Objective: Compare the structures of viruses to cells, and describe the role of viruses in causing diseases such as HIV and Influenza (TEKS 4C)

Bacteria _____________________ are unicellular organisms that do not have a nucleus. They are the _______________________________ ______________________________________________________ Bacteria are vital to maintaining life on earth. Some _____________________________ of bacteria are:

20-1 Bacteria Bacteria are unicellular organisms that do not have a nucleus. They are the _______________________________ ______________________________________________________ Bacteria are vital to maintaining life on earth. Some _____________________________ of bacteria are:

20-1 Bacteria Bacteria are unicellular organisms that do not have a nucleus. They are the smallest and most common prokaryotes. Bacteria are vital to maintaining life on earth. Some _____________________________ of bacteria are:

20-1 Bacteria Bacteria are unicellular organisms that do not have a nucleus. They are the smallest and most common prokaryotes. Bacteria are vital to maintaining life on earth. Some important functions of bacteria are: Anthrax bacteria

Being producers that capture sunlight _________________________________________) 2. __________________________ - they break down dead things

Being producers that capture sunlight (they start the food web) 2. __________________________ - they break down dead things

Being producers that capture sunlight (they start the food web) 2. Decomposers - they break down dead things

3. _________________________ – bacteria convert nitrogen gas into a form that plants can use.

3. Nitrogen Fixation – bacteria convert nitrogen gas into a form that plants can use.

4. ________________________ - E 4. ________________________ - E.coli bacteria helps you to digest food and assists your body in making vitamins.

4. Intestinal Use- E.coli bacteria helps you to digest food and assists your body in making vitamins.

5. __________________________ - Bacteria are helpful in cleaning oil spills because some can digest oil.

5. Environmental Use - Bacteria are helpful in cleaning oil spills because some can digest oil.

The structures of bacteria: Bacteria come in 3 main shapes: 1. _____________ – rod shaped 2. _______________ – spiral shaped 3. ___________– round balls

The structures of bacteria: Bacteria come in 3 main shapes: 1. Bacilli– rod shaped 2. _______________ – spiral shaped 3. ___________– round balls Bacilli

The structures of bacteria: Bacteria come in 3 main shapes: 1. Bacilli– rod shaped 2. Spirilla – spiral shaped 3. ___________– round balls Spirilla Bacilli

The structures of bacteria: Bacteria come in 3 main shapes: 1. Bacilli– rod shaped 2. Spirilla – spiral shaped 3. Cocci– round balls Spirilla Cocci Bacilli

Cell Walls: ______________ is used to tell the difference between the 2 types of cell walls that bacteria can have. ____________________ (gram+) bacteria stain dark purple because of the thick peptidoglycan in the cell wall ____________________ (gram-) bacteria stain pink because the cell wall is thinner.

Cell Walls: Gram stain is used to tell the difference between the 2 types of cell walls that bacteria can have. ____________________ (gram+) bacteria stain dark purple because of the thick peptidoglycan in the cell wall ____________________ (gram-) bacteria stain pink because the cell wall is thinner.

Cell Walls: Gram stain is used to tell the difference between the 2 types of cell walls that bacteria can have. Gram Positive (gram+) bacteria stain dark purple because of the thick peptidoglycan in the cell wall ____________________ (gram-) bacteria stain pink because the cell wall is thinner.

Cell Walls: Gram stain is used to tell the difference between the 2 types of cell walls that bacteria can have. Gram Positive (gram+) bacteria stain dark purple because of the thick peptidoglycan in the cell wall Gram Negative (gram-) bacteria stain pink because the cell wall is thinner.

Reproduction There are 3 ways that bacteria reproduces: 1. ______________________ – one bacterial cell grows large and divides in half to produce 2 daughter cells.

Reproduction There are 3 ways that bacteria reproduces: 1.Binary Fission– one bacterial cell grows large and divides in half to produce 2 daughter cells.

2. ____________________ - a bridge called a pilum.

2. Conjugation - a bridge called a pilum.

3. ______________________ – when conditions become unfavorable, some bacteria forms spores. Spores are crusty balls that can remain dormant for a long period of time until condition improve.

3. Spore Formation – when conditions become unfavorable, some bacteria forms spores. Spores are crusty balls that can remain dormant for a long period of time until condition improve.

Locomotion – movement Bacteria can move by: 1. ___________________________________________ 2. _______________________in a spiral motion 3. By using ___________________ – a long tail 4. By using _______ – small hairs that work like tiny legs.

Locomotion – movement Bacteria can move by: 1. Floating on secreted slime 2. _______________________in a spiral motion 3. By using ___________________ – a long tail 4. By using _______ – small hairs that work like tiny legs.

Locomotion – movement Bacteria can move by: 1. Floating on secreted slime 2. Spinning in a spiral motion 3. By using ___________________ – a long tail 4. By using _______ – small hairs that work like tiny legs.

Locomotion – movement Bacteria can move by: 1. Floating on secreted slime 2. Spinning in a spiral motion 3. By using flagellum– a long tail 4. By using _______ – small hairs that work like tiny legs.

Locomotion – movement Bacteria can move by: 1. Floating on secreted slime 2. Spinning in a spiral motion 3. By using flagellum– a long tail 4. By using cilia – small hairs that work like tiny legs.

Viruses are not living organisms! They are particles of nucleic acid, proteins, and sometimes lipids. A typical virus is composed of a core of DNA surrounded by a protein coat called a capsid. Capsid

DNA Capsid Tail sheath Tail Fibers This virus is called a bacteriophage

Bacteriophages attacking an e. coli bacterium

 Influenza Virus (the flu)

Tobacco Mosaic Virus

How viruses infect healthy cells: Every virus is surrounded by a ______________________. The capsid binds with the healthy host cell’s membrane and _________________________ into letting it inside. _____________________________ – the virus enters a host cell, makes copies of itself and then causes the host cell to explode. _____________________________ – the virus enters the host cell but does not kill it. Instead, it combines its DNA with that of the host cell and every time the cell replicates its RNA, the virus’ DNA is also copied.

How viruses infect healthy cells: Every virus is surrounded by a capsid The capsid binds with the healthy host cell’s membrane and _________________________ into letting it inside. _____________________________ – the virus enters a host cell, makes copies of itself and then causes the host cell to explode. _____________________________ – the virus enters the host cell but does not kill it. Instead, it combines its DNA with that of the host cell and every time the cell replicates its RNA, the virus’ DNA is also copied.

How viruses infect healthy cells: Every virus is surrounded by a capsid The capsid binds with the healthy host cell’s membrane and “tricks” the cell into letting it inside. _____________________________ – the virus enters a host cell, makes copies of itself and then causes the host cell to explode. _____________________________ – the virus enters the host cell but does not kill it. Instead, it combines its DNA with that of the host cell and every time the cell replicates its RNA, the virus’ DNA is also copied.

How viruses infect healthy cells: Every virus is surrounded by a capsid The capsid binds with the healthy host cell’s membrane and “tricks” the cell into letting it inside. Lytic Cycle – the virus enters a host cell, makes copies of itself and then causes the host cell to explode. _____________________________ – the virus enters the host cell but does not kill it. Instead, it combines its DNA with that of the host cell and every time the cell replicates its RNA, the virus’ DNA is also copied.

How viruses infect healthy cells: Every virus is surrounded by a capsid The capsid binds with the healthy host cell’s membrane and “tricks” the cell into letting it inside. Lytic Cycle – the virus enters a host cell, makes copies of itself and then causes the host cell to explode. Lysogenic Cycle – the virus enters the host cell but does not kill it. Instead, it combines its DNA with that of the host cell and every time the cell replicates its RNA, the virus’ DNA is also copied.

________________________ - a virus that contains RNA instead of DNA ________________________ - a virus that contains RNA instead of DNA. They work “backwards” in that they make ____________________________________. This is where the prefix “retro” comes from. May remain ________________________ (unnoticed) for several years _________________ is the retrovirus that causes AIDS.

Retrovirus- a virus that contains RNA instead of DNA Retrovirus- a virus that contains RNA instead of DNA. They work “backwards” in that they make ____________________________________. This is where the prefix “retro” comes from. May remain ________________________ (unnoticed) for several years _________________ is the retrovirus that causes AIDS.

Retrovirus- a virus that contains RNA instead of DNA Retrovirus- a virus that contains RNA instead of DNA. They work “backwards” in that they make DNA copies from RNA. This is where the prefix “retro” comes from. May remain ________________________ (unnoticed) for several years _________________ is the retrovirus that causes AIDS.

Retrovirus- a virus that contains RNA instead of DNA Retrovirus- a virus that contains RNA instead of DNA. They work “backwards” in that they make DNA copies from RNA. This is where the prefix “retro” comes from. May remain dormant (unnoticed) for several years _________________ is the retrovirus that causes AIDS.

Retrovirus- a virus that contains RNA instead of DNA Retrovirus- a virus that contains RNA instead of DNA. They work “backwards” in that they make DNA copies from RNA. This is where the prefix “retro” comes from. May remain dormant (unnoticed) for several years HIV is the retrovirus that causes AIDS.