Exam 1 Chapter 22 Prokaryotes

Question 1

Microbiome

Answer 1

The full array of microorganisms (the microbiota) that live on and in humans and, more specifically, the collection of microbial genomes that contribute to the broader genetic portrait, or metagenome, of a human. The genomes that constitute the human microbiome represent a remarkably diverse array of microorganisms that includes bacteria, archaea, fungi, and even some protozoans and nonliving viruses. Bacteria are by far the most numerous members of the human microbiome: the bacterial population alone is estimated at between 75 trillion and 200 trillion individual organisms, while the entire human body consists of about 50 trillion to 100 trillion somatic (body) cells

Question 2

prokaryote modern classification

Answer 2

based on sequencing of proteins, DNA, and RNA

Question 3

prokaryote facts

Answer 3

1) oldest organisms on Earth with fossils ~3.5 billion years old
2) structurally simplest organisms
3) most abundant life forms on earth
4) 90-99% unknown and undescribed.
5) lack a membrane bound nucleus and other organelles or cell inclusions.
6) Lack of cell compartments.
7) Include 2 domains Bacteria and Archaea.
Consider: Archaea and Eukarya share nucleic acid similarities so Eukarya split off from Archaea

Question 4

cyanobacteria

Answer 4

group of bacteria that produced oxygen and changed the Earth’s atmosphere from an anoxic one to one rich in oxygen.
Can photosynthesize

Question 5

Prokaryote vs Eukaryotes

Answer 5

Eukaryotes have organelles, nucleus. Both have ribosomes. (see more for this)

Question 6

Bacteria vs Archaea

Answer 6

1. cell wall composition
2. plasma membrane make-up
3. DNA replication
4. gene expression
5. Bacteria have peptidoglycan which Archae lack.

Consider: Archaea are able to live in the most extreme environments.

Question 7

prokaryote structure (bacteria)

Answer 7

have cell walls consisting of a network of polysaccharides connected by cross links of polypeptides (peptidoglycan)
flagella - used for movement
have enzymes used for cellular respiration attached to cell membrane
have 3 shapes (due to cell walls): bacillus, coccus, and spirillum
can form biofilms

Question 8

exchange of genetic material via horizontal transfer

Answer 8

occurs through conjugation (depends on presence of conjugative plasmids when genes are transferred through rigid, tubular sex pili), transduction (occurs when viruses (bacteriophage) package host DNA and transfer it upon subsequent infection), transformation (bacterial cells pick up free pieces of DNA from the medium-pieces that were released from dead bacteria), and exchange of R plasmids (plasmids are different from bacterial chromosomes in that plasmids have few genes, bacterial chromosome have many)
increases genetic diversity; helps infer phylogeny; common occurrence in bacteria; can produce large genetic change

Question 9

conjugation

Answer 9

• exchange of genetic material via horizontal transfer

- depends on presence of conjugative plasmids when genes are transferred through rigid, tubular sex pili

Question 10

transduction

Answer 10

• exchange of genetic material via horizontal transfer

- occurs when viruses (bacteriophage) package host DNA and transfer it upon subsequent infection

Question 11

transformation

Answer 11

exchange of genetic material via horizontal transfer

bacteria cells pick up free pieces of DNA from medium pieces that were released from dead bacteria

Question 12

R plasmids

Answer 12

have fewer genes than bacterial chromosomes

Question 13

gram positive

Answer 13

positive bacteria have thick peptidoglycan wall with small amounts of teichoic and lipoteichoic acid.
will stain PURPLE color

Question 14

gram negative

Answer 14

contain lipopolysaccharides, less peptidoglycan and no acids and do not retain purple colored dye.

Question 15

lipopolysaccharides

Answer 15

more resistance to penicillin

Question 16

E. coli

Answer 16

found in the lower intestine of warm blooded animals; 5000 genes, help host by producing vitamin K2
Consider: TB, cavities and several STDs caused by bacteria.

Question 17

endospores

Answer 17

thick-walled structures that contain chromosome and small amount of cytoplasm…these are formed in response to environmental stress (e.g., low nutrients)

Question 18

Beneficial bacteria

Answer 18

Decomposers play an important role in the environment. Decomposition differences between a fish caught in Canada and Florida when put on ice???

Question 19

Rhizobium

Answer 19

example of a diazotrophs (nitrogen fixing bacteria)…only organisms (bacteria group) capable of taking gaseous nitrogen and combining it with hydrogen to make ammonia

MAKES AMMONIA

Question 20

diazotroph

Answer 20

nitrogen fixing bacteria

Question 21

nitrogen fixation and use

Answer 21

this pathway begins with atmospheric nitrogen ( Dinitrogen; unusable by plants in this form because of strength of N-N triple bond), bacterial nitrogenase(enzyme that catalyzes the reactions); ammonia; conversion by plants or algae; synthesis of proteins

Question 22

binary fission

Answer 22

reproductive process that produces identical cells by simple splitting

Question 23

symbiosis

Answer 23

Types of symbiotic relationship and influence on evolution. (Mutualism, Commensalism and Parasitism)

Question 24

nucleoid region

Answer 24

area where prokaryotic DNA is found (no membrane)

Question 25

obligate aerobes

Answer 25

requires oxygen

Question 26

facultative aerobes

Answer 26

can use oxygen or not

Question 27

obligate anaerobe

Answer 27

poisoned by oxygen

Question 28

photoautotrophs

Answer 28

carry out photosynthesis (cyanobacteria)

Question 29

chemolithoautotrophs

Answer 29

energy through oxidizing inorganic substances (nitrifies oxidize ammonia or nitrite to obtain energy, producing nitrate for plants)

Question 30

photoheterotrophs

Answer 30

purple and green non sulfur bacteria use light as energy source and carbon from organic molecules

Question 31

chemoheterotrophs

Answer 31

obtain both carbon atoms and energy from organic molecules (humans)

Question 32

The three shapes of bacteria are

Answer 32

bacillus, coccus, and spirillum

Question 33

The response of bacteria that allows them to be identified as Gram-positive or negative is due to

Answer 33

whether their cell walls have a thin or thick layer of peptidoglycan.

Question 34

Which type of organism will form endospores when faced with unfavorable environmental conditions?

Answer 34

bacteria

Question 35

Bacterial cells pick up free pieces of DNA from the medium-pieces that were released from dead bacteria-in a process called

Answer 35

transformation

Question 36

What is the evolutionary relationship among Archaea, Bacteria, and Eukarya?

Answer 36

Archaea and Eukarya share nucleic acid similarities so Eukarya split off from Archaea.

Question 37

Which of the following is considered to be noncellular?

Answer 37

viruses