BACTERIAL STRUCTURE AND CLASSIFICATION

Question 1

what is a coccus?

Answer 1

any spherical-shaped bacterium

Question 2

what is a bacillus?

Answer 2

any rod shaped bacterium

Question 3

what are the 3 groups of spiral bacteria?

Answer 3

vibrio, spirillum, and spirochete

Question 4

what do spirilla bacteria look like?

Answer 4

a thick rigid spiral

Question 5

what do vibrio bacteria look like?

Answer 5

they are curved or comma shaped

Question 6

what do spirochete bacteria look like?

Answer 6

a thin flexibile spiral

Question 7

what are the 3 domains of life?

Answer 7

eukaryotes, archaea and bacteria

Question 8

how do we name bacteria?

Answer 8

in correct nomenclature…

family, genus, species and strain

Question 9

what structural properties do all bacteria have?

Answer 9

cytoplasm, ribosomes, cell wall and chromosomes

Question 10

what are plasmids?

Answer 10

small, circular, double-stranded DNA molecule that is distinct from a cell’s chromosomal DNA and replicate independantly.

Question 11

how are plasmids moved between bacteria?

Answer 11

by horizontal gene transfer

Question 12

whats the function of a flagella?

Answer 12

locomotion

Question 13

what are pili?

Answer 13

hort, hair-like structures on the cell surface of prokaryotic cells.
they have a role in movement and adhering to surfaces

Question 14

what are fimbriae?

Answer 14

long filamentous polymeric protein structures located at the surface of bacterial cells that allow the binding to specific receptor structures

Question 15

what are 4 ways in which we can categorise bacteria?

Answer 15

if theyre gram positive, gram negative or acid fast
by morphology
by nutritional and enzymatic properties
by their DNA sequence

Question 16

describe how you can determine where its a gram positive and gram negative bacteria?

Answer 16

if you stain with crystal violet and then wash with alcohol, gram positive bacteria stay purple whilst gram negatve bacteria look pink becayse they get washed out

Question 17

what are the structural characteristics of gram negative bacteria?

Answer 17

they have an outer membrane and a cytoplasmic membrane

in between there is a thin periplasm (peptidoglycan layer)

Question 18

what are the structural characteristics of gram positive bacteria?

Answer 18

they have a singular cytoplasmic membrane and a thick periplasm (peptidoglycan layer)

Question 19

how are chlamydia and mycoplasma different to other bacteria?

Answer 19

they dont have conventional cell walls

Question 20

how can we categorise bacteria based on morphology?

Answer 20

colony size
colour
size
appearance

Question 21

what is a bacterial capsule?

Answer 21

a large polysaccharide layer that lies outside the cell envelope that can help the bacterium avoid desiccation by preventing water loss and protects the cell from phagocytosis

Question 22

what are a bacteria with single cells and chains likely to be?

Answer 22

streptococcus

Question 23

what are spores?

Answer 23

when some gram positive bacteria are under stress they can make them to ensure they are highly resistant to decissation, chemicals and temperature

Question 24

what is serotyping?

Answer 24

to assign a microorganism to a specific serotype/strain

Question 25

what makes up the bacterial genome?

Answer 25

the chromosomes and plasmids

Question 26

what is horizontal gene transfer?

Answer 26

the non-sexual movement of genetic information between 2 bacteria (helped by bacteriophages)

Question 27

what is vertical gene transfer?

Answer 27

when genes are transferred down generations

Question 28

why do bacteria not take over our bodies if binary fission is so rapid?

Answer 28

because they run out of phosphate, carbon and nitrogen which they rely on

Question 29

outline the number of bacteria x time graph during bacterial growth?

Answer 29

the lag phase is first when the bacteria are still adapting to their conditions
exponential logarithmic phase happens as they multiply
stationary phase occurs as nutrients begin to run out
death phase when no nutrients are available