Biology 9700 · AS & A Level · Respiration

Respiration — practice question

Cereal crops, including sorghum and rice, are an important source of nutrients worldwide.
(a)[3]

Explain why cereal crops form an important part of many people’s diets.

(b(i))[1]

Alpha amylase is an enzyme made in germinating seeds, where it hydrolyses starch. Fig. 4.1 illustrates the effect of temperature on alpha amylase in germinating seeds of sorghum and rice. Name the part of the seed that contains starch.

(b)

Alpha amylase is an enzyme made in germinating seeds, where it hydrolyses starch. Fig. 4.1 illustrates the effect of temperature on alpha amylase in germinating seeds of sorghum and rice.

(b(ii))[3]

With reference to Fig. 4.1, compare the effect of temperature on alpha amylase in sorghum and rice.

(b(iii))[3]

Using the types of bonding in proteins, suggest how differences in the tertiary structure of alpha amylase in rice and sorghum could account for the differences in their activities shown in Fig. 4.1.

(c)[3]

Sorghum does not grow well at low temperatures. An investigation looked at how sorghum responds to low temperatures at different light intensities. With reference to Table 4.1, describe and explain how light intensity affects the rate of carbon dioxide uptake before cooling.

(c(ii))[2]

With reference to Table 4.1, describe how light intensity affects the ability of sorghum plants to survive cooling.

(ii)[2]

Describe how light intensity affects the ability of sorghum plants to survive cooling.

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