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Flashcards in An Introduction to Bacteria Deck (57)
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1
Q

What does the structure of bacteria contain?

A

Capsule

Cell wall

Cytoplasmic/inner/plasma membrane

Cytoplasm

Ribosomes

Single chromosome, no nucleus

Flagellum

Finbriae

2
Q

What does the cytoplasm do?

A

Contains nutrients taken up from the environment

3
Q

What do ribosomes do?

A

Site of protein synthesis

4
Q

What does the cytoplasmic membrane do?

A

Diffusion of ions and nutrients

5
Q

What does the cell wall do?

A

Combats osmotic stresses

6
Q

What does the capsule do?

A

Helps the bacteria to survive in humans, for example escaping macrophages

7
Q

What do flagellum do?

A

Allows the bacteria to move

8
Q

What does fimbriae do?

A

Important for attachment

9
Q

What do chromosomes do?

A

Contains DNA

10
Q

What does the plasmid do?

A

DNA outside of the chromosome

11
Q

What kind of bacteria has an additional membrane?

A

Gram negative bacteria

12
Q

What kind of bacteria has a thicker layer of peptidoglycan?

A

Gram positive bacteria

13
Q

What are the layers (going inwards to outwards) in gram positive bacteria?

A

Plasma membrane

Periplasmic space

Peptidoglycan

14
Q

What are the layers (going inwards to outwards) in the plasma membrane of gram negative bacteria?

A

Plasma membrane

Periplasmic space

Peptidoglycan

Periplasmic space

Outer membrane (lipopolysaccharide and protein)

15
Q

What does the outer membrane of gram negative bacteria contain?

A

Lipopolyassacharide and proteins

16
Q

What colour does gram positive bacteria appear in gram staining?

A

Purple

17
Q

What colour does gram negative bacteria appear in gram staining?

A

Red

18
Q

What are two classes of bacteria after aerobic/anaerobic?

A

Cocci or bacilli

19
Q

What do cocci bacteria look like?

A

Spherical shaped

20
Q

What do bacilli bacteria look like?

A

Rod shaped

21
Q

What proteins are present on the cell surface of bacteria that creates cross links?

A

Penicillin binding proteins (PBP)

22
Q

What are examples of penicillin binding proteins?

A

Transpeptidases

Carboxypeptidases

Endopeptidases

23
Q

What are lipopolysaccharides?

A

They are present only on gram negative bacteria and elicit a strong immune response in animals and humans

24
Q

What does the capsule provide bacteria with?

A

Water to survive in many environments

25
Q

What are the different kinds of flagellum?

A

A-monotrichous vibrio cholera (one)

B-lophotrichious spirillum spp (one point)

C-amphitchous rhondospirillum rabrum (both sides)

D-peritichous (all over)

26
Q

What do some bacteria release?

A

Spores which help it to obtain nutrients

27
Q

When does spore formation occur?

A

When there is not enough nutrients for fission or environmental factors do not allow it

28
Q

What does spore formation allow?

A

The bacteria to survive in tough environments

29
Q

What is the process of spore formation?

A

1) DNA condenses and lines itself in the centre of the cell
2) DNA divides into two copies
3) Mother cell invaginates to form developing forespore
4) Moth cell engulfs developing spore which is surrounded by two membranes
5) Mother cell DNA is degraded
6) Peptiglycan laid down to form cortex
7) Ca2+ enters and water is removed from the spore
8) Protein coat forms exterior to cortex
9) Some spores form exosporium
10) Enzymes destroy mother cell and mature spore is released

30
Q

What are exoporium?

A

Outer surface layer of mature spores

31
Q

What provides a mechanism for antibiotic resistance?

A

The plasmid

32
Q

What kinds of bacteria prefer what during mating?

A

Gram negative prefers gram negative

Gram positive prefers gram positive

33
Q

What is conjugation?

A

Process by which bacterium transfers genetic material to another through direct contact

34
Q

What are other names for gram positive and gram negative bacteria?

A

F+ are gram positive

F- are gram negative

35
Q

What do gram positive bacteria contain in terms of mating?

A

F plasmid which allows them to form F pills

36
Q

What eventually happens when gram positive and gram negative bacteria are mixed together?

A

They all become gram positive

37
Q

What is the process of conjugation?

A

1) F pills of donor cell (gram positive) recognises and binds to proteins on gram negative cell wall
2) Plasmid becomes mobilised for transfer
3) Single strand of plasmid enters the recipient cell
4) Inside recipient cell a complimentary strand is synthesised

38
Q

What is binary fussion?

A

The process by which bacteria replicates

39
Q

What may genetic variation occur due to?

A

Spontaneous mutations

Transfer of DNA

40
Q

What are spontaneous mutations?

A

Mutations that occur randomly with no influence from the environment

41
Q

What does transfer of DNA occur by?

A

Conjugation

Transformation

Transduction

42
Q

What is transformation?

A

Genetic alteration due to uptake of extracellular DNA that is advantageous

43
Q

What is transduction?

A

Foreign DNA is introduced into a cell by a virus

44
Q

What is transduction caused by?

A

Bacteriophages

45
Q

What are bacteriophages?

A

Viruses that infect bacteria

46
Q

What do bacteriophages contain?

A

Head

Collar

Tail

End plate

Tail fibre

47
Q

What does the end plate and the tail on a bacteriophage do?

A

Helps it to attach to bacteria cells

48
Q

What are the two cycles that bacteriophages enter their DNA into bacteria through?

A

Lytic

Lysogenic

49
Q

What is the lytic cycle?

A

Where the phage overtakes the machinery in the bacteria and starts replicating to form more phages, bacteria cell then bursts and releases them

50
Q

What is the lysogenic cycle?

A

DNA from the phage integrates with the hosts chromosome, it can remain dormant or replicate

51
Q

What can individual bacteria be seen by?

A

Microscope at 1000x with an oil immersion lens

Staining (such as gram or flourescent)

52
Q

What can the naked eye see?

A

Colonies of bacteria

53
Q

What is culturing used for?

A

To identify exactly what species of bacteria is present

54
Q

What do selective mediums allow?

A

Certains species to grow

55
Q

What is bacteria naming based on?

A

The genus and the species

For example for Staphylococcus aureus Staphylococcus is the genus and aureus is the species

56
Q

What properties do strains of bacteria within the same species have?

A

Similar characteristics

57
Q

What can be used to identify strains?

A

DNA typing