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The fermentation reaction shown occurs as yeast biomass increases - HSC - SSCE Biology - Question 33 - 2015 - Paper 1
Question 33
The fermentation reaction shown occurs as yeast biomass increases. Glucose → X + Y (i) Identify the products X and Y. (ii) Describe how, after the 18th century, t... show full transcript
Worked Solution & Example Answer:The fermentation reaction shown occurs as yeast biomass increases - HSC - SSCE Biology - Question 33 - 2015 - Paper 1
Step 1
Step 2
Describe how, after the 18th century, the fermentation of glucose was modified to increase the yield of yeast biomass.
Answer
After the 18th century, advances in fermentation technology allowed for better control of the fermentation environment. Continuous fermentation techniques were developed, which maintained optimal conditions for yeast growth. This included controlling temperature, pH, and oxygen levels, leading to increased rates of fermentation and thus higher yields of yeast biomass. Additionally, selective breeding of yeast strains that produced higher biomass was also employed.
Step 3
Describe separately the method used to get the DNA out of the cells, and the method used to isolate the DNA from other cell components in this setting.
Answer
To extract DNA from cells, a common method involves the use of a detergent solution to break down the cell membranes and release the DNA into the solution. This is often followed by adding salt to stabilize the DNA. For isolating DNA from other cellular components, techniques such as precipitation with alcohol (ethanol or isopropanol) can be used, allowing DNA to separate from proteins and other cellular debris, making it visible as a white, fibrous substance.
Step 4
Explain why the domestication of species for agriculture is described as a biotechnology. In your answer, refer to ONE specific domesticated organism.
Answer
The domestication of species for agriculture is considered a biotechnology because it involves the manipulation of living organisms for human benefit. This process has led to the selective breeding of plants and animals to enhance desired traits. For instance, the domestication of maize (corn) illustrates this concept well. Early agricultural societies selectively bred wild plants to produce larger ears of corn and more kernels, significantly increasing yield and reliability as a food source. This practice not only transformed agriculture but also shaped human societies.