Cell Growth pt. 3

Question 1

These intermediates are replaced by anaplerotic reactions

Answer 1

Replenishing intermediates

Question 2

Cells can also fix ________ to replace _______ (_________ carbon dioxide fixation)

Answer 2

1. carbon dioxide
2. intermediates
3. heterotrophic

Question 3

TCA cycle intermediates can be ________ for biosynthesis

Answer 3

funneled off

Question 4

Anaerobic respiration can occur by using ____ as a terminal electron acceptor in the ETC.

Answer 4

nitrate

Question 5

Many cells can also generate energy without the _____, but with a ________.

Answer 5

1. ETC (electron transport chain)
2. lower efficiency

Question 6

In _____________, no net oxidation or reduction since electron transport chain is not available to produce NAD+ required in TCA cycle.

Answer 6

Alcohol and Lactate Formation

Question 7

Pentose phosphate pathway generates ______ (reducing power for biosynthesis) and __________ (make up ATP, RNA, DNA, others).

Answer 7

NADPH
5 carbon sugars

Question 8

Cell growth is characterized by?

Answer 8

specific growth rate, μ

Question 9

Cells + _____ –> ______ + new cells + _______

Answer 9

1. substrate
2. extracellular products
3. original cells

Question 10

can be measured directly and/or indirectly.

Answer 10

Cell concentration

Question 11

Measuring cell concentration: mass or cell number basis

Answer 11

Direct

Question 12

Cell number counting: (3)

Answer 12

1. hemocytometer
2. plate counts
3. particle counters

Question 13

Type of Counting Cells

Advantage: accurate, typically low noise in measurement
Disadvantage: time consuming, carcinogenic, mutagenic stains

Answer 13

Hemocytometer

Question 14

Type of Counting Cells

Advantage: counts viable cells, fairly accurate
Disadvantage: noisy, takes days.

Answer 14

1. Plate counts

Question 15

Type of Counting Cells

Advantages: very quick, obtain a size distribution in addition to a count.
Disadvantages: solutions must be particle free for accurate count, finicky, hardware, expensive, complicated.

Answer 15

Particle Counters

Question 16

count colonies (CFUs = colony forming units) formed by individual cells (dilute sample).

Answer 16

petri dish or dilution plate counts

Question 17

Most common units to report biomass

Answer 17

Mass concentration

Question 18

Mass concentration can be obtained by _________, _________, and ____________.

Answer 18

centrifuging sample, drying and weighing

Question 19

_________________

Advantages: typical variable in models, simple, low tech method.
Disadvantages: Presence of solids makes inaccurate, difficult to measure low biomass concentrations.

Answer 19

Mass concentration

Question 20

Indirect Concentration Measurements
- _____________ (most common).
- ____________ uptake or product evolution.
- ____________/ATP fluorescence.
- Protein or _______________ concentration measurements.

Answer 20

• Turbidometer or spectrophotometer
• Substrate
• Luciferin
• DNA/RNA

Question 21

the measure of the amount of light that passes through a turbid sample

Answer 21

Optical density

Question 22

_____ is often measured in OD and converted to mass per volume with a standard curve

Answer 22

Biomass

Question 23

_______
- Fixed amount of ____________ (growth medium) present at beginning.
- Batch is seeded with an _________ (small amount of live cells to start growth).

Answer 23

1. Batch Cultures
2. substrate
3. inoculum

Question 24

5 Phases of Growth

Answer 24

1. Lag
2. Exponential
3. Deceleration
4. Stationary
5. Death

Question 25

_________ - Growth is **suppressed**, duration **1-10 hours**. . - Inoculum should be _________and from exponential phase culture. - Multiple ____ can exist with multiple growth substrates (**diauxic growth**)

Answer 25

1. Lag Phase 2. 5 volume % 3. lag phases

Question 26

___________ - Growth is **balanced** (intercellular concentrations remain constant) - __________ on substrate concentration (growing at intrinsic maximum growth rate). - Growth rate is __________ with respect to **cell concentration**, 0th order with respect to substrate concentration.

Answer 26

1. Exponential Growth Phase 2. No dependence 3. 1st order ,

Question 27

Changes depending on the types of kinetics.

Answer 27

Doubling Times

Question 28

_____________ - End of exponential phase. - Caused by either build-up of toxic products or ______________of substrate. - Cell _______ changes to favor survival over growth.

Answer 28

1. Deceleration Phase 2. depletion 3. physiology

Question 29

_______________ - Net growth rate is **zero**. - Cells produce _______ metabolites (not growth associated). - Cells begin to lose ability to ______. - Cells begin to lyse, ________ growth occurs. - Cells ________ energy reserves (eg; PHB) in endogenous metabolism

Answer 29

1. Stationary Phase 2. secondary 3. reproduce 4. cryptic 5. catabolize

Question 30

________ - is relative to the **population**, **always occurs**. - Commonly modeled as a ____ process with respect to **biomass**. - Some portion of cells remain _______ for a long time, but are altered.

Answer 30

1. Death Phase 2. 1st order 3. viable

Question 31

microorganisms produced per unit substrate utilized.

Answer 31

Growth yield

Question 32

This rate is similarly affected relative to **diffusion**.

Answer 32

Biological reaction rate

Question 33

Effects of pH pH optima: *1. bacteria , 2.. yeast , 1. molds , 1. plant cells , 1. animal cells .*

Answer 33

1. 3-8, 2. 3-6 3. 3-7 4. 5-6 5. 6.5-7.5

Question 34

Effects of pH - pH varies significantly during fermentation if system is not _______ or controlled for pH. - CO2 evolution and ______ as nitrogen source both lower pH. - ____ utilization raises pH.

Answer 34

1. buffered 2. ammonium 3. Nitrate

Question 35

____ can become limiting substrate.

Answer 35

Dissolved Oxygen

Question 36

At high DO concentration, growth is _______of [02].

Answer 36

independent

Question 37

Dissolved Oxygen Requirements - O₂ solubility in water ~7 ppm (25°C, 1atm). - **Bacteria** require ____ of saturation for [02] independent growth, **yeast** ___. - Rate of O₂ transfer usually limited by _______ around bubbles

Answer 37

1. ~10% , 10-50% 2. stagnant liquid

Question 38

CFU

Answer 38

Colony Forming Units