Week 2 Charachteristics Of Micro Organisms Flashcards

Question

Temperature Growth of Bacteria 3 groups

Answer 1

• Thermophiles: grow best at 56 degree Celsius, with a range from 45 - 70 degrees Celsius • Mesophiles: grow best at body temperature (37 degree Celsius), with range from 22-45 degrees Celsius • Psychrophiles: optimal growth at refrigerator temperature (7 degrees Celsius), with range from 1- 22 degrees Celsius

Answer 2

• Most bacteria that survive in the human body grow over a pH range from 5.5 to 8.5, with optimal growth at pH 7.0. • Acidogenic: bacteria that produce acids during growth • Aciduric: bacteria that survive and grow in an acidic environment usually below pH 5.5) Dental caries:

Answer 3

• Bacteria must synthesize all of the macromolecules of protein, polysacharides, lipids, and nucleic acids ( DNA and RNA) needed to grow. • These macromolecules are synthesized from the building blocks of amino acids, monosaccharides, fatty acids, etc. • Bacteria also must use a variety of smaller molecules, such as vitamins and inorganic substances. • Many bacteria make extracellular proteases, which are enzymes released into the environment that break down proteins into amino acids that can enter the cell.

Answer 4

• Obligate Aerobes- require oxygen at 20% concentration

Answer 5

• Microaerophiles: tolerate low (4%) oxygen concentration

Answer 6

Can NOT tolerate OXYGEN

Answer 7

• Facultative anaerobes- can grow with or without oxygen

Answer 8

Prevent Growth

Answer 9

Size: ~ extremely small; about one-tenth the size of bacteria ~ composed of a nucleic acid core (DNA or RNA), surrounded by a protein coat, called a capsid. Some viruses also have an outer structure of lipids. proteins, and polysaccharides, called the envelope. • * Viruses depend on a host cell for growth and replication "obligate intercellular parasites

Answer 10

1. Attachment or adsorption: virus binds to host cell surface (in order to replicate & infect a host) 2. Penetration: virus enters host cell 3. Uncoating: Capsid is degraded to release nucleic acid 4. Replication or syntheses of virus: virus uses host mechanisms to replicate, synthesize new viral nucleic acid & capsid 5. Assembly: capsid surrounds nucleic acid 6. Release from Host Cell: after invading host cell it must be able to release from host cell and replicate elsewhere

Answer 11

1. Their type of nucleic acid: DNA or RNA 2. The symmetry of the virus: helical, polyhedral, spherical, complex 3. Whether or not there is an envelope surrounding itself (enveloped or non-enveloped)

Answer 12

Human viruses may be transmitted by: 1. Droplets (e.g. sneezing) 2. Direct Transfer (e.g. Touching) 3. Contaminated food or water 4. Insects **** Most common route of transmission is through droplets. Many viruses will invade the respiratory tract by entering the nasal cavity. ***

Answer 13

Size: • They are the largest microorganism encountered in microbiology Characteristics: • Composed of a single cell, free living and thrive in water • Contain no chlorophyll in their cytoplasm so cannot produce carbohydrates by photosynthesis • Important as decomposers and recycle organic material and important in our food chain • Protozoa can be found in the stomach and break down cellulose and produce nutrients for their host

Answer 14

Fungi include: 1. Mushrooms 2. Molds 3. Yeasts

Answer 15

• Are eukaryotic cells • Contain a nucleus and nuclear membrane but lack chlorophyll • Most are Aerobic (requires O, for growth) • exception to some yeasts that can grow anaerobically and ferment to alcohol (Brewers yeast) 1. A yeast form: unicellular form 2. A mold: elongated cells and produce spores that can be airborne and transmitted

Answer 16

• Consist of unicellular or multi-cellular organisms. • Contain chlorophyll. • Have one or more flagella. • Are found in abundance in both freshwater or marine habitants. • Has a typical membrane-bound nuclei and cytoplasmic organelles. • Most do not produce human disease.