Classification and Structure of Prokaryotic Cells 1.3 and 1.4

Question 1

Prokaryotes

Answer 1

Simplest of all organisms and include all bacteria. Do not contain any membrane bound organelles. Their genetic material is organized into a single circular molecule of DNA concentrated in an area of the cell called the nucleoid region. ALL ARCHAEA AND BACTERIA ARE PROKARYOTES

Question 2

The three domains of life

Answer 2

Archaea, Bacteria, Eukarya

Question 3

Archaea

Answer 3

Single celled organisms that are visually similar to bacteria, but contain genes and several metabolic pathways that are more similar to eukaryotes than to bacteria. Historically considered extremophiles. Notable for their ability to use alternate sources of energy such as photosynthesis and chemosynthesis. It is hypothesize that eukaryotes and archaea share a common origin. Contain a single circular chromosome, divide by binary fission, or budding, and share a similar overall structure to bacteria.

Question 4

Bacteria

Answer 4

All bacteria contain a cell membrane, cytoplasm, and some have flagella or fimbriae (cilia like structures).

Side note: bacteria and eukaryotes often share analogous structures, making it difficult to develop medicines that target only bacteria. Bacterial ribosomes are significantly smaller than eukaryotic ribosomes.

Question 5

Three general shapes of bacteria

Answer 5

Spherical, known as cocci.
Rod shaped, known as bacilli.
Spiral shaped, known as spririlli.

Question 6

Facultative anaerobe

Answer 6

Bacteria that can toggle between metabolic processes, using oxygen for aerobic metabolism, if it is present, and switching to anaerobic metabolism if it is not.

Question 7

Aerotolerant anaerobes

Answer 7

Unable to use oxygen for metabolism, but are not harmed by its presence in the environment.

Question 8

Prokaryotic cell structure

Answer 8

Prokaryotes lack a nucleus and membrane bound organelles. Single celled organisms, meaning that each cell must be able to perform all the functions necessary for life on its own.

Question 9

Prokaryotic envelope

Answer 9

Consist of a cell wall, forming the outer barrier of the cell, and a cell membrane (plasma membrane), composed of phospholipids, similar to that of a eukaryote.

Question 10

Gram staining

Answer 10

The process to determine the cell wall and thus indicate the type of bacteria. If it absorbs crystal violet stain, it will appear deep purple and is gram positive. If it absorbs the safranin counterstain it will appear pink and is gram-negative.

Question 11

Gram positive

Answer 11

Consist of a thick layer of peptidoglycan, a polymer of amino acids and sugars. Turns deep purple when exposed to crystal violet stain.

Question 12

Gram negative

Answer 12

Cell wall is thin and also contain PEPTIDOGLYCANS, but in much smaller amounts, than it’s gram positive counterpart. Have outer membranes containing phospholipids and LYPOPOLYSACCHARIDES

Interesting note: LYPOPOLYSACCHARIDES contained in gram negative bacteria are known to trigger an immune response in humans. This is a much stronger inflammatory response than caused by gram positive bacteria.

Question 13

Flagella

Answer 13

Long whiplike structures that can be used for propulsion. Composed of a filament, a basal body, and a hook. Used for chemotaxis. Hollow, helical structure composed of flagellin.

Question 14

Prokaryotic DNA

Answer 14

Carried on a single circular chromosome, which can be found coiled around histone like proteins, and some bacteria.

Question 15

Plasmid

Answer 15

DNA acquired from external sources carried on small circular structures. Not necessary for survival of the prokaryote, and therefore is not considered part of the genome of the bacteria, but may confer an advantage such as antibiotic resistance.

Question 16

Three types of bacterial genetic recombination

Answer 16

Transformation, conjugation, and transduction

Question 17

Bacterial genetic recombination transformation

Answer 17

Results from the integration of foreign genetic material into the host genome.

Question 18

Bacterial genetic combination conjugation

Answer 18

Conjugation is the bacterial form of mating. Two bacterial cells form of conjugation bridge between them that facilitates the transfer of genetic material. To form a six pili, bacteria must contain plasmids known as sex factors.

Question 19

F (fertility) factor

Answer 19

Sex factor found in E. coli. Bacteria that possess the plasmid F factor are F+, those without are F-.

Question 20

Bacterial genetic recombination transduction

Answer 20

Transduction is the only genetic combination process that requires a vector. Is a virus that carries genetic material from one bacterium to another.

Question 21

Bacterial genetic recombination transduction

Answer 21

Transduction is the only genetic combination process that requires a vector. Is a virus that carries genetic material from one bacterium to another.

Question 22

Transposons

Answer 22

Transposons are genetic elements, capable of inserting and removing themselves from the genome

Question 23

Growth phases of bacteria

Answer 23

Lag phase, exponential phase (log phase), stationary phase, death phase.

Question 24

Growth phases of bacteria

Answer 24

Lag phase, exponential phase (log phase), stationary phase, death phase.

Question 25

Prokaryotic Flagellum Structure

Answer 25

Question 26

Defining characteristic between archaea and bacteria

Answer 26

Bacteria contain peptidoglycan in their cell wall, archaea do not.

Archaea are known for living in extreme environments, bacteria live in a great host of environments. Archaea share more genetic similarity to eukaryotes.