Surface area to volume ratio

Describe and explain the relationship between surface area to volume ratio of the human body and metabolic rate.

Table 2 shows the height and mass of two adults.

The surface area of a person is estimated using the following formula:

The volume of a person is estimated using the following formula:

Using suitable calculations, deduce which person has the smaller surface area to volume ratio.

Show your working and complete the sentence below.

Give your answer to 3 significant figures.

Which is not a possible explanation for the difference in surface area to volume ratio between person A and person B ?

Tick () one box.

Name two structural features of the gills of a fish that increase their surface area.

Figure 11 shows images of gills from two fish as seen through an optical microscope.

Image C shows gills from a fish with healthy gills.

Image D shows gills from a fish with damaged gills.

Figure 11

Figure 11 not reproduced here due to third-party copyright restrictions

To observe the fish gills with the optical microscope, the scientists used two different stains. The first stain binds to DNA; the second stain binds to the red blood cells.

Explain why a second stain would be needed to stain the red blood cells. Suggest which molecule the stain could bind to in the red blood cells.

Using Figure 11, the scientists calculated the surface area to volume ratios for each gill filament in these two fish. Some of their results are shown in Table 4.

Complete Table 4. State your calculated volume and surface area:volume ratio to 2 significant figures.

The damage to the gills causes uncontrolled cell division in the cells around the capillaries in the gill filaments.

Other than surface area:volume ratio, describe one way this uncontrolled cell division changes the gills, as shown in Figure 11.

Explain how this difference would affect gas exchange.

Figure 12 shows the general pattern of blood circulation in fish.

Use Figure 12 to complete Table 5 to show two differences between the circulation of blood in fish and the circulation of blood in a mammal.

Explain the advantage for larger animals of having a specialised system that facilitates oxygen uptake.

Figure 2 shows two models of oxygen uptake found in animals.

Suggest how the environmental conditions have resulted in adaptations of systems using Model A rather than Model B.

Figure 3 shows changes in concentration of oxygen in two gas exchange systems.

A student studied Figure 3 and concluded that the fish gas exchange system is more efficient than the human gas exchange system.

Use Figure 3 to justify this conclusion.

Explain how the counter-current principle allows efficient oxygen uptake in the fish gas exchange system.

Table 1 shows features of two mammals.

Bats are flying mammals; shrews are ground-living mammals.

Calculate how many times the lung volume per unit of body mass of the bat is greater than that of the shrew.

Give your answer to an appropriate number of significant figures.

Give one suggestion to explain this difference.

Ulva lactuca is an alga that lives on rocks on the seashore. It is regularly covered by seawater.

Figure 6 shows a diagram of one Ulva lactuca alga.

Unlike plants, Ulva lactuca does not have xylem tissue.

Suggest how Ulva lactuca is able to survive without xylem tissue.

Ulva lactuca has a haploid and a diploid form.

Figure 7 shows the life cycle of Ulva lactuca.

On Figure 7 complete each box with an appropriate letter to show the type of cell division happening between each stage in the life cycle. Use ‘ T ’ to represent mitosis and ‘ E ’ to represent meiosis.

Ulva prolifera also produces haploid, mobile single cells that can fuse to form a zygote.

Suggest and explain one reason why successful reproduction between Ulva prolifera and Ulva lactuca does not happen.

A scientist investigated the affinity for oxygen of horse haemoglobin and mouse haemoglobin.

Some of their results are shown in Table 7.

Plot the haemoglobin saturation data from Table 7 and use these points to sketch the full oxyhaemoglobin dissociation curves for a horse and a mouse.

The following equation can be used to estimate the metabolic rate of an animal.

BM = body mass in grams

Use this equation to calculate how many times faster the metabolic rate of a mouse is than the metabolic rate of a horse.

The data in Table 7 show differences between the oxyhaemoglobin dissociation curve for a mouse and the oxyhaemoglobin dissociation curve for a horse.

Suggest how these differences allow the mouse to have a higher metabolic rate than the horse.

Mammals such as a mouse and a horse are able to maintain a constant body temperature.

Use your knowledge of surface area to volume ratio to explain the higher metabolic rate of a mouse compared to a horse.

Write an essay on one of the topics below.

EITHER

The importance of nitrogen-containing substances in biological systems.

OR

The importance of diffusion in organisms.