Biology 11 Archaea Bacteria Notes Bandali Archaea Bacteria
Biology 11 Archaea & Bacteria Notes Bandali
Archaea & Bacteria Prokaryotes are • unicellular organisms • do not have a nucleus or membrane-bound organelles. Classified into two kingdoms • archaea • bacteria.
Archaea • Prokaryotes • Have a single bipolar layer of phospholipids • The phospholipids are bonded with ether bonds
Archaea • Can live in a huge range of habitats • Soil, swamps and ponds • Hot springs that are rich in minerals • Oceanic trenches • Not known to cause disease (not pathogens) • Methanogens (a type of archaea) form a symbiotic relationship in the intestines of mammals to help them metabolize organic material
Bacteria • Prokaryotes • Have a phospholipid bilayer • The phospholipids are bonded with ester bonds
Types: • Heterotrophic bacteria live almost everywhere. • Photosynthetic autotrophs- make their own energy by sunlight, so they live in places with sunlight. • Chemosynthetic autotrophs- make their own energy, but do not require sun.
Bacterium • Consists of very small cell. A bacterial cell has all the structures necessary to carry out its life functions.
Fighting bacteria • Most bacteria live in hypotonic environments, where water is always trying to enter the cell. • If you can damage the cell wall and allow the water in it will cause the cell to burst.
Penicillin • Sir Alexander Flemming discovered by mistake that penicillin would cause the cell walls of bacteria he was growing to be damaged. • Damaged cell wall = burst bacteria cell
Identifying Bacteria • Gram staining- the stain allows you to distinguish two groups because of their difference in the composition of bacteria cell walls. • Gram-stain positive turn purple • Gram-stain negative turn pink • Positive & negative react to different antibiotics.
Shape also identifies bacteria • Three most common: • Spheres- called cocci • Rods- called bacilli • Spirals – called spirilla
Patterns of Growth • Bacteria cells often grow in characteristic patterns. • Diplo – paired • Staphylo – resemble grapes • Strepto - chains
Binary Fission • Bacteria reproduces asexually & rapidly • Copies chromosome • They attach • Grow larger • 2 chromosomes separate, pull apart • Move to opposite ends of cell • Partition forms and you have 2 similar cells
Sexual Reproduction of Bacteria • Conjugation- some bacteria can do this. Transfers DNA through a bridge like structure called a pilus.
Importance of Bacteria • Disease causing bacteria are actually few compared to harmless and beneficial bacteria. • They help fertilize fields • Recycle nutrients on Earth • Produce foods & medicines.
“Good” Bacteria • Some bacteria convert N 2 into ammonia by nitrogen fixation and others that convert the ammonia into nitrites & nitrates which plants use. • Swiss cheese, pickles, yogurt all made by bacteria • Some produce antibiotics, like bacitracin
“Bad” Bacteria Can cause diseases like: • Strep throat • Tuberculosis • Tetanus • Lyme disease • Cavities • diptheria
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