Lab 2 (Prokaryotes)

Question 1

What domains of life are prokaryotes?

Answer 1

Archaea and Bacteria

Question 2

extremophiles

Answer 2

archaea - existing in extremes of temperature, pH, salinity, etc

Question 3

What makes Archaebacteria unique?

Answer 3

distincitve membranes, unusual cell walls, unique metabolic cofactors

the group shares rRNA sequences and other biochemical characteristics that are unique from those of other organisms

Question 4

What are the three shapes of bacteria?

Answer 4

bacillus - rod shaped
coccus - spherical
spirillum - spiral

Question 5

heterotroph

Answer 5

derive energy from organic molecules made from other organisms

Question 6

decomposers

Answer 6

feed on dead organic matter and release nutrients locked in dead tissue

Question 7

autotrophic

Answer 7

derive their energy from photosynthesis or the oxidation of inorganic molecules

Question 8

conjugation

Answer 8

all or part of the genetic material of one bacterium is transferred to another bacterium and a new set of genes is assembled

Question 9

Gram stain

Answer 9

based on different structural and chemical compositions of bacterial cell walls

Gram-positive - thick cell wall that retains a purple dye
Gram-negative - thinner cell wall that does not retain the dye

Question 10

How is a bacterial colony used for identification?

Answer 10

observation of shape, color, size, texture, and margins of colony

Question 11

nitrogen fixation

Answer 11

transform atropheric nitrogen into other nitrogenous compounds that can be used as nutrients by plants

uses enzyme nitogenase along with ATP, energized electrons, and water to convert nitrogen to ammonia

Question 12

nodules

Answer 12

formed on the roots between Rhizobium and hot roots for nitrogen fixation

Question 13

Why is nitrogen fixation called mutualism?

Answer 13

benefit to both plant and bacteria; plant provides sugars and nutrients to bacteria and the ammonia produced can be absorbed and used by plants to make other macromolecules

Question 14

sensitivity plate

Answer 14

petri dish of solid medium that has been uniformly inoculated on its entire surface; after 24 hours an effective antibiotic will produce a visible halo of clear surface around the discs where it inhibited growth of bacteria

smaller zone of inhibition - ineffective agent

Question 15

cyanobacteria

Answer 15

major group of photosynthetic bacteria; have chlorophyll a and accessory pigments

reproduce by fission and are surrounded by a sheath

Question 16

Oscillatoria

Answer 16

cyanobacteria grows as long chains of cells called trichomes