Chapter 5 Bacteria: Diatoms / Dinoflagellates

Bacteria unicellular small size (about 250,000 average-sized bacteria could fit on one period.) simplest organisms have a cell wall and cell membrane no nucleus nor membrane bound organelles

Two Domains Bacteria are found in most places (soil, water, internally, any surface) Archaea often found in extreme conditions (high temperatures, high salinity, extreme cold, no oxygen)

Bacteria Identification by shape bacillus (rod)

Bacteria Identification by shape coccus (sphere)

Bacteria Identification by shape spirilla (spiral)

Bacteria Identification by shape Ring amorphic (shapeless)

Bacteria Identification can be identified using Gram stain stain interacts with cell walls to color purple (positive) or pink (negative)

Bacteria Features flagella – Latin for “whip”; whip-like appendage that protrudes from the cell body and used for the propulsion or movement of the cell

Bacteria Features pilli – Latin for “hair”; hair-like appendage found on the surface of many bacteria used for the transfer of DNA between bacteria

Bacteria Features capsule –covering around cell wall; function is for protection or means of attachment DRAW BACTERIA CELL AND LABEL 3 MAIN PARTS

Bacteria Importance Beneficial (decomposition/recycling of nutrients; food chains; bioluminescence for animals) Harmful (food poisoning; disease)

Heterotrophic Bacteria get energy by consuming others consume organic matter, make up part of a food chain some are decomposers that break down dead matter which is important for recycling nutrients

Autotrophic Bacteria bacteria that make their own energy (2 types: photosynthetic and chemosynthetic) photosynthetic – uses sunlight chemosynthetic – uses chemical compounds like hydrogen, ammonia, hydrogen sulfide

Photosynthetic Bacteria (cyanobacteria) “blue-green algae” have chlorophyll like plants as well as phycocyanin (blue pigment) among the oldest living things thought to have added oxygen to the atmosphere

Chemosynthetic Bacteria were called “extremophiles” – lovers of the extreme found along hydrothermal vents and can survive EXTREME temperatures form part of the food chain and live inside animals like tube worms

Diatoms Eukaryotic single-celled photosynthetic algae Divided into two major groups based on the structure and shape of the valves. (Centrics and Pennates) do not propel themselves up and down in the water column, but are dependent on oceanic currents for transport

Diatoms The presence of chlorophyll and accessory pigments give them a golden color and serves to harvest light energy from the sun

Diatoms Cells are encased in transparent glass-like (silica) “container” called a frustule that resembles a petri-dish. The frustules can be ornate and very beautiful, and due to the resistance of silica, they form an important part of the fossil record

Diatoms Cells may form chains or colonies and may have distinctive shapes or structures which help them stay afloat. Up to 100,000 species of diatoms have been recorded world-wide.

Dinoflagellates Eukaryotic single-celled algae Many have two flagella, which allow the cells to have limited mobility Cells are covered by a theca (sheath) that can be smooth or ornamented

Dinoflagellates Some species are able to migrate vertically through the water column (vertical migration), seeking nutrients, prey, or protection from harmful UV rays.

Dinoflagellates Nearly half of known species are capable of photosynthesis and contain light-harvesting pigments (autotrophs) Some species survive by other nutritional modes, and may absorb organic matter or engulf prey (heterotrophs)

Dinoflagellates Of the 2000 known species, about 60 are able to produce complex toxins