Test 3 Chapter 9 Study Guide

Question 1

Daughter cells

Answer 1

Two completely identical cells formed as a result of binary fission

Question 1

Binary Fission

Answer 1

Most common method of prokaryotic division. Replicates DNA. Center constricts forming two daughter cells

Question 2

FtsZ Protein

Answer 2

Directs cytokinesis and cell division in prokaryotic cells

Question 3

First step of Binary fission

Answer 3

FtsZ forms a Z Ring on the cytoplasmic membrane

Question 4

Second step of Binary fission

Answer 4

Z ring is anchored by FtsZ-binding proteins defining the division plane

Question 5

Third step of Binary Fission

Answer 5

Additonal proteins added to z ring to form a divisome

Question 6

Final step of Binary Fission

Answer 6

Divisome leads to peptidoglycan production and septum formation

Question 7

Septum Formation

Answer 7

Forms new cell wall between the daughter cells at the end of binary fission

Question 8

Generation (doubling) time

Answer 8

Time it takes for the population to double through binary fission

Question 9

Formula for generation time

Answer 9

Number of cells = Starting cells x 2^number of generations

Question 10

Bacterial Growth Curve

Answer 10

Growth patter of microorganisms in a closed culture NO NUTRIENTS ADDED OR WASTES REMOVED

Question 11

Lag Phase

Answer 11

Immediately after adding bacteria to culture. No increase in number of living bacteria. Bottom of the curve.

Question 12

Log Phase

Answer 12

Exponential increase in number of bacteria cells. Rise on graph. Constant growth. IDEAL STAGE FOR RESEATCH AND MOST SUSCEPTIBLE TO ANTIMICROBIALS/DISINFECTANTS.

Question 13

Stationary phase

Answer 13

When New cells = dying cells. Plateau on graph. Endospores may form

Question 14

Death Phase

Answer 14

Dying cells > new cells. Down slope of graph. Persisters may remain.

Question 15

CFU/mL – if count 50 colonies on 1:10,000 dilution (10^-4)

Answer 15

CFU/mL = 50 * 10 * 10,000 = 5,000,000 = 5.00 x 10^-6 CFU/mL

Question 16

Serial Dilutions

Answer 16

1mL from original culture, added to 9 mL broth - makes a 1:10 dilution

Question 17

Biofilm

Answer 17

Ecosystems of bacteria. Many different bacteria hanging out.

Question 18

Bacteria Perks of Biofilm

Answer 18

Highly structured communities, selective advantage to bacteria. Resist antimicrobial, resource sharing, effective waste removal.

Question 19

Biofilm Structure

Answer 19

Embedded in a matrix with water channels interspersed. Allows nutrient, waste, gas movemement.

Question 20

Matrix of extracellular polymeric substances (EPS)

Answer 20

Polysaccharides and other macromolecules as a gel-like substance that holds biofilm together. Gives structure and integrity.

Question 21

Quorum Sensing

Answer 21

Cells coordinate activity in response to environment.

Question 22

Autoinducers

Answer 22

Communication molecules involved in Quorum Sensing

Question 23

Great Oxygenation Event

Answer 23

Early atmosphere was anoxic (no oxygen) Cyanobacteria increased oxygen in atmosphere killing most anaerobes.

Question 24

Reactive Oxygen Species (ROS)

Answer 24

By products of aerobic cellular respiration. Powerful redox reactions.

Question 25

Anaerobic ecosystems

Answer 25

Oxygen free environments - Deep in Earth's crust, Marshes, Bogs, Sewers, in the body.

Question 26

Obligate Aerobe

Answer 26

Needs oxygen to survive. Mycobacterium tuberculosis

Question 27

Obligate Anaerobe

Answer 27

Oxygen kills them. Lack enzymes to inactivate ROS. Bacteroides spp.

Question 28

Facultative Anaerobe

Answer 28

Aerobic bacteria, but can survive without oxygen. Grows best with oxygen. Staphylococci spp.

Question 29

Aerotolerant Anaerobe

Answer 29

Tolerate oxygen, some enzymes to deal with ROS. Lactobacilli

Question 30

Microaerophile

Answer 30

Obligate Aerobes, but require a very specific amount of oxygen. Around 1-10% oxygen. Campylobacter jejuni

Question 31

Obligate Aerobe in a Thioglycolate Medium (FTM test).

Answer 31

Bacterial cells all at the top of the tube, need oxygen

Question 32

Obligate anaerobes in a Thioglycolate Medium (FTM test).

Answer 32

Bacterial cells all at the bottom of the tube, killed by oxygen.

Question 33

Facultative Anaerobes in a Thioglycolate Medium (FTM test).

Answer 33

Bacterial cells mostly at the top some spread throughout tube.

Question 34

Aerotolerant Anaerobes Thioglycolate Medium (FTM test).

Answer 34

Bacterial cells spread throughout the tube.

Question 35

Microaerophile in a Thioglycolate Medium (FTM test).

Answer 35

Bacterial cells close to the top but not on top.

Question 36

Preoxidase

Answer 36

Breaks down hydrogen peroxide and turns it into water. Limits damage to membrane lipids

Question 37

Superoxide dismutase (SOD)

Answer 37

Breaks down superoxide anions generated by aerobic metabolism

Question 38

Catalase

Answer 38

Breaks down two hydrogen peroxide into 2 water and some oxygen

Question 39

pH and microbial growth at High pH

Answer 39

Hydrogen bonds between DNA strands are broken and lipids are hydrolyzed. pH imbalances denature proteins

Question 40

Optimum pH

Answer 40

Most favorable pH for organism growth

Question 41

Minimum pH

Answer 41

Lowest pH an organism can tolerate.

Question 42

Maximum pH

Answer 42

Highest pH an organism can tolerate,

Question 43

Neutrophile

Answer 43

Optimum growth range around pH of 7 (6-8) Location: Neutral environments.

Question 44

Acidophile

Answer 44

Have pumps to actively transport H+ out of the cell. Optimum Growth <5.5 Used for food fermentation. Location: Sauerkraut, pickles.

Question 45

Alkalinophile

Answer 45

Lipid and protein modifications. Optimum growth 8.0-10.5. Location: soda lakes Basic enviornments.

Question 46

Optimum Temp

Answer 46

temp where growth rates are highest

Question 47

Minimum temp

Answer 47

Lowest temperature where bacteria can divide

Question 48

Maximum temp

Answer 48

Highest temperature at which growth can occur

Question 49

Psychrophile

Answer 49

can grow at 0C but optimum is closer to 15C and rarely survive above 20C

Question 50

Psychrotrophs

Answer 50

4C - 25C

Question 51

Mesophile

Answer 51

Moderate Temperature between 20C - 45C

Question 52

Thermophile

Answer 52

Like it hot 50C - 80C

Question 53

Hyperthermophile

Answer 53

Really Hot 80C-110C

Question 54

What happens to bacteria in the cold

Answer 54

Membranes lose fluidity (become stiff & hard). ice crystals form. Proteins denature.

Question 55

Psychrophiles and Psychrotrophs (defenses)

Answer 55

Increased hydrophobic R groups in protein Antifreeze proteins Increase in unsaturated fatty acids – Harder to freeze because so fluid

Question 56

What happens to bacteria in the Hot

Answer 56

Membranes become too fluid (melt). Proteins denature. Nucleic Acids Denature.

Question 57

Thermophiles and hyperthermophiles (Defenses)

Answer 57

Increase in saturated fatty acids – harder to melt cause solid Higher GC content in DNA Additional bonds to allow protein stability

Question 58

Hypotonic

Answer 58

pressure inside the cell greater than outside. Net water movement into the cell

Question 59

Isotonic

Answer 59

Equal pressure inside and outside the cell Net water movement back and forth equal

Question 60

Hypertonic

Answer 60

Pressure outside the cell greater than inside, net movement out of the cell. Halo likes salt Halotolerant organisms Halophiles

Question 61

Halotolerant organisms

Answer 61

Tolerate high salt, not super high salt

Question 62

Halophiles

Answer 62

require high salt environment. Dead Sea

Question 63

Barophile

Answer 63

Require high pressure