bacteria - lqc 3a

Question 1

ribosomes in bacteria

Answer 1

site of translation, smaller than eukaryotic ones

Question 2

pilus in bacteria

Answer 2

allow bacteria to attach to surfaces and are involved conjugation

Question 3

plasmid in bacteria

Answer 3

small loop of dna

Question 4

capsule in bacteria

Answer 4

protective outer layer which prevents dehydration

Question 5

flagellum in bacteria

Answer 5

used for cell movement

Question 6

mesosome in bacteria

Answer 6

infolding of the cell surface membrane

Question 7

cell wall in bacteria

Answer 7

made of peptidoglycan. it’s composition makes bacteria either gram negative or gram positive

Question 8

how do bacteria reproduce

Answer 8

asexually by binary fission

Question 9

what do bacteria not make during asexual reproduction that animals cells do

Answer 9

spindle fibres

Question 10

singular of bacteria

Answer 10

bacterium

Question 11

plural of bacteria

Answer 11

bacteria

Question 12

diseases caused by pathogens are called

Answer 12

infectious diseases

Question 13

bacteria facts:

Answer 13

• prokaryotes
• size between 0.5 and 5 um
• they don’t have a nucleus or other membrane bound organelles
• do not produce a spindle during cell division
• produce 2 identical daughter cells

Question 14

2 classes of bacteria based on their cell walls:

Answer 14

gram positive, gram negative

Question 15

gram positive bacteria take up stain:

Answer 15

purple

Question 16

gram negative bacteria reject the stain:

Answer 16

pink

Question 17

label gram positive bacteria

Answer 17

Question 18

label gram negative bacteria

Answer 18

Question 19

how are gram negative bacteria different?

Answer 19

• cell wall is a thinner layer of peptidoglycan
• is a ‘periplasmic space’ between the cell wall and the cell membrane
• outer membrane contains lipopolysaccharides (LPS), porin channels and murein lipoprotein
• LPS is an endotoxin, it blocks antibiotics, dyes and detergents- so it protects the thin inner membrane and cell wall, this makes gram negative bacteria resistant to penicillin and lysozyme

Question 20

gram staining procedure:

Answer 20

1) begin with heat fixed cells
2) flood slide with crystal violet dye for 1 min
3) add iodine solution for 1 minute
4) wash slide with alcohol for 20 seconds
5) counter stain with safranin

Question 21

gram positive cell wall affects of staining procedure

Answer 21

1) cell wall remains clear
2) peptidoglycan cell wall is flooded with crystal violet and appears purple
3) a crystal violet- iodine complex is formed within the peptidoglycan cell wall trapping the purple stain
4) the crystal violet- iodine complex is trapped with the peptidoglycan cell wall and doesn’t wash out
5) as the peptidoglycan cell wall remains stained purple the red safranin has no effect

Question 22

gram negative cell wall affects of staining procedure

Answer 22

1) cell wall remains clear
2) cell wall is stained purple from the crystal violet dye
3) a crystal violet- iodine complex is formed but does not adhere to the cell wall due to the thin layer of peptidoglycan
4) the crystal violet- iodine structure is washed out of the thin peptidoglycan layer
5) the red safranin stains the washed gram negative cells