A Note On Bacteria

Submitted By Mishana-Ellison
Words: 931
Pages: 4
Open Document
Bacteria

Bacteria
• Are the most numerous organisms on
Earth!
• Were probably the first forms of life.
Fossils indicate they were about 1 billion years before eukaryotes.
• Are prokaryotes (no nucleus)
• Have been found almost everywhere!

Bacteria are very small!

Classification of Bacteria
• Must use the RNA sequences to classify them. • Two Kingdoms:
– Eubacteria (typical bacteria we encounter)
– Archaebacteria (more ancient)
• Methanogens (live in bottoms of swamps) • Halophiles (live in salty conditions)
• Thermoacidophiles (acidic, hot areas)

Shapes of Bacteria
• Bacilli
– Rod shaped

• Cocci
–
–
–
–

Sphere shaped
May be streptococci if in a chain
May be diplococci if in pairs of two
May be staphlococci if in grape-like clusters

• Spirilla
– Spiral shaped

Gram Stain Classification
• Bacteria species are often grouped into two categories based on a laboratory technique called Gram staining
• Gram-positive retain the Gram stain & appear purple
• Gram-negative do not retain the stain and appear pink from a secondary stain.

Gram Positive & Gram Negative Bacteria

Gram-positive and gram-negative bacteria differ in…
• Cell walls thickness (gram + has thicker cell wall but gram – has an outer membrane)
• Susceptibilities to antibacterial drugs • The toxic material they produce • Their reactions to disinfectants

Bacteria Phyla:
• Cyanobacteria (blue green algae)
– Photosynthetic, no nucleus or chloroplasts • Spirochetes
– Gram negative, spirals, corkscrew movement • Gram Positive bacteria
–
–
–

Not all are, but DNA is similar
Lactobacilli cause tooth decay
Actinomycetes form branching filaments

Bacteria Phyla:
• Proteobacteria
– Enteric (gut) bacteria
– Chemoautotrophs – feed off chemicals E. coli

Sec. 2: Biology of Bacteria
• Structure:
– Cell wall made of peptidoglycan
(short chains of amino acids and carbohydrates) •Gram negative bacteria have outer membrane of lipids and sugars that protects them from some antibiotics.

Cell Wall Structures: + and -

Biology of Bacteria
• Structure:
– Cell Membrane
•Composed of lipid bilayer
•Since bacteria have no mitochondria the cell membrane has enzymes that perform cellular respiration.
•Photosynthetic bacteria perform photosynthesis on thylakoid folds Biology of Bacteria
• Structure:
– Cytoplasm
• Contains ribosomes and DNA
• No membrane bound organelles
• DNA is found in main chromosome and also plasmids
(in some bacteria)

Biology of Bacteria
• Structure:
– Capsule
•An outer covering made of polysaccharides to protect it from dry conditions
•May be made of fuzzy, sticky sugars that help it to attach to surfaces of host cells

Biology of Bacteria
• Structure:
– Pili
•Short, hairlike structures that help bacteria to adhere to host cells. •May be used to transfer genetic material from one bacteria to another.

Biology of Bacteria
• Structure:
– Endospores
•Dormant structure to help bacteria survive in harsh conditions (high temps, harsh chemicals, radiation, drying)
•When favorable conditions return the bacteria will multiply again. Biology of Bacteria
• Structure:
– Movement Structures
•May have flagella (one or several) •May use slime layer to “glide”
•Wavelike contractions to
“propel”

Bacteria motility

Bacteria Structure

Nutrition and Growth
• Food getting:
– May be heterotrophic (saprophytes) and feed on dead and dying material
– May be autotrophic if they can use sunlight (cyanobacteria – simple algae)
– May be chemoautotrophic – they use chemicals for energy (nitrobacter in soil breaks down ammonia

Nutrition and Growth
• Oxygen Relationships:
– May be obligate anaerobes:
• Cannot survive in presence of oxygen (ex. tetanus bacteria)

– May be facultative aerobes
• Can live with or without oxygen
(ex. E. coli)

– May be obligate aerobes
• Cannot live without oxygen (ex.
Bacterium tuberculosis)

Growth Cycle of a Bacterial Culture
1. LAG PHASE: Growth is slow at first, while bacteria acclimate to the food and nutrients in new habitat. 2.
Show More

Related Documents: A Note On Bacteria

Essay on Bacterial Transformation Report

Transformation Lab Report I. Pre-lab Bacterial transformation occurs when an organism receives DNA from a different species and expresses the implemented gene, thus becoming a transgenic organism. The practice proceeds as follows: first cut the plasmid from one organism and DNA from another, using the same restriction enzyme on a palindromic sequence. The recombinant plasmids then enter the host bacteria and asexually reproduce infinitely. We can identify that the bacteria has the new DNA by testing…

Words 1615 - Pages 7

Living Organisms: Taxonomy, Kingdoms, Classification, and Types Essay

replicate(replicator). • First prokaryotic cell( survived in CO2 and water). • Organisms began to use light as an energy source-photosynthesis(oxygen was produced and was toxic). • Oxygen and UV combine to create the ozone layer( the atmosphere was formed). • bacteria and archaea, and eukaryotes combine...endosymbiosis. • Small organelles like mitochondria and chloroplast fuse into larger cells. • plant, animal, fungi lines begin to form • multicellular plants and water animals form. • the evolution of the…

Words 2104 - Pages 9

Types Of Evolution

Evolution unit test 2013 Content: 1. Mechanisms of evolution: pre and post zygotic 2. Pesticide resistance insects (same idea as antibiotic resistance bacteria) 3. Anti-biotic resistance bacteria 4. Types of natural selection: stabilizing, directional, disruptive 5. Allele frequency: lab activity 6. Genetic drift and bottleneck effect 7. Constructions of phylogenetic trees and analysis 8. Natural selection 9. Sexual selection/ non-random mating 10. Catastrophism, actualism, uniformitarianism…

Words 1744 - Pages 7

DNA Replication Essay

A- DNA replication DNA replication is a biological process by which a molecule of DNA is copied. This process starts at the origin of replication where the double helix of the parental DNA is being unwound by the helicase in two separated strands. Then, single-strand biding proteins bind on the unpaired strands keeping them from repairing. The topoisomerase helps relieve the strain by breaking and swiveling the DNA strands ahead of the replication fork. The primase synthesize a short stretch of…

Words 413 - Pages 2

Biology Essay

The macrophages engage the bacteria and set up a signal transduction system to activate the REL/NFKB transcription factors. REL/NFKB is blocked by IKB in the cytosol of that macrophage. Macrophage begins engulfment of bacteria and this activates a receptor to turn on a signal transduction cascade, which causes signal transduction leading to the degradation of IKB, which reveals the NLS AA sequence that is part of the REL/NFKB protein's sequences. So NLS carried by the Rel/NF-kB proteins is recognized…

Words 458 - Pages 2

Gradnerella Vaginalis Research Paper

is a bacteria pathogen also known as bacterial vaginosis. Gradnerella vaginalis is a disease that many women across the world suffer from. Some women are able to catch the bacteria disease earlier than others. Most women are diagnosed with Gardnerella vaginalis after an annual Pap smear has been done and the physician does test and realize what the problem with the patient. And then there are other women out there who cannot always make to the physician to get tested; therefore, the bacteria disease…

Words 1142 - Pages 5

Lob Liquid Medium Lab Report

LB liquid medium (pH = 7.0-7.2): yeast extract 5 g, tryptone 10 g, sodium chloride 10 g, double distilled water set to 1 L then autoclaved for 30 min and stored in the 4 ° C. LB solid medium: agar powder was added to LB liquid medium to a final concentration of 1.7% and autoclaved for 30 min. DAP stock solution (50 mg / mL): 1 g of DAP was dissolved in 20 mL of sterile water and sterilized by a 0.22 μm filter. Storage was performed at -20 ° C and the working concentration was adjusted at 50 μg /…

Words 506 - Pages 3

study guide on evolution Essay

improves an organisms fitness Embryological similarities Genetic Variation Mutations and genetic shuffling are the main sources The frequent use of pesticides, antibacterial soaps/lotions, and antibiotics will result in insects or bacteria developing resistance to these items this rendering their actions ineffective. Genetic drift random change in allele frequencies seen when a small group colonizes a new habitat affects smaller populations Isolating Mechanisms – prevent speciation…

Words 552 - Pages 3

The Vagina Essay

ol The vagina has a natural balance of “good” and “bad” bacteria. Bacterial vaginosis occurs when that balance is disrupted. [pic] One kind of bacteria, known as Lactobacillus acidophilus, protects the vagina from unhealthy organisms. Women diagnosed with bacterial vaginosis lose this protection and have an increase in harmful bacteria and decrease in good bacteria. Bacterial Vaginosis is the most common vaginal infection for women. One out of five women are diagnosed at the age of childbearing…

Words 925 - Pages 4

Veterinarian Research Paper

They have some things in common, like they have to go to pre-med veterinarian school, before they can call themselves veterinarians, and get into a major veterinary university. Theriogenology veterinarian focuses on reproduction, including the physiology and pathology of male and female reproductive systems in animals. They have to perform breeding qualification examination diagnostic testing, completing pregnancy checks, and perform pre-surgery examination.…

Words 479 - Pages 2