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Practical: Investigating Anaerobic Respiration in Yeast. Yeast can respire anaerobically (without oxygen), breaking down glucose in the absence of oxygen to produce ethanol and carbon dioxide. Anaerobic respiration in yeast cells is called fermentation.
1 Yeast can be used to make beer. This process takes place in anaerobic conditions. (a) (i) Name the group of organisms that includes yeast. (1)..... (ii) What is meant by the term anaerobic? (1)..... (iii) Write the word equation for anaerobic respiration in yeast. (2)
Anaerobic Respiration. Anaerobic respiration in yeast can be summarised as follows. How many molecules of carbon dioxide will be produced from the breakdown of two molecules of glucose? The diagram shows apparatus that can be used to measure the rate of anaerobic respiration of yeast.
Define anaerobic respiration as the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen . State the word equations for anaerobic respiration in muscles during vigorous exercise (glucose → lactic acid) and the microorganism yeast (glucose → alcohol + carbon dioxide) .
Anaerobic respiration provides enough energy to keep the overworked muscles going for a short period, but continuing the ‘burst’ activity makes lactic acid build up in the bloodstream, producing muscle cramps. The person then has to rest, to oxidise the lactic acid fully.
The muscle cells require an adequate supply of oxygen for respiration. If insufficient oxygen is available, the cells must respire anaerobically. Fig. 20.2 outlines the process of anaerobic respiration in muscle cells. (i) Identify the compounds labelled D and E in Fig. 20.2. D E [2] (ii) What is the role of compound D in anaerobic respiration? [1]
Cellular Respiration Summary so far • Two types of Cellular Respiration – Aerobic (with O 2 present) – Anaerobic (no O 2present) • Two types of Anaerobic Respiration – Lactic Acid Fermentation • Creates 2 ATP molecules from one Glucose • Creates Lactic Acid – Occurs in Animals and some bacteria – Alcohol Fermentation
