Chapter 3: Bacterial Cell Structure I & II, Structures & Energetics

Question 1

What is the purpose of the cytoplasmic membrane?

Answer 1

to separate the cytoplasm from the environment

Question 2

What type of molecules can travel by diffusion?

Answer 2

non-polar

Question 3

What kind of molecules have to be transported through channels?

Answer 3

polar

Question 4

What are hopanoids?

Answer 4

pentracyclic chemicals that stabilize the bacterial membrane

Question 5

What are the 3 functions of the cytoplasmic membrane?

Answer 5

Permeability barrier
Protein anchor
Energy conservation

Question 6

Where are lipids in the cytoplasmic membrane?

Answer 6

the phospholipid bilayer

Question 7

What are the parts of the phospholipid bilayer?

Answer 7

Polar heads (hydrophilic)
Non-polar hydrocarbon tails (hydrophobic)

Question 8

Saturated vs Unsaturated Fatty acids

Answer 8

Saturated fatty acids DO NOT contain double bonds
Unsaturated fatty acids DO contain double bonds

Question 9

Cis fatty acid

Answer 9

H bonds are on the same side of the double bond

Question 10

Trans fatty acid

Answer 10

H bonds are on opposite sides of the double bond

Question 11

What component of the phospholipid is linked to the phosphate group (head) and the fatty acids (tail)

Answer 11

Glycerol

Question 12

What is the inner leaflet of a gram negative cell composed of?

Answer 12

phospholipid

Question 13

What is the outer leaflet of a gram negative cell composed of?

Answer 13

Lipopolysaccharide (LPS)

Question 14

Interact with a variety of substrates or process large molecules for transport

Answer 14

outer surface proteins

Question 15

interact with substrates involved in energy-yielding reactions and other important cellular functions

Answer 15

inner surface proteins

Question 16

firmly embedded in the membrane

Answer 16

integral membrane protein

Question 17

one portion anchored in the membrane (do not span the membrane)

Answer 17

peripheral membrane protein

Question 18

What is the purpose of channels and carrier proteins?

Answer 18

movement of solute or something larger across the membrane

Question 19

Where are channels mostly found?

Answer 19

In the outer membrane of gram-negative bacteria

Question 20

What kind of transfer do channels facilitate?

Answer 20

passsive transfer

Question 21

What kind of transfer do carrier proteins facilitate?

Answer 21

active and passive transport

Question 22

What is the slime layer made of?

Answer 22

glycocalyx

Question 23

Functions of a receptor protein

Answer 23

bonds extracellularly and conformation change relays information to cell

Question 24

Uniporters

Answer 24

move molecules in one direction

Question 25

Symporter

Answer 25

moves more than one molecule in the same direction

Question 26

Antiporter

Answer 26

moves molecules simultaneously into and out of the cell

Question 27

functions of capsule and slime layers?

Answer 27

- Assist in attachment to surfaces - Protect against phagocytosis - Resist desiccation

Question 28

What are fimbriae?

Answer 28

Short, helical, filamentous structures Stick to surfaces or eachother

Question 29

What are pili?

Answer 29

thin filamentous protein structure longer than fimbriae

Question 30

functions of pili

Answer 30

- allow for bacterial attachment to surfaces - can allow for movement through twitching motility - help bacteria evade components of the innate immune system

Question 31

what does the conjugal pilus do?

Answer 31

Exchnage DNA form one bacteria to another

Question 32

what does the conjugal pilus do?

Answer 32

Exchnage DNA form one bacteria to another

Question 33

how does pili twitching motility work?

Answer 33

1. pili extends 2. pilli binds to receptor 3. pili retracts, pulling bacteria along

Question 34

how does pili DNA exchange work?

Answer 34

1. Donor binds to recipient through conjugal pilus 2. plasmids are sent to recipient on the pilus with conjugative proteins 3. DNA is now in the recipient cell

Question 35

what are flagella

Answer 35

Long protein filaments attached to a complex integral membrane protein

Question 36

how do flagella move the cell?

Answer 36

proton passage drives clockwise or counterclockwise rotation

Question 37

monotrichuous

Answer 37

single polar flagellum

Question 38

amphitricuous

Answer 38

a flagellum at each pole

Question 39

lophotricuous

Answer 39

multiple flagella localized at cell pole

Question 40

peritrichous

Answer 40

multiple flagella inserted at many locations in the cell membrane

Question 41

Which types of flagella move coutnerclockwise?

Answer 41

Peritrichous/Lophotricuous

Question 42

Which types of flagella move clockwise?

Answer 42

Monotrichuous/Amphitricuous

Question 43

What is taxis?

Answer 43

directed movement in response to chemical or physical gradients

Question 44

response to chemicals, the best studied movement system

Answer 44

Chemotaxis

Question 45

response to light

Answer 45

Phototaxis

Question 46

response to oxygen

Answer 46

Aerotaxis

Question 47

response to ionic strength

Answer 47

Osmotaxis

Question 48

response to water

Answer 48

Hydrotaxis

Question 49

How is chemotaxis measured?

Answer 49

by adding an attractant or repellant to a microbial space and then measuring movement

Question 50

What is an endospore?

Answer 50

Dormant, non-reproductive structure that allows bacteria survival in harsh environmental conditions

Question 51

How do you kill endospores?

Answer 51

autoclaving, they are resistant to most cleaning techniques

Question 52

Vegetative cell vs Endospore

Answer 52

- vegetative cells are still growing/reproductively active to grow endospores - endospores are dormant versions of the cell

Question 53

Structure of the bacterial nucleoid

Answer 53

single molecule of DNA in a closed loop

Question 54

How is DNA condensed?

Answer 54

supercoiling