A PPT about the parts of a cell.

1. General Biology 1
Type in the chat box
‘present sir’ for your
attendance.

2. Cell Structure
and Function

3. The Cell Theory

4. Cells
• Smallest living unit
• Most are microscopic

5. Discovery of Cells
• Robert Hooke (1660’s)
– Observed a slice of cork
– Saw “row of empty boxes”
– Coined the term ‘cell’

6. Cell theory
• Matthias Schleiden: “All plants are composed of
cells.” (1838)
• Theodor Schwann: “All animals are composed of
cells.” (1839)
“all living things are made of cells”
• Rudolf Virchow: “All cells came from cells.” (1855)

7. Principles of Cell Theory
1. All living things are made up of cells.
2. The smallest living unit of structure and
function of all organisms is the cell.
3. All cells arise from preexisting cells.
(this principle discarded the idea of
spontaneous generation)

8. additional
4. Energy flow occurs within cells.
5. Heredity information (DNA) is
passed from cell to cell.
6. All cells have the same
basic chemical composition.

9. Cell Size

12. Cells Have Large Surface
Area-to-Volume Ratio

13. Characteristics of All Cells
• It has surrounding membrane.
• Cytoplasm – cell contents in thick fluid
• Organelles – structures for cell function
• Control center with DNA

14. Cell Types
• Prokaryotic
• Eukaryotic

15. Prokaryotic Cells
• First cell type on earth
• Cell type of Bacteria and Archaea

16. Prokaryotic Cells
• No membrane bound nucleus
• Nucleoid = region of DNA concentration
• Organelles not bound by membranes

17. Eukaryotic Cells
• Nucleus bound by membrane
• Include fungi, protists, plant,
and animal cells
• Possess many organelles
Protozoan

19. Representative Animal Cell

20. Representative Plant Cell

21. Representative Bacterial Cell

22. Endosymbiotic Theory
-proposes that the mitochondrion and
the chloroplast were once prokaryotic
cells, living inside larger host cells. The
prokaryotes may initially have been
parasites or even an intended meal for
the larger cell, somehow escaping
digestion.

24. The Organelles
of the Cell

25. Bacteria-Like Organelles
• Derived from symbiotic bacteria
• Endosymbiotic theory
–Evolution of modern cells from cells
& symbiotic bacteria

26. Plasma Membrane
• Contains cell organelles
• Double layer of phospholipids & proteins

27. Phospholipids
• Polar
– Hydrophilic head
– Hydrophobic tail
• Interacts with water

29. Movement Across the Plasma Membrane
• A few molecules move freely
–Water, Carbon dioxide, Ammonia,
Oxygen
• Carrier proteins transport some
molecules
–Proteins embedded in lipid bilayer
–Fluid mosaic model – describes fluid
nature of a lipid bilayer with proteins

31. Review
1. This theory explains how eukaryotic cells
came about.
2. He said that all animals are made of cells.
3. The cell membrane allows all molecules
to pass through. (True/False)
4. Eukaryotic cells were the first organisms
on earth. (True/False)
5. The tail of a phospholipid is
hydrophobic. (True/False)

33. Organelles
• Cellular machinery
• Two general kinds
–Derived from membranes
–Bacteria-like organelles

34. Membrane Proteins
1. Channels or transport proteins
–Move molecules in one direction
2. Receptor proteins
–Recognize certain chemicals to
trigger a response inside the cell.
3. Adhesion Proteins
–Enables the cell to stick to another.

35. Membrane Proteins
4. Glycoproteins/ Recognition proteins
– Identify cell type; serves as 'name tags'
5. Enzymes
– Facilitates chemical reactions.

36. Membrane Proteins

37. Cell Walls
• Found in plants, fungi, bacteria & many
protists
• Surrounds plasma membrane

38. Cell Wall Differences
• Plants (and other protists) – mostly
cellulose
• Fungi – contain chitin
• Bacteria – made of peptidoglycan

39. Cytoplasm
• Viscous fluid containing organelles
• components of cytoplasm
– Interconnected filaments & fibers
– Fluid = cytosol
– Organelles (not nucleus)
– storage substances

40. Cytoskeleton
• Filaments & fibers
• Made of 3 fiber types
– Microfilaments
– Microtubules
– Intermediate filaments
• 3 functions:
– mechanical support
– anchor organelles
– help move
substances

41. A = actin, IF = intermediate filament, MT = microtubule

42. General Biology 1
Type in the chat box
‘present sir’ for your
attendance.

43. Cilia & Flagella
• Provide motility
• Cilia
– Short
– Used to move substances
outside human cells
• Flagella
– Whip-like extensions
– Found on sperm cells
• Basal bodies like
centrioles

44. Cilia & Flagella Structure
• Bundles of microtubules
• With plasma membrane

46. Ciliary Action

47. Centrioles
• Pairs of microtubular structures
• Play a role in cell division

48. Membranous Organelles
• Functional components within cytoplasm
• Bound by membranes

49. Nucleus
• Control center of cell
• Double membrane
• Contains
– Chromosomes
– Nucleolus

50. Nuclear Envelope
• Separates nucleus from rest of cell
• Double membrane
• Has pores

51. DNA
• Hereditary material
• Chromosomes
– DNA
– Proteins
– Form for cell division

52. Nucleolus
• Most cells have 2 or more
• Directs synthesis of RNA
• Forms ribosomes

53. Endoplasmic Reticulum
• Helps move substances within cells
• Network of interconnected membranes
• Two types
– Rough endoplasmic reticulum
– Smooth endoplasmic reticulum

54. Rough Endoplasmic Reticulum
• Ribosomes attached to surface
– Manufacture proteins
– Not all ribosomes attached to rough ER
• May modify proteins from ribosomes

55. Smooth Endoplasmic Reticulum
• No attached ribosomes
• Has enzymes that help build molecules
– Carbohydrates
– Lipids

56. Golgi Apparatus
• Involved in synthesis of plant cell wall
• Packaging & shipping station of cell

57. Golgi Apparatus Function
1. Molecules come in vesicles
2. Vesicles fuse with Golgi membrane
3. Molecules may be modified by Golgi

58. Golgi Apparatus Function
(Continued)
4. Molecules pinched-off in separate vesicle
5. Vesicle leaves Golgi apparatus
6. Vesicles may combine with plasma
membrane to secrete contents

60. Lysosomes
• Contain digestive enzymes
• Functions
– Aid in cell renewal
– Break down old cell parts
– Digests invaders

61. Vacuoles
• Membrane bound storage sacs
• More common in plants than animals
• Contents
– Water
– Food
– wastes

62. Bacteria-Like Organelles
• Release & store energy
• Types
– Mitochondria
(release energy)
– Chloroplasts
(store energy)

63. Mitochondrion
• pl. mitochondria
• Have their own DNA
• Bound by double membrane

64. Mitochondrion
• Break down fuel molecules (cellular respiration)
– Glucose
– Fatty acids
• Release energy
– ATP

65. Chloroplasts
• Derived form photosynthetic bacteria
• Solar energy capturing organelle

66. Photosynthesis
• Takes place in the chloroplast
• Makes cellular food – glucose