Chapter 1: Review

Question 1

Significance of Microorganisms

Answer 1

Ubiquitous, abundant, diverse (growth rate, metabolism, requirements of growth, staining characteristics, susceptibility to antibiotics)

Question 2

Job of clinical microbiologist:

Answer 2

culture organisms from patient specimens, classify/identify organism, predict and interpret antimicrobial susceptibility patterns

Question 3

Prokaryotes:

Answer 3

– No organelles
– Unicellular
– 70S ribosomes
– Bacteria will be our focus

Question 4

Eukaryotes:

Answer 4

– Organelles
– Unicellular or
Multicellular
– 80S ribosomes
– Protozoa and Fungi will be
our focus

Question 5

Where is ETC in bacterial cells?

Answer 5

plasma membrane

Question 6

Granules in cytoplasm are used for __

Answer 6

storage

Question 7

Bacteria with no cell wall include (2):

Answer 7

mycoplasma and ureaplasma

Question 8

Appendages (3):

Answer 8

flagella, pili, fimbriae

Question 9

Gram-positive cell wall:

Answer 9

One plasma membrane

Question 10

Gram-negative cell wall:

Answer 10

Two plasma membranes and LPS

Question 11

Endotoxins:

Answer 11

In the LPS, so only gram-negative

Question 12

Exotoxins:

Answer 12

Secrete toxins, mainly gram-positive cells.

Ex.) leukocidin, toxic shock syndrome toxin, diptheria toxin

Question 13

Typical bacteria size:

Answer 13

1-3 µm

Question 14

Microscopic shapes:

Answer 14

cocci, bacilli, spiral

Question 15

Cell wall of fungi is made up of __

Answer 15

polysaccharides

Question 16

Viruses:

Answer 16

• Acellular
• DNA or RNA
• Capsid
• Enveloped or non-enveloped
• Obligate intracellular parasites
• Host or host cell specific

Question 17

Taxonomy is based on __

Answer 17

genotype and phenotype

Question 18

Gram stain procedure:

Answer 18

1. Heat fix (methanol can be used)
2. Crystal violet (primary)
3. Iodine
4. Alcohol-acetone (decolorizer)
5. Safranin (counterstain)

negative = red or pink
positive = purple or blue

Question 19

Acid-fast stain:

Answer 19

• Ziehl-Neelsen method (heat)
• Kinyoun (detergent)
  – Carbolfuchsin (primary stain (red))
  – Acidified-alcohol (decolorizer)
  – Methylene blue (counterstain)
• Auramine-rhodamine
  – Fluorochrome stain (appears yellow or orange under fluorescent microscope)

Question 20

Major nutritional needs:

Answer 20

– Carbon source for cellular constituents

– Nitrogen source for proteins

– Adenosine triphosphate (ATP) energy source for cell functions

Question 21

Trace elements:

Answer 21

Phosphorus (P), sulfur (S), sodium (Na), potassium (K), chlorine (Cl), calcium (Ca)

Question 22

Types of growth media:

Answer 22

• Minimal medium
• Nutrient medium
• Enriched medium
• Selective medium
• Differential medium
• Transport medium

Question 23

Environmental Factors Influencing Growth:

Answer 23

• pH
• temperature
• gaseous composition of the atmosphere

Question 24

Generation time:

Answer 24

Time required for one cell to become two

Question 25

Growth curve:

Answer 25

Lag, log, stationary, death

Question 26

Determination of cell numbers:

Answer 26

Direct counts, plate, counts, density

Question 27

Fermentation:

Answer 27

– Anaerobic process carried out by both obligate, aerotolerant, and facultative anaerobes – Electron acceptor is an organic compound – Less efficient in energy generation than respiration

Question 28

Respiration:

Answer 28

– Aerobic respiration is an efficient energy-generating process in which molecular oxygen is the final electron acceptor – Certain anaerobes can carry out anaerobic respiration, they do not use molecular oxygen as final electron acceptor, but nitrate and sulfate for example

Question 29

DNA:

Answer 29

– Storage of genetic information (genetic potential) – Replication produces DNA copies.

Question 30

Types of fermentation:

Answer 30

Alcohol, homolactic, heterolactic, propionic, mixed acid, butanediol, butryic acid

Question 31

RNA:

Answer 31

– Produced by transcription of DNA – mRNA

Question 32

Translation:

Answer 32

mRNA is read by ribosome. Codon: a group of three nucleotides * tRNA matches codon with anticodon

Question 33

Transformation:

Answer 33

Uptake and incorporation of naked DNA

Question 34

Transduction:

Answer 34

Transfer of genes by bacteriophage

Question 35

Conjugation:

Answer 35

Transfer of genetic material from a donor to a recipient strain of bacteria

Question 36

Restriction enymes:

Answer 36

Enzymes that cut at specific sequences