Raven Johnson Mason Losos Duncan Biology Ch 27 (Prokaryotes)

Front 1

Who was the first to observe and accurately describe microbial life.

Back 1

Antony van Leeuwenhoek

Front 2

Robert Koch’s 4 postulates

Back 2

1. The microorganism must be present in every case of the disease and absent from healthy individuals.

2. The putative causative agent must be isolated and grown in pure culture.

3. The same disease must result when the cultured microorganism is used to infect a healthy host.

4. The same microorganism must be isolated again from the diseased host.

Front 3

8 characteristics of prokaryotes

Back 3

1. Unicellularity (most are single celled) can form associations and biofilms

2. Cell size varies but mostly < 1 μm in diameter.

3. Nucleoid: single circular DNA chromosome; often have plasmids

4. Cell division: binary fission (usually)

5. Genetic recombination: horizontal gene transfer- NOT sexual, but closest thing they have to it

6. Internal compartmentalization: no memb bound organelles or internal compartments. Can have infolded pm

7. Flagella: simple, dif from euk flagella

8. Metabolic diversity: oxgenic or anoxygenic photosynthesis// chemolithotrophic

Front 4

How do bacteria and archaea differ (4)?

Back 4

Pm, cell wall, DNA rep, gene expression

Front 5

Early means of classification (5)

Back 5

photosynth or not. Motile or not. Unicellular, colony forming, or filamentous. Spores or binary fission. Human pathogen or not.

Front 6

Molecular classification (5)

Back 6

1. Amino acid sequences of key proteins: look @ certain protein and compare

2.% CG content :compare CG content, similar= have similar numbers of CG

3. Nucleic acid hybridization: hybridizing nuc acids w antibodies to get complementary DNA/RNA

4. Gene and RNA sequencing compare a specific gene or RNA strand

5. Whole genome sequencing: compare entire genome

Front 7

How do you perform a Gram stain?

Back 7

1. Crystal violet applied

2. Iodine applied

3. Alcohol washes away purple from gram -

4. Red dye applied

Front 8

Structures of Graham positive and negative bacteria (general)

Back 8

+: thick network of peptidog. Lipoteichoic and teichoic acid.

-: thin peptidog. 2nd outer memb of LPS (lipopolysaccharide). Antibiotic resistance.

Front 9

S-layer (general)

Back 9

Rigid paracrystalline layer found in some bacteria and archaea. Outside of peptidoglycan or outer membrane layers in gram-negative and gram-positive bacteria. Diverse functions – often involves adhesion

Front 10

Endospores (general)

Back 10

Develop thick wall around genome w some cytoplasm in times of high environmental stress; improvement in conditions can lead to return in normal cell division

Front 11

Prokaryotic ribosomes?

Back 11

Smaller, differ in protein/RNA content, and can be targeted by antibiotics.

Front 12

Explain conjugation in prokaryotes

Back 12

Cell to cell contact (F+ and F-); similar to sexaul reproduction BUT ISN’T; F+ cell utilizes pillus to contact other bact. Unwinds DNA plasmid and gives only 1 strand. F+ and F- both sythesize to get double stranded and now both are F+.

Front 13

What are 2 types of transduction?

Back 13

1. Generalized- virus packages bacterial DNA and transfers in subsequent infection

2. Specialized- accidents in lysogenic cycle, imprecise excision of prophage DNA so that phage carries both phage and chromosomal genes

Front 14

What are two kinds of transformation?

Back 14

1. Natural- DNA released from dead cell picked up by live cell

2. Artificial- lab

Front 15

What is CRISPR?

Back 15

Adaptive immunity (specialized immune response); proks integrate short segments of viral nuc acid into CRISPR loci and produce RNA that degrades the viral nuc acid--- gene editing! Knockout genes.

Front 16

What kinds of fixation do prokaryotes participate in?

Back 16

N and C fixation

Front 17

Name some beneficial relationships between prokaryotes and animals

Back 17

Ruminants (cows, sheep) have cellulase producing bacteria. Cows can’t break down cellulose themselves but the bacteria can. Human microbiota protects against pathogens and help in digestion in exchange for a place to live.

Front 18

Bioremediation

Back 18

Bacteria can remove pollutants

Front 19

Biostimulation

Back 19

Addition of nutrients to encourage growth of naturally occurring microbes