Bacteria and Cynobacteria Flashcards
What are the main characteristics of a prokaryote?
- Single Celled
- No nucleus
- Single-stranded DNA
- No membrane-bound organelles
What are the six ways we classify bacteria?
a. Shape
b. locomotion
c. nutrition
d. colony appearance
e. pigmentation
f. structure of the cell wall - gram stain (positive or negative)
What are the 3 common shapes of bacteria?
- Bacilli (spherical)
- Cocci (circular)
- Spirilli (spiral)
What do bacteria use for locomotion?
Bacteria have flagella (singular flagellum). They could have 1 or more than 1. They also have pili which fall under 2 general categories: fimbriae and sex pilus (long)
What are organisms that only need carbon dioxide or related compounds called?
Autotrophs
Photoautotrophs
Organisms that can turn light into energy, they’re photosynthetic.
What do photoautotrophs need other than sunlight for photosynthesis to occur?
CO2 and H2O
What are the products of photosynthesis?
Glucose and Oxygen
Chemotrophs
Organisms that obtain energy from chemicals
What uses organic compounds for their energy source and carbon source?
Chemoheterotroph
What is a Heterotroph?
An organism that requires at least one organic nutrient to make another organic compound.
Obligate aerobic/anaerobic bacteria
Uses oxygen for cellular respiration, and can’t grow without it.
Poisoned by oxygen and may use fermentation or anaerobic respiration in which substances such as nitrates are used to produce energy.
Facultative anaerobic bacteria
Uses oxygen if present, but can live in an anaerobic environment.
What is a colony?
A visible cluster of bacteria growing on the surface of an agar plate, formed from a single bacterium. It’s formed by binary fission.
Gram Stain
Gram-positive bacteria stain purple, while gram-negative stain pink. The different stains are due to the structure of the bacterium’s cell wall. Gram-positive organisms have a higher peptidoglycan content, while negatives have higher lipid content.
What type of reproduction is bacterial binary fission?
Asexual
What special structure do bacteria use to transfer genetic material from one bacterium to another?
Cytoplasmic ridge and sex pilus
What is transferred when bacteria conjugate?
Plasmid
Why is conjugation important to the bacteria?
They get antibiotic genes.
What is antibiotic resistance?
When bacteria can continue to grow even after being exposed to an antibiotic. They become resistant through genes.
Antibiotic Sensitivity Test (Kirby Bauer Test)
Allows the patient’s bacteria to be grown in the presence of several different antibiotics. Helps doctors know which antibiotic is better for treating bacterial infections.
Kirby Bauer Test: What is the C disk in the middle?
It’s the control disk, it shows that the disks aren’t the things killing the bacteria.
Kirby Bauer Test: What are the numbered discs soaked in before being placed on the plate?
Antibiotics
Kirby Bauer Test: Why are some circles free of bacteria larger than others?
Bacteria are more sensitive to some antibiotics than others.
What is produced by the bacteria that allows them to become antibiotic-resistant?
Proteins that inactivate the antibiotic.
How can you prevent antibiotic resistance?
Take all prescribed antibiotics
What is a biofilm?
Slime-secreting bacteria. It’s a loosely associated layer of polysaccharides, ex. plaque.
Where can biofilms form?
Teeth, Contact lenses, surgical sutures and medical equipment, artificial joints
It can cause tooth decay, gum infection, and ear infections.
What is an endospore?
Protective structure formed during dry conditions and can be used in bioterrorism.
What are some bacterias that form from endospores?
Anthrax and Botulism
