microbiology 8 (other subcellular components)

Question 1

whereas _______ are found in both the gram negative and gram positive bacteria.

Answer 1

the fimbriae

Question 2

the _______are bristle-like short fibres occurring on the bacterial surface

Answer 2

fimbriae

Question 3

_______are long hair-like tubular microfibers found on the surface of bacteria

Answer 3

Pili

Question 4

Pili generally longer

true/false

Answer 4

true

Question 5

how are both pili and fimbriae involved in attachment of bacterial cell to host? list 2

Answer 5

• Bind to lectins on cell surfaces, e.g sugar binding proteins
• Gives tissue specificity

Question 6

Bacteria within a human host are constantly losing and reforming fimbriae

(true/false)

Answer 6

true

Question 7

pili and fimbriae aids in evasion of the immune system.

true/false

Answer 7

true

Question 8

which type of bacteria can change the antigenic structure of their pili/fimbriae

Answer 8

N. gonorrhoea

Question 9

_______ is Used by conjugative plasmids to transfer copies of itself to a new host

Answer 9

sex pili and conjugation

Question 10

Sometimes other genetic material is mobilised during conjugation

true/false

Answer 10

true

Question 11

After conjugation the previously _______has a copy of the ________and is able to pass it on to ________

Answer 11

• negative cell
• plasmid
• another cell

Question 12

______ is an Efficient manner for transfer of antimicrobial resistance

Answer 12

sex pili and conjugation

Question 13

state the four steps of sex pili and conjugation.

Answer 13

1. donor cell attaches to a recipient cell with its pilus. the pilus draws the cells together.
2. the cells contact one another
3. one strand of plasmid DNA transfers to the recipient.
4. the recipient synthesizes a complementary strand to become an F+ cell; the donor synthesizes a complementary strand restoring its complete plasmid.

Question 14

The ______of E. coli can also mobilise the _______to be transferred through _______

Answer 14

F plasmid

chromosome

cell to cell contact

Question 15

________ integrates into the chromosome and leads to transfer of large regions of the host genetic material and extensive genetic recombination.

Answer 15

episome

Question 16

Hfr is an ______

Answer 16

episome

Question 17

Cells already containing _______ are poor recipients for the same or similar plasmid

Answer 17

a plasmid

Question 18

state the four steps of Hfr-specific recombination

Answer 18

1. Hfr cells contain genes that allow them to transfer some or all of their chromosome to another cell.
2. conjugation tube connects Hfr cell to normal cell. copy of Hfr chromosome begins to move recipient cell.
3. homologous sections of chromosome synapse.
4. cells separate. section of Hfr chromosome integrates into recipient chromosome by crossing over.

Question 19

_______ consists of polysaccharide or sometimes protein. General term is glycocalyx

Answer 19

Capsules and slime layers

Question 20

what is capsule

Answer 20

Thick viscous gel outside and attached to cell wall

Question 21

what is slime

Answer 21

Capsule loosely attached to cell wall and easily washed off

Question 22

Capsules and slime layers are both are hydrophilic.

true/false

Answer 22

true

Question 23

what do Capsules and slime layers appear as in a gram stain?

Answer 23

Appear as halos around cells

Question 24

what are the features of the Microcapsule of E. coli and Salmonella spp?

Answer 24

• Too thin to be seen on light microscope

- Detected by antisera

Question 25

most capsules are ________

Answer 25

immunogenic and stimulate antibody response

Question 26

why aren’t Group B meningococci immunogenic and stimulate antibody response.

Answer 26

its capsule contains N-acetylneuraminic acid which is found on host cells

Question 27

why aren’t S. pyogenes capsule immunogenic and stimulate antibody response.

Answer 27

Hyaluronic acid of S. pyogenes capsule can lead to host cell damage because found on host cells.

Question 28

list 5 advantages of capsules to bacteria.

Answer 28

• Protect cells from desiccation and toxic material
• Attachment to host cells
• Soluble material released into solution blocks opsonising antibodies
• Resist complement alternative pathway
• Resist phagocytosis by neutrophils

Question 29

where do Prokaryotic protein synthesis take place?

Answer 29

Takes place on ribosomes, 70S (30S+50S) in the cytoplasm

Question 30

30S contains ________(small subunit)

while 50S contains_______ (large subunit)

Answer 30

16S RNA

23S RNA

Question 31

how many ribosomes in a prokaryote cell.

Answer 31

Up to 10,000 ribosomes

Question 32

Bacterial mRNA is __________

Answer 32

polycistronic (multiple genes on one mRNA)

Question 33

in bacteria mRNA can be translated________

Answer 33

by several ribosomes simultaneously

Question 34

in prokaryotes Protein translation is done via ____ and _____

Answer 34

tRNA and mRNA

Question 35

Location of protein encoding genes determined by ___________:

Answer 35

looking for Open Reading Frames (ORF)

Question 36

what are two components of cytoplasm.

Answer 36

• Enzymes and ions and a variety of granules

- Accumulation of food reserves (polysaccharides, lipids or polyphosphates)

Question 37

One of the most common inclusion bodies in cytoplasm consists of_______

Answer 37

poly-beta-hydroxybutyric acid

Question 38

_______ is used as storage for carbon and energy storage polymers.

Answer 38

cytoplasm

Question 39

plasmids are ______ and _______

Answer 39

circular and autonomously replicating