Biotechnology Flashcards – Cambridge IGCSE (9–1) Biology 0970 (Extended) (2026–2028)

What is yeast fermentation?

In the absence of oxygen, yeast respires anaerobically, converting sugar into ethanol and carbon dioxide.

Which product of yeast fermentation can be used as a biofuel?

Ethanol.

What two products does yeast produce from sugar during anaerobic respiration in bread dough?

Carbon dioxide and ethanol.

How does yeast respiration cause bread dough to rise?

Carbon dioxide becomes trapped in the dough, causing it to expand and rise.

What substance does pectinase break down?

Pectin.

What role does pectin play in fruit?

It helps hold fruit cells together.

How does breaking down pectin affect the amount of juice obtained from fruit?

It helps release juice, increasing the yield.

How does breaking down pectin affect the clarity of extracted fruit juice?

It makes the juice clearer.

How do enzymes in biological washing powders help remove stains?

They break down stain substances into smaller, more soluble molecules that can be washed away.

What three types of stain substance can different enzymes in biological washing powders act on?

Proteins, fats and starch.

How can the contribution of enzymes to washing-powder cleaning be investigated?

Compare how well a powder containing enzymes and one without enzymes remove equivalent stains, keeping washing conditions the same.

What two sugars are produced when lactase breaks down lactose, the sugar in milk?

Glucose and galactose.

How is lactase used to produce lactose-free milk?

Milk is treated with lactase to reduce its lactose content.

Who can benefit from lactose-free milk?

People who cannot digest lactose because they produce too little lactase.

What is a fermenter?

A vessel in which bacteria or fungi are grown in large quantities to produce useful materials.

What do microorganisms receive as they grow in a fermenter, and under what conditions?

They receive nutrients and grow under controlled conditions.

Where can useful products be collected from in a fermenter?

From the culture or from the microorganisms themselves.

How can bacteria be used to produce human insulin on a large scale?

Genetically modified bacteria produce insulin, which is then collected and purified.

Which fungus produces penicillin, and where is the penicillin obtained from?

Penicillium produces penicillin, an antibiotic obtained from the culture.

What is the useful product when fungi are grown to produce mycoprotein?

The protein-rich fungal biomass itself.