Bacteria
The First Cells
Bacteria are grouped
into one of 2 Kingdoms
• What is the difference between them?
– K. Archaebacteria
•
•
•
•
Harsh environments
Methanogens – no O2; marshes; cow gut
Halophiles – high salt; dead sea; great salt lake
Thermophiles – high heat; thermal vents of oceans
– K. Eubacteria
• Common bacteria, found all around us
The Big “5”
Type of cell
- prokaryotic
# of cells
- unicellular
Cell wall
- murien or peptidoglycan
– The other 2 traits are variable… examples of
bacteria exist for each trait
What structures do all bacteria have?
• ALL have…
– Cell membrane, ribosomes, DNA
• SOME have…
– Flagella, cell wall, capsule, endospore
Test Yourself!
What do each of the structures listed
above do?
What structures do all bacteria
have?
How do we classify bacteria?
• Based on SHAPE:
– Round cells (coccus)
– Rod cells (bacillus)
– Spiral cells (spirillum)
How do we classify bacteria?
• Based on GROUPINGS:
– Pairs (diplo)
– Clusters (staphylo)
– Chains (strepto)
Test Yourself!
What would these look like?
• Diplobacillus
• Streptococcus
• Staphylococcus
• Diplospirillum
How do bacteria reproduce?
• 1. binary fission
– Asexual (genetically same)
– Copies DNA & splits into 2 cells
– Very fast!
How do bacteria reproduce?
• 2. conjugation
– Sexual (genes
recombine)
– Transfer DNA
through tube
How do bacteria respire?
• Those that require oxygen are called aerobic
– Ex: Mycobacterium tuberculosis, attacks lungs
• Those that do not require oxygen are called
anaerobic
– Many are actually poisoned by O2
– Ex: Clostridium tetani, causes tetanus
Why are some bacteria so tough to kill?
• Endospores
– Tiny structures with tough coatings
– Resist high temps, dryness, & chemicals
– Holds copy of genes
– Ex: C. botulinum (botulism food poisoning)
What are some beneficial impacts
& uses of bacteria?
• 1. nitrogen-fixation – pull N2 from air & add
to soil (N needed to make proteins)
• 2. decomposition – break down dead stuff
• 3. O2-production – blue-green bacteria
• 4. foods – cheeses, pickles, yogurt, etc
• 5. human digestion – vitamin K
• 6. antibiotics – ex. Streptomycin &
acromycin
What are some harmful effects of
bacteria?
• 1. agricultural
– Crop damage; livestock disease; food spoilage
• 2. human disease
– Strep throat; tetanus; TB; pneumonia; Lyme
disease; dental cavities; food poisoning;
chlamydia; syphilis; gonorrhea
How do we defend ourselves
against bacteria?
• Non-specific immunity
ex. Skin cell barrier
antimicrobial fluids (tears, oils, wax)
white blood cells
• Antibiotics
ex. Penicillin, streptomycin
Penicillin “pokes” holes in the cell membrane
Streptomycin disrupts protein synthesis
The End
Quiz - Microbes
Use your own paper.
Do not write the question.
Does not need to be in complete sentences.
Quiz - Microbes
• 1. The method of asexual reproduction in
bacteria is called –
– A. conjugation
– B. sporulation
– C. budding
– D. binary fission
Quiz - Microbes
• 2. Which is a spirillum?
• 3. Which is a bacillus?
• 4. Which is a coccus?
A
B
C
Quiz - Microbes
• 5. The large, rounded structures shown within
the bacterial cells below are –
– A. capsules
– B. cell walls
-- C. endospores
-- D. pili
Quiz - Microbes
• 6. List three helpful things that bacteria do or
provide.
• 7. List two diseases caused by bacteria.
• 8. Of viruses and bacteria – which is easier to treat
with antibiotics?
• 9. What is penicillin actually doing when it kills a
pathogen?
Quiz – Microbes (alternate
ending)
• 6. List three helpful things that bacteria do or
provide.
• 7. How does the lysogenic cycle of viruses differ
from the lytic cycle?
• 8. Explain the importance of nonspecific immune
defenses. List 2 particular types of nonspecific.
• 9. What is meant by “specific immune response” as
related to your immune system?