Lecture 3: Microbial Cell Structure/Function Part 2

Question 1

What are pili?

Answer 1

Thin protein appendages on the outside of the cell that help with attachment and can facilitate horizontal gene transfer

Question 2

• What genus is this?
• What life domain does it belong to?
• What type of environement does it live in?

Answer 2

• Haloquadratum
• Archaea
• High salt environement

Question 3

What type of bacteria is this and why (2 reasons)?

Answer 3

Gran negative bacteria because there is an outer membrane and a THIN layer of peptidioglycan

Question 4

What kind of genetic material do archaea have?

Answer 4

Have circular, double stranded DNA chromosomes as well as plasmids

Question 5

What is methanogenesis?

What doman of life is it unique to?***

Answer 5

Biological production of methane gas (very potent greenhouse gas)

Unique to archaea

Question 6

What happens to the motion of a cell as the concentration of attractant increases?

Answer 6

Question 7

What is this flagellation pattern?

Answer 7

Polar (1 end of the cell) monotrichous

Question 8

• What organism is this?
• What life domain is it from?
• It is a source of _____ for ______

Answer 8

• Pyrociccus furiosus aka “rushing fireball”
  
  • one of Dr. Mohr’s favorite organisms
  • Hyperthermophile (85-113 degrees)
    
    • Can live in extremem environement due to the archaea membrane
  • Has more than 50 flagella
• Archaea
• Source of Pfu polymerase for PCR

Question 9

Do Archaea have plasma membranes?

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Answer 9

Yes, archaea have plasma membranes, aka lipid bilayer, cytoplasmic membrane

Question 10

What type of motion do repellents cause?

What’s that motion called?

Answer 10

Cause clockwise motion

Called tumble

The flagella fly apart, cells then tumble and change their direction

Question 11

What flagellation pattern is this?

Answer 11

Peritrichous—-flagella spread out all over the entire surface

Question 12

What is the collective pattern of runs + tumbles called?

Answer 12

Random walk

Question 13

What flagellation pattern is this?

Answer 13

Lophotrichous: cluster of flagella at one or both ends

This is specifically polar lophotrichous because flagella only at one end of the cell

Question 14

What temperature range do hyperthermophiles live in?

Answer 14

85-113+ degrees C

Question 15

How does the size of most archaea compare to bacteria?

Answer 15

Similar sized to bacteria, in the um (micrometer) range

Question 16

What are Type IV Pili?

Answer 16

Dynamic (can move) that can extend and retract, which is called

“twitching motility”

Question 17

Where do archaea live?

Answer 17

Live in terrestrial and aquatic environements

Question 18

What are the areas labelled called?

Answer 18

1. Filament
   
   1. Made up from flagellen protein
2. Hook
   
   1. Connects basal body to the filament
3. Basal body
   
   1. Series of rods and circular rings/discs that make up the motor
4. H+ protons moving into the cell to provide energy for the basal body (proton gradient)

Question 19

What are functions of external structures on microbes?

Answer 19

• Attachment
• Horizontal gene transfer (via sex pili)
• Movement (flagella)

Question 20

What kind of motion do attractants cause? (CW or CCW?)

What direction is that motion in?

What is it called?

Answer 20

Cause counterclockwise motion.

Flagella bundle together

Cells “run” forward

Question 21

How do archaea reproduce?

Answer 21

Asexually

Question 22

What are the proteins in the cell membrane?

What do they do/perform?

Answer 22

Chemoreceptors

They detect componds in the external environment and aid in chemotaxis (sensory system that enables microbes to move towards or away from specific chemicals)

Question 23

What temperature range do thermophiles live in?

Answer 23

Live in 45-85 degree C temperatures

Question 24

Do archaea have cell walls?

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Answer 24

Some archaea have cells walls, but DO NOT HAVE petidoglycan (NAG-NAM).

Other archaea don’t have cell walls but have a protein based S-layer