Bacteria - 9th Grade Bio

Bacteria are mostly…

Harmless

All bacteria are ___________ organisms.

Prokaryotic

What are prokaryotic organisms?

Single-celled organisms with no distinct nucleus or membrane-bound organelles.

How small are bacteria?

Smaller than eukaryotic cells, but larger than viruses

What do bacteria cells have?

Cell wall (peptidoglycan, or protein and sugar), capsule, Pili, and Genetic material

Do all bacteria have capsules?

No

What are pili?

Little arm thingies that stick out of the capsule/cell wall.

What is the genetic material inside of bacteria?

A single ring-shaped chromosome with a plasmid (extra DNA)

What is the autogenic hypothesis of how bacteria evolved?

Certain edge spots of the bacteria folded in on itself and was filled with eukaryotic organelles.

What is the endosymbiotic hypothesis of how bacteria evolved?

One species was living within the host; smaller chloroplasts and mitochondrias moving into larger prokaryotic cells forming cellular organelles

What are the two “kingdoms” of bacteria?

Eubacteria and Archaebacteria

What is Eubacteria?

What we typically think of as bacteria; can live anywhere and anywhere.

What is Archaebacteria?

The extremophiles that live in harsh environments and are more closely related to eukaryotic cells.

Eubacteria are classified by…?

Shapes and grouping, the way they move, the way they obtain energy, and their Gram staining characteristics

What are the shapes of bacteria?

Coccus (round), Bacillus (rod-like), Spirillum (spring-like), Vibrio (curved/comma shape)

What are the groupings of bacteria?

Diplo (pairs), strepto (chains), staphylo (clusters)

How do bacteria move?

Either through their appendages (using flagella to swim or pili to crawl), spirochetal movement (using flagella to spin/swim/creep), gliding (unsure of how it works), or no movement.

How do these autotrophs obtain energy?

They are either Photoautotrophs (use photosynthesis), Chemoautotrophs (use inorganic molecules to make energy), heterotrophs (decomposers), or photoheterotrophs (combo of photoautotrophs and heterotrophs)

How do bacteria reproduce?

They can reproduce through binary fission or conjugation.

What is binary fission?

It is essentially mitosis but for bacteria.

What is conjugation?

When two bacterium exchange genetic material (no new bacterium are created).

What do bacteria need to survive?

Moisture, food, warm temperatures, and oxygen (for the most part)

What will happen if they are missing something critical for their survival?

They will will either slow in growth, stop completely, or form spores

What are spores?

Spores are similar to a cave that a bear hibernates in, except instead of a bear, its bacteria. These spores are hard to destroy and, once favorable again, release the bacteria to resume normal function.

What are way to prevent or stop bacterial growth?

You can use antiseptics (skin), antibiotics (within the body), disinfectants, pasteurization (heating food to high temps), vaccines, and sterilization.

How can bacterium cause diseases?

Either by infecting the cells or toxins (they make toxins that spread throughout the blood stream).

How can bacteria be helpful?

They can be used to make more of a human protein (put human DNA inside of the plasmid, then harvest that DNA every once in a while).