chp. 27

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Campbell Biology
Chapter 27
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1

a type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles. they thrive almost everywhere including places to acidic, salty, cold, or hot for most other organisms.

Prokaryotes

2

Prokaryotes are divided into two domains:

Bacteria and Archaea

3

Prokaryotic cells have a variety of shapes; the three most common shapes are:

1) spheres (cocci)

2) rods (bacilli)

3) spirals

4

Bacterial cell walls contain _________, a network of sugar polymers cross-linked by polypeptides.

peptidoglycan

5

Using the ____ ____, scientists classify many bacterial species into Gram-positive and Gram-negative groups based on cell wall composition.

Gram stain

6

describing the group of bacteria that have a cell wall that is structurally less complex and contains more peptidoglycan than the cell wall of gram-negative bacteria.

Gram-positive

7

Describing the group of bacteria that have a cell wall that is structurally more complex and contains less peptidoglycan than the cell wall of gram-positive bacteria.

and they are more likely to be antibiotic resistant.

Gram-negative

8

In a heterogeneous environment, many bacteria exhibit _____, the ability to move toward or away from certain stimuli.

taxis

9

Most of the prokaryotic genome consists of a ________ _________.

circular chromosome

10

Some species of bacteria also have smaller rings of DNA called ________.

a small, circular, double-stranded DNA molecule that carries accessory genes separate from those of bacterial chromosome.

plasmids

11

The typical prokaryotic genome is a ring of DNA that is surrounded by a membrane and that is located in a ________

nucleoid region

12

Prokaryotes reproduce quickly by ______ ______ and can divide every 1-3 hours.

binary fission

13

Many prokaryotes form metabolically inactive ________, which can remain viable in harsh conditions for centuries.

A thick-coated, resistant cell produced by some bacterial cells when they are exposed to harsh conditions.

endospores

14

(Diverse nutritional and metabolic adaptations of prokaryotes)

prokaryotes that obtain energy from light:

Phototrophs

15

(Diverse nutritional and metabolic adaptations of prokaryotes)

prokaryotes that obtain energy from chemicals:

Chemotrophs

16

(Diverse nutritional and metabolic adaptations of prokaryotes)

prokaryotes that require CO 2 as a carbon source:

Autotrophs

17

(Diverse nutritional and metabolic adaptations of prokaryotes)

prokaryotes that require an organic nutrient to make organic compounds:

Heterotrophs

18

(Four major modes of nutrition)

Energy source: sunlight

Carbon Source: CO2

Photoautotroph

19

(Four major modes of nutrition)

Energy source: inorganic chemicals

Carbon source: CO2

Chemoautotroph

20

(Four major modes of nutrition)

Energy source: Sunlight

Carbon source: organic compounds

Photoheterotroph

21

(Four major modes of nutrition)

Energy source: Organic compounds

Carbon source: Organic compounds

Chemoheterotroph

22

(Prokaryotic metabolism with respect to O2)

require O2 for cellular respiration

Obligate aerobes

23

(Prokaryotic metabolism with respect to O2)

are poisoned by O2 and use fermentation or anaerobic respiration

Obligate anaerobes

24

(Prokaryotic metabolism with respect to O2)

can survive with or without O2 .

Favultative anaerobes

25

Prokaryotes can metabolize nitrogen in a variety of ways. In ________ ________, some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3).

nitrogen fixation

26

In some prokaryotic species, metabolic cooperation occurs in surface-coating colonies called:

also known as dental plaque

biofilms.

27

Cooperation between prokaryotes allows them to use environmental resources they could not use as individual cells.

In the cyanobacterium Anabaena, photosynthetic cells and nitrogen-fixing cells called __________ (or heterocytes) exchange metabolic products.

heterocysts

28

Some archaea live in extreme environment and are called:

extremophiles

29

Extreme ________ live in highly saline environments.

Extreme halophiles

30

Extreme _________ thrive in very hot environments.

Extreme thermophiles

31

________ live in swamps and marches and produce methane as a waste product. They are strict anaerobes and are poisoned by O2.

Methanogens

32

Chemoheterotrophic prokaryotes function as _________, breaking down corpses, dead vegetation, and waste products.

decomposers

33

_________ is an ecological relationship in which two species live in close contact: a larger host and smaller symbiont.

Prokaryotes often form symbiotic relationships with larger organisms.

Symbiosis

34

In __________, both symbiotic organisms benefit.

mutualism

35

In __________, one organism benefits while neither harming nor helping the other in any significant way.

commensalism

36

In __________, an organism called a parasite harms but does not kill its host.

parasitism

37

Parasites that cause disease are called:

pathogens

38

Some prokaryotes are ______ ________, causing half of all human diseases. Lyme disease is an example.

but others have positive interactions with humans.

human pathogens

39

Pathogenic prokaryotes typically cause disease by releasing exotoxins or endotoxins.

________ cause disease even if the prokaryotes that produce them are not present. they are proteins secreted by bacterial cells.

Exotoxins

40

Pathogenic prokaryotes typically cause disease by releasing exotoxins or endotoxins.

________ are released only when bacteria die and their cell walls break down.

Endotoxins

41

Experiments using prokaryotes have led to important advances in DNA technology.

Prokaryotes are the principal agents in __________, the use of organisms to remove pollutants from the environment.

bioremediation