This set of Bioprocess Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Aerobic Bioprocesses”.
1. Glycolysis is an aerobic process.
a) True
b) False
View Answer
Explanation: It is an anaerobic process. None of its nine steps involve the use of oxygen. However, immediately upon finishing glycolysis, the cell must continue respiration in either an aerobic or anaerobic direction; this choice is made based on the circumstances of the particular cell.
2. Yeast is only restricted to aerobic fermentation.
a) True
b) False
View Answer
Explanation: Yeast can use any of three major metabolic modes: aerobic fermentation in the presence of sugar and oxygen, anaerobic fermentation in the presence of sugar but absence of oxygen, and respiration (necessarily aerobic) in the presence of oxygen and a low concentration of fermentable sugar.
3. How much NADH is produced in the citric acid cycle?
a) One
b) Three
c) Six
d) Two
View Answer
Explanation: Products of the first turn of the cycle are one GTP (or ATP), three NADH, one QH2, and two CO2. Because two acetyl-CoA molecules are produced from each glucose molecule, two cycles are required per glucose molecule. Therefore, at the end of two cycles, the products are: two GTP, six NADH, two QH2, and four CO2.
4. How much ATP is produced in the citric acid cycle?
a) 32
b) 34
c) 36
d) 38
View Answer
Explanation: A total of 10 NADH’s is made (in glucolysis and the Krebs cycle) per glucose, and 2 FADH2‘s. We generally say that you get 3 ATPs per NADH and 2 per FADH2, so that these carriers produce a total of 30+4 = 34 ATPs and the Krebs cycle itself produces 2 GTPs, which are equivalent to 2 more ATPs, for a total of 38.
5. Citric acid is a weak organic acid.
a) True
b) False
View Answer
Explanation: Citric Acid is a naturally occurring preservative used in many applications including canning, flavoring, cleaning, and even photography development. As a weak organic acid, it is commonly purchased in powder form, but is found in all citrus fruits including lemons, limes, oranges, and tangerines.
6. Which of the following is a metal salt of citric acid used to prevent blood clot?
a) Trimagnesium citrate
b) Trisodium citrate
c) Dimagnesium citrate
d) Bisodium citrate
View Answer
Explanation: Metal salts of citric acid such as trisodium citrate are used to prevent blood clotting by complexing calcium. Trisodium citrate can be used in detergents and cleaners as a cleaning agent instead of phosphates.
7. What do you mean by surface fermentation?
a) Fermentation on semi-solid media
b) Fermentation on liquid media
c) Fermentation on liquid surface
d) Fermentation on solid media
View Answer
Explanation: The oldest and a relatively simple method for production of complex flavour extracts is the fermentation of flavour raw materials by bacteria and moulds (aspergillus, mucor) on solid nutrient media. The media is placed in simple thermostatic boxes on baking-tray like plates to which the micro-organisms are inoculated.
8. What do you mean by submerged fermentation?
a) Fermentation on semi-solid media
b) Fermentation on liquid media
c) Fermentation on semi-solid surface
d) Fermentation on solid media
View Answer
Explanation: Submerged fermentation is generally applicable for the manufacturing of cell products by propagation of micro-organisms and cell cultures in a fluid nutrient media.
9. Saccharomyces translation means:
a) Non-sugar Fungus
b) Non-sugar yeast
c) Sugar fungus
d) Sugar bacteria
View Answer
Explanation: Scientific name: Saccharomyces cerevisiae. Common name: Brewer’s yeast/ Baker’s yeast. Habitat: Saccharomyces when translated means “sugar fungus”. That is what this yeast uses for food. They are found in the wild growing on the skins of grapes and other fruits.
10. The crabtree effect is the repression of respiration.
a) True
b) False
View Answer
Explanation: The Crabtree effect describes the phenomenon whereby the yeast, Saccharomyces cerevisiae, produces ethanol(alcohol) in aerobic conditions and high external glucose concentrations rather than producing biomass via the tricarboxylic acid (TCA) cycle, the usual process occurring aerobically in most yeasts. The crabtree effect works by repressing respiration by the fermentation pathway, dependent on the substrate. The occurrence of alcoholic fermentation is not primarily due to a limited respiratory capacity.
11. Which type of drier is widely used for the production of dry yeast?
a) Spray driers
b) Roto–Louvre drier
c) Fluidized bed drier
d) Simple drier
View Answer
Explanation: Spray driers are the most widely used. A suspension with 10–20% yeast is atomized into a drying chamber and dried with hot air. The drying temperature and time are 50°C and 10–20 min, respectively.
12. Penicillin production occurs in which growth phase?
a) Lag phase
b) Log phase
c) Stationary phase
d) Death phase
View Answer
Explanation: Like all antibiotics, Penicillin is a secondary metabolite, so is only produced in the stationary phase as Bacteria produce secondary metabolite such as Antibiotics after the active stage (log phase) of the growth cycle.
13. Which sort of Fermenter is used for production of Penicillin?
a) Batch Fermenter, Fed-Batch Process
b) Fed-Batch Fermenter, Fed-Batch Process
c) Continuous Batch Fermenter , Fed-Batch Process
d) Fed-Batch Fermenter, Batch process
View Answer
Explanation: For Large production of Penicillin a Batch Fermenter, and a Fed-Batch Process is normally used to prolong the stationary period and so as to increase the production of Penicillin and Batch is used over continuous fermenter for large scale production and fed-batch process is used to overcome its disadvantages.
14. What do you mean by liquefaction?
a) Conversion of liquid to solid
b) Conversion of liquid to gas
c) Conversion of solid to liquid
d) Conversion of liquid to semi-liquid
View Answer
Explanation: Liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially.
15. Glucose and corn syrup is the same thing in accordance to sweeteners.
a) True
b) False
View Answer
Explanation: Both products are made from corn starch, but regular corn syrup is 100 percent glucose, while high-fructose corn syrup (HFCS) has had some of its glucose converted to fructose enzymatically.
Sanfoundry Global Education & Learning Series – Bioprocess Engineering.
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