CH3

Question 1

common size of bacteria

Answer 1

0.5-2.0μm in diameter and 2-5 μm long

Question 2

name and describe the 6 common shapes of bacteria

Answer 2

coccus- spherical
coccobacillus- elongated spheres
vibrio- curved rod shaped
bacillus- rod shaped
spirillum- gently curved spiral (rigid)
spirochete- thinner curved spiral (flexible)

Question 3

Name the 3 arrangements of bacteria and give examples

Answer 3

• spiral bacteria- single celled and arrangement depend on plane of cell division
• bacilli- single, streptobacillus, palisade
• cocci- diplococci, streptococci, tetrad, sarcinae, staphylococci

Question 4

similarities and differences between prokaryotic and eukaryotic plasma membranes

Answer 4

• both have selective permeable phospholipid membrane
• both have fluid membrane
• sterols in eukaryotic, hopanoid in prokaryotic
• ratio of protein:lipid is higher in prokaryotes

Question 5

why is the ratio of protein:lipid higher in prokaryotes than eukaryotes?

Answer 5

respiration takes place in in membranes of prokaryotes; respiration takes place in mitochondria of eukaryotes

Question 6

name the two types of bacterial cell walls and their structure

Answer 6

Gram +
-thick peptidoglycan sheath which is extremely strong but flexible, the sheath contains lipoteichoic acid and teichoic acid. The lipoteichoic acid is long and goes thru periplasmic space to the plasma membrane and the teichoic acid are shorter and are only in the peptidoglycan layer

Gram -
-membrane is three different layers: outer layer, periplasmic space and peptidoglycan, plasma membrane. The outer membrane layer contains porins that allow things to pass, Braun’s lipoproteins that connect to peptidoglycan, O-specific side chains of lipopolysaccharide (LPS), and lipid A. The periplasmic space has the thin peptidoglycan layer within it. And then plasma membrane

Question 7

how were bacterial cell wall structures discovered?

Answer 7

TEM

Question 8

what does penicillin do to the peptidoglycan layer in bacterial cells?

Answer 8

-penicillin kills the dividing/growing bacteria, it blocks peptidoglycan synthesis

Question 9

Which of the cell walls is more sensitive?

Answer 9

• (+) bc they are dependent of the peptidoglycan sheaths

Question 10

what happens to the + and - cell walls in staining reactions?

Answer 10

it has to do with the thickness of peptidoglycan layer

+ stains don’t rinse out easily bc of thick peptidoglycan layer and - stains rinse out easily

Question 11

enzyme that involves intracellular digestion and is in tears, saliva and sweat

Answer 11

lysozyme

Question 12

why can it be dangerous killing lipid A in gram - cell walls?

Answer 12

lipid A contains endotoxin and when lipid A is destroyed, the endotoxin is excreted and it can cause fever and vasodilation

Question 13

describe the glycocalyx of bacterial cells

Answer 13

• viscous layer around the bacterial cell wall that is usually polysaccharides
• capsule that is organized, thick, and firmly attached
• slime layer that has no definite shape, thin, loosely attached

Question 14

functions of glycocalyx

Answer 14

• adhesion
• protection form desiccation/drying
• prevents attachment of viruses
• protection from phagocytes
• traps nutrients/ excludes toxins

Question 15

• bags of water with inclusions
• simple cytoskeleton (cell division, shape, localize proteins)
• in cyanobacteria

Answer 15

cytoplasm

Question 16

• insoluble deposits- single/no membrane
• storage
• carboxysomes
• buoyancy

Answer 16

inclusion bodies

Question 17

what do inclusion bodies store?

Answer 17

• glycogen
• poly-B-hydroxyburyrate (in gram -)
• cyanophycin (store Nitrogen)
• polyphosphate (metachromatic)

Question 18

contain Rubisco, the key enzyme in calvin cycle reducing CO2

Answer 18

carboxysomes

Question 19

• protein and rRNA
• 2 subunits
• smaller in eukaryotes (70s vs 80s)
• in matrix, attached to PM

Answer 19

ribosomes

Question 20

• no membrane
• DNA (singular circular chromosome)
• some RNA and protein (no histones)

Answer 20

nucleoid

Question 21

-additional, non essential genes (<30)
-for antibiotic resistance (R), for metabolic pathways,
for virulence (toxin genes)
-often independent of chromosome
-starved bacteria lose this

Answer 21

plasmid

Question 22

• attachment to pili
• short projections
• tubes of protein (pilin)
• many to a thousand

Answer 22

fimbriae

Question 23

• conjunction (sex)
• hollow projections, longer
• protein
• transfer of genetic info
• 1-10 per cell (Gram -)

Answer 23

pili

Question 24

• motility, chemotaxis (will move away from high gradients)
• many rod shaped bacteria
• slender, rigid, longer than pili
• protein

Answer 24

flagella

Question 25

direction of flagella when running and tumbling

Answer 25

counter clockwise and clockwise

Question 26

types of flagella attachment

Answer 26

- polar- monotrichous and lophotrichous - amphitrichous - peritrichous - periplasmic flagella/ axial flagella

Question 27

single flagella

Answer 27

monotrichous

Question 28

cluster of flagella on one side

Answer 28

lophotrichous

Question 29

flagella on both ends

Answer 29

amphitrichous

Question 30

not polar and flagella stick out around

Answer 30

peritrichous

Question 31

in spirachetes, tube of bacteria that wind up and allows the spin to penetrate

Answer 31

periplasmic flagella/ axial flagella

Question 32

how do bacterial flagella move?

Answer 32

by spinning

Question 33

resist to drying and desiccation

Answer 33

cysts

Question 34

- survival structures - produced inside bacterial cell - 1 per cell and not for reproduction

Answer 34

endospores

Question 35

who discovered endospores?

Answer 35

Koch

Question 36

describe the structure of endospores

Answer 36

- complex, thick walled, highly resistant - shape- ovoid, spherical - location (in sporangium)- terminal, subterminal, central - size (relative to sporangium)- bulging, non-bulging