Biotechnology and Genetic Engineering
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Biotechnology and yeast
SubtopicBiotechnology and yeast under Biotechnology and Genetic Engineering for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
Which of the following is required for yeast to grow and reproduce in a fermenter?
A.Complete darkness
B.A source of amino acids and minerals
C.Toxic chemicals
D.High levels of carbon monoxide
- 2.
What role does yeast play in the production of some traditional cheeses or fermented foods?
A.It provides the structure of the food.
B.It contributes to the flavor and texture through metabolic activity.
C.It acts as a preservative by freezing the food.
D.It removes all the salt from the food.
- 3.
In the context of the environment, why is ethanol considered a 'biofuel'?
A.It is made from non-renewable oil.
B.It is produced from biological sources like plants and yeast.
C.It does not release any carbon dioxide when burned.
D.It is a mineral found in the ground.
- 4.
Which enzyme converts starch into simpler sugars that yeast can then ferment?
A.Lipase
B.Amylase
C.Protease
D.Pectinase
- 5.
Which enzyme would you add to a washing machine to specifically target a stain from a chocolate milkshake (which contains milk protein and fat)?
A.Protease only
B.Lipase only
C.A mixture of protease and lipase
D.Amylase and pectinase
- 6.
What is the purpose of adding a nutrient broth (containing minerals and nitrogen) to a fermenter?
A.To provide the energy for respiration
B.To allow the microorganisms to synthesize proteins and grow
C.To neutralize any acidic waste products
D.To prevent the ethanol from killing the yeast
- 7.
Which of the following is true about the use of yeast in the brewing industry?
A.Oxygen is pumped in throughout the entire process
B.The process must be kept anaerobic to produce ethanol
C.Yeast is added only to provide the bubbles of carbon dioxide
D.The temperature is kept at to speed up the reaction
- 8.
Why is the production of insulin in yeast considered a triumph of biotechnology compared to the previous method of extracting it from pigs?
A.The insulin produced is identical to human insulin, reducing the risk of allergic reactions and ethical concerns.
B.The yeast-derived insulin is much more potent and requires smaller doses.
C.Yeast can produce insulin without the need for any glucose or nutrient input.
D.Insulin from yeast is the only form that can be taken orally as it survives digestion.
- 9.
In an industrial fermenter, what is the role of the 'impeller' or 'agitator'?
A.To maintain a uniform concentration of nutrients and oxygen and to ensure even temperature distribution.
B.To physically break the yeast cells to release the intracellular enzymes into the broth.
C.To provide the mechanical energy needed for the formation of peptide bonds.
D.To filter out the dead yeast cells from the bottom of the tank during the log phase.
- 10.
What happens if the 'ligase' enzyme is omitted from the genetic engineering process?
A.The gene and the plasmid may associate via hydrogen bonds, but the recombinant DNA will fall apart due to the lack of covalent bonds in the backbone.
B.The restriction enzyme will continue to cut the DNA until it is completely degraded into single nucleotides.
C.The yeast cell will use its own DNA polymerase to fix the gaps once the plasmid is inside the cell.
D.The recombinant plasmid will still be functional, but it will only be able to replicate once.
Download the worksheet for Biotechnology and Genetic Engineering - Biotechnology and yeast to practice offline. It includes additional chapter-level practice questions.
Genetic engineering (Insulin production)
SubtopicGenetic engineering (Insulin production) under Biotechnology and Genetic Engineering for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
Which of these describes the bacteria after they have received the human gene?
A.Infected
B.Transformed
C.Deceased
D.Extinct
- 2.
What is the biological name for the circular DNA molecule found in bacteria that is manipulated in genetic engineering?
A.Chromosome
B.Plasmid
C.Nucleolus
D.Ribosome
- 3.
In a fermenter, why is the pH monitored and adjusted?
A.To keep the water clear
B.To provide the best environment for the enzymes within the bacteria
C.To change the bacteria into humans
D.To stop the paddles from rust
- 4.
What term is used for the extraction and purification of the protein product at the end of the industrial process?
A.Isolating
B.Transforming
C.Downstream processing
D.Ligating
- 5.
What happens to the recombinant bacteria once they reach the end of their productive lifespan in the fermenter?
A.They are released into the environment to help clean up waste
B.They are sterilized and killed before the insulin is extracted
C.They are reused for the next 100 batches without treatment
D.They are converted into human pancreatic cells
- 6.
In genetic engineering, what is the role of the 'origin of replication' (ori) on the plasmid?
A.It determines the starting point for the translation of insulin
B.It allows the plasmid to be copied by the bacterial cell's machinery
C.It is the site where the plasmid attaches to the ribosome
D.It prevents the plasmid from being digested by the bacteria
- 7.
Why is the bacteria's own DNA not cut by the restriction enzymes it produces?
A.Bacteria lack the recognition sequences for their own enzymes
B.Bacteria methylate their own DNA to protect it from the enzymes
C.The enzymes are only active outside the bacterial cell
D.The bacterial DNA is kept in a separate nucleus away from the enzymes
- 8.
Why must recombinant insulin be formulated with small amounts of zinc during the final stages of production?
A.Zinc ions promote the association of insulin monomers into stable hexamers, which are better for storage and injection.
B.Zinc acts as a preservative that prevents the growth of mold and bacteria in the insulin vial.
C.Zinc is a necessary co-factor for the insulin receptor in the human body to recognize the hormone.
D.Zinc helps the insulin to cross the blood-brain barrier more effectively after it has been injected.
- 9.
In a large-scale bioreactor, how is the 'impeller' or 'agitator' speed related to the yield of recombinant insulin?
A.Higher speeds increase the rate of oxygen dissolution but can cause 'shear stress' that damages the bacterial cells.
B.Higher speeds reduce the temperature of the broth, which prevents the insulin protein from folding correctly.
C.Lower speeds are necessary to allow the bacteria to settle at the bottom of the tank for easier harvesting.
D.Lower speeds increase the rate of plasmid transfer between bacteria, leading to a higher percentage of transformants.
- 10.
What is the specific role of 'sigma factors' in the transcription of the recombinant insulin gene in E. coli?
A.They are subunits of RNA polymerase that recognize and bind to the specific promoter sequences on the plasmid.
B.They are enzymes that add a protective methylated cap to the end of the insulin mRNA.
C.They act as chaperones that guide the newly formed insulin polypeptide to the ribosome for translation.
D.They are responsible for the excision of the C-peptide from the proinsulin molecule within the cytoplasm.
Download the worksheet for Biotechnology and Genetic Engineering - Genetic engineering (Insulin production) to practice offline. It includes additional chapter-level practice questions.