2.3: Internal and External structures

Question 1

cytoplasm

Answer 1

material bounded by cytoplasmic membrane (CM)

Question 2

protoplast

Answer 2

CM and everything within (CM and cytoplasm)

Question 3

what are the things in the protoplast

Answer 3

• Macromolecules -amino acids, nucleotides
• Soluble proteins
• DNA and RNA (since no nucleus, so floats in cytoplasm)
• Ribosomes
• Inclusions -any kind of storage for something in cytoplasm (only some have)

Question 4

Nucleoid

Answer 4

• Region that contains the genome

Question 5

what does the typical bacterial genome contain

Answer 5

• single circular double-stranded (ds) DNA chromosome
  -polymer of deoxyribonucleic acid (DNA)
  -carries all of the essential genes of th cell
• may have one or more plasmids

Question 6

what are plasmids

Answer 6

• smaller pieces of circular dsDNA that replicate independent of the chromosome
• carry non-essential genes (ex: genes for antibiotic resistance), beneficial but not always required

Question 7

what the function of bacterial ribosomes

Answer 7

• site of protein synthesis

Question 8

what type ribosomes do bacteria have

Answer 8

70S ribosomes

Question 9

each ribosome is made from 2 subunits 1 small, 1 large, made of protein and rRNA, what are these

Answer 9

• 30S subunit (small unit)
  -16S rRNA (most important, used to track evolutionary change)
• 50S subunit
  -23S (larger) and 5S (smaller) rRNA

Question 10

Cytoplasmic ribosomes synthesize…

Answer 10

cytoplasmic proteins (protein that will be soluble in cytoplasm)

Question 11

Membrane associated ribosomes synthesize…

Answer 11

• Membrane proteins
• proteins to be exported from the cell

Question 12

difference between capsules and slime layers (not strict)

Answer 12

• capsules- when polysaccharide is tightly bound and hard to wash away
• slime layers-generally less tightly bound

Question 13

what are capsules and slime layers made up of

Answer 13

Polysaccharide / protein layers (outside cell wall)

Question 14

true or false capsules and slime layers are always thick and rigid

Answer 14

false, may be thick or thin, rigid or flexible

Question 15

whats the function of capsules and slime layers

Answer 15

• assists in attachment to surfaces
• Protect against phagocytosis (being eaten)
• resist desiccation (drying out)

Question 16

what are fimbriae and their function

Answer 16

• Hair-like protein appendages
• Anchored to the cytoplasmic membrane and extend through the cell wall
• allows adhesion to solid surfaces

Question 17

how does Neisseria gonorrhoeae use fimbriae

Answer 17

To help it stick to epithelial cells on mucous membranes.

Question 18

what are pili and their function

Answer 18

• Hair-like protein appendages
• Typically longer than fimbriae
• assist in surface attachment and facilitate genetic exchange between cells (conjugation)

Question 19

Fimbriae and Pili can be used interchangeably but what is one function that only refers to pili

Answer 19

only pili facilitate genetic exchange between cells (conjugation)

Question 20

what type pili are involved in twitch motility

Answer 20

• type IV

Question 21

what are cell inclusions

Answer 21

Visible aggregates in cytoplasm

Question 22

what are the 4 Carbon storage polymers (cell inclusions)

Answer 22

• Poly-B-hydroxyalkanoate (PHA) -lipid storage (and lipids store the carbon)
• Glycogen -polymer of glucose

Question 23

what is the most prominent way bacteria store carbon and energy

Answer 23

in Glycogen (polymer of glucose)

Question 24

what cell inclusion stores accumulations of inorganic phosphate

Answer 24

Polyphosphate granules (volutin)

Question 25

what cell inclusion stores elemental sulfur

Answer 25

sulfur globules (do anerobic photosynthesis)

Question 26

Many bacteria and archaea produce a PHA called...

Answer 26

Polyhydroxybutyrate (PHB)

Question 27

What can PHB (type of PHA in bacteria and archaea) be used for

Answer 27

* can be harvested and used to produce plastics * these plastics are then biodegradeable by other bacteria, archaea, and fungi

Question 28

What are Magnetosomes intracellular granules made of

Answer 28

Intracellular granules of Fe3O4 or Fe3S4

Question 29

what do magnetosomes allow for

Answer 29

Gives the cell magnetic properties * allowing it to orient in a magnetic field * bacteria migrate along Earth's magnetic field- magnetotaxis. ## Footnote (taxis means to move)

Question 30

what are gas vesicles

Answer 30

* spindle-shaped, gas-filled structures made of protein * confer buoyancy to planktonic (free floating/swimming) prokaryotes

Question 31

what kind of bacteria commonly use gas vesicles

Answer 31

* Photosynthetic Cyanobacteria -use gas vesicles to adjust their vertical position in the water column to where light intensity is optimal for photosynthesis -allows them to form "blooms" in lakes

Question 32

who are endospores produced by? what are two genera that produce endospores?

Answer 32

* only some gram positive bacteria, not all * *Bacillus sp* -aerobic Gram positive rods * *Clostridium sp* -anaerobic Gram positive rods

Question 33

whats a vegatative cell

Answer 33

normal cell doing what bacteria do, normal growth, metabolically active.

Question 34

what's an endospore? when is it triggered?

Answer 34

* dormant cell with complete copy of genetic material, formed inside of a mother cell * metabolically inactive * triggered by lack of nutrients ## Footnote (specialized to only certain bacteria)

Question 35

how long do endospores take to build

Answer 35

* takes about 8-10 hours to build

Question 36

describe the lifecycle of a spore forming bacterium

Answer 36

* **stage 1: asymetric cell division ** -DNA replicates, identical chromosomes pulled to opposite ends of the cell * ** stage 2: Septation** -divides cell into 2 unequal compartments -forespore (prespore) -mother cell * ** stage 3: Mother cell engulfs the forespore** -forespore surrounded by two membranes * **stage 4: Formation of the cortex** -thick layers of peptidoglycan form between the two membranes -highly cross-linked layer -**core wall** -loosely cross-linked layer -**cortex** (~1/2 of spore volume) *** stage 5: Coat synthesis** -protein layers surround the core wall -spore coat -inner more tightly bound, always formed -exosporium -looser layer, sometimes formed * **stage 6: Endospore matures** -core is dehydrated -~10-30% of a vegatative cell's water content ** * Stage 7: Mother cell is lysed** -Mother cell disintegrates -mature spore is released

Question 37

What accumulates in the core of an endospire in coat synthesis, what do they do

Answer 37

Calcium, diplicolinic acid and small acid soluble proteins (SASPs) -helps stabilize DNA

Question 38

what are the protective features of the endospore, and what they protect against

Answer 38

* Layers (spore coat and cortex)-protect against chemicals, enzymes, physical damage, heat * core -dehydrated -protects against heat -Ca-diplicolinic acid and SASPs -protect against DNA damage

Question 39

what are 5 things endospores can resist

Answer 39

* boiling for hours * UV radiation * Chemical disinfectants * Dessication * Age