Bacteria Viruses and Protists Bacteria What bacteria are

Bacteria, Viruses and Protists

Bacteria • What bacteria are? • Are they important? • One gram of soil can have billions of them

Characteristics of bacteria • • Prokaryote, unicellular Eubacteria and Archaebacteria Small in size (microscopic) A few can be relatively larger

Characteristics of bacteria • Shape – Bacilli (rod-shaped) – Cocci (spherical) – Spirilla (spiral) • Some bacteria have flagella

Characteristics of bacteria

Bacterial reproduction • Binary fission

Endospore • Endospore – Inactive form – Protective function – Regeneration – Found in some bacteria

Kingdom Eubacteria • Diversity in shapes, functions and interactions • Classified by the means of acquiring food – Producers (make their own food) – Consumers (eat other organisms) – Decomposers (feed on dead matter)

Kingdom Eubacteria • Cyanobacteria – Producers and contain chlorophyll – Usually live in water – Can have other pigments as well

Kingdom Archaebacteria • Considered to be primitive • Mostly in extreme conditions • The major types include – Thermophiles (living at high temperature) – Halophiles (living at high salt concentration) – Methanogens (produce methane)

Kingdom Archaebacteria

Good bacteria • Nitrogen fixation

Good bacteria • Recycling materials • Cleaning up

Good bacteria • Bacteria in foods (yoghurt, cheese etc. ) • You eat bacteria with your food

Good bacteria • • Making medicines and pharmaceuticals Insulin Industrial products Genetic engineering

Bad bacteria • Harmful bacteria • Pathogenic bacteria (cause diseases) • Antibiotics and vaccines • Plants (rot, crown gall, spots etc. ) • Animals and humans (anthrax, tuberculosis, dysentery)

Viruses

Viruses • • Smaller than bacteria Can change rapidly Can cause diseases (parasites) Require a host for propagation

Viruses • Are they alive? – – Virus is not a cell No organelles, can’t break food, can’t function on its own Contain protein and nucleic acid Require a host for reproduction

Viruses

Viruses • Classification – DNA or RNA virus • Can infect other living things (bacteria, plants, animals, humans) • Flu, polio, AIDS, chicken pox • Vaccination

Viruses • Life cycle – Dormant vs. destructive

Protists

Protists • Members of kingdom Protista • Characteristics – Most are single celled, some could have many cells, others live in a colony. All are eukaryotes – Some make their own food, some eat other organisms – Some can move – Less complex – do not have specialized tissues

Protists • Have many different shapes

Protists and their food • Some are producers (contain chlorophyll) autotrophs • Others heterotrophs (decomposers or parasites) – animal like e. g. amoeba, paramecium – Plant like e. g. euglena, chlamydomonas – Fungi like e. g. slime mold