Bactéries : biologie et classification 1

Question 1

Les bactéries appartiennent aux _____________

Answer 1

Procaryotes

Question 2

In contrast to eucaryotes, procaryotes lack what ? (4)

Answer 2

noyau,
réticulum endoplasmique,
d’appareils de Golgi
mitochondries

Question 3

Difference in reproduction between eucaryotes, procaryotes

Answer 3

Bacteria (procaryotes): Reproduction asexuée (fission binaire)

Question 4

How is ATP produced in bacteria?

Answer 4

Production d’ATP se fait via la membrane cytoplasmique (et non des mitochondries)

Question 5

What color is a gram + bacteria? And why?

Answer 5

It is blue.

This is because a gram positive bacteria has a thick peptidoglycan layer (lots of spaghetti) that keeps the gram colorant stuck during the washout

Question 6

Describe the Coloration de Gram

Answer 6

1. Before the coloration the bacteria are “ghosts”
2. We then add violet de cristal. This will make all bacteria blue
3. We then use Lugol in order to glue the coloration
4. We then use alcool to wipe away the color. Gram + keeps the color. Gram - looses it
5. Finall step, we do Coloration à la safranine
6. Here gram + will stay blue while the gram - will be colored red

Question 7

True or False
A Gram positive has an outer membrane

Answer 7

False
A Gram negative has an outer membrane:

Question 8

True or False
The cytoplasmique membrane is the same for gram positive and negative.

Answer 8

True

Question 9

Where do we find these? Lipopolysaccharide

Answer 9

Gram negative bacteria (outer membrane)

Question 10

Roles of a Membrane cytoplasmique? (3)

Answer 10

1. Produit de l’énergie (ATP) : joue le rôle des mitochondries
2. Permet l’entrée de certains nutriments et la sortie de certaines
3. Contient des protéines structurales qui contribuent à la forme de la bactérie (ex. forme spiralée, forme droite)

Question 11

Which type of bacteria will have peptidoglycan?

Answer 11

Both gram negative and gram positive but
Gram negative have a thin peptidoglycan layer

Question 12

What is the role of technoic acid and where is it found?

Answer 12

Gram positive
Strenghtens the cell wall

Question 13

Capsule

Décrire la composition et la fonction des structures suivantes : la capsule, le biofilm, les pili, les flagelles, les spores.

Answer 13

Makes it harder to get eaten by immune system

Question 14

biofilm

Décrire la composition et la fonction des structures suivantes : la capsule, le biofilm, les pili, les flagelles, les spores.

Answer 14

Attach to corps étranger. When putting a catheter or a tube, the bacteria can bind to that using their biofilm. Must remove as quickly as possible

Question 15

pili

Décrire la composition et la fonction des structures suivantes : la capsule, le biofilm, les pili, les flagelles, les spores.

Answer 15

To attach to different cells or exchange DNA info

Échanger du matériel génétique

Question 16

flagelles

Décrire la composition et la fonction des structures suivantes : la capsule, le biofilm, les pili, les flagelles, les spores.

Answer 16

Mobility

Question 17

Gram + vs Gram -

Outer membrane?

Answer 17

Outer membrane present in gram negative only (think lipopolysaccharide)

Question 18

Gram + vs Gram -

Peptidoglycan?

Answer 18

Peptidoglycan present in both but thin in gram - and thick in gram positive

Question 19

Gram + vs Gram -

Sporulation?

Answer 19

Present in some gram positive only
(resistance. Leave it there for a year it will still be there)

Question 20

Gram + vs Gram -

Capsule?

Answer 20

Present in both sometimes

Question 21

What are Bactéries sporulées?

Answer 21

Uniquement chez certains bâtonnets Gram +
The bacteria when facing harsh conditions enters a round very resistant structure in order to survive

Passage de la bactérie de la forme végétative vers la forme
sporulée lorsque les conditions de survie sont dangereuses pour la
bactérie.

Question 22

Expliquer pourquoi la coloration de Gram n’est pas utile dans le diagnostic des infections causées par les mycobactéries et les mycoplasmes

Answer 22

Mycobactéries : paroi riche en acide mycolique (waxy outer shell) qui interfère avec la
coloration de Gram.

Mycoplasma : absence de peptidoglycane dans la paroi cellulaire

Chlamydia : très petites bactéries, non cultivables sur des géloses (lives inside cells)