Types of Heterotrophic Nutrition

Methods of Feeding1. Saprophytic Nutrition

– feed on dead organic matter, get energy from it, and recycle it back into the environment.• decomposers.

2. Parasitism– organism (parasite) feeds off of another (host) at the expense of

the host.

3. Predation– - organism (predator) hunts, kills, and eats another organism

(prey).

4. Scavenging– feed on organisms killed by something else.

What are Bacteria?• Bacteria are PROKARYOTES–The smallest known living cells

They are found everywhere!! Bacteria on

head of a pin Starr, 317

Bacteria in dental plaque microbeworld.org

Did you know? There are over 80 species of bacteria in your mouth!

Obtaining Energy• Autotrophs (make energy)– Photoautotrophs- capture energy

from light• Ex- cyabobacteria

– Chemiautotrophs- obtain energy from chemical reactions with inorganic molecules (ammonia, hydrogen sulfide, nitrites, sulfur, Iron)• Ex. Ocean vent bacteria

Cyanobacteria bloom

Obtaining Energy cont…

• Heterotrophs- most bacteria obtain their energy from organic molecules– These bacteria are often feeding in, on and

around us…• Some bacteria are photoheterotrophs– Capture sunlight and digest organic molecules

Releasing Energy• Bacteria can use both cell respiration and

fermentation• Many bacteria have different oxygen

requirements:– Obligate aerobes- must have oxygen for respiration– Facultative anaerobes- can function with or without

oxygen– Obligate anaerobes- poisoned by oxygen (use

fermentation)

Three basic shapes of Bacteria

• Spherical – coccus

• Rod – bacillus• Coiled - spirillum

Schraer, 633

Shapes of Bacteria

Coccus

• Spheres• Cocci (plural) • a variety of arrangements

Diplobacillus (paired)

Bacillus • Cylindrical or rod-shape • Bacilli (plural) • Variations in cell arrangement

Spirals

• Vibrio• Spirillum• Spirochete

Simple Colonies Staphylo = clusters

Strepto = chains

Staphylococcus wisc.edu

Diplo = double

Diplococcus cat.cc.md.us

Streptobacillus

Some have flagella - made of rope-like proteins, not microtubules.

Some slide on a slimy secretion.

Many can form dormant

cells called endospores to survive harsh conditions.

Salmonella www.iwate.jp

Streptomyces spores

Many can MOVE

Bacterial Reproduction

• Bacterial cells reproduce asexually through fission which is the splitting of a cell into two new cells.

Bacterial Reproduction cont…• Some bacteria utilize conjugation to

exchange pieces of genetic information to increase variation– *Not considered sexual reproduction- not

complete exchange of DNA, no offspring made