Bacteria Cell Surface and Morphology

Question 1

list some differences between eukaryotic and prokaryotic cells

Answer 1

prokaryotic: small + simple, no membrane bound organelles or mitochondria, binary fission, 70S ribosomes

eukaryotic: mostly large + complex, membrane bound organelles and mitochondria, 80S ribosomes

Question 2

what are the different shapes of bacteria

Answer 2

coccus, bacillus, spirillum, spirochete, budding + appendaged bacteria, filamentous

Question 3

what are the 5 types of cocci

Answer 3

diplococci, streptococci, tetrad, sarcinae, staphylococci

Question 4

what are the 4 types of bacilli

Answer 4

single bacillus, diplobacilli, coccobacillus, streptobacilli

Question 5

what are the three types of spirilla

Answer 5

vibrio, spirillum, spirochete

Question 6

what are the 4 types of uncategorized bacterial shape

Answer 6

filamentous, rectangular, pleomorphic, star shaped

Question 7

what are the types of flagellar distribution

Answer 7

peritrichous, polar monotrichous, polar lophotrichous, peritrichous

Question 8

how do spirochetes move

Answer 8

they have axial filaments which allow a corkscrew motility

Question 9

write a quick note on fimbriae and pili

Answer 9

fimbriae are short proteinaceous fibres- used to stick to surfaces. not all bac have them

pili are longer than fimbriae, involved in attachment to tissues. can be involved in DNA transfer + motility in certain cases

Question 10

describe how DNA is packaged in the nucleoid

Answer 10

packaged in an organised way to allow transcription - supercoiling which is facilitated by enzymes gyrases and topoisomerases and are stabilised by structural proteins

Question 11

give some examples of plasmid functions

Answer 11

antibiotic resistance, toxin synthesis, DNA transfer

Question 12

describe the prokaryotic ribosomes

Answer 12

30S and 50S subunit -> 70S ribosome

Question 13

what is the svedberg unit

Answer 13

a measure of how quickly particles sediment in an ultracentrifuge

Question 14

what are the functions of storage granules

Answer 14

energy storage, structural building blocks to be used when environmental sources are depletedwh

Question 15

what is the most common storage granule

Answer 15

poly-b-hydroxybutrate

Question 16

what is a magnetosome

Answer 16

an intracellular inclusion of the iron mineral magnetite which imparts a permanent magnetic dipole to the cell- bacteria can orientate themselves and travel along geomagnetic field lines

Question 17

what are the purposes of gas vesicles

Answer 17

confer buoancy on cells and can be a means of motiloty as cyanobacteria can put themselves in water for optimum light harvesting

Question 18

write a quick note on endospore formation

Answer 18

sporulation = production of an endospore
can be quite a difficult and complex process. endospores can germinate back to vegetative cells very quickly

Question 19

what are the three categories of bacterial endospore formation

Answer 19

terminal, subterminal, central