Chapter 27

Question 1

__________ thrive almost everywhere, including places too acidic (pH of 0.03), salty, cold, or hot for most other organisms

Answer 1

Prokaryotes

Question 2

The two domains of prokaryotes

Answer 2

1) Bacteria
2) Archaea

Question 3

The three most common shapes of prokaryotic cells

Answer 3

1) Spheres (cocci)
2) Rods (bacilli)
3) spirals

Question 4

T/F: All bacteria are harmful

Answer 4

False; Some bacteria cause infections, but most species are harmless or perform beneficial functions

Question 5

Beneficial bacteria are called _________ bacteria

Answer 5

commensal

Question 6

An important feature of nearly all prokaryotic cells is their…

Answer 6

cell wall, which maintains shape, provides protection, and prevents bursting in hypotonic environments

Question 7

Eukaryote cell walls are made of _______ or _______

Answer 7

cellulose; chitin

Question 8

Bacterial cell walls contain _________

Answer 8

peptidoglycan

Question 9

Peptidoglycan

Answer 9

a network of sugar polymers cross-linked by polypeptides

Question 10

T/F: Archaea contain polysaccharides, proteins, and peptidoglycan

Answer 10

False; they contain polysaccharides and proteins, but lack peptidoglycan

Question 11

Scientists use the __________ to classify bacteria by cell wall composition

Answer 11

Gram stain

Question 12

Gram-positive

Answer 12

bacteria have simpler walls with a large amount of peptidoglycan

Question 13

Gram-negative

Answer 13

bacteria have less peptidoglycan and an outer membrane that can be toxic

Question 14

Many __________ target peptidoglycan and damage bacterial cell walls

Answer 14

antibiotics

Question 15

__________ bacteria are more likely to be antibiotic resistant

Answer 15

Gram-negative

Question 16

Fimbriae

Answer 16

Short, hair-like protein structures on bacterial cell surfaces; allow some prokaryotes who have them to stick to their substrate or other individuals

Question 17

Pili (or sex pili)

Answer 17

longer than fimbriae and allows prokaryotes to exchange DNA

Question 18

taxis

Answer 18

movement toward or away from a stimulus exhibited by many bacteria

Question 19

__________ is the movement toward or away from a chemical stimulus

Answer 19

Chemotaxis

Question 20

Flagella

Answer 20

Found in bacteria, archaea, and eukaryotes; are composed of different proteins and allow for mobility; likely evolved independently

Question 21

Bacterial flagella are composed of a ______, ______, and ______

Answer 21

motor; hook; filament

Question 22

Prokaryotic cells usually lack _____________

Answer 22

complex compartmentalization

Question 23

Transformation

Answer 23

A prokaryotic cell takes up and incorporates foreign DNA from the surrounding environment

Question 24

Transduction

Answer 24

the movement of genes between bacteria by bacteriophages

Question 25

Bacteriophage

Answer 25

viruses that infect bacteria

Question 26

Conjugation

Answer 26

the process where genetic material is transferred between prokaryotic cells

Question 27

In bacteria, the DNA transfer is _________

Answer 27

one way

Question 28

In conjugation, a donor cell attaches to a recipient by a ______, pulls it closer, and __________

Answer 28

pilus; transfers DNA

Question 29

R plasmids

Answer 29

carry genes from antibiotic resistance

Question 30

Antibiotics kill sensitive bacteria, but not bacteria with specific __________

Answer 30

R plasmids

Question 31

biofilms

Answer 31

surface-coating colonies; often partake in metabolic cooperation between individuals in the biofilm

Question 32

Cyanobacteria

Answer 32

Photoautotrophs that generate O₂

Question 33

Plant chloroplasts likely evolved from _________ by the process of __________

Answer 33

cyanobacteria; endosymbiosis

Question 34

Pathogenic Bacteria

Answer 34

Bacteria that cause diseases

Question 35

T/F: Bacteria cause about a third of all human diseases

Answer 35

False; cause about half