M2 U2 Bacterial Growth and Nutrition

Question 1

Microbial growth pertains to the ___

Answer 1

Number of Cells

Question 2

Bacteria increase in number by an asexual means of reproduction

Answer 2

Binary Fission

Question 3

The time required for the bacterial cell to divide, thus doubling their population is referred to as ___

Answer 3

Generation time (doubling time)

Question 4

Generation time can be expressed mathematically as ___

Answer 4

GT = t/n

Question 5

Bacterial growth is in ___ progression

Answer 5

Geometrical

Question 6

A graph that represents the number (expressed as logarithm) of viable cells in a bacterial population over a period of time

Answer 6

Bacterial growth curve

Question 7

Bacteria are adapting to their new environment

Answer 7

Lag phase

Question 8

Period of intense metabolic activity

Answer 8

Lag phase

Question 9

There is little or no cell division so it appears relatively a “flat” period in the graph

Answer 9

Lag Phase

Question 10

Bacteria are most active metabolically

Answer 10

Log (or exponential) phase

Question 11

Cell division proceed at maximal rates

Answer 11

Log (or exponential) phase

Question 12

Where generation time is constant

Answer 12

Log (or exponential) phase

Question 13

Period of equilibrium

Answer 13

Stationary phase

Question 14

Balance between cell division and cell death

Answer 14

Stationary phase

Question 15

Growth curve becomes horizontal and at its greatest population density, thus also known as the plateau phase

Answer 15

Stationary phase

Question 16

Cell division stops completely

Answer 16

Decline (or death) phase

Question 17

Bacterial population is decreasing in a logarithmic rate

Answer 17

Decline (or death) phase

Question 18

A process by which chemical substances (nutrients) are acquired by the bacterium from the environments and used in cellular activities such as metabolism and growth

Answer 18

Nutrition

Question 19

This is designed to provide all the essential nutrients

Answer 19

Cell membrane

Question 20

In the laboratory, all essential nutrients required for bacterial growth are provided by the ___

Answer 20

Culture medium

Question 21

Major elements

Answer 21

C, H, O, N, S, P, K, Mg, Fe, Ca

Question 22

• Supplied by inorganic ions, water molecules, small molecules, and macromolecules
• Serve as either structural or functional role in cells

Answer 22

Major elements

Question 23

Required by certain cells in small amounts that is difficult to detect or measure

Answer 23

Trace elements

Question 24

Trace elements

Answer 24

Mg, Co, Zn, Cu, Mo

Question 25

Important cofactors for essential enzymatic reactions to proceed

Answer 25

Trace elements

Question 26

Structural backbone of living matter

Answer 26

Carbon

Question 27

Organic compounds essential for growth

Answer 27

Growth factors

Question 28

Growth factors required by bacteria are ___

Answer 28

Purines and Pyrimidines, Amino acids, and Vitamins

Question 29

Required for synthesis of nucleic acids

Answer 29

Purines and Pyrimidines

Question 30

Used by some bacteria for synthesis of proteins

Answer 30

Amino acids

Question 31

Needed by some bacteria as coenzymes and functional groups of some enzymes

Answer 31

Vitamins

Question 32

Bacteria that have special nutritional requirements

Answer 32

Fastidious

Question 33

Atmospheric gases that most influence bacterial growth are __

Answer 33

Oxygen and Carbon dioxide

Question 34

Completely dependent on atmospheric O2 for growth

Answer 34

Obligate aerobe

Question 35

Does not tolerate O2 at all and die in its presence

Answer 35

Obligate anaerobe or Strict anaerobe

Question 36

An aerobe but can grow in the absence of O2

Answer 36

Facultative anaerobe

Question 37

An anaerobe but can grow in the presence of O2

Answer 37

Aerotolerant anaerobe

Question 38

Requires reduced O2 concentration

Answer 38

Microaerophile

Question 39

Oxygen is also a powerful oxidizing agent that exists in many toxic forms known as ___

Answer 39

Oxygen Free Radicals

Question 40

An extremely reactive molecule produced by both living and non-living processes

Answer 40

Singlet oxygen

Question 41

Formed in small amounts during the normal respiration of organisms that use oxygen as a final electron acceptor, forming water

Answer 41

Superoxide radical or superoxide anion

Question 42

Forms when an oxygen molecule combines with another oxygen molecule

Answer 42

Peroxide anion

Question 43

Formed in the cell cytoplasm by ionizing radiation

Answer 43

Hydroxyl radical

Question 44

Several bacteria produce ___ that allow them to detoxify harmful forms of oxygen and not be affected by its presence

Answer 44

Enzymes

Question 45

Converts the superoxide radical into molecular oxygen and hydrogen peroxide 2O2- + 2H+ => H2O2 + O2

Answer 45

Superoxide dismutase

Question 46

- Produced by some bacteria in response to formation of toxic hydrogen peroxide during normal aerobic respiration - Converts H2O2 into water and oxygen

Answer 46

Catalase

Question 47

- Another enzyme that breaks down hydrogen peroxide | - However, it doesn't produce oxygen

Answer 47

Peroxidase

Question 48

A chemical that absorbs O2 gas and renders it unavailable to the bacteria

Answer 48

Thioglycolate

Question 49

Use of thioglycolate broth, the O2 content of the medium decreases with depth until the medium becomes anoxic, toward the bottom of the tube; its progress can be shown by the ___

Answer 49

Red dye resazurin

Question 50

Bacteria that grow best at a higher CO2 tension than is normally present in the atmosphere

Answer 50

Capnophile or capneic

Question 51

Each bacterial species exhibits three cardinal temperatures, which describe the temperature range or temperature it grows at best

Answer 51

Minimum, Optimum, and Maximum temperature

Question 52

- Grow best at low temperatures (0-15C) | - Generally cannot grow at 20C

Answer 52

Psychrophiles

Question 53

Optimum temperature for growth that fall into the range of 20C to 40C

Answer 53

Mesophiles

Question 54

- Microorganisms that grow optimally at temperatures greater than 45C - Many are spore-forming organisms

Answer 54

Thermophiles

Question 55

Bacteria that grow best at pH range 1.0 to 5.5

Answer 55

Acidophile

Question 56

Bacteria that grow best at pH greater than 8.5

Answer 56

Alkalinophile

Question 57

Bacteria that grow best between 6.0 to 8.0

Answer 57

Neutrophile