Question 1

Which of the following best describes the main advantage of yeast immobilisation in industrial fermentation processes?

Accepted Answer

It allows for the physical confinement of yeast cells, leading to increased substrate uptake and product yield.

Question 2

Which equation correctly represents the overall process of alcoholic fermentation by Saccharomyces cerevisiae?

Accepted Answer

$$\mathrm{Glucose\ (C_6H_{12}O_6$) \rightarrow 2\ Ethanol\ (C_2H_5OH) + 2\ CO_2$}$$

Question 3

Why does Saccharomyces cerevisiae perform fermentation even in the presence of oxygen (Crabtree effect)?

Accepted Answer

To outcompete other microorganisms by rapidly consuming sugars and producing toxic ethanol.

Question 4

Which scientist is credited with demonstrating that microbes are responsible for fermentation?

Accepted Answer

Louis Pasteur

Question 5

During the brewing process, what is the main purpose of the mashing step?

Accepted Answer

To hydrolyze starch and proteins in the crushed cereals, producing fermentable sugars.

Question 6

Which of the following is NOT a typical sugar found in the wort after mashing in beer production?

Accepted Answer

Lactose

Question 7

What is the correct taxonomic classification for Saccharomyces cerevisiae?

Accepted Answer

Kingdom: Fungi; Division: Ascomycota; Genus: Saccharomyces

Question 8

Which of the following best explains why brewers use airlocks or blow-off tubes during fermentation?

Accepted Answer

To safely vent excess $$CO_2$$ produced during fermentation and prevent vessel rupture.

Question 9

Which metabolic pathway is also known as the Embden-Meyerhof-Parnas (EMP) pathway?

Accepted Answer

Glycolysis

Question 10

What is the main difference between aerobic respiration and fermentation in yeast metabolism?

Accepted Answer

Aerobic respiration yields significantly more ATP per glucose molecule than fermentation.

Question 11

Which of the following is a direct benefit of yeast immobilisation for industrial bioethanol production?

Accepted Answer

Increased resistance to toxic and inhibitory compounds

Question 12

Which of the following best describes the role of invertase in Saccharomyces cerevisiae?

Accepted Answer

It hydrolyzes sucrose into glucose and fructose in the periplasmic space.

Question 13

Which historical discovery is correctly matched with its scientist and significance in brewing science?

Accepted Answer

Emil Christian Hansen – First isolation of pure yeast strain

Question 14

Which of the following best explains why yeast fermentation is crucial in bread making?

Accepted Answer

It produces $$CO_2$$, which causes the dough to rise and creates the bread's texture.

Question 15

Which of the following is a correct statement about the life cycle of Saccharomyces cerevisiae?

Accepted Answer

It can alternate between haploid and diploid forms, with both capable of asexual reproduction by budding.

Question 16

In winemaking, what is the main difference between red and white wine fermentation?

Accepted Answer

White wine is fermented after the skins and pomace are removed, while red wine is fermented on the pomace.

Question 17

Which of the following best describes the Pasteur effect?

Accepted Answer

The inhibition of fermentation by oxygen in most cells.

Question 18

Which of the following is a plausible reason for the evolutionary advantage of ethanol production by yeast?

Accepted Answer

Ethanol is toxic to competing microorganisms, giving yeast a competitive edge.

Question 19

Which of the following is a correct summary of the ATP yield from glucose metabolism in yeast under aerobic and anaerobic conditions?

Accepted Answer

Aerobic: 32 ATP; Anaerobic: 2 ATP

Yeasts as Metabolic Factories: Microbial Biotechnology and Industrial Applications

Study Guide - Practice Questions