Microbiology Chapter 6

Question 0

Bacterial binary fission 4 step description?

Answer 0

Cell elongation and dna replication

Cell wall and plasma membrane constrict

Cross walls seperate two copis of dna

Cell seperation

Question 1

Microbial growth refers to

Answer 1

Number of cells not cell size

Question 2

Which Fts protein = filamentous temperature sensitive found in prolaryotes mitochondria abd chloroplast is important for ?

Answer 2

Cell divsion because they form a divisome

Question 3

Other ftsz functions

Answer 3

Attracts other ftsz tp form ring

Ftsz depolymerizes

Hydrolyze gtp for energy

Question 4

Assembly of polymers occurs outside the cytoplasmic membrane. What enzyme cuts and insert peptidoglycan

Answer 4

Autolysins

Question 5

Lipid carrier molecules known as bactoprenol transport building blocks across the membrane, what building blocks do they transfer

Answer 5

: NAG/NAM/pentapeptide

Question 6

what is the bactoprenol mechanism

Answer 6

Carrier inserts the building block into the glycan backbone, then moves back inside the cell to pick up another building block

Question 7

what process involves Initially 2 alanine residues at the end of the peptidoglycan precursor
One splits off during transpeptidation
Bond between two Ala residues activates subterminal D-Ala, favoring reaction with DAP
No energy outside membrane - transpeptidation replaces requirement for energy

Answer 7

transpeptidation

Question 8

how to find generation time and number of generations

Answer 8

of generations =Log number of cells (end) − Log number of cells (beginning)/ Log number of 2

generation time = (60 min x # of hours)/number of generations

Question 9

four parts of a bacterial growth curve called

1. Intense activity preparing for population growth, but no increase in population.
2. Logarithmic, or exponential, increase in population.
3. Period of equilibrium; microbial deaths balance production of new cells.
4. Population Is decreasing at a logarithmic rate.

Answer 9

1. Lag Phase
2. Log phase
3. Stationary Phase
4. Death Phase

Question 10

Direct or Indirect method of measuring bacterial growth
Plate counts
Filtration
MPN
Direct microscopic count =petroff hausser cell counter

Answer 10

Direct

Question 11

Direct or Indirect method of measuring bacterial growth
Turbidity =light sensitive detector
Metabolic activity
Dry weight

Answer 11

Indirect

Question 12

two methods for preparing plates for counting

Answer 12

Pour and spread plate methods

Question 13

Temperature, PH osmostic pressure are physical or chemical contraints for growth?

Answer 13

physical

Question 14

Carbon
Nitrogen, sulfur, and phosphorous
Trace elements
Oxygen
Organic growth fact
are physical or chemical contraints for growth?

Answer 14

chemical

Question 15

temperature range for General danger zone for bacteria

Answer 15

150-30F an 63 to 0C

Question 16

pychrophily or thermophily
Enzymes function optimally in the cold
Denatured or inactivated at higher temperatures
More -helix and less -sheet
More polar and fewer hydrophobic amino acids
Active transport occurs at low temperatures
Cytoplasmic membranes contain higher content unsaturated fatty acids
Maintain semi-fluid state at lower temp
Some lipids also contain polyunsaturated fatty acids and long chain hydrocarbons with multiple double bonds

Answer 16

pychrophily

Question 17

pychrophily or thermophily
Enzymes and other proteins stable to heat
Critical amino acid substitutions
Increased number salt bridges
Densely packed highly hydrophobic interiors of proteins
Protein synthesizing machinery and structures such as cytoplasmic membrane are also heat stable
Membranes rich in saturated fatty acids
Form stronger bonds than unsaturated fatty acids

Answer 17

thermophily

Question 18

Microbe PH ranges

Answer 18

Most bacteria grow between pH 6.5 and 7.5
Molds and yeasts grow between pH 5 and 6
Acidophiles grow in acidic environments
Critical factor in growing in non-neutral pH is cytoplasmic membrane

Question 19

Hypertonic environments, or an increase in salt or sugar, cause plasmolysis
Extreme or obligate halophiles require high ____
Facultative halophiles tolerate high _____

Answer 19

Osmostic pressure

Question 20

Effescts of ocygen on growht of bacteria

Answer 20

powerpoint chapter 6 page 35

Question 21

Reducing media
Contain chemicals (thioglycolate or oxyrase) that combine O2
Heated to drive off O2 examples?

Answer 21

candle jar and anaerboic chamber

Question 22

what bacteria requires Microbes that require high CO2 conditions
CO2 packet
Candle jar

Answer 22

Capnophiles

Question 23

characteristics of biolfilms: like biolfilms in the mouth

Answer 23

Microbial communities
Form slime or hydrogels
Bacteria attracted by chemicals via quorum sensing
Share nutrients
Sheltered from harmful factors

Question 24

Culture medium: nutrients prepared for microbial growth
Sterile: no living microbes
Inoculum: introduction of microbes into medium
Culture: microbes growing in/on culture medium

Answer 24

culture media terms

Question 25

Chemically defined media: exact chemical composition is known
Complex media: extracts and digests of yeasts, meat, or plants
Nutrient broth
Nutrient agar

Answer 25

culture media

Question 26

Complex polysaccharide 
Used as solidifying agent for culture media in Petri plates, slants, and deeps
Generally not metabolized by microbes
Liquefies at 100°C
Solidifies at ~40°C

Answer 26

agar

Question 27

Make it easy to distinguish colonies of different microbes? Differential, Selective and Enrichment

Answer 27

Differential

Question 28

Suppress unwanted microbes and encourage desired microbes?Differential, Selective and Enrichment

Answer 28

Selective

Question 29

Encourages growth of desired microbe
Assume a soil sample contains a few phenol-degrading bacteria and thousands of other bacteria
Only phenaol metabolizing will be growing?

Answer 29

Enrichment

Question 30

A colony is a population of cells arising from a single cell or spore or from a group of attached cells
A colony is often called a

Answer 30

Colony forming unit CFU

Question 31

explain the biosafety levels 1-4

Answer 31

BSL-1: no special precautions
BSL-2: lab coat, gloves, eye protection
BSL-3: biosafety cabinets to prevent airborne transmission
BSL-4: sealed, negative pressure
Exhaust air is filtered twice