A spherical unicellular alga relies solely on passive diffusion across its cell surface membrane to supply its cytoplasm with dissolved carbon dioxide. During a growth phase, the cell remains spherical but its volume increases by 237.5% (representing a final volume 3.375 times its initial volume).

Which of the following correctly describes the change in the cell's surface-area-to-volume ( $S A : V$ ) ratio and the biological consequence of this scaling?

The $S A : V$ ratio decreases by a factor of $3.375$ (to approximately $29.6%29.6\%$ of its original value), reducing the rate of carbon dioxide supply per unit volume of cytoplasm.

The $S A : V$ ratio decreases by a factor of $1.5$ (to approximately $66.7%66.7\%$ of its original value), reducing the rate of carbon dioxide supply per unit volume of cytoplasm.

The $S A : V$ ratio decreases by a factor of $1.84$ (to approximately $54.3%54.3\%$ of its original value), reducing the rate of carbon dioxide supply per unit volume of cytoplasm.

The $S A : V$ ratio increases by a factor of $1.5$ (to $150%150\%$ of its original value), increasing the rate of carbon dioxide supply per unit volume of cytoplasm.

Which of the following correctly describes the change in the cell's surface-area-to-volume ( $S A : V$ ) ratio and the biological consequence of this scaling?

The $S A : V$ ratio decreases by a factor of $3.375$ (to approximately $29.6%29.6\%$ of its original value), reducing the rate of carbon dioxide supply per unit volume of cytoplasm.

The $S A : V$ ratio decreases by a factor of $1.5$ (to approximately $66.7%66.7\%$ of its original value), reducing the rate of carbon dioxide supply per unit volume of cytoplasm.

The $S A : V$ ratio decreases by a factor of $1.84$ (to approximately $54.3%54.3\%$ of its original value), reducing the rate of carbon dioxide supply per unit volume of cytoplasm.

The $S A : V$ ratio increases by a factor of $1.5$ (to $150%150\%$ of its original value), increasing the rate of carbon dioxide supply per unit volume of cytoplasm.

2.1 Supplying the cell

Question 39

Markscheme

2.1 Supplying the cell

Question 39

Markscheme

2.1 Supplying the cell

Question 39

2.1 Supplying the cell Questions

2.1 Supplying the cell

Question 39

2.1 Supplying the cell Questions