BACTERIA, VIRUSES, AND THE IMMUNE SYSTEM Biology Objective 4.03 Assess, describe, & explain adaptations affecting survival & reproductive success in disease-causing viruses & microorganisms.
BACTERIA, VIRUSES, AND THE
IMMUNE SYSTEM
Biology
Objective 4.03
Assess, describe, & explain adaptations affecting
survival & reproductive success in disease-causing
viruses & microorganisms.
Cell Type of Bacteria
Prokaryotic
No nucleus or membrane bound organelles
Lots of ribosomes
Thick cell wall
Some have a sticky capsid
outside of cell wall
Circular chromosome (DNA)
Unicellular
Bacteria
Energy Source
Can be autotrophic or heterotrophic
Reproduction: Asexual Reproduction
Called Binary Fission
Makes an exact copy
Happens quickly
Binary Fission
1.Bacteria Grows
2.DNA is copied
3.Cytokinesis Occurs
4.Two identical cells
LABEL
YOUR
NOTES
Environment Depends on the Kingdom
Archaebacteria
Harsh environment
High temperatures
High salinity
Acidic
Eubacteria
Normal
Environment
Everywhere else
Bacteria…Good, Bad or Both?
Bacteria is good!
food (yogurt)
medicines
(insulin)
recycles nutrients
decomposer
nitrogen fixation(in plants)
Bacteria is bad!
Decay/rot food
Rot teeth (cavities)
Cause disease/
infections
(strep throat)
Antibiotics
Antibiotics are used to clear up bacterial infections.
Antibiotics put holes into bacterial cell walls causing them to burst and die
Bacteria Growth Patterns
Shapes:
- Coccus = round
- Bacillus = rod
- Spirillum = spiral
Growth:
- Diplo- = in pairs
- Staphylo- = in clusters
- Strepto- = in chains
Viruses
Considered to be nonliving because it cannot reproduce on its own and does not use energy
General Structure
Protein coat on the outside
Nucleic acid on the inside (DNA or RNA)
Examples of Viruses
Influenza- the flu
HIV- AIDS
Varicella- chicken pox & shingles
Polio virus- polio
Rubella or measles- measles
Rhinovirus- cold
How Viruses Reproduce
Lytic Cycle
1. Virus DNA enters the host cell
2. Hijacks host to make DNA and
protein
3. Uses cell to puts virus together
4. Cell bursts and releases virus
5. Virus is active: OUTBREAK!
Reproductive Cycles
Lysogenic Cycle
1. Virus DNA is integrated into host cell
2. Every time the cell divides, the virus is in each new
cell
3. Virus is dormant: HIDDEN!
4. Cell eventually enters lytic cycle (bursts and
becomes active)
Examples of Viruses with Lysogenic
Cycles
HIV
Herpes Simplex I = cold sores
Herpes Simplex II = genital warts
Chicken Pox/Shingles
Lines of Defense
1st line: skin and mucus
Skin acts as a barrier
Mucus traps microorganisms
2nd line: cells release chemicals
blood flow to invaded region increases (swelling)
raises body temperature (fever)
3rd line: special white blood cells attack invaders
foreign antigens are detected and Helper T white
blood cells are alerted
Helper T cells “activate” white blood cells called B
cells
B cells multiply and either become plasma cells or
Memory B cells
Plasma cells produce antibodies that attach to the
foreign antigens and “mark” them for destruction
Memory B cells stay in the body in case another
infection arises
Uh Oh!
What if a cell is already infected?!
Helper T cells alert Killer T cells
Killer T cells poke holes in the infected cell to kill it
Types of Immunity
Active Immunity
Exposed to disease
Develop disease and become immune
Longer lasting
Passive Immunity
Injected with antibody that another organism made
Not permanent
Vaccines are an example
Some vaccines have to be received every year (Flu) because it is always mutating (changing) Adapting!!