Microbiology

Question 1

4 basic groups

Answer 1

bacteria, viruses, fungi and protozoa

Question 2

Bacteria

Answer 2

no distinct nucleus - genetic information is in plasmids and chromosomes.

Question 3

Classification of bacteria

Answer 3

Shape, size and colour, nutritional requirements, staining, immunological, biochemical and molecular criteria

Question 4

Three basic shapes of bacteria

Answer 4

Coccus, road/bacillus and spiral

Question 5

Types of coccus

Answer 5

Single, paired, Chain/streptococcus, bunch/staphylococcus

Question 6

Nutritional requirements of bacteria

Answer 6

Food, water, CO2, neutral or alkaline conditions. Strict/obligate aerobes.

Question 7

Fungi

Answer 7

Eukaryotic cell - contains a nucleus with DNA. not invasive unless being opportunistic.

Question 8

Viruses

Answer 8

HIV, bird flu, SARS.
possess either DNA or RNA, never both. Contained within a capsule. Can only survive within cells.
affect host by infecting it and killing it. No effect but potentially infectious. Transformation of cell to malignant form

Question 9

Protozoa

Answer 9

unicellular microbes inhabiting mainly soil and water which cause severe disease.

Question 10

CANDIDA

Answer 10

thrush - common in people with weaker immune systems

Question 11

opportunistic infection

Answer 11

pathogens take advantage of an opportunity not normally available.

Question 12

gram positive bacteria

Answer 12

thick, protein based cell wall, cell membrane

Question 13

gram negative bacteria

Answer 13

thinner cell wall, then another lipid based layer outside. This prevents staining.

Question 14

What can happen when gram negative bacteria enters blood?

Answer 14

outer layer can break off and release toxins.

Question 15

Stages of gram staining

Answer 15

1) Flood slide with crystal violet for 1 min. All cells will be purple.
2) Add iodine solution for 3 mins. All cells remain purple.
3) Decolourise briefly with acetone for 20 secs. G+ stay purple, G- turn colourless.
4) Counterstain with safranin for 1-2 minds. G+ cells remain purple. G- turn pink.

Question 16

Binary fission

Answer 16

main way of bacteria reproduction. Division of single bacteria into two or more parts and the regeneration of those parts to separate entities resembling the original.

Question 17

Transformation

Answer 17

genetic alteration of cell by uptaking bacteria DNA

Question 18

Conjugation

Answer 18

transfer of genetic material between bacterial cells (e.g. resistance code)

Question 19

Transfection

Answer 19

forced introduction of small molecules such as DNA or RNA into eukaryotic cells OR intro of bacteriophage into bacterial cells

Question 20

Pathogenesis

Answer 20

progress of disease

Question 21

Commensal bacteria

Answer 21

bacteria that do no harm desite being in body

Question 22

Virulence

Answer 22

severity of disease

Question 23

Fomites

Answer 23

objects likely to carry infection

Question 24

Vector

Answer 24

carrier of disease e.g. mosquito carrying malaria

Question 25

Antimicrobial stewardship

Answer 25

systematic effort to educate and persuade prescribers of antimicrobials to follow evidence-based prescribing, in order to prevent antibiotic overuse, and thus antimicrobial resistance.