Intro to Prokaryotic Cells

Question 1

What are the basic shapes of bacteria?

Answer 1

Bacilli: rod shaped

Cocci: spherical shaped

Vibrio: comma shaped

Stella: star shaped

Coccobacilli: ovoid

Spirochetes: spiral shaped

Question 2

What are the basic arrangements of bacteria?

Answer 2

Diplococci: paired cocci

Streptococci: chains of cocci

Staphylococci: grapelike clusters

Diplobacilli: paired bacilli

Streptobacilli: chains of bacilli

Palisade: clusters of bacilli

*staph=clusters

*strep= chains

*diplo= pairs

Question 3

How do bacteria divide through binary fission?

Answer 3

• cell preparing to divide copies its DNA containing chromosome
• cell grows
• copied chromosome is drawn to opposite ends of the cell
• septum begins to form at midpoint
• septum eventually walls off the resulting two daughter cells from one another

Question 4

Active Transport

Answer 4

-requires energy to transport substances through channels or carrier proteins

Question 5

Primary Active Transport

Answer 5

• uses ATP to drive transport (basically the sodium potassium pump)
• transport of substances against their concentration gradient

Question 6

Secondary Active Transport

Answer 6

• uses an ion gradient to drive transport
  symport: ions and solute flow in the same direction
  antiport: ions and solute flow in opposite direction

Question 7

Passive Transport

Answer 7

• no energy investment
• transport of substances without an energy investment by the cell

Question 8

Simple Diffusion

Answer 8

-small noncharged molecules, gases, and lipid-soluble substances enter and exit cells

Question 9

Facilitated Diffusion

Answer 9

• moves substances along their concentration gradient with the help of membrane proteins
• channel proteins and carrier proteins

Question 10

What is an endospore?

Answer 10

-metabolically inactive structures that allow certain cells to enter a dormant state

Question 11

Why should healthcare providers be concerned about spore forming bacteria?

Answer 11

• highly resistant to environmental stresses (heat, starvation, drying, freezing, chemicals, etc.)
• the capacity to make endospores allows dangerous pathogens (Clostridium tetani, Clostridium botulinum, etc.) to survive for extended periods on surfaces

Question 12

How and why do endospores form?

Answer 12

• are a response to nutrient limitation
• highly resistant structure formed by a species of Bacillus and Clostridium when nutrient supplies are low
• endospores are formed through sporilation
  1. copying of DNA
  2. packaging of DNA, ribosomes, and special enzymes into the spore coat
  3. surrounding the spore coat with several heat and chemical resistant layers
  4. release of spore

Question 13

What is dipicolinic acid?

Answer 13

-contributes to the hardiness of the dormant structure by stabilizing the cell’s DNA and adding heat resistance

Question 14

What types of bacteria have acid fast cell walls?

Answer 14

• Nocardia
• Myobacterium

Question 15

Describe the acid fast wall

Answer 15

• acid fast staining detects a waxy lipid called mycolic acid in cell walls
• acid fast cells appear red/pink following acid fast staining procedure
• nutrients do not readily cross the waxy cell wall therefore acid fast bacteria grow very slowly

Question 17

Why are we concerned about acid fast bacteria in medicine?

Answer 17

-drugs do not easily cross the waxy cell wall therefore long multidrug therapies in patients infected with acid fast pathogens is necessary