1. Basic Structure of a Cell

2. Introduction to Cells Cells are the basic units of organisms
Cells can only be observed under microscope
Basic types of cells:
Bacterial Cell
Animal Cell
Plant Cell

3. Number of Cells Organisms may be: Unicellular – composed of one cell
Multicellular- composed of many cells that may organize

4. Cells May be Prokaryotic or Eukaryotic
Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles
Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals)

5. Prokaryotes Nucleoid region contains the DNA Cell membrane & cell wall
Contain ribosomes (no membrane) to make proteins in their cytoplasm

6. History of Cell Theory mid 1600s – Anton van Leeuwenhoek
Improved microscope, observed many living cells
mid 1600s – Robert Hooke
Observed many cells including cork cells
1850 – Rudolf Virchow
Proposed that all cells come from existing cells

7. Cell Theory All organisms are composed of one or more cells.
Cells are the smallest living units of all living organisms.
Cells arise only by division of a previously existing cell. 7

8. Eukaryotic Cell Contain 3 basic cell structures: Nucleus Cell Membrane
Cytoplasm with organelles

9. Two Main Types of Eukaryotic Cells
Animal Cell
Plant Cell

10. Organelles Very small size Can only be observed under a microscope
Have specific functions
Found throughout cytoplasm

11. Golgi Bodies Stacks of flattened sacs
Have a shipping side & a receiving side
Receive & modify proteins made by ER
Transport vesicles with modified proteins pinch off the ends
Transport vesicle

12. Lysosome Contain digestive enzymes
Break down food and worn out cell parts for cells
Programmed for cell death (lyse & release enzymes to break down & recycle cell parts)

13. Nucleolus Cell may have 1 to 3 nucleoli Inside nucleus
Disappears when cell divides
Makes ribosomes that make proteins

14. Nucleus Nuclear envelope
Structure
Nuclear envelope
Two Phospholipid bilayers with protein lined pores
Each pore is a ring of 8 proteins with an opening in the center of the ring
Nucleoplasm – fluid of the nucleus

15. bilayer facing cytoplasm bilayer facing nucleoplasm
Nuclear pore
bilayer facing cytoplasm
Nuclear envelope
bilayer facing nucleoplasm

16. Nucleus DNA is arranged in chromosomes
Chromosome – condensed threads of chromatin and the proteins attached to the DNA
Chromatin – Thread like material all of the cell’s DNA and the associated proteins

17. Nucleus Nucleolus Area of condensed DNA
Structure, continued
Nucleolus
Area of condensed DNA
Where ribosomal subunits are made
Subunits exit the nucleus via nuclear pores

18. Smooth & Rough Endoplasmic Reticulum
Smooth ER lacks ribosomes detoxifies poisons
Rough ER has ribosomes on its surface & makes proteins to EXPORT
Both act as passageways and keep chemical rxn in the cell separate.

19. Mitochondrion (mitochondria) Inner membrane in folds called cristae
Cell Powerhouse
Mitochondrion (mitochondria)
Inner membrane in folds called cristae
Rod shape
Site of Cellular respiration
cristae

20. In Animal Cells: Mitochondria
Active cells like muscles have more mitochondria
Burn sugars to produce energy ATP

22. Vacuoles
Vacuoles are membrane sacs that are generally larger than vesicles.
Examples:
Food vacuole - formed when protists bring food into the cell by endocytosis
Contractile vacuole – collect and pump excess water out of some freshwater protists
Central vacuole – found in plant cells

23. Cytoskeleton

24. Microfilaments
Smallest
Make up muscle fibers

25. Cytoskeleton Intermediate filaments
Present only in animal cells of certain tissues
Anchor organelles in place.
Permanent cell shape

26. Cytoskeleton Microtubules – largest in size
Anchor organelles and act as tracks for organelle movement
Move chromosomes around during cell division
Used to make cilia and flagella

27. Cilia and flagella (structures for cell motility)

28. Animal Cell Organelles
Near the nucleus
Paired structures
Help cell divide
Found in an area called the centrosome 28 28

29. Surrounding the Cell Cell membrane
Lies immediately against the cell wall in plant cells
Made of protein and phospholipids
Selectively permeable

30. Cytoskeleton All are proteins Function Structure
gives cells internal organization, shape, and ability to move
Structure
Interconnected system of microtubules, microfilaments, and intermediate filaments (animal only)
All are proteins

31. Cell or Plasma Membrane
Cell membrane
Living layer
Controls the movement of materials into and out of the cell

32. Cytoplasm of a Cell Cytoplasm
Jelly-like substance enclosed by cell membrane
Provides a medium for chemical reactions to take place

33. More on Cytoplasm Cytoplasm
Contains organelles to carry out specific jobs
Examples: chloroplast & mitochondrion

34. Cell Wall Cell wall Nonliving layer
Gives structure and shape to plant and bacterial cells

35. Plant Cell Organelles Chloroplast
Contain the green pigment chlorophyll
Traps sunlight to make to make sugars (food)
Process called photosynthesis

36. Plant Cell Organelles Vacuole Have a large central vacuole
Surrounded by tonoplast
Contains cell sap
Sugars, proteins, minerals, wastes, & pigments

37. Different kinds of plant cells
Onion Epidermal Cells
Root Hair Cell
root hair
Guard Cells

38. Animal cell No cell wall or chloroplast
vacuole
cytoplasm
No cell wall or chloroplast
Stores glycogen in the cytoplasm for food energy
nucleus
mitochondrion
cell membrane
glycogen granule

39. Different kinds of animal cells
white blood cell
red blood cell
cheek cells
sperm
nerve cell
muscle cell
Amoeba
Paramecium

40. Similarities between plant cells and animal cells
Both have a cell membrane surrounding the cytoplasm
Both have a nucleus
Both contain mitochondria

41. Differences between plant cells and animal cells
Relatively smaller in size
Relatively larger in size
Irregular shape
Regular shape
No cell wall
Cell wall present

42. Differences between Plant Cells and Animal Cells
Vacuole small or absent
Large central vacuole
Glycogen as food storage
Starch as food storage
Nucleus at the center
Nucleus near cell wall

43. The cell is the Basic Unit of Life
Cell is the smallest unit of living organisms
Unicellular organisms are made of one cell only
The cells of multicellular organisms are specialized to perform different functions
e.g. mesophyll cells for photosynthesis and root hair cells for water absorption

44. Differences between Prokaryotic Cells and Eukaryotic Cells
Prokaryotic Cells are smaller and simpler in structure than eukaryotic cells.
Typical prokaryotic cell is __________
Prokaryotic cells do NOT have:
Nucleus
Membrane bound organelles

45. Prokaryotic Cell Structure
Structures
Plasma membrane
Cell wall
Cytoplasm with ribosomes
Nucleoid
Capsule*
Flagella* and pili*
*present in some, but not all prokaryotic cells

46. Prokaryotic Cell

48. TEM Prokaryotic Cell

49. Levels of Organization
CELLS (muscle cells,nerve cells)
TISSUES (muscle, epithelium)
ORGANS (heart, lungs, stomach)
SYSTEMS (circulatory system)
ORGANISM (human)

50. Levels of organization
Cells are grouped together and work as a whole to perform special functions

51. Tissue A group of similar cells to perform a particular function
Animals : epithelial tissue, muscular tissue
Plants : vascular tissue, mesophyll

52. Organ
Different tissues group together to carry out specialized functions
Heart : consists of muscles, nervous tissue and blood vessels
Leaf : consists of epidermis, mesophyll and vascular tissue

53. The Structures of a Leaf (Plant Organ)
Chloroplast
Palisade Mesophyll Cell
Spongy Mesophyll Cell
Air Space
Stoma

54. The Structures of a Heart (Animal Organ)
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System
Several organs and tissues work together to carry out a particular set of functions in a co-ordinated way
Human : digestive, respiratory, excretory, circulatory and reproductive systems
Plant : root and shoot systems
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56. Human Body Systems Examples of systems : Digestive System
Respiratory System
Circulatory System
Nervous System
Reproductive System

57. Examples of a Human Body System
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58. Examples of a Human Body System
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59. Examples of a Human Body System
Circulatory System
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60. Examples of a Human Body System
Nervous System

61. It’s You!