bellringer what is the difference between a bacteria and a virus? are bacteria and viruses harmful,...

Bellringer

• What is the difference between a bacteria and a virus?

• Are bacteria and viruses harmful, helpful, or neither?

• If so, how are they harmful, helpful, or neither?

Bacteria and Viruses

Bacteria

• Prokaryotes-single celled organism lacking nucleus

Eukaryote, remember?

Bacteria: ShapesShapes:

1. Bacilli-rods

2. Cocci- spheres

3. Spirilla- spiral, corkscrew

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Bacillus bacteria

are rod or sausage shaped

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Coccus bacteria

are sphere or ball

shaped

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Spirillium bacteria have a corkscrew shape

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The tip of a needle

The red and yellow dots are

bacteria

Metabolic Diversity

• Heterotrophs– Must take in organic

molecules for energy and supply or carbon

– Chemoheterotroph: Most common.

– Photoheterotroph: Least common

– Use photosynthesis for energy but need to take in organic compounds for a carbon source

• Autotrophs

– Make their own food.

– Chemoautotrophs: make organic carbon molecules but do not require light as a source of energy.

– Photoautotrophs: make organic carbon molecules and require light as a source of energy

Bacteria: Cell Walls

Cell walls:• Bacteria with

peptidoglycan absorb violet dye=gram positive

• Bacteria with less peptidoglycan absorb red dye=gram negative

Bacteria: Motility

Movement:• Flagella allow reaction towards chemical or

physical signals

Bacteria: ReproductionReproduction:

1. Binary fission-replicates, divides

2. Conjugation-bridge forms, genetic transfer; Diversity!

3. Endospore- enclose DNA, remain dormant until better conditions; forms spores

Endospore

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CONJUGATION

Bacteria Functions in Biosphere1. Decomposer (chemical

recycling)

2. Nitrogen Fixers

3. Bioremediation

4. Human uses for food

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Helicobacter pylori

is the pathogenic bacteria that can

causes ulcers

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Leprosy is a bacterial

infection that decreases

blood flow to the

extremities resulting in

the deterioration of toes, ears, the nose and the fingers.

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LYME DISEASE

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TUBERCULOSIS

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STRUCTURE

• Nonliving• Composed of Nucleic acid and protein• Cause many diseases• Virology – Study of Viruses• Comparison of Viruses and Cells below

Char. Of Life Virus Cell

Growth No Yes

Homeostasis No Yes

Metabolism No Yes

Mutation Yes Yes

Nucleic acid DNA or RNA DNA

Reproduction Only within host cell Independently by cell division

Structure Nucleic acid core, protein covering, some have envelope

Cytoplasm, cell membrane, etc..

VirusesVirus- particles of nuclei

acid and protein which reproduce by infecting living things

DRAW and label

Tobacco Mosaic Virus causes tobacco plants to develop a pattern of spots

22Some virus are pushed out by the cell, taking

some of the cell membrane with them.

Viruses• Lytic infection-virus enters cell, makes copies,

bursts out of cell

Viruses• Lysogenic infection- virus embeds DNA into DNA

of host cell and replicated along with host cell’s DNA

VirusesRetroviruses- contain RNA as genetic

info; reverse transcription takes place (HIV)

Viruses

Prions- contain no DNA or RNA, only protien (Mad Cow Disease)

Diseases Caused by Bacteria and Viruses

• Bacteria produce disease in one of 2 general ways. Some damage the cells and tissues of the infected organism directly by breaking down the cells for food. Others release toxins that travel throughout the body interfering with the normal activity of the host.

Vaccine: preparation of weakened or killed pathogen.

• Antibiotics: compounds that block the growth and reproduction of bacteria

Viral Diseases

• Like bacteria, viruses produce disease by disrupting the body’s normal equilibrium.

• Viroid; single stranded RNA molecules that have no surrounding capsids.

• Prions: protein infectious particles.

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Viruses and Human Disease

• Control and Prevention of spread.– Vaccination & Antiviral drugs

• Ex.) chickenpox vaccine, AZT, Acyclovir, protease inhibitors.

• Emerging Viruses – exist in isolated habitats– Do not usually infect humans unless environmental

conditions favor contact.

• Several viruses are now linked to cancers such as leukemia, liver cancer, Burkitt’s lymphoma, cervical cancer.

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Which US President had polio?

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HERPESVIRUSES

BACK

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RHABDOVIRUSES

BACK

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RETROVIRUSES

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