1. Microbiology: The Microbial World (2)

Question 1

Microorganisms are divided into what 2 catagories?

Answer 1

prokaryotes eukaryotes

Question 2

What is the meaning of “prokaryotes”?

Answer 2

“pre nucleus” karyon= nucleus

Question 3

What is a prokaryote?

Answer 3

A cell whose genetic material is not enclosed in a nuclear membrane.

Question 4

What are characteristics of prokaryotes?

Answer 4

They are smaller and simpler than eukaryotes (~1 micrometer in diameter). DNA is one circular chromosome with a length of about 1 mm. The ability to exchange small packets of genetic information (may be carried on plasmids). Do not possess separate internal membrane-bound organelles (All internal structures are extensions of the cytoplasmic membrane).

Question 5

What is a nucleoid?

Answer 5

The region of the cell containing the DNA.

Question 6

What are plasmids?

Answer 6

Are small, extrachromosomal genetic elements that are capable of replication within prokaryotic cells. In some cases, may be transferred from one cell to another and thus may carry sets of specialized genetic information through a population.

Question 7

What are the divisions within the prokaryotes?

Answer 7

Bacteria Archaea

Question 8

What are bacteria?

Answer 8

Prokaryotes that possess peptidoglycan cell walls.

Question 9

What is the meaning of eukaryotes?

Answer 9

“true nucleus”

Question 10

What are eukaryotes?

Answer 10

Cells or organisms having a unit membrane-bound nucleus and usually membrane-bound organelles.

Question 11

What are archaea?

Answer 11

Prokaryotes that lack peptidoglycan cell walls. Are often found in extreme environment.

Question 12

What is the meaning of eukaryotes?

Answer 12

“True nucleus”

Question 13

What are microbial eukaryotes?

Answer 13

They are cells or organisms having a unit membrane-bound nucleus and usually membrane-bound organelles.

Question 14

What are characteristics of eukaryotes?

Answer 14

Their DNA is enclosed in a nuclear membrane and is found in multiple chromosomes. Cell division occurs via mitosis. Genetic transfer depends upon fusion of haploid gametes to form a diploid cell containing a full set of genes derived from each gamete. They possess membrane-bound organelles, including mitochondria, endoplasmic reticulum, etc.

Question 15

What are the divisions within the Eukarya?

Answer 15

Algae. Fungi. Protozoa.

Question 16

What are Algae?

Answer 16

They are photosynthetic eukaryotes (contain chlorophyll).and the cell walls are composed of cellulose

Question 17

What is mitosis?

Answer 17

chromosomes replicate and an identical set is distributed into each of two nuclei

Question 18

What are Fungi?

Answer 18

They are immotile, nonphotosynthetic, unicellular or multicellular eukaryotes. They produce asexual and sexual spores.

Question 19

What are Protozoa?

Answer 19

These are unicellular, motile eukaryotes that lack the cell walls of algae and fungi. Many are free-living microorganisms or parasites that absorb or ingest organic compounds from their environment. They can reproduce sexually or asexually.

Question 20

What is a Prion? (Proteinaceous infectious particles)

Answer 20

Is a small (30nm), infectious, abnormally folded protein, with no nucleic acid.

Question 21

The prion protein (PrP) is encoded by what?

Answer 21

The host’s chromosomal DNA.

Question 22

An abnormal isoform of the PrP is the only known component of the prion and is associated with what?

Answer 22

transmissibility.

Question 23

The abnormal isoform of the PrP differs physically from the normal cellular isoform by what?

Answer 23

Its high Beta-sheet content. its insolubility in detergents. its propensity to agregate, its relative resistance to proteolysis by proteases.

Question 24

What kind of prions are protease-sensitive?

Answer 24

Normal prions

Question 25

What are transmissible spongiform encephalopathies?

Answer 25

Several neurodegenerative diseases in humans and animals that prions are responsible for. The diseases are irreversible and uniformly fatal.

Question 26

What are some diseases from the basic lesion (spongiform degeneration in the gray matter of the brain)?

Answer 26

scrapie bovine spongiform encephalopathy kuru Creutzfeld-Jakob disease

Question 27

What are the differences in the sizes of prokaryotes to eukaryotes?

Answer 27

prokaryotes- small, 0.5-3.0 micrometers eukaryotes- larger, >5 micrometers

Question 28

What are the differences in the nucleus of prokaryotes to eukaryotes?

Answer 28

prokaryotes- no nuclear membrane eukaryotes- true nucleus, consists of nuclear membrane and nucleoli

Question 29

What are the differences in the chromosomes of prokaryotes to eukaryotes?

Answer 29

prokaryotes- single, circular DNA haploid genome eukaryotes- multiple, DNA diploid genome

Question 30

What are the differences in the membrane-bound organelles of prokaryotes to eukaryotes?

Answer 30

prokaryotes- absent eukaryotes- many types always present

Question 31

What are the differences in the cytoplasmic membrane of prokaryotes to eukaryotes?

Answer 31

prokaryotes- does not contain sterols (except Mycoplasma spp.) eukaryotes- contains sterols

Question 32

What are the differences in the cytoplasm of prokaryotes to eukaryotes?

Answer 32

prokaryotes- no cytoskeleton eukaryotes- has a cytoskeleton

Question 33

What are the differences in the cell wall of prokaryotes to eukaryotes?

Answer 33

prokaryotes- usually present, chemically complex eukaryotes- present in fungi, absent in others

Question 34

What are the differences in the ribosomes (sedimentation co-efficient) of prokaryotes to eukaryotes?

Answer 34

prokaryotes- 70S (50S+30S) eukaryotes- 80S (60S+ 40S)

Question 35

What are the differences in the respiratory system of prokaryotes to eukaryotes?

Answer 35

prokaryotes- located in cytoplasmic membrane eukaryotes- via mitochondria or chloroplast

Question 36

What are the differences in the reproduction of prokaryotes to eukaryotes?

Answer 36

prokaryotes- asexual (binary fission) eukaryotes- sexual and asexual (mitosis)