Hannah
CHAPTER 6- virus/Monera
6-1- VIRUSES
-viruses do not have a cell parts
VIRUS-a piece of nucleic acid covered with an “overcoat” of protein
Called a capsid
Gives shape
Some viruses have a membrane that surrounds the capsid
CLASSIFICATOIN OF VIRUSES
Because viruses do not have all the characteristics of living things they are not classified into the 5 kingdoms
Biologists classify according to host they invade
3 groups of viruses:
1. Bacterial
2. Plant
3. Animal
SPREAD OF VIRUSES
Several ways they are spread from one living organism to another
Air, contaminated food/water, animal or insect bites, same insects carry on body, sexual contact
VIRAL REPLICATION (PAGE 95 FIGURE 6-4)
When a virus enters a cell it takes over cells hereditary material, and causes the cell to make new viruses then the new virus escape the cell
A virus can enter a host cell and remain inactive to dormant for a long period of time
Aids or cold sores
VIROIDS AND PRIONS
Viroids- smaller than viruses
Made up of very short pieces of nucleic acids without a capsid
Causes diseases in plants
Prions-very small proteins that may or may not lack nucleic acid
Only way to reproduce is inside a living cell
6-2 MONERANS
All organisms in his kingdom are bacteria
Bacteria-single celled organisms with very simple structures
Does not have a membrane around its nucleus
Does not have a true nuclei
Does not have the organelles found in most other cells
Microscope
Form large masses called colonies
KINDS OF BACTERIA
3 shapes:
1. Cocci-spherical or egg shaped
Diplococcic- cocci that forms pairs
Streptococci-forms chains
Staphylococci-form grape like bunches
2. Bacilli- cylindrical or rod shaped
Diplobacilli- bacilli in pairs
Streptobacilli-forms chains
Do not form in bunches
Bacilli are often found in soil or the air
These kinds are used to make antibiotics
Antibiotics-substances that kill harmful bacteria
Some types of bacilli are harmful to people
Types that cause botulism- a type of food poising
3. Spirilla-curved or spiral shaped
Live only as single cells
3 shapes:
Comma shaped
Wavy
Cork screw AKA(spirochete)
A spirochete causes syphilis
UNUSUAL BACTERIA
Blue-green bacteria-uses sunlight to make food for energy (photosynthesis)
Has the green pigment chlorophyll
Rickettsia-classified between bacteria and viruses
Parasite that can live only inside a host
Spread by ticks and lice
Causes rocky mountain spotted fever
BACTERIAL INTRODUCTION
Bacteria reproduce by binary fission-form of asexual reproduction (only one parent)
6-3 IMPORTANCE OF BACTERIA
Helpful-decomposers- feed upon the remains of dead