The Prokaryotes Flashcards
Archaebacteria Characteristics
Contained in the Archaea domain
Anaerobic cells found almost everywhere
What are the 3 groups of Archaebacteria
Thermophiles: love heat, found in hot acidic waters and around ocean vents or sulphur springs
Halophiles: love high salt concentration
Methanogens: take in CO2 and hydrogen gas and release methane, found in swamps, sewage and intestines of animals
Eubacteria Characteristics
Only kingdom in the bacteria domain
Smallest and Most abundant thing on earth
Slime Capsule (Bacteria Cell)
sticky gelatinous layer that surrounds some bacteria
Cell Wall (Bacteria Cell)
Contains peptidoglycan (unique to bacteria domain)
Circular DNA (Bacteria Cell
single chromosome arranged as a giant ring of DNA
Plasmids (Bacteria Cell)
smaller rings of DNA that contain only a few genes
Pili
Short hair like stuctures that help bacteria attach to things and exhange DNA
Flagella
Long corkscrew shaped tails found in swimming bacteria to assist with movement
What are the 3 shapes of bacteria
Cocci: spherical
Baccili: straight rod shaped
Spirilla: Spiral shaped
2 Ways of getting nutrients in bacteria.
Autotrophs: can make their own food through sunlight or chemical reactions
Heterotrophs: rely on other organisms (many feed on dead organisms or waste material)
2 Types of Respiration Requirements
Aerobic: need oxygen to live
Anaerobic: grow best in oxygen rich environments but can survive without oxygen
Describe Binary Fission
DNA replicates
Cell elongates
Cell divides into 2
Types of Genetic Variation in Bacteria
Mutations result from mistakes in copying, harmful chemicals, UV and radiation
Conjugation: donor cell forms a sex pilus and transfers a copied set of DNA
Transformation: bacteria can take and use free DNA left in the environment
Transduction: Viruses can infect bacteria and transfer genes from one cell to another
Endospore
Inactive state where bacteria DNA is enclosed in minimal cytoplasm and a thick cell wall called an endosphere
Bacteria remain in this state until favourable conditions return
Explain Bacterias Role in the Nitrogen Cycle
Nitrogen-fixing bacteria converts nitrogen into ammonium
Nitrifying bacteria carry out nitrification (ammonium is turned into nitrites then nitrates) so plants can absorb it from the soil (plants are at the bottom of the food chain so everything gets nitrogen through plants/animals that ate plants)
Waste from organisms gets broken down by decomposing bactreia, ammonifying bacteria makes nitrogenous waste into ammonium
Deniftrifyting bacteria turn unused nitrates into atmospheric nitrogen
Explain Bacterias Role in the Carbon Cycle
Decomposing bacteria break down waste and decaying organic material and release CO2
Decaying matter would accumulate otherwise and ther would be less CO2
Explain Bacterias role in Oxygen Production
Cyanobacteria are considered to be earths first oxygen producing organisms, they carry out photosynthesis
Explain Bacterias role in the Human Body
About a 10:1 ratio
Most harmless or helpful
Aid in digestion
What are Pathogenic Bacteria?
Disease causing bacteria
Use up nutrients in the body to spread and multiply throughout the body
Body sends white blood cells to eliminate harmful organisms
What are the types of Toxins produced by pathogenic bacteria?
Endotoxins: chemical substances found in the cell wall of Gram negative bacteria, released during binary fission, rarely cause death
Exotoxins: Highly toxic, released by some gram-positive and some gram-negative bacteria. May act locally or target specific sites
What is the difference between Gram-negative and Gram-positive bacteria?
Gram-negative have a thin layer of peptidoglycan and absorb the red counterstain
Gram-positive have a thick layer of peptidoglycan and absorb the purple stain
How do antibiotics work?
Chemicals selectively kill or stop the growth of bacteria cells without harming the body (target cell structures or processes found only in bacteria
Explain the issue with the overuse of antibiotics.
Overuse leads to killing the bacteria which are affected by the antibiotics and leaving the bacteria that are resistant
This leads to the resistance being passed on to offspring and eventually only bacteria with resistance will remain
