Bacteria

Question 1

3 Common shapes of Bacteria

Answer 1

1) coccus: spherical
2) bacillus: rod
3) spiral
i. spirillum: thick, rigid spiral
ii. spirochete: thin, flexible spiral

Question 2

What is a bacterial cell wall?

Answer 2

An extra layer of peptidoglycan that surrounds the cell membrane.

Question 3

What’s the difference between gram-positive bacteria and gram-negative bacteria?

Answer 3

-Gram-positive bacteria can be stained crystal violet due to its thick peptidoglycan layer. Ex: staphylococcus (bunch) and streptococcus (line)
-Gram-negative bacteria can’t be stained crystal violet due to its extra lipopolysaccharide layer. Ex: Escherichia and salmonella

Question 4

What are Flagella?

Answer 4

Flagella are whip-like appendages used for swimming.
Ex: helicobacter pylori

Question 5

What are bacterial Fimbriae?

Answer 5

Fimbriae are shorter, hair-like extensions that adhere to surfaces.
Ex: Neisseria Gonorrhoeae

Question 6

What is a bacterial capsule?

Answer 6

A sticky outer layer that adheres to surfaces and serves as a defense barrier.
Ex: Streptococcus mutans

Question 7

What is a bacterial endospore?

Answer 7

A tough bacterial spore that can resist damage and remain dormant. During dormancy, metabolism halts. When it rehydrates in the proper environment, it resumes metabolism. The endospore can survive UV, desiccation (drying out), high temperatures, freezing, and chemical disinfectants.
Ex: clostridium botulinum

Question 8

What are bacterial pili?

Answer 8

Appendages that join bacteria to exchange DNA.

Question 9

What is a nucleoid?

Answer 9

A region of cytosol that contains chromosomes.

Question 10

What are plasmids?

Answer 10

Small rings of DNA that are separate from the chromosome.

Question 11

No organelles (3 analogies)

Answer 11

1) Plasma membrane can have complicated folds to create compartments.
2) Thylakoid folds similar to chloroplast for photosynthesis
3) Cristae-like folds like mitochondria for aerobic respiration

Question 12

2 means of Bacterial Genetic Diversity

Answer 12

1) Rapid reproduction (by binary fission) and mutation
2) Genetic recombination: horizontal gene transfer

Question 13

3 means of Genetic Recombination

Answer 13

1) Transformation: uptake of foreign DNA from the environment
2) Transduction: uptake of foreign DNA via a virus
3) Conjugation: DNA transfer between 2 prokaryotic cells via a pilus.

Question 14

2 means of bacterial Conjugation

Answer 14

1) F-Factor (fertility): 25 genes needed to form a pilus
i. F-plasmid - F-factor on a plasmid can
transfer the conjugation ability
2) Antibiotic Resistance: genes that give bacteria the ability to survive specific antibiotics
i. R-Plasmid: plasmid with antibiotic
resistance genes
a. plasmid can contain resistance to
multiple antibiotics
b. plasmid can contain F-factor

Question 15

3 types of bacteria

Answer 15

1) Autotrophs: “Self-feeding”; make their own food
2) Heterotrophs: “Eat others”; consumes material from living or dead tissue
3) Symbiosis: two different organisms living in close physical association

Question 16

2 Autotroph examples

Answer 16

1) cyanobacteria: photosynthesis and carbon fixation
2) Nitrogen fixation: convert inorganic N2 into organic NH3

Question 17

Heterotroph example

Answer 17

-Fermentation : anaerobic method to generate energy
Ex: Lactobacillus bulgaricus

Question 18

Symbiosis- 3 types and examples

Answer 18

1) Mutualism: Both species benefit
Ex: Rhizobium leguminosarum - nitrogen
fixing root nodule of legume plants
2) Commensalism: One benefits while the other is unaffected
Ex: Staphylococcus aureus
3) Parasitism: One benefits while the other is harmed
Ex: Pathogens

Question 19

What are pathogens?

Answer 19

Pathogens are toxins that are secreted by bacteria and that interfere with normal bodily functions.
Ex: Treponema pallidum

Question 20

What are the 2 types of toxins secreted by bacteria (pathogens)?

Answer 20

1) Endotoxins: chemicals secreted by the bacteria cut out of the cell. They still cause symptoms even if the bacteria isn’t there.
2) Exotoxins: chemicals in cell wall released when the bacteria dies. Also causes symptoms even if the bacteria isn’t there.

Question 21

What are the 2 examples of endotoxins?

Answer 21

1) Vibrio cholera - cholera toxins that causes diarrhea
2) Clostridium botulinum - botulinum toxin causes botulism: muscular paralysis, then respiratory failure (because the diaphragm is paralyzed), and then death.

Question 22

What are the 2 examples of exotoxins?

Answer 22

1) Salmonella typhi - causes typhoid fever
2) Salmonella enterica

Question 23

What causes an opportunistic infection (pathogens)?

Answer 23

Commensal bacteria that take advantage of an opening.
Ex: staphylococcus aureus “flesh eating disease” and MRSA, the methicillin-resistant staphylococcus aureus

Question 24

What are the 6 phylum of Domain Bacteria?

Answer 24

1) Proteobacteria
2) Cyanobacteria
3) Spirochaete
4) Chlamydiae
5) Firmicutes
6) Thermatogae

Question 25

Domain Bacteria
Phylum: Proteobacteria

Answer 25

Major phylum of gram negative bacteria
-Escherichia, Salmonella, Vibrio, and Rhizobium

Question 26

Domain Bacteria
Phylum: Cyanobacteria

Answer 26

Photosynthetic bacteria
-Anabaena and Oscillatoria

Question 27

Domain Bacteria
Phylum: Spirochaete

Answer 27

Spiral, gram-negative bacteria
-Treponema (syphillis)

Question 28

Domain Bacteria
Phylum: Chlamydiae

Answer 28

Extremely small intracellular pathogen
Ex: Chlamydia

Question 29

Domain Bacteria
Phylum: Firmicutes

Answer 29

Spore-forming bacteria
Ex: Staphylococcus, bacillus, and clostridium

Question 30

Domain Bacteria
Phylum: Thermotogae

Answer 30

Thermophilic Bacteria found in hot springs, sulfur pools, and near thermal vents