Gas Exchange Surfaces And Cell Membranes
State which three properties determine the efficiency of a gas exchange surface.
A cube of side length 2 cm has a surface area to volume ratio that, compared to a cube of side length 1 cm, is:
Fick’s Law states that the rate of diffusion is proportional to:
Alveolar walls thicken from 0.5 µm to 2.0 µm due to fibrosis. Assuming surface area and concentration difference are unchanged, the rate of diffusion will:
Which feature of the mammalian lung does NOT contribute to maintaining a steep concentration gradient across the alveolar wall?
The alveolar wall and the capillary wall together form the diffusion barrier in the lung. Which tissues form these two walls?
Which statement correctly describes the arrangement of phospholipids in the cell membrane?
What is the primary function of cholesterol in the cell membrane?
A scientist fuses a mouse cell with a human cell, having labelled the membrane proteins of each species with different fluorescent dyes. After 40 minutes, the dyes are completely intermixed across the fused membrane. This experiment provides direct evidence for which property of the membrane?
Why was the Davson-Danielli “sandwich” model of the membrane replaced by the fluid mosaic model?
In the beetroot membrane permeability practical, why is it essential to wash the beetroot cylinders thoroughly under running water before placing them in the test tubes?
In the beetroot practical, why does absorbance rise sharply once the temperature exceeds approximately 40°C?
Which is the correct dependent variable in the beetroot temperature investigation?
A student claims that a blue whale must have very efficient diffusion across its skin because it has an enormous surface area. Which response is correct?
A patient with pulmonary fibrosis has thickened alveolar walls. A patient with emphysema has destroyed alveolar walls, merging many small alveoli into fewer large ones. Using Fick’s Law, which statement correctly compares the effects on diffusion?
Which property of glycoproteins makes them essential for cell signalling?
A student investigating membrane permeability uses 60% ethanol on beetroot and observes a high absorbance reading. What is the best biological explanation?