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BIOLOGY, M1 2020 VCE 40 MC

A student investigated the effect of the presence of four different molecules, R, S, T and U, on the rate of cellular respiration in human liver cells. The production of carbon dioxide by the cells was recorded over a five-minute interval. The final concentration of carbon dioxide was recorded. The data collected is shown below.

\begin{array} {|c|c|}
\hline
\rule{0pt}{2.5ex} \textbf{Molecule present } \rule[-1ex]{0pt}{0pt} & \textbf{Concentration of carbon dioxide (ppm) after five minutes } \\
\hline
\rule{0pt}{2.5ex} \textbf{R} \rule[-1ex]{0pt}{0pt} & 400 \\
\hline
\rule{0pt}{2.5ex} \textbf{S} \rule[-1ex]{0pt}{0pt} & 800 \\
\hline
\rule{0pt}{2.5ex} \textbf{T} \rule[-1ex]{0pt}{0pt} & 600 \\
\hline
\rule{0pt}{2.5ex} \textbf{U} \rule[-1ex]{0pt}{0pt} & 1000 \\
\hline
\end{array}

The student presented the results as a graph.

Which one of the following graphs is the best representation of the results?

 
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\(A\)

Show Worked Solution

→ The data is quantitive but not continuous, therefore the column graph is the most appropriate way to represent the results.

\(\Rightarrow A\)

BIOLOGY, M1 2021 VCE 3

Scientists measured the metabolic activity of mammalian cells by measuring the uptake of glucose into the cells. The cells were maintained at 37 °C with a pH of 7.4 and suspended in a nutrient solution containing glucose. The uptake of glucose into the cells was recorded for the next 30 minutes.

  1. Explain why the uptake of glucose into the cells could be used to measure the metabolic activity of the cells.   (2 marks)

  1. The scientists repeated the experiment. They kept all conditions the same as for the first experiment, except that the cells were kept in low-oxygen conditions.

    Would the uptake of glucose into the cells be expected to be higher, lower or the same as for the first experiment? Justify your response.   (4 marks)

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a.    → Metabolic activity requires energy in the form of ATP molecules.

→ ATP molecules are made via aerobic cellular respiration, a process which requires glucose.
 

b.    Low oxygen environment:

→ By depriving the cell of oxygen it would struggle to respire aerobically, producing less ATP per molecule of glucose.

→ This would lead to a higher uptake of glucose to produce the same amount of ATP.
 

Answer could also include:

→ Being deprived of oxygen would cause the cell to respire anaerobically, producing toxins that damage the cell. 

→ This anaerobic respiration does not require glucose. Therefore, the uptake of glucose by the cell would be less than in an oxygen rich environment.

Show Worked Solution

a.    → Metabolic activity requires energy in the form of ATP molecules.

→ ATP molecules are made via aerobic cellular respiration, a process which requires glucose.

♦ Mean mark (a) 47%.

b.    Low oxygen environment:

→ By depriving the cell of oxygen it would struggle to respire aerobically, producing less ATP per molecule of glucose.

→ This would lead to a higher uptake of glucose to produce the same amount of ATP.
 

Answer could also include:

→ Being deprived of oxygen would cause the cell to respire anaerobically, producing toxins that damage the cell. 

→ This anaerobic respiration does not require glucose. Therefore, the uptake of glucose by the cell would be less than in an oxygen rich environment.

♦ Mean mark (b) 45%.