stacks are called Grana which are connected Stroma gel like material surrounding thylakoids 68

69 Never in animal or bacterial cells Chloroplasts contain their own DNA Chloroplasts 69

70 70

71 Cell to Cell Interactions Gap Junctions Tight Junctions Desmosomes 71

72 Gap Junctions Gap junctions (yellow) are clusters of channels that form tunnels of aqueous connectivity between cells. These permit the free passage of ions and small molecules between cells (ex: nerve impulse through heart muscle cells) 72

73 Tight Junctions Tight junctions (blue dots) between cells are connected areas of the plasma membrane that stitch cells together. They prevent the passage of molecules and ions through the space between cells. So materials must actually enter the cells (by diffusion or active transport) in order to pass through the tissue. 73

74 Desmosomes Desmosomes are even stronger connections that join the intermediate filaments of neighboring cells. Desmosomes are localized patches that hold two cells tightly together. They are common in epithelia (e.g., the skin) 74

75 Bacterial Cell Know this diagram and what each thing is! 75

76 Bacterial Cells Bacteria cells have 3 major shapes: coccus (round), bacillus (rods), and spirilla (coils). Bacterial cells can be arranged in different patterns including: strepto (chains), staphylo (clusters), palisades (hinged together), diplo (groups of 2), tetrads (groups of 4), or sarcina (groups of 8, 16 or more). Bacteria are classified and named based upon their genetic structure, physical structure, and metabolism 76

77 77

78 78

79 Bacterial Growth Curve There are 4 phases in the bacterial growth cycle: lag, log, stationary, and death. Factors that impact microbial growth and survival include: nutrient availability, temperature, ph, moisture, oxygen requirements and light. 79

80 Bacterial Phases Lag Phase getting accustomed and starting to eat food/haven t started to reproduce Log/Exponential phase taking in nutrients and reproducing Stationary phase- no change in number of bacteria - # birth=#death. Bacteria are running out of resources Decline/Death phase - accumulation of waste products and depletion of nutrients so bacteria start dying. 80

81 81

82 82

83 Gram Staining Bacteria Procedure used to identify different types of bacteria 83

The diagram to the right shows Gram-positive Staph aureus at

84 Gram Staining Bacteria that retain the color of the dye are called Gram positive; bacteria that don't are Gram negative. The diagram to the right shows Gram-positive Staph aureus at the top and Gram-negative Pseudomonas aeruginosa at the bottom 84

Basic Structure of a Cell

Basic Structure of a Cell Prokaryotic Cells No nucleus Archaea & Eubacteria One circular chromosome Extremely small Eukaryotic Cells Has a nucleus!!! Membrane-bound organelles Plants, Animals, Fungi, &