Unit 2 · 2.2 — Cell Size [cite: 9]

Everything to learn here

• Concept: As biological cells increase in volume, their surface area-to-volume ratio decreases rapidly, impairing the efficiency of material and thermal exchange across the membrane [cite: 13, 21].
• Concept: In endothermic mammals, overall organism body size has an inverse relationship with metabolic rate; smaller animals require higher metabolic rates per unit of mass to maintain body temperature [cite: 21, 24].
• Equation: Equation/Process: Surface Area to Volume Ratio: $SA:V = \frac{\text{Surface Area}}{\text{Volume}}$ [cite: 31].
• Skill: FRQ Task Verb "Justify" — Calculate SA:V for differently sized models (cubes/spheres) and mathematically justify why cells must remain small to survive [cite: 14, 16, 31].
• Concept: Analyze how surface area-to-volume ratios influence the efficiency of nutrient intake and waste removal.
• Equation: $$V=s^{3}andSA=6s^2;usedtocalculatesurfacearea-to-volumeratiosforexchangeefficiency.$$

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