1. Cell Structure and Function

2. Cells
Smallest living unit
Most are microscopic

3. Discovery of Cells Robert Hooke (mid-1600s) Observed sliver of cork
Saw “row of empty boxes”
Coined the term cell

4. Cell theory (1839)Theodor Schwann & Matthias Schleiden
“ all living things are made of cells”
(50 yrs. Later) Louis Pasteur
“all cells come from cells”

5. Principles of Cell Theory
All living things are made of cells
Smallest living unit of structure and function of all organisms is the cell
Cells carry out the functions needed to support life.
All cells arise from preexisting cells
(this principle discarded the idea of
spontaneous generation)

6. Why study cells? Cells  Tissues  Organs  Bodies
bodies are made up of cells
cells do all the work of life!

7. The Work of Life
What jobs do cells have to do for an organism to live…
“breathe”
gas exchange: O2 in vs. CO2 out
eat
take in & digest food
make energy
ATP
build molecules
proteins, carbohydrates, fats, nucleic acids
remove wastes
control internal conditions
homeostasis
respond to external environment
build more cells
growth, repair, reproduction & development
ATP

8. Cell Size

9. Characteristics of All Cells
A surrounding membrane
Cytoplasm – cell contents in thick fluid
Organelles – structures for cell function
Control center with DNA

10. Cell Types
Prokaryotic
Eukaryotic

11. Two Types of Cells Prokaryotes First cells to evolve No nucleus
Hereditary info is contained within cytoplasm
Ex. Bacteria
Eukaryotes
Evolved from Prokaryotes
Have a nucleus
Hereditary Info is contained within the nucleus
Ex. Plants, Animals, Fungi

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

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

14. Bacterium Shapes

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

16. Representative Animal Cell

17. Representative Plant Cell

18. Organelles
Cellular machinery

19. Cell Walls Found in plants, fungi, & many protists
Surrounds plasma membrane
Made of cellulose
Is rigid
Provides support and
protection for the cell

20. Cell Wall Differences
Plants – mostly cellulose
Fungi – contain chitin

21. Cell membrane Surrounds all cells
In a plant cell, it lies beneath the cell wall
– In animal cells, it is the outer boundary (made of cholesterol)
Lipid bilayer with embedded proteins
• Provides cell with – Protection
Control of movement of materials in/out of cell
 Support

22. Cytoplasm Found in both plant and animal cells
Viscous fluid containing organelles
components of cytoplasm
Interconnected filaments & fibers
Fluid = cytosol
Found in both plant and animal cells
Located beneath cell membrane
Supports and protects cell organelles

23. Organelles
Functional components within cytoplasm

24. Nucleus Function Structure control center of cell protects DNA
instructions for building proteins
Structure
nuclear membrane
nucleolus
ribosome factory
chromosomes
DNA

25. DNA
Hereditary material
Chromosomes

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

27. Endoplasmic Reticulum
Helps move substances within cells
Network of interconnected tubes
Two types
Rough endoplasmic reticulum
Smooth endoplasmic reticulum

28. Rough Endoplasmic Reticulum
Ribosomes attached to surface
Manufacture proteins
Not all ribosomes attached to rough ER

29. Smooth Endoplasmic Reticulum
No attached ribosomes
Has enzymes that help build molecules
Carbohydrates
Lipids

30. Golgi Apparatus Function Structure
finishes, sorts, labels & ships proteins
like UPS headquarters
shipping & receiving department
ships proteins in vesicles
“UPS trucks”
Structure
membrane sacs
vesicles
carrying proteins
transport vesicles

32. Lysosomes Found only in animal cells Contain digestive enzymes
Functions
Aid in cell renewal
Break down old cell parts
Digests invaders

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

34. Mitochondria Have their own DNA Bound by double membrane
Has inner foldings (Cristae) that increase the internal surface area

35. Mitochondria Break down fuel molecules (cellular respiration)
Glucose
Fatty acids
Release energy
ATP

36. Mitochondria ATP Function in both animal & plant cells
make ATP energy from cellular respiration
sugar + O2  ATP
fuels the work of life
ATP
in both animal & plant cells

37. Plants make energy two ways!
ATP
Mitochondria
make energy from sugar + O2
cellular respiration
sugar + O2  ATP
Chloroplasts
make energy + sugar from sunlight
photosynthesis
sunlight + CO2  ATP & sugar
ATP = active energy
sugar = stored energy
build leaves & roots & fruit out of the sugars
sugar
ATP

38. Chloroplasts
Solar energy capturing organelle

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

40. Mitochondria are in both cells!!
animal cells
plant cells
chloroplast
mitochondria

41. Cells need workers = proteins!
Making proteins
to run daily life & growth, the cell must…
read genes (DNA)
build proteins
structural proteins (muscle fibers, hair, skin, claws)
enzymes (speed up chemical reactions)
signals (hormones) & receptors
organelles that do this work…
nucleus
ribosomes
endoplasmic reticulum (ER)
Golgi apparatus

42. endoplasmic reticulum nucleus
protein on its way!
DNA
TO:
RNA
vesicle
TO:
TO:
vesicle
ribosomes
TO:
protein
finished protein
Golgi apparatus
Making Proteins

43. Cells need to make more cells!
Making more cells
to replace, repair & grow, the cell must…
copy their DNA
make extra organelles
divide the new DNA & new organelles between 2 new “daughter” cells
organelles that do this work…
nucleus
centrioles

44. Centrioles Function Structure help coordinate cell division
only in animal cells
Structure
one pair in each cell

45. Cell Summary Cells have 3 main jobs make energy make proteins
need food + O2
cellular respiration & photosynthesis
need to remove wastes
make proteins
need instructions from DNA
need to chain together amino acids & “finish” & “ship” the protein
make more cells
need to copy DNA & divide it up to daughter cells
Our organelles do all those jobs!

46. Plasma Membrane Contains cell contents
Double layer of phospholipids & proteins

47. Phospholipids Polar Interacts with water Hydrophylic head
Hydrophobic tail
Interacts with water

48. 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

50. Molecule Movement & Cells
Passive Transport
Active Transport
Endocytosis
(phagocytosis & pinocytosis)
Exocytosis

51. Passive Transport No energy required Move due to gradient
differences in concentration, pressure, charge
Move to equalize gradient
High moves toward low

52. Types of Passive Transport
1. Diffusion
2. Osmosis
3. Facilitated diffusion

53. Diffusion
Molecules move to equalize concentration

54. Osmosis Special form of diffusion
Fluid flows from lower solute concentration
Often involves movement of water
Into cell
Out of cell

55. Solution Differences & Cells
solvent + solute = solution
Hypotonic
Solutes in cell more than outside
Outside solvent will flow into cell
Isotonic
Solutes equal inside & out of cell
Hypertonic
Solutes greater outside cell
Fluid will flow out of cell

57. Facilitated Diffusion
Differentially permeable membrane
Channels (are specific) help molecule or ions enter or leave the cell
Channels usually are transport proteins
(aquaporins facilitate the movement of water)
No energy is used

58. Process of Facilitated Transport
Protein binds with molecule
Shape of protein changes
Molecule moves across membrane

59. Active Transport Molecular movement Requires energy (against gradient)
Example is sodium-potassium pump

60. Endocytosis Movement of large material Movement is into cells
Particles
Organisms
Large molecules
Movement is into cells
Types of endocytosis
bulk-phase (nonspecific)
receptor-mediated (specific)

61. Process of Endocytosis
Plasma membrane surrounds material
Edges of membrane meet
Membranes fuse to form vesicle

62. Forms of Endocytosis Phagocytosis – cell eating
Pinocytosis – cell drinking

63. Exocytosis
Reverse of endocytosis
Cell discharges material

64. Exocytosis Vesicle moves to cell surface Membrane of vesicle fuses
Materials expelled

65. Membrane Proteins 1. Channels or transporters 2. Receptors
Move molecules in one direction
2. Receptors
Recognize certain chemicals

66. Membrane Proteins 3. Glycoproteins 4. Enzymes Identify cell type
Catalyze production of substances

67. Review of Eukaryotic Cells

68. Review of Eukaryotic Cells