Basic Fermentation Technology Questions and Answers on “Fermentation Biochemistry – Wort Nutrients Assimilation”.
1. Ale strains of Saccharomyces cerevisiae cannot easily ferment ______________
A. Fructose
B. Trehalose
C. Sucrose
D. Raffinoseid5fdba58d328d3″
Answer: B
Clarification: Ale strains of Saccharomyces cerevisiae can ferment glucose, fructose, maltose, sucrose, galactose, raffinose, maltotriose. They cannot ferment trehalose easily. Lager strains of Saccharomyces cerevisiae are also able to ferment melibiose. Therefore, there is some variability between individual strains.
2. Which of the following carbohydrate is assimilated first?
A. Sucrose
B. Maltotriose
C. Glucose
D. Fructoseid5fdba58d328fb”
Answer: A
Clarification: Sucrose is utilized first and the hydrolysis causes an increase in the concentration of fructose. Fructose and Glucose are taken up more or less simultaneously and is disappeared from wort within 24 hours. After glucose, maltose is assimilated and at last, after maltose, maltotriose is utilized.
3. Which of the following is not utilized by the brewing strains?
A. Dextrins
B. Starch
C. Maltotriose
D. Melibioseid5fdba58d32909″
Answer: A
Clarification: Higher polysaccharides, the dextrins are not utilized by the brewing strains and these contribute to beer flavor by way of imparting fullness. Although many attempts have been made to utilize dextrins.
4. Who introduced the first method of dextrin utilization?
A. Vakeria and Hinchliffe
B. Oura
C. Bisson and Fraenkel
D. Does and Bissonid5fdba58d32913″
Answer: A
Clarification: Vakeria and Hinchliffe introduced the first method for the utilization of dextrins. They introduced an appropriate enzyme into the brewing yeast by genetic manipulations. These modifications lead to the utilization of dextrin.
5. SUC2 helps in the hydrolyzes of _____________
A. Sucrose and Glucose
B. Maltose and Sucrose
C. Sucrose and Raffinose
D. Glucose and Maltoseid5fdba58d3291c”
Answer: C
Clarification: In Saccharomyces cerevisiae, the enzyme encoded by the SUC2 gene and it helps in the hydrolyzes of sucrose and raffinose. After hydrolyzes, fructose and glucose are taken up via glucose transporters.
6. Who concluded the patterns of loss of glucose?
A. Maurico and Salmon
B. Does and Bilson
C. Bisson and Fraenkel
D. Vakeria and Hinchliffeid5fdba58d32925″
Answer: A
Clarification: Maurico and Salmon in 1992 concluded the differential patterns of loss of glucose transporters due to nitrogen starvation formed the basis of differences in ethanol productivity in two strains of S.cerevisiae.
7. Who recognized different amino acid transport systems in yeast?
A. Bilson
B. Maurico
C. Grenson
D. Horakid5fdba58d3292e”
Answer: D
Clarification: Horak in 1986 recognized 16 different amino acid transport systems in yeast. Of these 12 are constitutive and remaining are subject to regulation by the nitrogen sources present in the growth medium. This phenomenon is termed as nitrogen catabolic repression.
8. Which of the following is a Class A amino acid?
A. Histidine
B. Lysine
C. Leucine
D. Prolineid5fdba58d32937″
Answer: B
Clarification: Lysine is a class A amino acid. Some of the other class A amino acids are Arginine, Aspartic acid, Glutamate, Serine. Histidine and Leucine are Class B amino acids and Proline is a class D amino acid in order of assimilation during fermentation.
9. Glycine belongs to _____________ in order of assimilation during fermentation.
A. Class A
B. Class B
C. Class C
D. Class Did5fdba58d3293f”
Answer: C
Clarification: Glycine belongs to Class C amino acid. Tyrosine, tryptophan, Alanine, Phenylalanine, etc. belong to class C amino acid. Glycine is an amino acid that contains single H-bond as a side chain. It is a proteingenic amino acid.
10. What do you mean by aerobic sterol exclusion?
A. High uptake occurs
B. No uptake occurs
C. Low uptake occurs
D. Moderate uptake occursid5fdba58d32948″
Answer: B
Clarification: Aerobic sterol means no uptake occurs. Under anaerobic conditions, no uptake occurs in the stationary phase. This was termed by Lewis et al. in 1998.
11. SUT1 gene is involved in _______________
A. Sterol uptake
B. Carbohydrate uptake
C. Protein uptake
D. Metal ion uptakeid5fdba58d32951″
Answer: A
Clarification: The product of SUT1 gene is involved in the sterol uptake. Bourot and Karst in 1995 isolated a SUT1 from yeast and provided evidence that it is involved in sterol uptake under conditions of anaerobiosis, or in the absence of haem biosynthesis.
12. Biosorption is a ____________ process.
A. Active
B. Passive
C. Controlled
D. Feedbackid5fdba58d32959″
Answer: B
Clarification: Biosorption is a passive process in which the metal ions become attached to the cell wall. It is however rapid, insensitive to temperature, and does not require metabolic energy. It is also not inhibited by the metabolic inhibitors.
13. Bioaccumulation is a faster process.
A. True
B. Falseid5fdba58d32961″
Answer: B
Clarification: Bioaccumulation is a slower and well-regulated process. However, it is dependent on temperature and is blocked by metabolic inhibitors. Many genes have been identified which appear associated with the uptake of metal ions. An example is a FRE1 gene.
14. Proline is a class 1 wort amino acid based on the effect of fermentation performance.
A. True
B. Falseid5fdba58d32969″
Answer: A
Clarification: Proline is a class 1 wort amino acid based on the effect of fermentation performance. Proline is a proteingenic amino acid that is involved in the biosynthesis of proteins. It is non-essential amino acid to human beings.
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