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2. Biology: What is Life? life study of Properties of Life
Cellular Structure: the unit of life, one or many
Metabolism: photosynthesis, respiration, fermentation, digestion, gas exchange, secretion, excretion, circulation--processing materials and energy
Growth: cell enlargement, cell number
Movement: intracellular, movement, locomotion
Reproduction: avoid extinction at death
Behavior: short term response to stimuli
Evolution: long term adaptation

3. Cell Structure
Prokaryotic
before
nucleus
Eukaryotic
true
nucleus

4. Antonie van Leeuwenhoek 1632-1723
Developed microscopes for observing living organisms
1674 discovered live protist cells
1677 discovered spermatozoa
1682 discovered striated muscle fibers

5. http://www. molecularexpressions

6. Mouth “animalcules” (bacteria) 1684

7. Cell Theory 1839 Theodor Schwann Prussian Zoologist 1810-1882
Theodor Schwann
Prussian Zoologist
Matthias Schleiden
German Botanist
1. All living organisms consist of one or more cells.
2. Some organisms are unicellular, so cells are the fundamental unit of life.
3. New cells come from pre-existing cells by cell division.
We can now add:
4. Cells must show all the properties of life.
5. All cells are basically similar in chemical and structural composition.

8. Comparing Cell Sizes Mycoplasma 0.3-0.8 µm E. coli 1x2 µm
Cyanobacteria 10 µm diam
Plant Cell 30x75 µm
Obviously eukaryotic
Nucleus present
Mitochondrion  Bacterium
Chloroplast  Cyanobacterium
Endosymbiosis: Eukaryotes are Chimeras!

9. Cell Structure: Boundary
Mycoplasma
Water and enzymes for fermentation, glycolysis, Kreb’s cycle, Calvin cycle, naked circular DNA for transcription, 70S ribosomes for translation
cell membrane bilayer
glycolipid, sulfolipid
transport proteins
cytosol
regulates input/output
ETS for PSN, Resp
Gram Positive
Gram Negative
cell wall-murein
peptidoglycan
muramic acid - peptide
prevents dye release
prevents bursting
turgor pressure
penicillin sensitive
additional
membrane bilayer
glyco- sulfo-lipids
releases dye

10. Prokaryotic Cell Shapes
Coccus - cocci
Bacillus - bacillus
Spirillum - spirilli
Vibrio - vibrios

11. Scanning Electron Microscope (SEM) image..the shape?

12. Light microscopy would be even less detailed!
Ribosomes
This is a cartoon image created by an artist to emphasize certain structures.
Plasmids
Cytoplasm
Chromosome
Flagellum
This is a transmission electron microscopy image that inspired the cartoon.
Light microscopy would be even less detailed!
Plasma
membrane
Cell wall
Figure 7-1 Page 120

13. The cytoplasm area shows the nucleoid (DNA) area at the top.
This cartoon is not labeled, so it merely acts as a key, to orient the viewer to the enlarged portion of the TEM image.
Cytoplasm
The cytoplasm area shows the nucleoid (DNA) area at the top.
The cell membrane shows that it is a bilayer. The cell wall shows that it is multilayered.
Plasma
membrane
Cell wall
Figure 7-2 Page 121

14. This diagram shows you a further enlargement of a TEM.
The DNA double helix is further twisted to form the coils you are seeing here.
DNA
Supercoiled DNA
in chromosome
Figure 7-3 Page 121

15. Those found in the eukaryotic cytosol are 80S in “size.”
Ribosomes are 70S in “size” in prokaryotes, mitochondria, and plastids.
Those found in the eukaryotic cytosol are 80S in “size.”
Ribosome
Large subunit
of ribosome
Small subunit
of ribosome
Figure 7-4 Page 121

16. Cyanobacteria carry out photosynthesis with chlorophyll bound to proteins in thylakoid membranes
Photosynthetic
membranes
Figure 7-5 Page 122
This is an artificially-colored micrograph from transmission electron microscopy (TEM)

17. Cyanobacterial Vegetative Cell (photosynthesis)
cell wall
mesosome
cell membrane
cyanophycean starch
cyanophycin
vacuole
lipid droplet
polyphosphate granule
thylakoids
70S ribosome
nucleoid
polyhedral body

18. ? ? Transmission Electron Microscope (TEM) image..the shape?

19. Sulfolobus acidocaldarius
TEM or SEM? Of Archaeon
Extremophile
Sulfur metabolism
pH 1 to 6
75°C Optimum
Strict aerobe
Partial monolayer (C40) membranes
Multiple DNA Circles
Introns in DNA
DNA binding proteins
rRNA similarity
RNA synthase similarity
Operon style regulation
70S ribosomes
Shape?

20. Bacterium of the Genus: Leptospira
TEM or SEM?
Shape?
Bacterium of the Genus: Leptospira

21. What are the shapes of these disease bacteria?
Vibrio cholerae
Helicobacter pylori
Are they motile?
If so, by what mechanism?

22. Cell Structure: Movement
hook
directional rotation?
basal rings and rod
anchorage
rotation
stiff helical flagellum
flagellin protein
is rotated by “motor apparatus”
in the membrane by H+ ATPase
at rates of rps
(>12,000 rpm!)
Taxis:
movement toward stimulus
Exceptions:
phototaxis:
movement toward light
myxomycetes, some cyanobacteria use slime, but how?
spirochetes have flexible internal microtubules
(endosymbiotic source of flagella in eukaryotes?)
((gut parasite in termites have spirochete symbiosis))
chemotaxis:
movement to chemicals

23. Prokaryotic Growth Cells are generally very small
Cells may double in size but only before binary fission
Growth mostly in terms of cell number or colony size, etc.
Doubling time in cell numbers may be 20 minutes in ideal conditions
Could quickly take over the earth if conditions could remain ideal
Very competitive in ideal environments
Ultimate survivors billion years!

24. Cell Structure: Nucleoid
Nucleoid - genome
one circular DNA molecule
no histone protein association
attached to cell membrane
transcription by RNA polymerase
replication by DNA polymerase
separation of chromosomes
cytokinesis by furrowing
70S Ribosome
Process called binary fission
NOT mitosis!
Genome and copy are identical
Genome is haploid
There is no synapsis
There is no recombination
rRNA + protein + ribozymes
translation of mRNA into protein

25. Cell Associations ? Coccus Diplococcus Streptococcus - filamentous
Staphylococcus - colonial ?
Streptobacillus

26. What shapes and associations are shown in these SEMs?

27. An artificially colored TEM of a cyanobacterium.
Thylakoids contain chlorophyll a (green)
Metabolism?
Association?
Shape?

28. Anabaena --a cyanobacterium w/ division of labor Vegetative Cells
(Photosynthesis)
Akinete
(hypnospore)
Heterocyst (N2 fixation)

29. Cyanobacterial Heterocyst (N2 fixation)
cell wall
O2 block
cell membrane
nucleoid
mesosome
ETS for O2 reduction
cytosol
Nitrogenase reduces N2 (requires anaerobic conditions)
pore in wall
fuel input for respiration

30. Cyanobacterial Akinete (hypnospore)
cell wall
cell membrane
cyanophycean starch
polyhedral body
lipid droplet
polyphosphate granule
vacuole
cyanophycin
thylakoids
nucleoid

31. Germinating akinetes (producing vegetative filaments)

32. Internal Membranes and Organelles
How do Prokaryotic and Eukaryotic Cells Differ?
Location of DNA
Internal Membranes and Organelles
Cytoskeleton
Overall Size
Bacteria and Archaea
In nucleoid area but may have plasmids or replicons
Mesosomes, thylakoids, vacuoles
Limited except in spirochetes
Normally about size of mitochondrion
Eukaryotes
In nucleus surrounded by envelope, but also in mitochondrion, chloroplast
Large number of and kinds of organelles, endomembrane system
Extensive microtubules and microfilaments
Most are much larger than any prokaryotic cell
Adapted from: Pearson Benjamin Cummings © 2008
Figure 7-5-Table 7-1 Page 122