Biodiversity: Bacteria Flashcards
(28 cards)
Explain germ theory
Germ theory was developed by Louis Pasteur in 1860. It states that many diseases are caused by microorganisms such as bacteria, viruses, protozoa or fungi
Explain the discovery of bacteria
Antoine von leeuwenhoek was the first one to observe bacteria. He used the lenses he created to look at cloth to look at water and saw bacteria for the first time.
What are pathogens, what are the types and describe them with an example.
Pathogens are any organisms which can cause diseases. These include bacteria, viruses, fungi and protozoa. Bacteria are single called organisms without a nucleus and can cause diseases like tuberculosis. Viruses are thread like particles which reproduce by taking over living cells and can cause diseases like the common flu. Fungi are simple organisms such as mushrooms and yeast that grow as single cells or thread like filaments and can cause diseases like ringworm disease. Protozoa are single called organisms with a nucleus that cause diseases such as malaria.
What are the routes of transmission of bacterial infection?
Airborne, Anthropod, Direct contact, Food or water born
What are the habitats of bacteria
Bacteria are found in every conceivable habitat on earth including our skin
List the domain, kingdom, cell type, number of cells, cell wall material, nutrition and primary means of reproduction and an example of bacteria.
Domain: Bacteria
Kingdom: Bacteria
Cell type: prokaryote
Cell number:unicellular
Cell wall material: peptidoglycan
Nutrition: Autotrophs and heterotrophs
Primary means of reproduction: Asexual
Example: Salmonella
Explain a prokaryotic cell structure
Prokaryotic cells are made up of a nucleoid contained in a cytoplasm which also has ribosomes and plasmids which are seperate DNA that can replicate on its own, surrounded by a cell membrane, cell wall and capsule with protruding pilli (hair like structures) and a flagella (tail like structure)
Most bacteria fall into which category?
Eubacteria
Explain Cyanobacteria
- blue green algea
- Ancestors to modern plants? We don’t know for sure
- only prokaryotic organism which performs oxygenic photosynthesis
- generally held responsible for the rise of oxygen in the atmosphere and oceans
Are bacteria Aerobic or anaerobic
Anaerobic, most do not need oxygen to carry out cellular respiration
Explain bacterial reproduction
Bacteria reproduce very quickly, genes mutate 1000 times as often as eukaryotic genes
BINARY FISION
Asexual reproduction similar to mitosis.
- chromosomes duplicate
- DNA moves apart as cell elongates
- division into 2 daughter cells
What are the alternate methods of bacterial reproduction, explain them
- Transduction: virus transfers genetic material from one bacteria to another
2: Transformation: bacterial cells take in used pieces of DNA from the environment
3: Conjugation: two bacteria cells join and exchange genetic material in the form of plasmids through a connection called a pilus
Explain what an endospore is and it’s formation
-Endospores are a dormant, tough and non reproductive structure produced by certain bacteria from the fir I cute phylum
-Bacteria forms a thick wall around DNA and cytoplasm
-occurs in unfavourable conditions
-bacteria remains dormant until favorable conditions return
-wall breaks down and active bacteria returns
Explain bacterial adhesion
Bacterial adhesion is when bacteria attaches itself to host cells. This occurs in 3 phases, primary adhesion where bacteria begins attaching itself to the host cell, cellular aggregation where bonds begin forming between attached bacteria and the final phase where slime glcyocalyx layer forms around the bacteria.
How do bacteria grow?
Moisture
Ideal temperature
Ideal pH
Source of food
Oxygen presence or absence depending on species
What type of bacteria grows in which temperatures?
Psychrophiles - low 10-20 ish
Mesophiles - medium 15-45 ish
thermophiles - high 40-80 ish
Hyperthermophiles - very high 65 to 105 ish
How do you get rid of Bacteria
Antibiotics
Antiseptics
Disinfectants
Heat or cold
Acid
Radiation
How to tell bacteria apart
Shape/structure
Arangment
Nutrition
Respiration
Gram strain
Lifestyle
What shapes and arrangements are bacteria found in?
Spherical - coccus, rod shaped - bacillus, spiral - spirillium
Diplo - pairs, staphylo - clumps, strepto - strings
Explain bacteria nutrition
Autotrophs: photoautotrophs (energy source - light, carbon source - CO2) chemoautotrophs (energy source - inorganic chemicals, carbon source - CO2)
Heterotrophs: photoheterotrophs (energy source - light, carbon source - organic compounds) chemoheterotrophs (energy source - organic compounds, carbon source - organic compounds)
Explain bacteria respiration
No mitochondria or chloroplasts
3 types:
Obligate aerobes (need oxygen to live)
Facultative anaerobes (oxygen not required, can conduct fermentation when needed)
Obligate anaerobes (absolutely no oxygen or they will die)
Explain gram stains
Reaction to dyes
There is + and -
Gram-positive bacteria: have a thick peptidoglycan layer, stain purple, ex mycobacteria, non pathogenic
Gram-negative bacteria: have a thin peptidoglycan layer, stain pink, ex E. Colli, pathogenic
Explain toxins
Endotoxins: found inside the bacteria cell, usually produce fever, weakness and capillary damage
Exotoxins: products of metabolism secreted into the surroundings of the bacteria cell, one of the strongest poisons known to man and can cause violent reactions in the host organisms
Explain Plaque Formation
Plaque is a sticky substance made from leftover food and saliva particles. If plaque is not regularly removed from your teeth by proper brushing and flossing, it mineralized into tartar, a hard, yellow, brown deposit that tightly adheres to the teeth.
