Bacterial structure and classification

Question 1

Are fungi and parasites eukaryotes or prokaryotes?

Answer 1

Eukaryotes

Question 2

Are bacteria eukaryotes or prokaryotes?

Answer 2

Prokaryotes

Question 3

Name 2 infectious agents which aren’t ‘alive’

Answer 3

virus, prions

Question 4

What are prions?

Answer 4

Misfolded proteins which characterise several fatal neurodegenerative diseases in humans.

Question 5

What type of microscope can be used to see bacterium?

Answer 5

Light microscope

Question 6

Serotype

Answer 6

A distinct variation within a species of bacteria/virus/immune cells of different individuals. Classified together based on cell surface antigens.

Question 7

E.coli K12

Answer 7

commensal gut, non-hazardous

Question 8

E.coli O157:H7

Answer 8

cause of food poisoning/hemolytic uraemia

Question 9

What is the name of extra chromosomal DNA which can be transferred between bacteria?

Answer 9

Plasmids

Question 10

Gr- cell wall

Answer 10

2 membranes (inner and outer) with a thin layer of peptidoglycan in periplasm.
Outer membrane contains LPS (lipopolysacchardies)

Question 11

Gr+ cell wall

Answer 11

One membrane with thick peptidoglycan layer.
Teichoic acid on outer membrane
No LPS

Question 12

Which type of bacteria can form spores?

Answer 12

Gr+

Question 13

What are spores?

Answer 13

Highly resistant, dormant structures formed in response to adverse environmental conditions. Contain genetic information.

Question 14

Give 2 examples of bacteria which form spores

Answer 14

Clostridium difficile, Clostridium botulinum

Question 15

Name 2 exceptions to Gr-/Gr+ bacteria

Answer 15

(1) Acid fast bacteria (e.g. Mycobacterium tuberculosis). Contains mycelia acid which resist gram stain.
(2) No conventional cell wall (e.g. Chlamydia)

Question 16

4 ways of classifying bacteria based on nutritional/biochemical properties.

Answer 16

(1) Oxygen requirement and tolerance
(2) Carbon source usage
(3) Presence of enzymatic activity
(4) Gas formation

Question 17

Strict anaerobic

Answer 17

Only anaerobic, will die in high pO2

Question 18

Facultative anaerobic

Answer 18

capable of switching to anaerobic respiration when O2 is absent

Question 19

Microaerophillic

Answer 19

Can stand small amounts of O2 but not too much

Question 20

Why RNA component of ribosomes are unique to each bacterial structure

Answer 20

16s rRNA sequence

Question 21

2 mechanisms of bacterial diversity

Answer 21

Mutations, Genetic exchange

Question 22

3 types of horizontal gene transfer

Answer 22

Transformation, tranductions, conjugation

Question 23

Transformation

Answer 23

Free DNA is taken up by the cell (e.g. plasmids)

Question 24

Transduction

Answer 24

Bacteriophage mediate transfer of non-phage DNA between bacteria

Question 25

Conjugation

Answer 25

Sex. Conjugative plasmid moves from one bacterium to another

Question 26

Transposons

Answer 26

jumping genes, mobile genetic units that integrate into the genome

Question 27

How do bacteria divide

Answer 27

Binary fission

Question 28

Growth phases of bacteria

Answer 28

Lag, exponential/log, stationary, death

Question 29

Lag phase

Answer 29

Bacteria adjust to new environment

Question 30

Log phase

Answer 30

growth of bacteria

Question 31

Stationary phase

Answer 31

essential nutrient runs out