Viruses and Bacteria

Viruses

Discovered 1935

From the Latin meaning “poison”

Tiny non-living particles that reproduce in cells

Most are very specific- can only infect a certain type of cell

Viruses can infect all living things

Cold

Flu

Herpes

Some Cancers

HIV

Mumps

Chickenpox

These are all caused by viruses

Viruses can infect all living things

Bacteriophage-

virus that infects

a bacterium

Bacteriophage virus

Bacterium

Viruses- Bacteriophage

No!!!

The tulip mosaic virus

Produces highly

prized variegated tulips

Are all viruses bad?

Why are Viruses not

Considered Living?

They do not respire, eat, excrete, or reproduce.

By itself, a virus can not do anything.

Host cell- cell a virus invades to replicate (make copies), cannot reproduce on its own

What are the parts of a virus?

Capsid- outer coat of protein, protein coat determines shape

Nucleic Acid- DNA or RNA Bacteriophage

Capsid

DNA

RNA

DNA

Capsid

Capsid

Viruses come in many shapes and sizes depending on the cell they infect.

What are the

shapes of viruses?

Viruses come in many shapes and sizes depending on the cell they infect.

What are the

shapes of viruses?

10 x

smaller

100 x

smaller

1000 x

smaller

What are the sizes of viruses?

Viruses- The Lytic Cycle

Lytic Cycle

Attachment- virus attaches to cell

Entry-viral nucleic acids invades host cell

Replication-makes many copies of DNA and capsid

Assembly-viruses are put together

Lysis- host cell breaks open and viruses are released

Viruses Lytic Cycle

This is how viral replication appears in ‘Real Life.’

Viruses- The Lysogenic Cycle

Attachment-virus attaches to cell wall

Entry-viral nucleic acid enters cell

Provirus/Prophage formation-viral DNA is incorporated into the host’s DNA. Viral DNA is produced along with the host cell’s DNA. This is called a provirus or prophage

Can go into lytic cycle at any time

Lysogenic cycle

Viruses- Lytic and Lysogenic Cycle

Summary of Both

http://www.youtube.com/watch?v=wLoslN6d3Ec http://www.youtube.com/watch?v=Rpj0emEGShQ

Retrovirus

retrovirus- virus made of RNA, once RNA enters the cell, it is converted into DNA using an enzyme called reverse transcriptase

HIV is a retrovirus

Bacteria

Kingdom Monera

Kingdom Archaebacteria

Kingdom Eubacteria

Bacteria Structure

Structure p 503

Bacteria

Kingdom Archaebacteria

Live in extreme environments

Usually no oxygen present

Contains a cell wall

Prokaryotic cell

Archaebacteria- 3 types

o 1. heat and acid loving deep thermal vents

Bacteria in boiling hot springs in Yellowstone Park

Types of Archaebacteria

2. salt loving

Great Lakes, Dead Sea

Salt loving archaebacteria and algae swimming among salt crystals

Salt crystals appear pink because millions of halobacteria are trapped within the crystals.

Archaebacteria- 3 types

3. methane producing

found in swamps, cow’s gut, sewage plants

Swamps and wetlands

Guts of herd animals

Raw sewage

Bacteria

Kingdom Eubacteria

Types of nutrition

Parasitic- feed on living tissues

Saprophytic- feed on dead tissues

Autotrophic- make own food

Chemosynthetic- break down chemicals

Eubacteria- Nutrition

Parasitic bacteria like these rods cause Tuberculosis

Cyanobacteria- a photosynthetic bacterium

Eubacteria- Nutrition

Discovered during a dive to Hydrothermal Vents in 1977, Chemosynthetic Bacteria is a very unique organism.

These bacteria are the food source for many deep water organisms. Vent communities are completely isolated from other organisms from the marine world.

The discovery of chemosynthetic bacteria and the vent communities was as remarkable as finding life on another planet

Bacteria

Toxins- bacteria growing in anaerobic environment (sealed cans) produce these poisons-

causes botulism

Bacteria- Shapes

Shapes

Coccus –round

Bacillus- rod

Spirilla – spirals

Bacteria- Arrangements

o Diplococcus- two cells

o Streptococcus- chain

o Staphylococcus- like

bunches of grapes

Bacteria- Reproduction

Reproduction

1. Binary fission- asexual, cell splits in two

Bacteria- Reproduction

Conjugation- sexual, cells exchange genetic information

Bacteria

Colonies- large groups of bacteria cells

Antibiotics- inhibit growth of bacteria

Bacteria- Importance

1. Nitrogen Fixation- Important role is converting atmospheric/inorganic nitrogen to compounds plants can use

Bacteria- Importance

2. Decomposition- recycle nutrients

Bacteria- Importance

3. Food – yogurt, cheese, vinegar

Bacteria- Importance

4. Medicine –

streptomycin,

erythromycin,

neomycin