Introduction to Microbiology

Question 1

Name two advantages of a bacterial cell being small.

Answer 1

Increases rate of nutrients and waste in and out/ Higher growth rate for faster adaptation.

Question 2

What are the typical structures of a prokaryotic cell?

Answer 2

Cell wall (plus flagella, pilli), Cell membranes, Cytoplasm, Nuclear region.

Question 3

What is in the cytoplasm?

Answer 3

Enzymes, regulatory proteins and protein synthesis machinery

Question 4

What are the phospholipid membrane proteins functions?

Answer 4

Transport of nutrients, energy generation, secretion, synthesis of peptidoglycan, regulatory proteins

Question 5

What are the two groups bacteria can be divided into based upon cell walls?

Answer 5

Gram- positive or gram- negative

Question 6

What is meant by gram- positive?

Answer 6

The bacteria has retained the crystal violet-iodine complex

Question 7

What is the difference in cell walls of gram positive and negative?

Answer 7

Gram positive- thick peptidoglycan layer, 1 cell membrane. Gram negative- inner and outer membrane and thin peptidoglycan layer

Question 8

Name an example of gram- positive/negative bacteria

Answer 8

+ Streptococcus spp

- E.coli

Question 9

What is peptidoglycan made from?

Answer 9

polysaccharide backbone of two sugar derivatives linked by peptide bridge. N-acetylglucosamine/ N-acetylmuramic acid.

Question 10

Why is acid-fast staining used?

Answer 10

Acid fast microorganisms do not stain well

Question 11

What are exampled of acid fast organisms?

Answer 11

M.Bovis and M.Tuberculosis

Question 12

Why do acid fast bacteria not stain well?

Answer 12

Mycolic acid and lipids in the cell wall which interfere.

Question 13

What is a mycoplasma?

Answer 13

Bacteria with no cell wall

Question 14

What does a mycoplasma require externally?

Answer 14

Cholesterol, amino acids and fatty acids

Question 15

What is the space between two membranes in a gram negative bacteria called?

Answer 15

Periplasm- where the peptidoglycan is

Question 16

What is lipopolysaccharide?

Answer 16

an endotoxin which causes fever (pyrogenic) on the very outer layer of a gram negative bacteria

Question 17

What are the three parts to a lipopolysaccharide?

Answer 17

O-antigen, core polysaccharide, Lipid A

Question 18

What are cell surface structures?

Answer 18

Flagella, fimbriae and pilli, capsules.

Question 19

What is the function of a flagella?

Answer 19

Motility of the cell

Question 20

What are the function of fimbriea and pilli?

Answer 20

The hair like structures which attach to surfaces and for sexual reproduction by transferring plasmids

Question 21

What is a capsule?

Answer 21

a discrete layer of polysaccharides outside the cell

Question 22

What is a slime layer?

Answer 22

A less discrete structure which embeds the cell for attachment

Question 23

What are phenotypic ways of classification?

Answer 23

Staining, cell morphology- cocci, oxygen requirements, culture properties, colony morphology

Question 24

What are genetic ways of classification?

Answer 24

DNA based, rRNA sequences

Question 25

Why can bacteria be incorrectly classified?

Answer 25

Horizontal gene transfer

Question 26

What is mycology?

Answer 26

The study of fungi

Question 27

What is a disease called caused by a fungus?

Answer 27

Mycoses

Question 28

Are fungi eukaryotes or prokaryotes?

Answer 28

Eukaryotic

Question 29

Are fungi aerobes?

Answer 29

All fungi are aerobes some are strict aerobes

Question 30

What is the optimum range of temperature for fungi growth?

Answer 30

20-30 degrees C

Question 31

Can fungi photosynthesise?

Answer 31

No they lack chlorophyll pigment

Question 32

where do fungi obtain their nutrients from?

Answer 32

Absorption from substrates they are living on

Question 33

Why are fungi non-motile?

Answer 33

They have rigid cell walls

Question 34

What is a fungi's reproductive body called?

Answer 34

Spores

Question 35

What is a fungi's cell wall made from?

Answer 35

Chitin

Question 36

What do fungi have instead of cholesterol?

Answer 36

Ergosterol

Question 37

What are the three main morphological forms of fungi?

Answer 37

Yeast, Mould, Dimorphic

Question 38

How do yeast reproduce?

Answer 38

Budding- a blip appears at the end of a cell and grows out unit it breaks away

Question 39

What is formed when yeast cells reproduce but the cell fails to detach?

Answer 39

A long chain of elongated cells forming pseudohyphae

Question 40

What are mould fungi composes of?

Answer 40

Hyphae which branch to form a network called a mycelium

Question 41

What appearance does mould have in a lab?

Answer 41

Large fluffy colonies, often with distinct pigmentation

Question 42

Where do hyphae on mould grow from?

Answer 42

Grow from their tips, new hyphae are formed by branching

Question 43

What are the two major types of asexual spore?

Answer 43

Sporangiospores and condia

Question 44

What are fungal spores important for?

Answer 44

identification, germination, spreading of fungi

Question 45

What are fungi important for?

Answer 45

Biodegradation, industrial fermentation, direct source of food, bioremediation- reduce concentration of toxicity, aggreculture (mycorrhizae)

Question 46

What are the three main causes of mycotic diseases?

Answer 46

True mycosis- tissue invasion, Mycotoxicoses- food products contaminated by fungi which produce toxins, Hypersensitivity- allergic reaction

Question 47

What is superficial mycosis?

Answer 47

Invasion of hair, skin, nails

Question 48

What is subcutaneous mycosis?

Answer 48

fungal invasion of the dermis often following penetration of foreign body

Question 49

What is systemic mycosis?

Answer 49

A group of fungal diseases that invade internal organs

Question 50

What type of mycosis causes ring worm?

Answer 50

Superficial mycosis (dermatophytes)

Question 51

What are geophilic, zoophilic and anthropophilic dermatophytes?

Answer 51

Geophilic- soil associated, Zoophilic- animals and humans, Anthropophilic- humans

Question 52

What are opportunistic fungi?

Answer 52

Infections of the body in patients whose normal defence is impaired

Question 53

What factors may allow opportunistic infection?

Answer 53

prolonged antibiotic therapy, underlying disease, breakdown of mucocutaneous barrier

Question 54

What are its most common forms of infection of aspergillosis?

Answer 54

Nasal in dogs, pulmonary infection in birds, mycotic in cattle, guttural pouch in horses

Question 55

What is mycotoxicosis?

Answer 55

Animal diseases caused by mycotoxins