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• Eubacteria
  – Live almost everywhere
  – Surrounded by a cell wall
  – Cell walls contain peptidoglycan
• Archaebacteria
  – Lack peptidoglycan
  – DNA is similar to eukaryotes
• Identified by shape, chemical nature of cell
  walls, way they move, and way the obtain
• Shapes: Bacilli = rod shaped, Cocci =
  spherical, Spirilla = spiral
• Movement: Propelled by flagella
• Heterotrophs:
  – Chemoheterotrophs: get energy from organic
  – Photoheterotrophs: get energy from light
• Autotrophs:
  – Photoautotrophs: Use light energy
  – Chemoautotrophs: Organic molecules from
• Binary fission : cell splits into two cells
• Conjugation: Exchange of genetic
  information across cells
• Spores: makes bacteria inactive and well-
• Vital to maintaining the world
• Decomposers
  – Recycle nutrients
• Nitrogen fixers
  – Make NH3 for plants to use
          Web resources
•Particles of nucleic acid, protein, and in some cases, lipids

•Can ONLY reproduce by infecting other living cells

•Composed of a core of DNA or RNA surrounded by a protein coat

•Viruses protein coat: capsid

•Cell specific- binds to specific proteins on the outsides of cells

•Bacteriophage-virus that can infect bacteria
                        Lytic Infection
1. Bacteriophage injects DNA into bacterium

1. Bacteriophage DNA forms a circle

1. Causes synthesis of new bacteriophage proteins and nucleic acids
   by taking over bacterium’s metabolism

1. Newly created proteins and nucleic acids assemble into complete
   bacteriophage particles

1. Bacteriophages break the cell wall and go to attack other cells
          Lysogenic Infection-dormant
1. Bacteriophage injects DNA into bacterium

1. Bacteriophage DNA forms a circle

1. Bacteriophage DNA inserts itself into the bacterial

1. DNA replicates possibly for many generations

1. Bacteriophage DNA exits bacterial chromosome and
   enters lytic cycle

1. Lytic cycle
                           Other Facts

Retrovirus: Only contain RNA as their genetic information-must produce
a DNA copy of its RNA when infects a cell (Dormant for long periods of

Viruses considered parasites for they live off of other cells to grow and

NOT considered alive for they can’t survive independently

Produce diseases by disrupting body’s equilibrium
How a pathogen enters and
what happens next…
A pathogen or foreign substance can
 penetrate into the body by entering through:
 cuts or gashes in the skin, mouth/nose
 (inhaling), and other open areas throughout
 external view of the body.
 Once a pathogen or foreign substance enters
 the body, an immediate process takes place
 called the immune response.
Types of immune responses

 The   two types of immunity are:
1) Humoralimmunity- where the body fights
 against a familiar pathogen that has been in
 the body before.
               immunity- where the body
2) Cell-mediated
 reacts to abnormal pathogens or substances.
Order of defenses
T-cells attach to the antigen exposed using its antibodies,
and releases a chemical called cytokines, which
retrieves other B-cells and T-cells.

The inflammatory response occurs in which capillaries
expand allowing lymphocytes to pass through from the
bloodstream and get to the infected site

The first line of the nonspecific defense is the skin,
not allowing substances to enter the body.

 Lymphocytes ingest the pathogen, revealing its antigen
 on the phagocyte’s surface
Killer T-cells inject                                              Entering B-cells attach onto
cytotoxins into the                                                the antigen of the pathogen
infected cells, killing them.                                      and , some, turn into
in the end,                                                        plasma cells that make
suppressor T-cells come                                            antibodies against that
                                  Helper T-cells activate Killer
around and                                                         specific pathogen. Other B-
                                  T-cells and B-cells
demolish all the killer T-cells                                    cells continue to ingest the
so that                                                            pathogens, displaying the
they don’t kill too many cells                                     antigen on a MHCII
or                                                                 molecules, for phagocytes
healthy cells.                                                     to come and eat them.
1.) Which of these about Eubacteria is false?
  a) live nearly everwhere
  b.) Surrounded by a cell wall
  c.) Cell walls lack peptidoglycan
  d.) Cell wall contains peptidoglycan
2.) Which of these is not a known shape of
  a.) bacilli
  b.) cocci
  c.) triangular
  d.) spirilla
3.) Which of these get energy from light?
  a.) Chemoheterotrophs
  b.) Photoheterotrophs
  c.) Photoautotrophs
  d.) Chemoautotrophs
4.) What is the result of Binary fission?
  a.) cell splits into two cells
  b.) two cells join together
  c.) cells explode
  d.) cells form endospores
5.) What is the main function of decomposers?
  a.) to soak up nutrients
  b.) to destroy nutrients
  c.) to recycle nutrients
6.) What is the only way viruses can
  a.) asexually
  b.) by infecting other cells
  c.) sexually
7.) What is not a particle of a virus?
  a.) nucleic acid
  b.) cell wall
  c.) proteins
  d.) lipids
8.) How do viruses infect a cell?
  a.) they can pass through easily w/out any
  b.) create a hole in the cell membrane
  c.) through cell specific receptors
9.) Which infection cycle involves possibly
  becoming dormant in the cell for a period of
  a.) lytic
  b.) lysogenic
  c.) lactic
  d.) lactose
10.) In the lysogenic cycle what does
  bacteriophage not do?
  a.) injects its DNA into the bacteria
  b.) its DNA inserts itself into the bacteria
  c.) it attaches to a receptor so the cell
  consumes it
  d.) its DNA forms a circle
11.) which is false about viruses?
  a.) they are not considered alive
  b.) they are considered parasites
  c.) they are considered alive
  d.) they survive off other cells
12.) viruses produce diseases by disrupting the
  body’s _____
  a.) organs
  b.) structure
  c.) equilibrium
  d.) skin
13.) which is some place where foreign
  substances can not enter the body?
  a.) toe nails
  b.) cuts
  c.) mouth/nose
  d.) openings in the skin
14.) what response takes place after a foreign
  substance enters the body?
  a.) respiratory
  b.) immune
  c.) hormonal
  d.) equilibrium
15.) which is not a type of immunity?
  a.) cell mediated
  b.) humoral
  c.) response
16.) T-cells attach to
  a.) antigens
  b.) antibodies
  c.) antrogens
17.) what is the first line of non-specific
  a.) T-cells
  b.) skin
  c.) blood
  d.) B-cells
18.) what ingest the pathogens?
  a.) T-cells
  b.) B-cells
  c.) antigens
  d.) lymphocytes
19.) T-cells inject what into the infected cells?
  a.) cytotoxins
  b.) toxic chemicals
  c.) antigens
  d.) antibodies
20.) what activates T-cells and B-cells?
  a.) killer t-cells
  b.) helper t-cells
  c.) b-cells
  d.) plasma cells
Answer key:
1. c
2. c
3. b
4. a
5. c
6. b
7. b
Answer key:
8. c
9. b
10. c
11. c
12. c
13. a
14. b
Answer key:
15. c
16. a
17. b
18. d
19. a
20. b

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