1.1 Bacteria: structure and classification Flashcards

1
Q

Eukaryote

A

an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus

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2
Q

Prokaryote

A

a microscopic single-celled organism that​ has neither a distinct nucleus with a membrane nor other specialized organelles

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3
Q
A

Eukaryote

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4
Q
A

Prokaryote

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5
Q

Eukaryotes and prokaryotes both have?

A

Cell membran + cytoplasm + DNA

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6
Q

Have a nucleus and membrane bound​ organelles?

A

eukaryotes

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7
Q

no-membrane bound organelles, no nucleus

A

prokaryote

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8
Q

large, complex cells

A

eukaryotes

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9
Q

small, simple cells

A

prokaryotes

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10
Q

Gram Staining process:

A
  1. Crystal​ violet
  2. iodine
  3. alcohol (decolorization)
  4. safranin (counterstain)
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11
Q

morphology and color are based on

A

cell wall structure

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12
Q
A

gram negative

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13
Q
A

gram positive

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14
Q
A

Pairs (diplococci)

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15
Q
A

Chains (streptococci)

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16
Q
A

Clusters (staphylococci)

17
Q

rods =

A

bacilli

18
Q

The first steps to identification…

A
19
Q

Flagella:

A
  • present in some bacteria
  • involved in motility and chemotaxis
20
Q

Fimbriae / Pili:

A
  • Predominantly found in Gram-negative bacteria
  • Shorter, straighter, and thinner than flagella

Fimbriae: attachment to surfaces, including other cells
Pili: join bacterial cells for conjugation (DNA transfer)

21
Q

Capsule:

A
  • polysaccharides
  • confers mucoid appearance to colonies
  • protection from phagocytosis, antimicrobials
  • enhances adherances
22
Q

play a part in enveloping the cell?

A

cell wall
outer membrane
plasma membrane

23
Q

cell wall:

A

maintain bacterial shape
- prevent cell from osmotic lysis
- extends as needed while volume of cell increases

24
Q

Is a target for antimicrobials?

A

cell wall ( not present in eukaryotes)

25
Q

the cell wall is made up of?

A

peptidoglycan

26
Q

Unusual case, doesn’t​ve a cell wall?

A

Mycoplasma spp antimicrobials targeting​ this cell wont work

27
Q

bacterial envelope: gram-positive​

A
  • many layers of peptidoglycan
  • technic​ acid: provides rigidity​ and used for antigentic typing
28
Q

bacterial envelope: gram-negative

A
  • thin peptidoglycan
  • outer membrane
29
Q

Gram +: alcohol

A

dehydrates PG = more permeable

30
Q

Gram -: alcohol

A

dissolves crystal violet and makes holes in thin PG = crystal violet washed out

31
Q

crystal violet enters via

A

cell walls

32
Q

what does iodine do?

A

binds crystal violet = to big to leave cell wall

33
Q

Phospholipid bilayer:

A
  • Hydrophilic head
  • Hydrophobic tails
  • Only small lipid-soluble compounds can enter the cell by passive diffusion
  • Transporters/porins​ for transport of other molecules
34
Q

outer membrane =

A

LPS

35
Q

outer membrane function:

A
  • Protect from phagocytosis
  • Barrier to antimicrobials e.g. penicillins * & enzymes, detergents, bile salts etc
36
Q

Plasma (cytoplasmic) membrane

A
  • Encloses the cytoplasm
  • Phospholipid bilayer and proteins
  • Permeability barrier with transport systems for selective transport of substances in and out of the cell (selective permeability)
  • Bacterial respiration (ATP synthesised using electron transporters on membrane)
  • Anchor for external structures
  • Target for disinfectants and antimicrobials
37
Q

cytoplasm:

A
  • Facilitate chemical reactions and to dissolve solutes
  • Contains cell components (e.g. nucleoid and ribosomes)
  • aqueous solution to macromolecules, small molecules, and inorganic ions
38
Q

site of protein synthesis?

A

ribosomes