Chapter 9: Single-celled Organisms & Viruses

Characteristics of living things All living things… Have cells (organized) Grow & develop Adapt Respond to the environment Reproduce Use energy

Levels of Organization Cells Tissue Organ Organ system Organism Levels of Organization

Needs of Life All living things need : Energy – comes from the food and eventually the sun Materials – such as carbon dioxide, oxygen, & water Living Space – ex) plants die if weeds invade their living space

Unicellular – living thing made up of a single cell Usually to small to see with the human eye 1 cell carries out all life functions Ex. bacteria and most protists

Chapter 9: Single-celled Organisms & Viruses Section 2

Bacteria the simplest kind of life known on Earth composed of just one cell without a nucleus genetic material is in loops within the cell reproduces using binary fission

Anatomy of Bacteria Capsid

Arrangement Paired: diplo- Grape-like clusters: staphylo- Chains: strepto-

may occur singly or in chains Rod shaped Bacteria Bacilli (Bacillus) may occur singly or in chains

Spiral Shaped Spirillia Occur in single strands

Round Shaped Bacteria Coccus singly or in pairs, chains, or clusters

Examples of bacterial names Streptococcus: chains of spheres Staphylospirillum: Grapelike clusters of spirals Streptobacillus: Chains of rods

Bacteria are grouped by their environmental jobs

Producers transform energy from sunlight into energy that can be used by cells & are a food source for organisms that cannot make their own food.

Decomposers get energy by breaking down materials in decaying organisms & help other organisms reuse materials in decaying matter.

Parasites live in a very close relationship either inside or on the surface of a host & cause harm to their hosts.

Archaea are grouped by where they live…

Archaea single-celled organisms that can survive in the largest range of environments. environments may be in hot, very cold, or contain poisonous materials

Methanogens Produce the natural gas methane & die if exposed to oxygen Live in muddy swamps and marshes, and guts of animals such as cows and termites.

Halophiles live in very salty bodies of water (ex. Dead Sea) & can die if there is too little salt in water can survive drying and begin dividing again when water returns to a pond

Thermophiles thrive in extreme heat or cold may live in hot springs, near hot vents deep under the sea, or buried deep in the ice

Bacteria… Is it GOOD or BAD?!?

Viruses Section 3 Dead or alive?

Viral structure Viruses are not cells. Basic structure: Protein coat Nucleic acid core (RNA or DNA) Lipoprotein coat (second coat – only in enveloped viruses)

Virus Categories DNA viruses – stable, do not mutate rapidly Single-stranded or double-stranded Smallpox, Hepatitis B RNA viruses – mutate rapidly, unstable HIV, Rhinovirus

Are viruses alive? Only 1 characteristic of life: reproduction Can only reproduce inside a host cell! Process of reproduction = lytic cycle

Lytic Cycle Attachment The virus attaches to the surface of a bacterium.

Lytic Cycle Injection The virus injects its DNA into the bacterium.

Lytic Cycle Production Using the same machinery used by the host cell for copying its own DNA, the host cell makes copies of the viral DNA.

Lytic Cycle Assembly New viruses assemble from the parts that have been created.

Lytic Cycle Release The cell bursts open, releasing 100 or more new viruses.

DNA/RNA Do Now: Draw Me

9.4 Notes Protists

Protists Have a nucleus Do not fit into: They are the “left overs” Plant Animal Fungus They are the “left overs” Mostly single celled Live in water

Protists obtain energy in 3 ways Eating other organisms (animal-like) Making their own food (plant-like) Absorbing their food (fungus-like)

Algae Both multi- & unicellular Are plant-like protists Are producers Types of protists Algae Both multi- & unicellular Are plant-like protists Are producers

Types of movement in protists Pseudopods (false feet) – tiny extensions of the body move out and drag the protist along. Found in Amoeba

Types of movement in protists Flagella – Whip-like tail (or tails) Act as a rutter and moves back and forth pushing the protist forward and directing it Ex) Euglena

Types of movement in protists Cilia – tiny hairs Act as many tiny boat oars and sweep back and forth to move the protist Ex) Paramecium