Chapter 27: Bacteria And Archaea

Question 1

Peptidoglycan

Answer 1

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

Question 2

Gram Positive

Answer 2

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

Question 3

Gram Negative

Answer 3

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

Usually more toxic

Question 4

Capsule

Answer 4

In many prokaryotes, a dense and well defined layer of polysaccharide of protein that surrounds the cell wall and is sticky, protecting the cell and enabling it to adhere to substrates or other cells.

Question 5

Endospore

Answer 5

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

Question 6

Fimbria

Answer 6

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

Question 7

Pili / Pilus

Answer 7

In bacteria, a structure that links one cell to another at the start of conjugation

Question 8

Taxis

Answer 8

An alienated movement towards or away from a stimulus

Chemotaxis - in response to chemicals

Positive - towards nutrient

Negative - away from nutrient

Question 9

Bacterial Flagella

Answer 9

Prokaryotic flagella are thinner and are not covered by plasma membrane

The flagella of bacteria, archaea, and eukaryotes have similar function but are composed of different proteins, which suggests they developed independently, so they are analogous

Question 10

Exaptation

Answer 10

Structures originally adapted for one function take on new functions through descent with modification

Question 11

Nucleoid

Answer 11

A non-membrane enclosed region in a prokaryotic cell where its chromosome is located

Question 12

Plasmid

Answer 12

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

Question 13

Rapid Reproduction and Mutation of Prokaryotes

Answer 13

Most of the offspring of prokaryotic cells are genetically identical to the original parent, but if errors occur during DNA replication, some of the offspring cells may differ genetically. Since prokaryotes reproduce so rapidly, there is a greater chance for mutation

Question 14

Genetic Recombination

Answer 14

the combining of DNA from two sources

Question 15

Transformation

Answer 15

A change in genotype and phenotype due to the assimilation of external DNA by a cell. When external DNA is from a member of a different species, transformation results in horizontal gene transfer

Question 16

Transduction

Answer 16

A process in which phages, or 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

Question 17

Conjugation

Answer 17

The direct transfer of DNA between two cells that are temporarily joined. When two cells are members of different species, conjugation results in horizontal gene transfer

Question 18

Horizontal gene transfer

Answer 18

The transfer of genes from one genome to another through mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusion of different organisms

Question 19

Spirochetes

Answer 19

Helical gram positive heterotrophs that move by rotating internal flagellum-like filaments

Question 20

Proteobacteria

Answer 20

Large and diverse clade of gram-negative bacteria that include photoautotrophs, chemoautotrophs, and heterotrophs

Evidence indicates that mitochondria evolved from a heterotroph Proteobacteria

Question 21

Cyanobacteria

Answer 21

Only prokaryotes with plant like photosynthesis

Chloroplasts are thought to have evolved from Cyanobacteria

Question 22

Chlamydias

Answer 22

Parasites that can only survive within an animal call. Gram-negative walls lack peptidoglycan

Question 23

Gram-positive bacteria

Answer 23

Gram-positive bacteria rival the Proteobacteria in diversity

Question 24

Methanogen

Answer 24

An organism that produces methane as a waste product of the way it obtains energy

Question 25

Decomposer

Answer 25

An organism that absorbs nutrients from non living organic material such as corpses, or fallen plant material and converts them to inorganic forms.

Break down organic material to release supplies of carbon, nitrogen, and other elements

Question 26

Nitrogen Fixation

Answer 26

The conversion of atmospheric nitrogen to ammonia

Often this is in a mutualistic relationship with plants, in which the plants use the ammonia produced

Question 27

Mutualistic bacteria

Answer 27

Human well being depends on many mutualistic prokaryotes

Many species of bacteria in the gut break down food that out own intestines are not able to break down

Question 28

Parasite

Answer 28

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

Question 29

Pathogenic Bacteria

Answer 29

Cause illness by producing poisons that are classified as exotoxins or endotoxins

Question 30

Exotoxins

Answer 30

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 31

Endotoxins

Answer 31

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