Question

the effect of glucose concentration on yeast fermentation
based on the data, there is a direct relationship between the concentration of glucose and the rate of co2 production during yeast fermentation. the greater the glucose concentration, the faster carbon dioxide is produced

1. propose an explanation for the relationship described above. (1 pt)
2. if you were to repeat this experiment but with a glucose concentration of 60 g/l, what would you predict the rate of co2 production to be? justify your prediction. (2 pt)
3. describe how photosynthesis changes the location of carbon atoms using the image and what you know about the photosynthesis formula. be sure to include the starting and stopping location of carbon atoms. (2 pts)
4. describe how respiration changes the location of carbon atoms using the image and what you know about the respiration formula. be sure to include the starting and stopping location of carbon atoms. (2 pts)

Explanation:

Question 6

Yeast fermentation is a metabolic process where yeast breaks down glucose for energy. Glucose is the substrate for the fermentation pathway (glycolysis and subsequent steps). Higher glucose concentration means more substrate is available for yeast cells to metabolize. With more substrate, the rate of enzymatic reactions in fermentation (like glycolysis) increases, leading to more pyruvate production, which is then converted to ethanol and CO₂. So, more glucose → more metabolic activity → faster CO₂ production.

Step1: Analyze the trend in the data.

From the table, as glucose concentration increases from 0 to 50 g/L, the rate of CO₂ production increases, but the rate of increase slows down (from 0→10: +2.1; 10→20: +1.7; 20→30: +1.4; 30→40: +0.9; 40→50: +0.4). This suggests a diminishing return as glucose concentration rises, likely due to enzyme saturation or other limiting factors.

Step2: Predict for 60 g/L.

Since the rate of increase is slowing, at 60 g/L, the rate will still be higher than at 50 g/L (6.5 mL/min) but the increase will be small. Let's see the pattern: from 40→50, increase is 0.4; so 50→60 might be an increase of ~0.3 - 0.4. So predicted rate: ~6.5 + 0.3 - 0.4 = 6.8 - 6.9 mL/min (or a bit more, but the key is justifying the trend of increasing but at a slower rate).

The photosynthesis formula is \( 6\text{CO}_2 + 6\text{H}_2\text{O} \xrightarrow{\text{light energy}} \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \). Carbon atoms start in carbon dioxide (CO₂, in the atmosphere or dissolved in water) and end in glucose (\(\text{C}_6\text{H}_{12}\text{O}_6\)) and other organic compounds (like starch) in plants. During photosynthesis, plants use light energy to fix CO₂ into organic molecules (carbon fixation), so carbon moves from inorganic CO₂ to organic glucose (and plant biomass).

Answer:

Yeast uses glucose as a substrate for fermentation. Higher glucose concentration provides more substrate for yeast's metabolic pathways (e.g., glycolysis), increasing the rate of reactions that produce CO₂, so CO₂ production rate rises with glucose concentration.

Question 7