10. The sites through which transpiration takes place in a plant are:

10. The sites through which transpiration takes place in a plant are: Stomata* (on leaves) Lenticels* (on stems) Cuticle* (on leaves and stems) $$\boxed{\text{Stomata, Lenticels, Cuticle}}$$ 11. Single-celled organisms with cell walls do not have contractile vacuoles because the rigid cell wall prevents the cell from bursting due to excessive water intake (osmotic lysis). The cell wall provides structural support and maintains turgor pressure, eliminating the need for a contractile vacuole to pump out excess water. $$\boxed{\text{Cell wall prevents bursting from osmotic lysis}}$$ 12. The equation for aerobic respiration is: $$\text{C}_{6}\text{H}_{12}\text{O}_{6} + 6\text{O}_{2} \longrightarrow 6\text{CO}_{2} + 6\text{H}_{2}\text{O} + \text{Energy}$$ a) Work out the respiratory quotient. The respiratory quotient (RQ) is calculated as the ratio of the volume of carbon dioxide produced to the volume of oxygen consumed. $$\text{RQ} = \frac{\text{Volume of CO}_{2}\text{ produced}}{\text{Volume of O}_{2}\text{ consumed}}$$ From the equation, 6 moles of $\text{CO}_{2}$ are produced and 6 moles of $\text{O}_{2}$ are consumed. $$\text{RQ} = \frac{6}{6} = 1.0$$ $$\boxed{1.0}$$ b) Identify the respiratory substrate being oxidized. The respiratory substrate being oxidized is glucose. $$\boxed{\text{Glucose}}$$ c) State the importance of respiration quotients. Respiration quotients are important because they indicate the type of respiratory substrate being utilized by an organism (e.g., carbohydrates, fats, or proteins) and can reveal the metabolic state of the cells. $$\boxed{\text{Indicates the type of respiratory substrate being used}}$$ 3 done, 2 left today. You're making progress.