1. Prokaryote and Eukaryote Cells
IB Topic
Prokaryote and Eukaryote Cells

2. Cell Theory A. There are 3 main points
1. All living organisms are composed of cells.
2. Cells are the smallest unit of life.
3. All cells come from pre-existing cells

3. Cell theory: history and evidence
The discovery of cells is linked to technological advancements (microscopes)
B Jansen developed the compound microscope (it had two lenses)
C Robert Hooke discovered the cell
1. Looking at cork
D Leeuwenhoek discovered unicellular organisms

4. E Mathius Schleiden
discovered all plants are
made of cells
F Theodore Schwann
discovered all animals are
G Rudolph Virchow discovers all organisms are made of cells
**organism=any living thing

5. Characteristics of Life: (single cell or multi-cell)
1. Order (organization) – from small to large
-Ex: Organelles make up cells.
Cell make up tissues.
Tissues make up organs.
Organs make individuals.
2. Metabolism- organisms take in and release energy
3. Response (to the environment)- response to stimuli
4. Growth and development- heritable programs of DNA direct growth and development (change in one’s shape during life)
5. Homeostasis- organisms have regulatory mechanisms to maintain their internal environments
Examples: body temperature, blood sugar, osmoregulation
6. Reproduction- the ability to reproduce ones own kind
7. Evolutionary adaptation- life evolves as a result of interaction between organisms and their environment

6. Multicellular organisms
A. Multicellular organisms show emergent properties
B. Emergent properties arise from interaction of the components:
- The whole is greater than the parts (Ex: a heart cannot function without the whole body)
- A single cell can do nothing on its own, but when you put all of the cells together they can perform many functions

7. Multicellular organisms and differentiation
A. Multicellular organisms differentiate to carry out specialized functions
B. All cells originated from the same place and all carry the genetic information to perform any function (your toe cell could have been a brain cell)
C. In each cell there is only a small amount of activated genetic material
Ex: All cells have the genes for taste. The only cells with activated ‘taste’ genes are on your tongue.

8. Stem Cells Have ability to reproduce and differentiate
Embryo cells all start out as stem cells
Valuable for scientific research
May be able to differentiate stem cells to desired cell type
These may replace damaged cells
Sources:
Embryonic – cells from human blastocysts
Fetal – cells from aborted fetuses
Umbilical cord stem cells – cells from the umbilical cord of newborns
Placenta derived stem cells – cells from the placenta and amniotic fluid of newborns
Adult – cells from adult tissue (bone marrow, fat...)

10. DO NOT USE WIKIPEDIA AS YOUR RESOURCE!!
Homework-Outline one therapeutic use of stem cells for humans or some other animal.
DO NOT USE WIKIPEDIA AS YOUR RESOURCE!!
You may use any government or university website. Their websites generally end in .edu or .gov.

11. Viewing Cells 2. Electron microscopes: Light microscopes :
See color images
have a larger field of view
prepare samples easily
observe living and non-living material
**We cannot see most cell organelles
2. Electron microscopes:
- must be dead and no real colors
Scanning Electron (SEM):
- electron beams that bounce off the specimen
Transmission Electron (TEM):
- Used electron beams that pass through specimen
(more detail because they have a higher resolution)

12. Transmission Microscope (guess what these structures are...)
Scanning Microscope 12

13. Microscope Vocabulary
1. Resolution- describes clarity of pictures -higher resolution = more detailed pictures 2. Magnification- makes objects larger 3. An increase in magnification may reduce the resolution

14. Calculating Linear Magnification
A. The formula- Magnification = size of image size of specimen B. Example-the object is magnified by two
This is the magnified
image.
This is the original
object.
Diameter of the image=4cm
Diameter of the specimen=2 cm
Find the magnification.

15. Common SI Unit Conversions
1nm (nanometer) = 1 x 10-9 m
1ųm (micrometer) = 1 x 10-6 m
1mm (millimeter) = 1 x 10-3 m
1cm (centimeter) = 1 x 10-2 m
1m (meter) = 1m
1km (kilometer) = 1 x 103 m

16. Calculating linear magnification
Take a measurement of the drawing (width or length)
Take this same measurement of the specimen  
Remember to convert units if needed to
Place your values into the equation
Magnification = length of drawing / length of actual specimen
You can also calculate the length of the specimen if this is unknown: length of the drawing / magnification.
VIDEO:

17. Limitations to Cell Size
A. Cells cannot grow indefinitely B. They reach a maximum size and divide. C. Bigger cells are less efficient. -They have to transport materials further. -The smaller the surface area to volume ratio the harder it is for the cell.

18. How Big Is A Cell? OBJECT SIZE Eukaryotic 10-100 μm Prokaryotic 1-5 μm
Nucleus
10-20 μm
Chloroplast
2-10 μm
Mitochondrion
0.5-5 μm
Large virus (HIV)
100 nm
Ribosome
25 nm
Cell membrane
7.5 nm
DNA dbl. helix
2 nm
H atom
0.1 nm

19. Diagram of a typical prokaryote

20. Prokaryote organelles
1. Cell wall- gives the cell structure and strength (covered by sticky capsule)
2. Plasma membrane- separates the internal features from the outside environment
3. Cytoplasm- holds cell’s organelles and
enzymes
4. Pili- help the cell hold on to other
structures and aid in movement
5. Flagella- aid in organism movement
6. Ribosomes- make protein from mRNA
7. Nucleoid- area containing naked DNA
(ring)
8. Slime capsule- a protective barrier
around the cell (may help shield it from
antibiotics)

21. An electron micrographs of E. coli
** For IB you must be able to identify the structures on a micrograph.

22. (b) A thin section through the
bacterium Bacillus coagulans
(TEM)
Pili: attachment structures on
the surface of some prokaryotes
Nucleoid: region where the
cell’s DNA is located (not
enclosed by a membrane)
Ribosomes: organelles that
synthesize proteins
Plasma membrane: membrane
enclosing the cytoplasm
Cell wall: rigid structure outside
the plasma membrane
Capsule: jelly-like outer coating
of many prokaryotes
Flagella: locomotion
organelles of
some bacteria
(a) A typical
rod-shaped bacterium
0.5 µm
Bacterial chromosome

23. Prokaryote reproduction
1. Most prokaryotes divide by binary fission

24. Eukaryote Cells

25. Eukaryote Information
1. All eukaryotes have enclosed nuclei and other membrane bound organelles
2. Eukaryotes are true cells (‘eu’ = true)
3. Eukaryotic cells are present in protists, plants, fungi and animal
4. Animal cells have a secretory vesicle
-It secretes glycoproteins that makeup the extracellular matrix
-The extracellular matrix functions in support, adhesion and movement

26. Animal Cell Organelles:
Nucleus: contains genetic material, controls the cell
Ribosome: synthesizes proteins from mRNA.
Free floating, rough ER, chloroplast and mitochondria.
Rough ER: synthesizes proteins to be excreted by the cell
Smooth ER: synthesizes lipids and carbs
Golgi Apparatus: modifies, packs and ships via vesicles
Lysosome: digestion (enzymes)
Peroxisome: produces and breaks down hydrogen peroxide
Mitochondrion: aerobic respiration, converts chemical energy into ATP using oxygen

27. Intermediate filaments ENDOPLASMIC RETICULUM (ER)
A animal cell
Rough ER
Smooth ER
Centrosome
CYTOSKELETON
Microfilaments
Microtubules
Microvilli
Peroxisome
Lysosome
Golgi apparatus
Ribosomes
In animal cells but not plant cells:
Lysosomes
Centrioles
Flagella (in some plant sperm)
Nucleolus
Chromatin
NUCLEUS
Flagelium
Intermediate filaments
ENDOPLASMIC RETICULUM (ER)
Mitochondrion
Nuclear envelope
Plasma membrane
Figure 6.9

28. Plant Cells Organelles found in plants only: - cell wall:
-provides rigid support for the cells
-made mostly of cellulose
-plays important role in turgor (hardening of cells by the intake of water)
-prevents cells from taking in too much water
- chloroplasts- organelle required for photosynthesis
- vacuole- membrane bound sac used for storage of organic compounds

29. Ribosomes (small brwon dots)
A plant cell
Ribosomes (small brwon dots)
Central vacuole
Microfilaments
Intermediate
filaments
Microtubules
Rough
endoplasmic
reticulum
Smooth
Chromatin
NUCLEUS
Nuclear envelope
Nucleolus
Chloroplast
Plasmodesmata
Wall of adjacent cell
Cell wall
Golgi apparatus
Peroxisome
Tonoplast
Centrosome
Plasma membrane
Mitochondrion
CYTOSKELETON
In plant cells but not animal cells:
Chloroplasts
Central vacuole and tonoplast
Cell wall
Plasmodesmata
Figure 6.9

30. Summary of differences between eukaryotes and prokaryotes!
Prokaryotic Cells
Eukaryotic cells
small cells (< 5 mm)
larger cells (> 10 mm)
always unicellular
often multicellular
no nucleus or any membrane-bound organelles
always have nucleus and other membrane-bound organelles
DNA is circular, without proteins (naked)
DNA is linear and associated with proteins to form chromatin
(not naked)
ribosomes are small (70S)
ribosomes are large (80S)
no cytoskeleton
always has a cytoskeleton
cell division is by binary fission
cell division is by mitosis or meiosis
reproduction is always asexual
reproduction is asexual or sexual