Microorganisms General characteristics

Question 1

prokaryotes

Answer 1

small, “simple” cells that typically have a cell walland cytoplasmic membrane surrounding their cytoplasm, which contains ribosomesand a single chromosome (contains genes made up of DNA), but have nomembranes surrounding their nucleus or organelles

Question 2

eukaryotes

Answer 2

large, complex cells with a nucleus that containsmultiple chromosomes (contains genes of DNA) surrounded by a membrane and cytoplasm containing ribosomes and membrane-bound organelles, such as mitochondria, vacuoles, chloroplasts (plants only), golgi bodies, etc.

Question 3

viruses

Answer 3

non-cellular, non-living entities, made up of genetic information (DNA or RNA) enclosed in a protein coat (some also have a membranecalled an envelope), which can reproduce themselves only by infecting cells and utilizing cellular materials and processes

Question 4

growth

Answer 4

process of cell enlargement and proliferation (increase in number)

Question 5

Nutritional requirements

Answer 5

Water

Question 6

essential elements

Answer 6

(C, H, O, N, P, S)

Question 7

Trace elements

Answer 7

(Ca, Mg, Fe, Na, K, Zn, Co, Mn, etc.)

Question 8

Organic growth factors

Answer 8

vitamins, essential nutrients, etc.;energy

Question 9

(growth physical req.) Temperature:

Answer 9

cells may grow best below 20°C (psychrophilic), or from 20 to 40°C (mesophilic), or above 40°C (thermophilic)

Question 10

(growth physical req.) Oxygen:

Answer 10

aerobes, facultative aerobes, microaerophiles, anaerobes

Question 11

(growth physical req.) PH:

Answer 11

most cells “prefer” neutral conditions (pH between 6 and 8), but many can thrive in acid (pH down to 3) or alkali (pH up to 10)

Question 12

(growth physical req.) salts:

Answer 12

regulate enzyme activity, osmotic pressure