Chapter 27 Bacteria and Archaea

Question 1

Transformation

Answer 1

(1) The conversion of a normal animal cell to a cancerous cell. (2) A change in genotype and phenotype due to the assimilation of external DNA by a cell. When the external DNA is from a member of a different species, transformation results in horizontal gene transfer.

Question 2

Transduction

Answer 2

(1) A process in which phages (viruses) carry bacterial DNA from one bacterial cell to another. When these two cells are members of different species, transduction results in horizontal gene transfer. (2)In cellular communication, the conversion of a signal from outside the cell to a form that can bring about a specific cellular response; Also called signal transduction.

Question 3

Conjugation

Answer 3

(1) In prokaryotes, the direct transfer of DNA between two cells that are temporarily joined. When the two cells are members of different species, conjugation results in horizontal gene transfer. (2) In ciliates, a sexual process in which two cells exchange haploid micronuclei but do not reproduce.

Question 4

F Factor

Answer 4

In bacteria, the DNA segment that confers the ability to form pili for conjugation and associated functions required for the transfer of DNA from donor to recipient. The F factor may exist as a plasmid or be integrated into the bacterial chromosome.

Question 5

F plasmid

Answer 5

The plasmid form of the F factor.

Question 6

R plasmid

Answer 6

A bacterial plasmid carrying genes that confer resistance to certain antibiotics.

Question 7

Peptidoglycan

Answer 7

A type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides.

Question 8

Gram stain

Answer 8

A staining method that distinguishes between two different kinds of bacterial cell walls; may be used to help determine medical response to an infection.

Question 9

Gram-positive

Answer 9

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 bacterial. Gram-positive bacteria are usually less toxic than gram-negative bacteria.

Question 10

Gram-negative

Answer 10

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. Generally more toxic.

Question 11

Capsule

Answer 11

(1) In many prokaryotes, a dense and well-defined layer of polysaccharide or protein that surrounds the cell wall and is sticky, protecting the cell and enabling it to adhere to substrates or other cells. (2) The sporangium of a bryophyte (moss, liverwort, or hornwort).

Question 12

Fimbria

Answer 12

A short, hairlike appendage of a prokaryotic cell that helps it adhere to the substrate or to other cells.

Question 13

Pilus

Answer 13

IN bacteria, a structure that links one cell to another at the start of conjugation; also known as a sex pilus or conjugation pilus.

Question 14

Taxis

Answer 14

An oriented movement toward or away from a stimulus.

Question 15

Nucleoid

Answer 15

A non-membrane bound region in a prokaryotic cell where the DNA is concentrated.

Question 16

Plasmid

Answer 16

A small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome; in DNA cloning, used as vectors carrying up to about 10,000 base pairs of DNA. Plasmids are also found in some eukaryotes, such as yeasts.

Question 17

Endospores

Answer 17

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

Question 18

Obligate Aerobes

Answer 18

An organism that requires oxygen for cellular respiration and cannot live without it.

Question 19

Obligate Anaerobe

Answer 19

An organism that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it.

Question 20

Anaerobic Respiration

Answer 20

A catabolic pathway in which inorganic molecules other than oxygen accept electrons at the “downhill” end of electron transport chains.

Question 21

Facultative Anaerobe

Answer 21

An organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present.

Question 22

Nitrogen Fixation

Answer 22

The conversion of atmospheric nitrogen (N2) to ammonia (NH3). Biological nitrogen fixation is carried out by certain prokaryotes, some of which have mutualistic relationships with plants.

Question 23

Heterocyst

Answer 23

A specialized cell that engages in nitrogen fixation in some filamentous cyanobacteria; also called a heterocyte.

Question 24

Biofilms

Answer 24

A surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation.

Question 25

Extremophiles

Answer 25

An organism that lives in environmental conditions so extreme that few other species can survive there.

Question 26

Extreme Halophile

Answer 26

An organism that lives in a highly saline environment, such as the Great Salt Lake or the Dead Sea.

Question 27

Extreme Thermophiles

Answer 27

An organism that thrives in hot environments (often 60-80 C or hotter).

Question 28

Methanogens

Answer 28

An organism that produces methane as a waste product of the way it obtains energy. All known methanogens are in the domain Archaea.

Question 29

Decomposer

Answer 29

An organism that absorbs nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms and converts them to inorganic forms; a detritivore.

Question 30

Symbiosis

Answer 30

An ecological relationship between organisms of two different species that live together in direct and intimate contact.

Question 31

Host

Answer 31

The larger participant in a symbiotic relationship, often providing a home and food source for the smaller symbiont.

Question 32

Symbiont

Answer 32

The smaller participant in a symbiotic relationship, living in or on the host.

Question 33

Mutualism

Answer 33

A symbiotic relationship in which both participants benefit.

Question 34

Commensalism

Answer 34

A symbiotic relationship in which one organism benefits but the other is neither helped nor harmed.

Question 35

Parasitism

Answer 35

A symbiotic relationship in which one organism, the parasite, benefits at the expense of another, the host, by living either within or on the host.

Question 36

Parasite

Answer 36

An organism that feeds on the cell contents, tissues, or body fluids of another species (the host) while in or on the host organism. Parasites harm, but usually do not kill their hosts.

Question 37

Pathogen

Answer 37

An organism, virus, or prion that causes disease.

Question 38

Exotoxin

Answer 38

A toxic protein that is secreted by a prokaryote or other pathogen and that produces specific symptoms, even if the pathogen is no longer present.

Question 39

Endotoxin

Answer 39

A toxic component of the outer membrane of certain gram-negative bacteria that is released only when the bacteria die.

Question 40

Bioremediation

Answer 40

The use of organisms to detoxify and restore polluted and degraded ecosystems.