201 VIRUSES

1
CHAPTER 20

• 20-1 VIRUSES
• 20-2 BACTERIA

2
VIRUSES

• ARE THEY ALIVE???

3
VIRUSES

• NUCLEIC ACID (DNA OR RNA) CORE ENCASED IN A
  PROTEIN COAT
• CAN INFECT CELLS AND REPLICATE WITHIN THEM
• CANNOT REPRODUCE ON THEIR OWN
• SCIENTISTS DO NOT CONSIDER THEM TO BE ALIVE

4
VIRUSES

• MANY SHAPES

5
VIRUSES

• MANY VIRUSES ARE PATHOGENS AGENTS THAT CAUSE
  DISEASE

6
VIRUSES

• MAMMALS PRODUCE ANTIBODIES TO PROTECT THEMSELVES
  FROM VIRAL INFECTIONS
• ANTIBODIES ARE SPECIFIC TO THE VIRUSES
  GLYCOPROTEINS
• VIRUSES OFTEN MUTATE AND CHANGE THEIR
  GLYCOPROTEINS MAKING IT DIFFICULT TO FIGHT OFF

7
BACTERIA

• IN A SINGLE GRAM OF SOIL THERE MAY BE 2.5 BILLION
  BACTERIA

8
BACTERIA

• BACTERIA PLAY A VERY IMPORTANT PART IN THE WEB OF
  LIFE.

9
BACTERIA

• ALTHOUGH BORN WITH NO BACTERIA, WITHIN HOURS OF
  BIRTH THE HUMAN BODY IS HOST TO ABOUT A QUARTER
  OF A POUND OF BACTERIA LITERALLY BILLIONS OF
  BACTERIA

10
BACTERIA

• BACTERIA CAUSE SOME OF THE MOST DEADLY DISEASES.

11
BACTERIA

• BACTERIA ARE UBIQUITOUS!
• BACTERIA ARE PRESENT IN EVERYTHING WE EAT AND ON
  EVERYTHING WE TOUCH.

12
BACTERIA

• THERE ARE TWO BRANCHES (KINGDOMS) OF BACTERIA
• ARCHAEBACTERIA
• EUBACTERIA

13
BACTERIA

• GRAM POSITIVE BACTERIA
• GRAM NEGATIVE BACTERIA

14
BACTERIA

• BACTERIA ARE PROKARYOTIC
• BACTERIA LACK A CELL NUCLEUS
• BACTERIA HAVE NO INTERNAL COMPARTMENTS OR
  MEMBRANE SYSTMEMS

15
BACTERIA

• BACTERIA CELLS ARE VERY SMALL ABOUT 1 MICRON IN
  DIAMETER
• MOST EUKARYOTIC CELLS ARE TEN TIMES AS LARGE

http//www.cellsalive.com/howbig.htm
16
BACTERIA

• ALL BACTERIA ARE SINGLE CELLS.

17
BACTERIA

• BACTERIA SHAPES
• BACILLUS ROD SHAPED
• COCCUS A SPERICAL CELL
• SPIRILLUM A SPIRAL CELL

18
BACTERIA

• BACTERIAL CHROMOSOMES ARE A SINGLE CIRCULAR PIECE
  OF DNA.

19
BACTERIA

• CELL DIVISION (REPRODUCTION) IN BACTERIA
  TYPICALLY TAKES PLACE BY BINARY FISSION.

http//www.microbe.org/news/news.asp
20
BACTERIA

• BACTERIA HAVE MANY METABOLIC ABILITIES THAT
  EUKARYOTES LACK
• ANAEROBIC AND AEROBIC RESPIRATION
• OXIDIZING INORGANIC COMPOUNDS SUCH AS SULFUR
• FIX ATMOSPHERIC NITROGEN

21
BACTERIA

• PHOTOSYNTHETIC BACTERIA
• PHOTOSYNTHESIS EVOLVED IN BACTERIA LONG BEFORE
  EUKARYOTES EXISTED
• CYANOBACTERIA (BLUE-GREEN ALGAE) WERE RESPONSIBLE
  FOR THE INTRODUCTION OF OXYGEN INTO THE EARTHS
  ATMOSPHERE

22
BACTERIA

• CHEMOAUTOTROPHIC BACTERIA OBTAIN ENERGY BY
  REMOVING ELECTRONS FROM INORGANIC MOLECULES SUCH
  AS AMMONIA, METHANE, OR HYDROGEN SULFIDE.
• IMPORTANT TO THE ENVIRONMENT AND AGRICULTURE
  OXIDIZE AMMONIA INTO NITRATE WHICH IS USED BY
  PLANTS.

23
BACTERIA

• HETEROTROPHIC BACTERIA FEED ON ORGANIC MATERIAL
  FORMED BY OTHER ORGANISMS.
• THEY ARE THE PRINCIPAL DECOMPOSERS OF THE LIVING
  WORLD.
• ANTIBIOTICS ARE PRODUCED BY A BACTERIA FOUND IN
  SOIL

24
BACTERIA

• http//pubs.caes.uga.edu/caespubs/pubcd/B693.htmW
  ash