1. Mid-Term Exam Review

2. Microscopes provide windows to the world of the cell
The light microscope enables us to see the overall shape and structure of a cell

3. Electron microscopes~ can view ultrastructures of cells
They use a beam of electrons instead of light
The greater resolving power of electron microscopes

4. The Cell Theory
Robert Hooke (1600’s/ English)) used a compound light microscope to study cork, the dead cells of oak bark.
Cells are the basic building blocks of all living things.
Schleiden & Schwann (1830;s, German) their observations & conclusions are summarized as the cell theory

5. The cell theory is made up of three main ideas:
1.All organisms are composed of one or more cells.
2. The cell is the basic unit of organization of organisms.
3. All cells come from preexisting cells.

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

7. The Jobs of Cells Cells have 3 main jobs make energy make proteins
need energy for all activities
need to clean up waste produced while making energy
make proteins
proteins do all the work in a cell, so we need lots of them
make more cells
for growth
to replace damaged or diseased cells
Our organelles do all these jobs!

8. 2 Types of cells plant cells animal cells bacteria cells Prokaryote
- no organelles
Eukaryotes
- organelles
plant cells
animal cells

9. Prokaryotic cells-Bacteria
small, relatively simple cells
They do not have a nucleus
enclosed by a plasma membrane and is usually encased in a rigid cell wall
Inside the cell are its DNA and other parts

10. Eukaryotic cells are partitioned into functional compartments
All other life forms are made up of one or more eukaryotic cells
These are larger and more complex than prokaryotic cells
Eukaryotes are distinguished by the presence of a true nucleus
The cytoplasm contains organelles
Many organelles have membranes as boundaries
These compartmentalize the interior of the cell
This allows the cell to carry out a variety of activities simultaneously

11. Animal Cell

12. Plant Cell

13. Animal vs. Plant Cells What are the main differences? Animal ONLY has
Extracellular matrix
Flagellum or cilia
Centrioles
Cellular Junctions
Gap junctions
Tight Junctions
Desmosomes

14. Animal vs. Plant Cells What are the main differences? Plant ONLY has
Large Central Vacuole
Chloroplasts
Rigid Cell Wall
Plasmodesmata

15. Prokaryotes vs. Eukaryotes
Prokaryotes ONLY have?
Nucleoid
Pili – attachment structure
Cell Wall with peptidoglycan

16. Prokaryotes vs. Eukaryotes
Eukaryotes ONLY have?
Membrane Bound Organelles
Cytoskeleton
Cellular Junctions
Centrioles (No mitosis in prokaryotes)

17. Prokaryotes vs. Eukaryotes
What is common to both?
Chromosomes
Ribosomes
Cell membrane (Plasma membrane)
Cytosol (Cytoplasm)

18. Cell sizes vary with their function
Cell size and shape relate to function

19. Cell size comparison most bacteria eukaryotic cells Animal cell
Bacterial cell
Animal cell
most bacteria
1-10 microns
eukaryotic cells
microns
micron = micrometer = 1/1,000,000 meter
diameter of human hair = ~20 microns

20. Natural laws limit cell size
a cell must be large enough to house the parts it needs to survive and reproduce
The maximum size of a cell is limited by the amount of surface needed to obtain nutrients from the environment and dispose of wastes

21. A small cell has a greater ratio of surface area to volume than a large cell of the same shape
Total surface area of 27 small cubes = 16,200 µm2
Surface area of one large cube = 5,400 µm2

22. Organelles Organelles do the work of cells
each structure has a job to do
keeps the cell alive; keeps you alive
They’re like mini-organs!
Model Animal Cell

23. 1. Cells need power! Making energy
to fuel daily life & growth, the cell must…
take in food & digest it
take in oxygen (O2)
make ATP
remove waste
organelles that do this work…
cell membrane
lysosomes
vacuoles & vesicles
mitochondria
ATP

24. Cell membrane Function Structure separates cell from outside
phosphate “head”
Function
separates cell from outside
controls what enters or leaves cell
O2, CO2, food, H2O, nutrients, waste
recognizes signals from other cells
allows communication between cells
Structure
double layer of fat
phospholipid bilayer
receptor molecules
proteins
lipid “tail”

25. cytoplasm
jelly-like material holding organelles in place
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

26. Vacuoles & vesicles Function Structure moving material around cell
storage
Structure
membrane sac
small food particle
vacuole filled w/ digestive enzymes
vesicle
vesicle filled w/ digested nutrients

27. Vacuoles have diverse functions in cell maintenance
membrane-bound sacs with varied functions.
Food vacuoles, from phagocytosis, fuse with lysosomes.
Contractile vacuoles, found in freshwater protists, pump excess water out of the cell.
Central vacuoles are found in many mature plant cells.

28. Food & water storage plant cells animal cells food vacuole
central vacuole
animal cells
contractile vacuole

29. cytoplasm
jelly-like material holding organelles in place
vacuole & vesicles
transport inside cells
storage
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

30. Lysosomes Function digest food clean up & recycle Structure
used to make energy
clean up & recycle
digest broken organelles
Structure
membrane sac of digestive enzymes
Lysosomes
lysosomes
digesting broken organelles
vacuole
small food particle
digesting food

31. A Job for Lysosomes
6 weeks
15 weeks

32. Connection: Abnormal lysosomes can cause fatal diseases
Lysosomal storage diseases are hereditary
They interfere with other cellular functions
Examples: Pompe’s disease, Tay-Sachs disease

33. ENERGY-CONVERTING ORGANELLES

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

35. cytoplasm
jelly-like material holding organelles in place
lysosome
food digestion
garbage disposal & recycling
vacuole & vesicles
transport inside cells
storage
mitochondria
make ATP energy from sugar + O2
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

36. 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

37. Chloroplasts found in plants and some protists
convert solar energy to chemical energy in sugars

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

39. cytoplasm
jelly-like material
around organelles
central vacuole
storage: food, water or waste
cell wall
support
mitochondria
make ATP in cellular respiration
lysosome
digestion & clean up
chloroplast
make ATP & sugars in photosynthesis
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

40. 2. 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

41. Proteins do all the work!
one of the major job of cells is to make proteins,
because…
proteins do all the work!
structural
enzymes
signals
receptors
DNA
proteins
cells

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

43. cytoplasm
jelly-like material holding organelles in place
nucleolus
produces
ribosomes
lysosome
food digestion
garbage disposal & recycling
vacuole & vesicles
transport inside cells
storage
nucleus
protects DNA
controls cell
chromosomes
DNA
mitochondria
make ATP energy from sugar + O2
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

44. Ribosomes Function Structure protein factories
read instructions to build proteins from DNA
Structure
some free in cytoplasm
some attached to ER
Ribosomes on ER

45. cytoplasm
jelly-like material holding organelles in place
nucleolus
produces
ribosomes
lysosome
food digestion
garbage disposal & recycling
vacuole & vesicles
transport inside cells
storage
nucleus
protects DNA
controls cell
mitochondria
make ATP energy from sugar + O2
ribosomes
build proteins
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

46. Endoplasmic Reticulum
Function
works on proteins
helps complete the proteins after ribosome builds them
makes membranes
Structure
rough ER
ribosomes attached
Make membranes
smooth ER
Synthesizes lipids

47. cytoplasm
jelly-like material holding organelles in place
lysosome
food digestion
garbage disposal & recycling
vacuole & vesicles
transport inside cells
storage
nucleus
protects DNA
controls cell
mitochondria
make ATP energy from sugar + O2
ribosomes
builds proteins ER
works on proteins
makes membranes
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

48. 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

49. cytoplasm
jelly-like material holding organelles in place
lysosome
food digestion
garbage disposal & recycling
vacuole & vesicles
transport inside cells
storage
nucleus
protects DNA
controls cell
mitochondria
make ATP energy from sugar + O2
ribosomes
builds proteins ER
helps finish proteins
makes membranes
Golgi apparatus
finishes, packages & ships proteins
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

50. nucleolus
make ribosomes
endoplasmic reticulum
processes proteins
makes membranes
nucleus
control cell
protects DNA
ribosomes
make proteins
cytoplasm
jelly-like material
around organelles
central vacuole
storage: food, water or waste
Golgi apparatus
finish & ship proteins
cell wall
support
mitochondria
make ATP in cellular respiration
lysosome
digestion & clean up
chloroplast
make ATP & sugars in photosynthesis
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

51. 3. 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

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

53. cytoplasm
jelly-like material holding organelles in place
lysosome
food digestion
garbage disposal & recycling
vacuole & vesicles
transport inside cells
storage
nucleus
protects DNA
controls cell
centrioles
cell division
ribosomes
builds proteins ER
helps finish proteins
makes membranes
mitochondria
make ATP energy from sugar + O2
Golgi apparatus
finishes, packages & ships proteins
cell membrane
cell boundary
controls movement of materials in & out
recognizes signals

54. THE CYTOSKELETON
The cell’s internal skeleton that functions in cell structural support and motility
A network of protein fibers makes up the cytoskeleton

55. three main types of fibers in the cytoskeleton: microtubules, microfilaments, and intermediate filaments.
Microfilaments enable cells to change shape and move
Intermediate filaments reinforce the cell and anchor certain organelles
Microtubules
give the cell rigidity
provide anchors for organelles
act as tracks for organelle movement
INTERMEDIATE FILAMENT
MICROFILAMENT
MICROTUBULE

56. Cilia and flagella
locomotor appendages that protrude from certain cells
Clusters of microtubules drive the whipping action of these organelles

57. 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!