Lecture 21: Micro-organisms: Classification, structure, and replication

Question 1

Characteristics of Bacteria:

Answer 1

Bacteria are simple, single cell organisms.
Bacterial cells lack a membrane bound nucleus.
Cells like these are prokaryotes not eukaryotes
Not all prokaryotes are bacteria!

Question 2

What are the three domains?

Answer 2

1) bacteria

2) archaea

3) eukaryotes

Question 3

What two Linnean subgroups are used when naming bacteria?

Answer 3

genus and species

Question 4

What genetics are used in modern classification of bacteria?

Answer 4

hypervariable regions in 16S ribosomal RNA

Question 5

Name two places where genetic information is found in bacteria:

Answer 5

1) nucleoid

2) plasmids

Question 6

How many chromosomes do bacteria cells have?

Answer 6

1

Question 7

Where is the bacterial chromosome located?

Answer 7

nucleoid

Question 8

What is the function of the flagella?

Answer 8

Locomotion

Question 9

What term is used to describe a single flagella at a single pole of the cell?

Answer 9

monotrichous

Question 10

What term is used to describe numerous flagella at a single pole of the cell?

Answer 10

lophotrichous

Question 11

What term is used to describe single flagella at two opposite poles of a cell?

Answer 11

amphitrichous

Question 12

What term is used to describe multiple flagella at opposite poles of a cell?

Answer 12

pertirichous

Question 13

What is the function of pilli/ fimbriae?

Answer 13

adhesion to other cells

Question 14

What type of macromolecule makes up bacterial plasmids?

Answer 14

polysaccharide

Question 15

What 3 things do bacterial plasmids protect bacteria from?

Answer 15

1) phagocytosis and immune responses

2) antibiotics

3) desiccation

Question 16

What is desication?

Answer 16

Drying out

Question 17

What is another term for a capsule?

Answer 17

slime layer

Question 18

What is a biofilm?

Answer 18

a community of bacteria grouped by a surrounding extracellular polymeric capsule

Question 19

What are endospores?

Answer 19

inert versions of bacteria that store genetic material in harsh conditions

Question 20

Give two genuses of bacteria that can form endospores:

Answer 20

1) Bacillus

2) Clostridium

Question 21

Describe gram positive cell walls:

Answer 21

thick peptidoglycan layers (up to 40 layers)

Question 22

Give 4 gram positive bacterial genuses:

Answer 22

1) Clostridium

2) Bacillus

3) Streptococcus

4) Staphylococcus

Question 23

Why is it that gram positive bacteria are likely to be found on the skin?

Answer 23

the thick peptidoglycan wall prevents the bacteria from drying out

Question 24

Describe gram negative cell walls:

Answer 24

thin peptidoglycan layer with an inner and outer membrane

Question 25

Why is it that many gram negative bacteria are resistant to numerous antibiotics?

Answer 25

Why is it that many gram negative bacteria are resistant to numerous antibiotics?

Question 26

What molecules cover the outer membrane of gram negative bacteria?

Answer 26

lipopolysaccharide endotoxins

Question 27

Describe mycobacterial cell walls:

Answer 27

waxy outer layer

Question 28

Give an example of a bacteria genus that has no peptidoglycan in their cell wall:

Answer 28

Chlamydia

Question 29

What colour does gram positive bacteria turn in a gram stain test?

Answer 29

blue/ purple

Question 30

What colour does gram negative bacteria turn in a gram stain test?

Answer 30

Pink

Question 31

What is the name given to spherical bacteria?

Answer 31

coccus

Question 32

What is the name given to rod shaped bacteria?

Answer 32

Bacillus

Question 33

What is the name given to long, wiggly bacteria?

Answer 33

Spirochele

Question 34

What is the name given to long, thin and overlapping bacteria?

Answer 34

Filamentous

Question 35

What is the name of two spherical bacteria joined together?

Answer 35

Diplococci

Question 36

What is the name of a chain of spherical bacteria?

Answer 36

Streptococci

Question 37

What is the name of a grape bunch of spherical bacteria?

Answer 37

Staphylococci

Question 38

What mechanism of replication does bacteria use?

Answer 38

binary fission

Question 39

What is horizontal gene transfer?

Answer 39

the movement of genetic material between cellular organisms

Question 40

What are the three types of horizontal gene transfer seen in bacteria?

Answer 40

1) conjugation 2) transformation 3) transduction

Question 41

What is conjugation horizontal gene transfer?

Answer 41

a pilus providing union between cells for lateral genetic transfer

Question 42

What is transformation horizontal gene transfer?

Answer 42

a cell grabbing genetic material from the external environment and adding it to the genome via homologous recombination

Question 43

What is transduction horizontal gene transfer?

Answer 43

where a bacteriophage adds genetic material to a bacterial cell via homologous recombination

Question 44

What is a bacteriophage?

Answer 44

A virus that infects bacteria

Question 45

Are fungi eukaryotic or prokaryotic?

Answer 45

Eukaryotic

Question 46

What molecule is a key component in fungal cell walls?

Answer 46

Chitin

Question 47

What are yeasts

Answer 47

Unicellular fungi

Question 48

What are moulds?

Answer 48

multicellular, filamentous fungi

Question 49

Is thrush caused by a yeast or mould?

Answer 49

Yeast

Question 50

What infectious effects do moulds have?

Answer 50

they cause common superficial infections such as ring worm and athletes foot

Question 51

True or false: moulds can reproduce sexually or asexually

Answer 51

True

Question 52

Give two examples of helminths:

Answer 52

1) Schistosoma 2) Taenia

Question 53

True or false: parasites can be unicellular or multicellular eukaryotes

Answer 53

True

Question 54

True or false: parasites can reproduce sexually or asexually

Answer 54

True

Question 55

What is a common survival mechanism used by parasites in reproductive cycles?

Answer 55

Cyst formation

Question 56

True or false: viruses are livng organisms

Answer 56

false

Question 57

Describe the basic structure of viruses:

Answer 57

nucleic acid core wrapped in a protein coat

Question 58

Where do viruses get their lipid envelopes from?

Answer 58

host cells (helps them evade host's immune system)

Question 59

How do retroviruses add their genetic material to host cell genomes?

Answer 59

they convert their RNA into cDNA using reverse transcriptase

Question 60

Describe the virus cycle: (5)

Answer 60

1) they attach to host cells using receptors and enter via endocytosis 2) they un-coat and target the nucleus with its genetic material 3) this leads to the production of early viral proteins such as integrase and polymerase 4) later, late viral proteins such as capsid molecules are produced 5) viruses are released from host cells via cell lysis or budding

Question 61

What are prions?

Answer 61

Misfolded proteins

Question 62

How do prions cause disease?

Answer 62

they aggregate and cause misfolding of native proteins

Question 63

Give two examples of prion diseases:

Answer 63

1) Creutzfeldt Jakob disease 2) Kuru