1. Basic Structure of a Cell

2. History of Cells & the Cell Theory
Cell Specialization

3. First to View Cells In 1665, Robert Hooke
used a microscope to examine a thin slice of cork (dead plant cell walls)
What he saw looked like small boxes
Coined the term “cell”

4. Anton van Leeuwenhoek
In 1673, Leeuwenhoek (a Dutch microscope maker), was first to view organism (living things)
Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth

5. Beginning of the Cell Theory
In 1838, a German botanist named Matthias Schleiden
Studied plants
concluded that all plants were made of cells
Schleiden is a cofounder of the cell theory

6. Beginning of the Cell Theory
In 1839, a German zoologist named Theodore Schwann
Studied animals
concluded that all animals were made of cells
Schwann also cofounder of the cell theory

7. Beginning of the Cell Theory
In 1855, a German medical doctor named Rudolph Virchow observed,
Studied human diseases
Looked at cells dividing
He reasoned that all cells come from other pre-existing cells by cell division

8. CELL THEORY All living things are made of cells
Cells are the basic unit of structure and function in an organism (basic unit of life)
Cells come from the reproduction of existing cells (cell division)

9. Discoveries Since the Cell Theory

10. ENDOSYMBIOTIC THEORY
In 1970, American biologist, Lynn Margulis, provided evidence that some organelles within cells were at one time free living cells themselves
Supporting evidence included organelles with their own DNA
Chloroplast and Mitochondria

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

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.

13. Which Cell Type is Larger?
_________ > _____________ > ___________
Plant cell
Animal cell
bacteria

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

15. How Big is a Micron ( µ ) ?
1 cm = 10,000 microns 1” = 25,000 microns

16. Cell Size
Question: Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse?
About the same size, but …
The elephant has MANY MORE cells than a mouse!

17. Cells Smallest unit that can carry out all the processes of life.
Why are cells so small?
Cells are small because a large surface-to-volume ratio allows them to easily exchange food and wastes.

18. Cell Size
When the surface area is no longer great enough to get rid of all the wastes and to get in enough food and water, then the cell must divide
Therefore, the cells of an organism are close in size

19. Simple or Complex Cells

20. Cells All cells have at least 3 components in common.
Plasma (or cell) membrane
Genetic material (DNA)
Cytoplasm
Nucleus (only eukaryotes)

21. Prokaryotes – The first Cells
No nucleus
No membrane-bound organelles
DNA is not located in the nucleus
DNA is circular
Includes bacteria
Simplest type of cell

22. Eukaryotes Unicellular or multicellular HAS a nucleus
HAS membrane-bound organelles
DNA located in nucleus
DNA is linear-double helix
Includes protists, fungi, plants, and animals
More complex type of cells

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

24. CELL MEMBRANE (also called plasma membrane)
SEE HOW
MEMBRANES FORM
PHOSPHOLIPID BILAYER with PROTEINS Hydrophobic tails face in Hydrophilic heads face out
Composed of double layer of phospholipids and proteins
Surrounds outside of ALL cells
Controls what enters or leaves the cell(selectively permeable)
Living layer
Outside
of cell
Inside
(cytoplasm)
Cell
membrane
Proteins
Protein
channel
Lipid bilayer
Carbohydrate
chains
Membrane Image from: © Pearson Education Inc, Publishing as Pearson Prentice Hall; All rights reserved Phospholipid image from:

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

26. Click here to See Fluidity
FLUID MOSAIC MODEL
Click here to See Fluidity
Molecules in cell membranes are constantly moving and changing
Animation from:

27. selectively permeable ~ gases & hydrophobic molecules can pass through
CELL MEMBRANES
act as boundary
selectively permeable ~ gases & hydrophobic molecules can pass through

28. copyright cmassengale
Look at the organelles in your packet and choose 2 that you know. Star them. Write down a word or two about their function. *Give One Get One
copyright cmassengale

29. Organelles: What you should know 

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

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

32. Plant Cell Organelles

33. CYTOPLASM (Between nucleus and cell membrane)
Image from:
CYTOPLASM (Between nucleus and cell membrane)
Jelly-like substance enclosed by cell membrane
Provides a medium for chemical reactions to take place
Helps give cell its shape
Includes organelles that carry out
specific functions
Includes water, salt, organic molecules,
and organelles
Found in ALL cells
CYTOSOL-semi-fluid “goo”
Image from:

34. The Control Organelle – Nucleus (Brain)
Surrounded by DOUBLE membrane called a (Nuclear envelope)
Nuclear pores-allow molecules in & out
Controls the normal activities in the cell
Contains the DNA in chromosomes
Usually the largest organelle
“Brain or Boss”
Control center for two processes: Replication (DNA → DNA) Transcription (DNA → RNA)

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

36. What Does DNA do?
DNA is the hereditary material of the cell
Genes that make up the DNA molecule code for different proteins, those proteins make us who we are- brown hair, etc.

37. NUCLEOLUS Produces ribosomal RNA Assembles ribosomes (RNA & proteins)
Dark spot in nucleus
Produces ribosomal RNA
Assembles ribosomes (RNA & proteins)
Image from:

38. 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

39. Cytoskeleton Helps cell maintain cell shape Anchors organelles
Made of proteins
Microfilaments are threadlike & made of ACTIN
Microtubules are tube-like & made of TUBULIN

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

41. CENTRIOLES/MITOTIC SPINDLE
Made of MICROTUBULES (Tubulin)
Image from:

42. Mitochondrion (plural = mitochondria)
“Powerhouse” of the cell
Generate cellular energy (ATP)
More active cells like muscle cells have MORE mitochondria
Both plants & animal cells have mitochondria
Site of CELLULAR RESPIRATION (burning glucose)

43. Interior called MATRIX
MITOCHONDRIA
Surrounded by a DOUBLE membrane
Has its own DNA
Folded inner membrane called CRISTAE (increases surface area for more chemical
Reactions)
Interior called MATRIX

44. Interesting Fact ---
Mitochondria Come from cytoplasm in the EGG cell during fertilization
Therefore …
You inherit your mitochondria from your mother!

45. What do mitochondria do?
“Power plant” of the cell
Burns glucose to
release energy (ATP)
Stores energy as ATP

46. Endoplasmic Reticulum – ER (Roadways)
Network of hollow membrane tubules
Helps to move materials throughout the cell
Connects to nuclear envelope & cell membrane
Functions in Synthesis of cell products & Transport
Two kinds of ER ---ROUGH & SMOOTH

47. Rough Endoplasmic Reticulum (Rough ER)
Has ribosomes on its surface
Makes products for use outside of the cell
Proteins are made by ribosomes on ER surface
They are then threaded into the interior of the Rough ER to be modified and transported

48. Smooth Endoplasmic Reticulum
Smooth ER lacks ribosomes on its surface
Is attached to the ends of rough ER
Makes cell products that are USED INSIDE the cell
Makes membrane lipids (steroids)
Regulates calcium (muscle cells)
Destroys toxic substances (Liver)

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

50.  Ribosomes Made of PROTEINS and rRNA “Protein factories” for cell
Join amino acids to make proteins
Process called protein synthesis 

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

52. Golgi Bodies/Apparatus/Complex
Stacks of flattened sacs
Have a shipping side (trans face) and receiving side (cis face)
Receive proteins made by ER
Transport vesicles with modified proteins pinch off the ends
CIS
TRANS
Transport vesicle

53. Golgi Bodies Modify, sort, & package molecules from ER
Look like a stack of pancakes
“UPS” of cell
Modify, sort, & package
molecules from ER
for storage OR transport out of cell

54. Golgi Animation
Materials are transported from Rough ER to Golgi to the cell membrane by VESICLES
Animation from:
See a Golgi movie

55. EVERYTHING’S CONNNECTED!

56. Lysosomes - membrane-bound vesicles containing digestive enzymes
Breaks down
food
unwanted cell parts
bacteria
helps in APOPTOSIS “programmed cell death”
See lysosomes
in action:

57. “PROGRAMMED CELL DEATH” Cell maintenance Signal to self destruct
APOPTOSIS
Embryo development
Cell maintenance Signal to self destruct
lost in cancer cells

58. Cilia & Flagella Made of protein tubes called microtubules
Function in moving cells, in moving fluids, or in small particles across the cell surface
Cilia are shorter and more numerous on cells
Flagella are longer and fewer (usually 1-3) on cells

59. What’s the Difference
Cilia- Many and short
Flagella- Few and long

60. Vacuoles Fluid filled sacks for storage
Small or absent in animal cells
Plant cells have a large Central Vacuole
No vacuoles in bacterial cells
In plants, they store Cell Sap
Includes storage of sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes

61. VACUOLES can store WATER

62. Freshwater organisms have contractile vacuoles to control excess water in cells (HOMEOSTASIS)

63. Chloroplasts
Found only in producers (organisms containing chlorophyll)
Use energy from sunlight to make own food (glucose)
Has own DNA
Double Membrane
Contains thylakoid sacs with chlorophyll for photosynthesis
Never in animal or bacterial cells

64. WHAT’S SPECIAL ABOUT PLANT CELLS?
Cell wall
HUGE vacuoles
Chloroplasts
No centrioles

65. Cell Wall Cell wall Nonliving layer
A rigid layer that lies outside of the cell membrane
Supports and protects cell
Found in plants, fungi, & bacteria
Plants: Cellulose makes it “sturdy”
Bacteria: have peptidoglycan
Made of chitin in Fungi
Cell wall

66. WHAT’S DIFFERENT ABOUT BACTERIAL CELLS?
Cell wall
NO NUCLEAR MEMBRANE
DNA is circular
No membrane bound organelles

67. _________ > _____________ > ___________
WHICH IS BIGGER?
Plant cell
Animal cell
bacteria
_________ > _____________ > ___________

68. DIFFERENCES IN ANIMAL CELLS, PLANT CELLS, AND BACTERIA ANIMAL CELL
Eukaryotes
Prokaryotes
Cell membrane
Nuclear membrane
NO nuclear membrane
NO cell wall
Cell wall made of CELLULOSE
Cell wall made of PEPTIDOGLYCAN
Has ribosomes
DNA in multiple chromosomes
DNA in multiple chromosomes
DNA is a single circular ring
CYTOSKELETON
Small vacuoles
Really big vacuole
NO vacuoles
Has lysosomes
Few lysosomes
NO lysosomes
Has centrioles
NO centrioles
NO chloroplasts
Chloroplasts
SMALLER size
SMALL size
SMALLEST size