Introduction to Micro

Question 1

Characteristics of prokaryotes

Answer 1

• circular DNA
• no organelles
• 70S ribosome
• ETC in cell membrane
• binary fission

Question 2

characteristics of eukaryotes

Answer 2

• membrane bound organelles
• 80S ribosomes
• ETC in mitochondrial membrane
• linear DNA
• replicate by mitosis

Question 3

Eukaryotic microbes

Answer 3

Fungi (mold and yeasts)
Protozoa
Helminths (parasitic worms)

Question 4

prokaryotic microbes

Answer 4

bacteria

Question 5

acellular microbes

Answer 5

viruses

Question 6

Size and microscopy of types of microbes from smallest to largest

Answer 6

Viruses (EM) –> smallest bacteria (EM) –> most bacteria (EM, LM) –> eukaryotic cells (LM) –> roundworm (eye)

Question 7

Types of external bacterial cell appendages?

Answer 7

Flagella- for motility and chemotaxis

Pili-shorter than flagella, sex pilus, fimbriae

Question 8

Capsule vs slime layer

Answer 8

Capsule- Distinct, gelatinous covering, glycocalyx, can allow bacteria to evade the immune system

Slime layer- diffuse, irregular and loosely attached

Question 9

Structure of cell walls

Answer 9

Contains peptidoglycan

Question 10

gram pos vs gram neg cell walls

Answer 10

Gram pos- has THICK peptidogycan layer, gel like material between layers, teichoic acid

Gram neg- thinner peptidoglycan layer, outer membrane layer, thick periplasm space, LPS in outermembrane

Question 11

Gram stain procedure

Answer 11

1. Stain cells with crystal violet (both cells stain blue)
2. Use iodine as a mordant to fix dye in cells (can’t penetrate the gram-neg cell)
3. Use alcohol as a decolorant (weakens gram-neg cell wall and dye is lost)
4. Use safranin counterstain (gram-neg cells stain red, gram-pos cells stain blue)

Question 12

Structure of the cell membrane

Answer 12

Outer membrane: blocks passage of many, more selectively permeable than gram positive cells.

LPS

Question 13

endospores

Answer 13

Hard, dry dormant forms of bacterial cells

Produced by: Bacillus, clostridium

Significance: survive harsh condition

Question 14

Ways to classify bacteria?

Answer 14

Strain or variety

type

Genus

Species

Question 15

strain or variety of bacteria

Answer 15

culture derived from a single parent that differs in structure or metabolism from other cultures of that species

Question 16

genus

Answer 16

taxonomical grouping, closely related but non-interbreeding species

Question 17

type of bacteria

Answer 17

subspecies that can show differences in antigeneic makeu, susceptibility to bacterial viruses, and in apthogenicity

Question 18

acid fast stain

Answer 18

• Primary dye solubilizes the lipid material of mycobacterial cell wall (red)
• decolorized but acid fast cells are resistant due (presence of lipoidal materail) preventing penetration of decolorant
• counterstain
• Non acid fast cells appear blue
• Acid fast cells appear red

Question 19

bacillus

Answer 19

• Gram positive
• rod shaped
• Obligate aerobes or facultative anaerobes
• test positive for catalase
• can produce endospores

Question 20

dipicolinic acid

Answer 20

part of bacterial spore; responsable for heat resistance of the endospore

Question 21

mycoplasma

Answer 21

bacteria that lack a cell wall; extremely variable shape

Question 22

murein

Answer 22

Peptidoglycan, consists of sugars and amino acids forming a mesh like layer outside the plasma membrane of most bacteria

Question 23

nucleoid

Answer 23

non-membrane bound area of the cytoplasm that contains the chromosome in the form of looped coils

Question 24

NAG

Answer 24

part of glycan chain

Question 25

NAM

Answer 25

part of peptidoglycan chain

Question 26

lipotechoic acid

Answer 26

surface associated adhesion amphiphile from gram positive bacteria and regulator of autolytic wall enzymes.