Chapter 27: Bacteria and Archaea

Question 1

Archaea + Extreme Environments

Answer 1

• Because of adaptation, archaea can live in extremely hot conditions, extreme radiation, extremely acidic conditions

Question 2

Prokaryotic Cell Overview

Answer 2

• Most prokaryotes are unicellular, have diameters of 0.5-5 micrometers, variety of shapes (spherical, rod, spiral)

Question 3

Function of cell wall in prokaryotes

Answer 3

• Serves to protect, prevent from bursting in hypotonic environment, in bacteria contain peptidoglycan

Question 4

Capsule (of cell wall)

Answer 4

• Sticky layer of polysaccharide or protein coating on cell wall

Question 5

Endospores

Answer 5

• Original cell produces copy of chromosome and surrounds copy with tough multilayered structure to form; when water is removed, metabolism halts and cell lyses to release endospore

Question 6

Taxis

Answer 6

Directed movement toward or away from stimulus (chemotaxis: change movement pattern in response to chemicals)

Question 7

Nucleoid

Answer 7

Region of cytoplasm that is not encode by a membrane

Question 8

Plasmid

Answer 8

Smaller rings of independently replicating DNA molecules carrying only a few genes

Question 9

Reproduction

Answer 9

• Reproduce by binary fission (divides into two different cells, so on and so forth)
• Small, reproduce by binary fission, often have short generation times and consist of trillions of individuals in a population

Question 10

Genetic Recombination

Answer 10

• Combining of DNA from two sources; horizontal gene transfer occur in archaea and bacteria occasionally

Question 11

Transformation

Answer 11

• Genotype and possibly phenotype of prokaryotic cell altered by uptake of foreign DNA from surroundings

Question 12

Transduction

Answer 12

• Phages carry prokaryotic genes from one host cell to another

Question 13

Conjugation

Answer 13

DNA transferred between two prokaryotic cells that are temporarily joined

Question 14

Archaea

Answer 14

• Can live in extreme environments

- Extremophiles (lovers of extreme conditions)

Question 15

Extreme Halophiles

Answer 15

• Archaea that live in highly saline environments

Question 16

Extreme Thermophiles

Answer 16

• Archaea that thrive in hot environments

Question 17

Functions of archaea

Answer 17

• Some are decomposers (chemoheterotrophic)

- Convert molecules to forms that can be taken up by other organisms (cyanobacteria make sugars, fix O2)

Question 18

Symbiosis

Answer 18

Ecological relationship in which two species live in close contact with each other

Question 19

Symbiont

Answer 19

Smaller organism in symbiotic relationship

Question 20

Mutualism

Answer 20

Ecological interaction between two species in which both benefit

Question 21

Commensalism

Answer 21

Ecological relationship in which one species benefits while the other is not harmed/helped in any significant way

Question 22

Pathogens

Answer 22

Parasites that cause disease (most of these are prokaryotic)

Question 23

Endotoxins

Answer 23

Lipopolysaccharide components of the outer membrane of gram-negative bacteria; released when bacteria die and walls break down

Question 24

Bioremediation

Answer 24

Use of organisms to remove pollutants from soil, air, or water

Question 25

Flagella

Answer 25

Structures used by most motile bacteria for propulsion; can move toward or away from stimuli

Question 26

Sex pilus

Answer 26

Appendage that facilitates conjugation

Question 27

Obligate aerobes

Answer 27

Require O2 to survive

Question 28

Obligate anaerobes

Answer 28

Poisoned by O2

Question 29

Exotoxins

Answer 29

Toxin released by living bacterial cell