Bacteria

Question 1

what are the 3 classifications of bacterial cells

Answer 1

1. Gut microbiota → Beneficial gut bacteria which aid in digestion, vitamin production and protection against pathogens
2. Probiotics → live microorganisms which may give health benefits when consumed in adequate amounts
3. Pathogenic Bacteria → Bacteria that cause disease by invading, releasing toxins and triggering immune responses

Question 2

what are the different types of bacterial shapes (10)

Answer 2

Cocci - ball
Bacilli - pill shapes
Club rod - dumbbell-shaped
Vibro - banana-shaped
Spirillum
Helical form
Spirochete
Filamentous
Hypha
Stalk

Question 3

How are bacteria identified through staining (4)

Answer 3

Gram ve- = pink & thin walled (vesicles)

Gram ve+ = purple & thick walled (channels)

Question 4

What are the structures and functions of a bacterial cell that enables infection? (3)

Answer 4

1. Capsule - protects the bacteria from desiccation by helping cells adhere to surfaces. And providing resistance to phagocytosis.
2. Fimbriae - which assists with adherence to host and colonisation (infection).
3. Pili - assist in surface attachment and facilitate conjugation (genetic exchange).

Question 5

What is the structure and function of a bacterial cell that enables motility. (2)

Answer 5

1. The flagellum assists in swimming and bacterial mobility
2. they are helical in shape and exist in 3 different arrangements: PERITRICHOUS, POLAR, LOPHOTRICHOUS

Question 6

What are the steps of sporolation (6)

Answer 6

1. vegetative growth stops and DNA is duplicated.
2. septum forms and divides the cell unsymmetrically.
3. larger compartment engulfs smaller compartment.
4. forespore is formed in the mother cell (smaller compartment).
5. peptidoglycan material is layed down between the two membranes surrounding the forespore.
6. the cell is degraded and the endospore is released.

Question 7

What is the cytoplasmic membrane (2)

Answer 7

1. separates the cytoplasm from the external environment
2. Highly selective allowing the concentration of specific metabolites and the excretion of waste products.

Question 8

What are endospores (3)

Answer 8

1. highly differentiated cells resistant to heat, chemicals and radiation.
2. They are the dormant stage of the bacterial life cycle
3. only present in gram ve+ bacteria

Question 9

What are the phases in the bacterial growth curve (4)

Answer 9

Lag phase
Log phase
Stationary phase
Death phase

Question 10

What are the big 6 food-borne illnesses (6)

Answer 10

Norovirus
Hepatitis A
E-coli
Salmonella (non-typhoidal)
Salmonella (typhoidal)
Shingles

Question 11

what are the 3 arrangements of flagellum (3)

Answer 11

Peritrichous
lophotricous
polar

Question 12

what are the types of bacterial infections (3)

Answer 12

1. Streptococcus pneumoniae - pneumonia
2. Escherichia coli (E.coli) - food poisoning, UTIs
3. mycobacterium tuberculosis - tuberculosis

Question 13

what are Enterobacteriaceae (4)

Answer 13

1. many species are a part of normal gut microbiota
2. 80% clinically significant gram ve- bacilli
3. Account for most gram ve- healthcare-associated infections
4. meningitis, bacillary dysentery, gastroenteritis, UTI, septicaemia

Question 14

What is the bacteria cell structure (6)

Answer 14

1. capsule
2. cell wall
3. plasma membrane
4. nucleoid
5. ribosome
6. plasmid

Question 15

what is the cyanobacteria cell structure (14)

Answer 15

1. slime coat
2. capsule
3. mucoid sheath
4. outer membrane
5. peptidoglycan layer
6. inner membrane
7. phycobilisome
8. lipid droplet
9. carboxysome
10. cyanophycin granule
11. nucleoid
12. vacuole
13. ribosome
14. thylakoid

Question 16

what is the bacterial cell surface (5)

Answer 16

1. capsules, slime layers, fimbriae, pili
2. polysaccharide layers - thick/thin, rigid/flexible
3. assist in attachment to surfaces (fimbriae & pili)
4. protect against phagocytosis
5. resist desiccation

Question 17

what are pili (3)

Answer 17

1. filamentous protein typically longer than fimbriae
2. assist in surface attachment
3. facilitate genetic exchange between cells (conjugation)