Lecture 4

Question 1

Where in the cell envelope would you find
Hopanoids?
Porins?
D-Alanine and D-Glutamic acid?

Answer 1

• Cell membrane
• Outer membrane
• Link peptidoglycan

Question 2

THE NUCLEOID

Answer 2

Where genetic content is stored

Question 3

Eukaryotic cells have a well-defined nucleus delimited by a ____

Answer 3

Nuclear membrane

Question 4

Prokaryotic cells have a ______ region that extends throughout the cytoplasm

Answer 4

Nucleoid

[pic]

Question 5

DNA IS ORGANIZED IN THE NUCLEOID

Answer 5

The E. coli nucleoid appears as clear regions that exclude the ribosome and contain the DNA strands
[pic]

Question 6

The nucleiod forms about ____

Answer 6

50 loops or domains

Question 7

The midpoint on the DNA is the ____

Answer 7

origin of replication

• Attached to the cell envelope at a point on the cell’s equator

Question 8

Within each domain, the DNA is supercoiled and compacted by_____ and ______

Answer 8

gyrases & DNA-binding proteins

[PIC]

Question 9

TRANSCRIPTION AND TRANSLATION

In prokaryotes happen together

Answer 9

-RNA polymerase transcribes DNA into a single strand of RNA
-mRNA immediately binds to a ribosome for translation into a polypeptide
-In prokaryotes, translation is tightly coupled to translation
[pic]

Question 10

THE RIBOSOME IS A TARGET FOR ANITBIOTICS

Answer 10

[pic has important info]

Question 11

PROTEIN SYNTHESIS AND SECRETION

Multiple proteins are made from the same

Answer 11

mRNA

Question 12

In prokaryotes, membrane proteins and secreted proteins are synthesized in association with the cell membrane

Answer 12

• Aided by the signal recognition particle (SRP), which binds to the growing peptide
[PIC]

Question 13

CELL DIVISION

Bacterial cell division, or fission \_\_\_

Answer 13

requires highly coordinated growth and expansion of all the cell’s parts

• doing all these things at the same time
• transl and transc.

Question 14

Unlike eukaryotes, prokaryotes synthesize ___ and ____ continually while the cell’s DNA undergoes replication

Answer 14

RNA

Proteins

Question 15

Bacterial DNA replication

Answer 15

is coordinated with the expansion of the cell wall and ultimately the separation of the cell into two daughter cells

Question 16

Replication begins at the ___

Answer 16

origin of replication

Question 17

The DNA double helix unzips and forms two replication forks

Answer 17

At each fork DNA is synthesized by DNA polymerase with the help of accessory proteins (replisome)

Question 18

As the ______ site is replicated, the two replisomes separate from the DNA

Answer 18

Termination

[pic]

Question 19

VIDEO

Answer 19

[PIC]

Question 20

SEPARATION COMPLETES CELL DIVISION

Replication of DNA termination site triggers ___

Answer 20

Growth of the dividing partition of the envelope, Called the Septum

Question 21

The septum grows __ from the sides of the cells, constricting and sealing off the two daughter cells

Answer 21

Inward

Question 22

SEPTATION IN COCCI

The spatial orientation of septation has a key role in determining the \_\_\_\_ and \_\_\_\_\_\_ of cocci

Answer 22

Shape & arrangement

Question 23

If septation occurs in:

Answer 23

• Parallel planes – cells form chains (Streptococcus)
• Random orientations – cells form compact hexagonal arrays (Staphylococcus)
• Right angles to the previous division – cells form tetrads and cubical octads (sarcinae)
[pic]

Question 24

CELL POLARITY AND AGING

   Bacterial cell poles (ends of bacteria) differ in their origin and age a phenomenon called \_\_\_\_

Answer 24

Polar aging

Question 25

The process of ______ generates daughter cells with chemically different poles

Answer 25

Cell division

Question 26

“Old” poles continue to age; cell wall material degrades slightly, increasing ____

Answer 26

Chance of cell lysis (disintegration of a cell by rupture of the cell wall/ membrane

Question 27

Cells with different _______ may differ in the resistance to antibiotics

Answer 27

Polar ages | [pic]

Question 28

SPECIALIZED STRUCTURES (PHOTOTROPHS) Thylakoids

Answer 28

Extensively folded intracellular membrane • Consists of layers of folded sheets (lamellae) or tubes of membranes packed with chlorophyls (cells that do photosynthesis) and electron carriers

Question 29

Carboxysomes

Answer 29

polyhedral bodies packed with the enzyme Rubisco for CO2 fixation

Question 30

Gas vesicles

Answer 30

to increase buoyancy | [pic]

Question 31

SPECIALIZED STRUCTURES Storage granules

Answer 31

* Glycogen, PHB, and PHA for energy | * can store Sulfur, for oxidation

Question 32

Magnetosomes

Answer 32

* Membrane-embedded crystals of magnetite, Fe3O4 | * Orient the swimming of magnetotactic bacteria

Question 33

Pili

Answer 33

or fimbriae – straight filaments of pilin protein | • Used in attachment

Question 34

Sex pili

Answer 34

used in conjugation

Question 35

Stalks

Answer 35

membrane- embedded extensions of the cytoplasm | • Tips secrete adhesion factors called holdfasts

Question 36

Nanotubes

Answer 36

intercellular connections that pass material from one cell to the next [pic]

Question 37

SPECIALIZED STRUCTURES- FLAGELLA Many bacteria and archaea can swim by means of ________

Answer 37

Rotary flagella

Question 38

Peritrichous cells (e.g. E. coli, Salmonella)

Answer 38

have flagella randomly distributed around the cell | • Flagella rotate together in a bundle behind the swimming cell

Question 39

Lophotrichous cells (e.g. Rhodospirillum rubrum)

Answer 39

have flagella attached at one or both ends

Question 40

Monotrichous cells (e.g. Caulobacter swarmer)

Answer 40

have a single flagellum on one end

Question 41

Each flagellum is a spiral filament of protein monomers called ______

Answer 41

Flagellin (FliC)

Question 42

Filament rotates by means of a motor driven by the ___

Answer 42

Proton motive force

Question 43

Flagella either rotate clockwise (CW) or counterclockwise (CCW) relative to the _____

Answer 43

Cell | [pic]

Question 44

CHEMOTAXIS

Answer 44

Is the movement of bacterium in response to a chemical gradient

Question 45

Attractants cause CCW rotation

Answer 45

* Flagella bundle together • Push cell forward | * “Run”

Question 46

Repellants cause CW rotation

Answer 46

• Flagella bundle falls apart • “Tumble” • Bacterium briefly stops, then changes direction [pic]

Question 47

The alternating runs and tumbles cause a ______

Answer 47

“Random walk”

Question 48

Receptors detect attractant concentrations

Answer 48

Sugars, amino acids

Question 49

Attractant concentration increases and prolongs run

Answer 49

• Termed a “biased random walk” • Causes a net movement of bacteria toward attractants (or away from repellants) [pic]

Question 50

ARCHAEAL CELL STRUCTURE AND FUNCTION ( archaeal aren’t pathogens) Archaea are the most ______ diverse of the three domains

Answer 50

Ecological

Question 51

Extremophiles

Answer 51

Psychrophiles, hyperthermophiles, halophiles, acidophiles, methanogens

Question 52

Archaea are also abundant in moderate habitats

Answer 52

Open ocean, soil, and surface of plant roots

Question 53

Surprisingly, the archaeal domain lacks ______

Answer 53

Pathogens | [pic]

Question 54

DISTINCT ARCHAEAL TRAITS

Answer 54

[important pic with info]

Question 55

ARCHAEAL CELL MEMBRANE | Depending at where they are living

Answer 55

``` • Use L-glycerol instead of D- glycerol • Ether linkages instead of ester *More stable; requires more energy to break • Isoprenoid chains * Branched at every 4th carbon ```

Question 56

Cross linked lipids

Answer 56

Ends of side chains linked covalently to form a tetraether

Question 57

Cyclopentane rings

Answer 57

Strengthen membrane at high temperatures | [PIC]

Question 58

ARCHAEAL S-LAYER AND CELL WALL Most archaea possess a _______ membrane without any outer membrane

Answer 58

Single

Question 59

Many also do not have a cell wall, but only an S-layer of proteins plugged into the ______

Answer 59

Tetraether membrane

Question 60

Some do have a cell wall composed of _____ or ______

Answer 60

Pseudomurein Or pseudopeptidoglycan • Instead of N-acetylmuramic acid have N-acetyltalosaminuronic acid and beta(1,3) linkage [pic]

Question 61

ARCHAEAL GENOMES Similarities to bacteria

Answer 61

* Circular genome * Gene size and density * Has operon

Question 62

Similarities to eukaryotes

Answer 62

* RNA polymerase has TBP (tata binding proteins), TFB (transcription factor B) * Has proteins similar to histones

Question 63

Unique

Answer 63

• Some have reverse gyrases • Guanosine analog archaeosine [PIC]

Question 64

THE BACTERIAL CELL

Answer 64

[PIC]