pastpaper B144~microbes Flashcards
(34 cards)
Autotrophic bacteria obtain their carbon from inorganic compounds, such as…
carbon dioxide (CO2)
organic compounds are metabolised by…
heterotrophic
if bacteria use chemical compounds to obtain their energy, they are called…
chemotrophic
if they(bacteria) use radiant energy e.g. sunlight they are called
phototrophic
cyanobacteria are classified as
photoautotrophs
some bacteria gain their energy from anaerobic respiration e.g. (name the compound)
sulfate -reducing bacteria
name the 5 components of a crosscut of a bacterial cell wall (from top top bottom)
- capsule
- outer membrane
- peptidoglycan layer
- plasma membrane
- cytoplasm
viruses come in different forms and shapes. Name the 5 groups differentiated based on their capsid structure
- naked icosahedral
- naked helical
- enveloped icosahedral
- enveloped icosahedral
- complex
Tyndalization refers to an antibacterial treatment method based on (dry heat/moist heat/irradiation)?
moist heat
flowing steam at 100 degrees celcius for 30 min for 3 consecutive days = breaks heat-sensitive chemical bonds
(Ultraviolet/X-ray/gamma) irradiation damages the thymine (T) building blocks in DNA
ultraviolet (UV)
sterilization by (autoclaving/filtration/dry heat) does not denature vitamins
filtration
some (Archaea/eubacteria) are known to grow at 121 degrees celcius, and are called (pseudophiles/mesophiles/hyperthermophiles)
Archaea
hyperthermophiles
cells in a (hypertonic/hypotonic) solution increase in volume and eventually lyse
hypotonic
Light microscopy shows that a fresh sample of milk is contaminated with bacteria. Describe 2 methods (name and process) that are routinely used to treat milk before it is sold to the public
- Pasteurization
- LTLT: low temp long time 63 degrees Celsius for 30 min
- HTST: high temperature short time 72 degrees Celsius for 15 seconds
- only reduces the numbers and/or types of microbe, but is a relatively short term solution since eventually microbes with start growing again - sterilization
- UHT ultra high temperature 141 degrees Celsius for 2 seconds
- completely sterilizes milk without denaturing it
OXYGEN REQUIREMENT:
can grow anaerobically but grow better with O2
Facultative anaerobe
OXYGEN REQUIREMENT:
require 20% oxygen for survival
aerobe
obligate-I would add
OXYGEN REQUIREMENT:
can grow in the presence or absence of air
aerotolerant
OXYGEN REQUIREMENT:
require small amounts of O2 (2-10%)
microaerophile
OXYGEN REQUIREMENT:
cannot tolerate O2 (toxic to them)
obligate anaerobe
Explain the difference between a chemically defined and a complex medium
Chemically defined media
-Growth media that is composed of known ingredients at known concentrations
Complex media
- is rich in vitamins and other nutrients, of which precise chemical composition is undefined and can vary depending on the suppliers e.g. yeast extract
a food company experiences a problem with contamination in their product line. Microscopy of the contaminants indicates the presence of 3 different types of cells. Based on your knowledge of yeast morphology, identify the 3 yeast species
- Saccharomyces cerevisiae
- budding yeast - Schizosaccharomyces pombe
- fission yeast - Candida albicans
- pseudohyphae
Supply definitions or explain the following terms related to fungi/yeast:
Arbuscular mycorrhizae
a mutualistic symbiotic relationship between fungi and the roots of plants
Supply definitions or explain the following terms related to fungi/yeast:
Lichens
mutualistic symbiotic relationships between fungi and either green algae or cyanobacteria (photosynthetic bacteria)
Supply definitions or explain the following terms related to fungi/yeast:
Coenocytic hyphae
hyphae, the long, continuous cells are not divided by septa (they are aseptate)
