Ch. 25 Bacteria And Archaea

Question 1

Almost all prokaryotes have walls that hold them into one of three basic forms:

Answer 1

• Rods (bacilli)
• spheres (cocci)
• long coils (spirilla)
• protoplasm

Question 2

Bacteria and archaeans are almost invariably unicellular and never have __ or __

Answer 2

Tissues or organs

Question 3

There is no nuclear envelope; instead, DNA occurs as one or several masses called ___ within the cytoplasm

Answer 3

Nucleoids

Question 4

DNA is in the form of ___

Answer 4

Closed circles

Question 5

They have __ ribosomes

Answer 5

70S

Question 6

In gram-Positive cells, the cell wall consists of a thick layer of a polymer called ___

Answer 6

Peptidoglycan

Question 7

In gram-negative bacteria, the peptidoglycan layer is present but thin, and a layer of ____ lies exterior to it

Answer 7

Lipopolysaccharide (LPS)

Question 8

Many bacteria have flagella, composed of just one type of protein, ___

Answer 8

Flagellin

Question 9

Cell division occurs by ____

Answer 9

Binary fission

Question 10

Binary fission

Answer 10

Cell simply pinches in two

Question 11

___ occurs when some bacteria die and their DNA breaks into rather large pieces, each with one or several genes

Answer 11

Transformation

Question 12

___ is similar to transformation but occurs when a virus invades a cell and reproduces

Answer 12

Transduction

Question 13

___ involves specific structures and metabolisms that are the result of natural selection favoring genetic exchange

Answer 13

Conjugation

Question 14

Prokaryotes have numerous alternate methods for metabolic processes:

Answer 14

Several types of photosynthesis, multiple types of respiration, and numerous sources of energy other than sunlight or sugars exist

Question 15

Prokaryotes are almost all ___, so they have very little anatomy and virtually no morphology

Answer 15

Unicellular

Question 16

Their systematics and classification have been based almost entirely in their..

Answer 16

• metabolism
• wall chemistry
• ability to carry out photosynthesis and use various substrates
• sensitivity to oxygen

Question 17

___ is now the most powerful and reliable technique for analyzing prokaryote evolution

Answer 17

Nucleotide sequencing

Question 18

Archaeans are distinct ___, but they remember other prokaryotes ___

Answer 18

Metabolically; structurally

Question 19

Archaean cell walls contain ___, ___, or ___, but they lack a true peptidoglycan component

Answer 19

Protein, glycoprotein, or polysaccharide

Question 20

The overall metabolism of archaeans is exotic in that most thrive in certain ___ environments

Answer 20

Rare

Question 21

Domain ____ contains many more species than does domain archaea

Answer 21

Bacteria

Question 22

Gliding bacteria

Answer 22

Move only when in contact with a solid surface; they have no flagella

Question 23

Cytophaga

Answer 23

• gliding bacteria

- digest celluloid and chitin

Question 24

Nitrogen-metabolizing becteria

Answer 24

Affect the amount of nitrogen available to all other life forms

Question 25

Nitrogen-fixing bacteria

Answer 25

Convert atmospheric N2 into nitrites, nitrates, and ammonium

Question 26

Nitrifying bacteria

Answer 26

Oxidize ammonia in the environment to nitrate or nitrite

Question 27

Denitrifying bacteria

Answer 27

Convert nitrogen compounds to N2 gas

Question 28

Mycoplasma

Answer 28

Bacteria that completely lack a cell wall

- many are pathogenic

Question 29

Until the 1970s, Cyanobacteria were thought to be closely related to true algae and were called ___

Answer 29

Blue-green algae

Question 30

The walls of Cyanobacteria are like those of other gram-negative bacteria, but they also produce an..

Answer 30

Extra layer of mucilage that binds cells and filaments together into a small, loose aggregation

Question 31

Cyanobacteria are of special interest because they seem to be most closely related to the organisms that might have given rise to ___

Answer 31

Chloroplasts

Question 32

The ability of Cyanobacteria to ___ is important ecologically because these are widespread and often more active than other nitrogen-fixing bacteria

Answer 32

Fix nitrogen

Question 33

Cyanobacteria inhabit numerous extremely harsh environments, withstanding intense ___ and periods of almost complete ___

Answer 33

Insolation; desiccation

Question 34

Stromatolites

Answer 34

When Cyanobacterial growths become gigantic and so heavily encrusted with calcium carbonate that they appear to be stones

Question 35

Prokaryotes are composed of three groups:

Answer 35

Bacteria, Cyanobacteria, and archaebacteria