1. Ch. 6 Warm-Up
What are the 2 main types of cells? Which Domains do they consist of?
List 3 ways that eukaryotes differ from prokaryotes.

2. Ch. 6 Warm-Up How is the size of a cell related to its function?
Name 5 organelles or cell structures and their function.

3. Pick up handout on back counter.
Warm-Up Activity:
Pick up handout on back counter.
Complete this handout for your warm-up activity.

4. Compare and contrast Animal vs. Plant Cells Animal Cell Plant Cell
Ch. 6 Warm-Up
Compare and contrast Animal vs. Plant Cells
Animal Cell
Plant Cell

5. Ch. 6 Warm-Up What is the structure & function of: Microtubules
Microfilaments
Intermediate filaments

6. Ch. 6 Warm-Up What is the function of: Plasmodesmata Gap junctions
Tight junctions
Desmosomes

7. Chapter 6
A Tour of the Cell

8. Three differences between prokaryotic and eukaryotic cells.
You Must Know
Three differences between prokaryotic and eukaryotic cells.
The structure and function of organelles common to plant and animal cells.
The structure and function of organelles found only in plant cells or only in animal cells.

9. How We Study Cells
Biologists use microscopes and the tools of biochemistry to study cells

10. Size range of cells
Note that light microscopes can not magnify as well as electron microscopes

11. Light Microscopy (LM) vs. Electron Microscopy (EM)

12. Cell Size and Scale
Scale of the Universe:
rse_2012

13. Cells must be small to maintain a large surface area to volume ratio
Large S.A. allows  rates of chemical exchange between cell and environment

14. Limits to cell size Metabolic requirements set upper limit aa aa aa aa
in large cell, cannot move material in & out of cell fast enough to support life aa aa
What process is this? CH
NH3 aa
CHO O2 CH
CHO
CO2
CHO
CO2
CO2
What process is this?
diffusion
What’s the solution?
cell divides
make a multi-celled creature = lots of little cell, rather than one BIG cell aa
NH3 O2
NH3 O2
CHO
NH3 aa
CO2 CH aa CH O2 aa O2
What’s the solution?

15. How to get bigger? aa aa aa O2 aa aa aa
Become multi-cellular (cell divides)
But what challenges do you have to solve now?
CO2
CO2 O2
NH3 aa
NH3 aa
CO2
NH3 O2
CO2
CO2 CH
CHO
CO2
NH3
Larger organisms do not generally have larger cells than smaller organisms — simply more cells
What’s challenges do you have to solve now?
how to bathe all cells in fluid that brings nutrients to each & removes wastes from each aa O2
NH3
NH3
CO2
CO2
CO2
CHO aa
NH3
NH3
NH3 CH
CHO
CO2
CO2 O2 aa aa CH

16. Surface Area Example (Animal):
Small Intestine: highly folded surface to increase absorption of nutrients
Villi: finger-like projections on SI wall
Microvilli: projections on each cell

17. Folds  Villi  Microvilli

18. Surface Area Example (Plant):
Root hairs: extensions of root epidermal cells; increase surface area for absorbing water and minerals

19. Cell characteristics All cells: surrounded by a plasma membrane
have cytosol
semi-fluid substance within the membrane
cytoplasm = cytosol + organelles
contain chromosomes which have genes in the form of DNA
have ribosomes
tiny “organelles” that make proteins using instructions contained in genes

20. 2 Types of Cells:
Prokaryotes: Domain Bacteria & Archaea
Eukaryotes (Domain Eukarya): Protists, Fungi, Plants, Animals

21. A Prokaryotic Cell (bacteria)

22. Prokaryote Vs. Eukaryote
“before” “kernel”
No nucleus
DNA in a nucleoid
Cytosol
No organelles other than ribosomes
Small size
Primitive
i.e. Bacteria & Archaea
“true” “kernel”
Has nucleus and nuclear envelope
Cytosol
Membrane-bound organelles with specialized structure/function
Much larger in size
More complex
i.e. plant/animal cell

23. Why organelles? Specialized structures specialized functions
mitochondria
Specialized structures
specialized functions
cilia or flagella for locomotion
Containers
partition cell into compartments
create different local environments
separate pH, or concentration of materials
distinct & incompatible functions
lysosome & its digestive enzymes
Membranes as sites for chemical reactions
unique combinations of lipids & proteins
embedded enzymes & reaction centers
chloroplasts & mitochondria
chloroplast
Golgi
Why organelles?
There are several reasons why cells evolved organelles. First, organelles can perform specialized functions. Second, membrane bound organelles can act as containers, separating parts of the cell from other parts of the cell. Third, the membranes of organelles can act as sites for chemical reactions.
Organelles as specialized structures
An example of the first type of organelle is cilia, these short filaments act as "paddles" to help some cells move.
Organelles as Containers
Nothing ever invented by man is as complex as a living cell. At any one time hundreds of incompatible chemical reactions may be occurring in a cell. If the cell contained a uniform mixture of all the chemicals it would not be able to survive. Organelles surrounded by membranes act as individual compartments for these chemical reactions. An example of the second type of organelle is the lysosome. This structure contains digestive enzymes, these enzymes if allowed to float free in the cell would kill it.
Organelle membranes as sites for chemical reactions
An example of the third type of organelle is the chloroplast. The molecules that conduct the light reactions of photosynthesis are found embedded in the membranes of the chloroplast. ER

24. Nucleus Function: control center of cell Contains DNA
Surrounded by double membrane (nuclear envelope)
Continuous with the rough ER
Nuclear pores: control what enters/leaves nucleus
Chromatin: complex of DNA + proteins; makes up chromosomes
Nucleolus: region where ribosomal subunits are formed

25. Nucleus Contains DNA Function: control center of cell
Surrounded by double membrane (nuclear envelope)
Continuous with the rough ER
Nuclear pores: control what enters/leaves nucleus
Chromatin: complex of DNA + proteins; makes up chromosomes
Nucleolus: region where ribosomal subunits are formed

26. Ribosomes Function: protein synthesis Composed of rRNA + protein
Large subunit + small subunit
Types:
Free ribosomes: float in cytosol, produce proteins used within cell
Bound ribosomes: attached to ER, make proteins for export from cell

27. Endomembrane System:
Regulates protein traffic & performs metabolic functions

28. Endoplasmic Reticulum (ER)
Network of membranes and sacs
Types:
Rough ER: ribosomes on surface
Function: package proteins for secretion, send transport vesicles to Golgi, make replacement membrane
Smooth ER: no ribosomes on surface
Function: synthesize lipids, metabolize carbs, detox drugs & poisons, store Ca2+

29. Endoplasmic Reticulum (ER)

30. Golgi Apparatus
Function: synthesis & packaging of materials (small molecules) for transport (in vesicles); produce lysosomes
Series of flattened membrane sacs (cisternae)
Cis face: receives vesicles
Trans face: ships vesicles

31. Lysosomes
Function: intracellular digestion; recycle cell’s materials; programmed cell death (apoptosis)
Contains hydrolytic enzymes

32. Vacuoles
Function: storage of materials (food, water, minerals, pigments, poisons)
Membrane-bound vesicles
Eg. food vacuoles, contractile vacuoles
Plants: large central vacuole -- stores water, ions

36. Parts of plant & animal cell p 108-109

38. Mitochondria Function: site of cellular respiration
Double membrane: outer and inner membrane
Cristae: folds of inner membrane; contains enzymes for ATP production; increased surface area to  ATP made
Matrix: fluid-filled inner compartment

39. Chloroplasts Function: site of photosynthesis Double membrane
Thylakoid disks in stacks (grana); stroma (fluid)
Contains chlorophylls (pigments) for capturing sunlight energy

40. Endosymbiont theory Mitochondria & chloroplasts share similar origin
Prokaryotic cells engulfed by ancestors of eukaryotic cells
Evidence:
Double-membrane structure
Have own ribosomes & DNA
Reproduce independently within cell

41. Peroxisomes Functions: break down fatty acids; detox alcohol
Involves production of hydrogen peroxide (H2O2)

42. Cytoskeleton: network of protein fibers
Function: support, motility, regulate biochemical activities

43. Extracellular Matrix (ECM)
Outside plasma membrane
Composed of glycoproteins (ex. collagen)
Function: Strengthens tissues and transmits external signals to cell

44. Intercellular Junctions (Animal cells)
Tight junctions: 2 cells are fused to form watertight seal
Desmosomes: “rivets” that fasten cells into strong sheets
Gap junctions: channels through which ions, sugar, small molecules can pass

45. Plant Cells Cell wall: protect plant, maintain shape
Composed of cellulose
Plasmodesmata: channels between cells to allow passage of molecules

46. Plant Cells Only
Animals Cells Only
Central vacuoles
Lysosomes
Chloroplasts
Centrioles
Cell wall of cellulose
Flagella, cilia
Plasmodesmata
Desmosomes, tight and gap junctions
Extracellular matrix (ECM)

47. Harvard cell video
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