DC Bio II Chapter 26

Viruses are not

Cellular

Viruses are considered to be

Infectious agents

Basic structure of viruses

Nucleic acid core surrounded by proteins

Viruses are obligate intracellular parasites

Means that they are required to live in a host cell. They then take control of that host cell and cause harm to the point where the cell dies.

Virus Genomes

Viruses that can have different kinds of genetic material, either DNA or RNA, and can be single or double stranded.

Retroviruses

Have RNA but not DNA. Uses this RNA to make DNA inside of the cell.

How do retroviruses turn RNA into DNA?

By employing reverse transcriptase.

How do you classify a virus?

By analyzing the disease they cause, the host they infect, and what their genome expression is.

How do viruses reproduce?

Viral genomes trick the host cell into making viruses.

Viruses can only reproduce inside of where?

Inside of cells.

Viruses lack their own what for protein and nucleic acid synthesis?

Ribosomes and enzymes.

What are the steps of the lyctic cycle?

Attachment or adsorption, penetration or injection, synthesis, assembly, and release.

Attatchment or adsorption

The target part of bacterial outer surface.

Penetration or injection

Virus pokes through the cell wall and injects the viral genome.

Synthesis

Virus takes over the cell’s replication and protein synthesis to make viral parts.

Assembly

Assembly of components

Release

The new viruses leave the cell either by bursting it open or by slowly pushing out through the cell wall.

Latent Phase of the Lysogenic Cycle

The virus does not immediately kill infected host cell. Also puts its genetic material into the cell’s DNA.

Influenza

One of the most lethal viruses in human history.

What does HIV do?

Infects and ultimately destroys certain types of immune cells.

Latent Infections

Viruses that hide in the host to avoid the immune system. Can establish lifelong latent infections.

Antony Van Leeuwenhoek

The first to observe and accurately describe microbial life.

Louis Pasteur

Proved spontaneous generation to be wrong.

Prokaryote Traits

No nucelus, no organelles

Prokaryotic Trait: Unicellularity

Most prokaryotes are single-celled but can stick together to form associations (biofilms).

Prokaryotic Trait: Nucleoid

The area where one circular, double-strand DNA is found.

Prokaryotic Trait: Division

Most divide by binary fission (double the DNA then split it in half).

Plasma Membrane

All prokaryotic cells have Plasma Membrane.

Cell Wall

All prokaryotic cells have Cell Walls.

Bacteria

Have Peptidoglycan

Archaea

Lack Peptidoglycan

What is the shape of a Bacillus?

Rod-shaped

What is the shape of a Coccus?

Spherical

What is the shape of a Spirillum?

Helical-shaped

Gram Stain

A test by Dr. Hans to tell you what type of bacteria it is based on the cell wall.

Gram-Positive Bacteria

Thicker peptidoglycan wall and stains a purple color.

Gram-Negative Bacteria

Contains less (thinner) peptidoglycan, retains counterstain and looks pink.

Flagella

Goes in locomotion and spins like a propeller

PiLi

Helps with attachments and exchange of information (conjunction).

Endospores

Develops a thick wall around their genome and some of the cytoplasm when exposed to environmental stress, making them highly resistant. When conditions improve, it can germinate and return to normal cell division.

BMC

Isolates specific metabolic processes

Conjugation

Cell - to - cell contact

Transduction

By viruses

Transformation

From the environment

Transfer of F plasmid

Occurs through conjugation bridge.

How do viruses package bacterial DNA and transfer it in a subsequent infection?

By transduction

Antibiotic resistance codes for…

Resistance genes

Genes from pathogenic species are transferred by…

Plasmids or transduction.

Mutations can..

Arise spontaneously in bacteria.

Radiation and chemicals increase the likelihood of..?

Mutations

What do Chemotrophs do?

Oxidize reduced chemicals from the environment

What do Phototrophs do?

Transform energy by harvesting light.

Commercial Industries

Use fermentation by-products

Fermentation By-products

Releases a dead organism’s atoms to the environment

Fixation

Photosynthesizers that fix carbon into sugars

How do the photosynthesizers in fixation work?

They change nitrogen gas (N2) to ammonia (NH3).

What is the mutually beneficial association between plants and bacteria?

Nitrogen-fixing bacteria on plant roots?

What is the mutually beneficial association between animals and bacteria?

Cellulase-producing bacteria in ruminants.

What is bioremidiation used for?

It’s bacteria used to clean pollution from water, and soil.

What does biostimulation do?

Adds nutrients to help naturally occuring microbes grow.

What improved the Bacterial disease?

Sanitation and antibiotics

What did bacterial diseases do?

Triggered inflammatory responses/produced toxins that caused damage.

How do pathogens survive bacterial diseases?

They have special features that help them live and survive inside of a host.

What are the characteristics of Protists?

They are not plants, animals, or fungi. They vary in a lot of other ways.

Some protists have..

Plasma membrane and extracellular maxtrix (ECM) in some.

One of the cell structures are…

Pseudopodia, “false feet”, locomotion for amoebas.

Nutrition

Autotrophs, Heterotrophs, Mixotrophs

What is the typical mode of reproduction?

Asexual Reproduction

When do species produce sexually?

Some of them produce like this regularly, and others produce like this under stress.

What is Giardia?

A parasite

Euglena

Has two anterior (and unique) flagella.

Trypanosomees

Can cause human diseases like African sleeping sickness by the tsetse fly.

Stramenopiles

Include brown algae, the seaweeds.

Diatoms

Photosynthetic, unicellular organisms with unique double shells made of silica.

Oomycetes

“Water molds” that caused the Irish potato famine.