CSEC Biology Paper 2 January 2015 - Free CXC Past Paper with Answers

Measure the length of the radicle of the seedling on EACH day and record your measurements in Table 1.

TABLE 1: LENGTH OF RADICLE AFTER GERMINATION

Plot the data in Table 1 on the graph paper below. Put days on the horizontal (x) axis.

State TWO factors, other than water, that are required for the germination of the seed shown in Figure 2.

Describe an investigation to test the hypothesis, 'Water is needed for the germination of seeds'.

Suggest why the cotyledons (seed leaves) become smaller as the primary leaves increase in size.

Identify the structures labelled I, II, III, IV and V in Figure 3.

I: II: III: IV: V:

Suggest TWO reasons why the locations indicated in (a) (ii) are suitable for protein digestion to take place.

Give TWO reasons why living organisms need protein.

Using the symbol, X, indicate on Figure 3, TWO places where protein digestion takes place.

In the liver, excess protein is converted to urea which is excreted by some animals. Briefly describe ONE route by which the nitrogen excreted from animals (in the form of urea) is made available to plants.

Suggest TWO signs of nitrogen deficiency in plants.

Identify the structures labelled P, Q and R in Figure 5 and state the role of EACH in photosynthesis.

Figure 5. Internal structures of leaves from two plants

Describe ONE difference in the cuticles and ONE difference in the lower epidermis of the two plants, A and B, and explain the significance of these differences.

Suggest the type of environment in which each plant, Plant A and Plant B would be found growing, and THREE adaptations expected in Plant B, other than those shown in Figure 5.

For which category of diseases would gene therapy be appropriate?

Suggest TWO ways, other than gene therapy, in which genetic engineering is used for the prevention and treatment of diseases.

Name TWO diseases transmitted by a named insect vector.

Suggest TWO measures that could be used to control the population of the insect vector named in (d) (i).

Draw a clearly labelled diagram to show the internal structure of human skin.

A biologist travels to the Sahara desert to study its organisms. Daytime temperatures in the desert are very high and night-time temperatures are very low. (i) Explain how the biologist’s skin allowed him to maintain a relatively normal body temperature during his first day and night in the desert. (7 marks) (ii) Suggest TWO ways the biologist could modify his behavior during the day, and ONE way during the night, to help regulate his body temperature in the desert. (3 marks)

Explain how the biologist’s skin allowed him to maintain a relatively normal body temperature during his first day and night in the desert.

Suggest TWO ways the biologist could modify his behavior during the day, and ONE way during the night, to help regulate his body temperature in the desert.

Table 2 is an incomplete table showing organisms and their natural habitat. (i) Complete Table 2 to match EACH organism with its natural habitat.

TABLE 2: ORGANISMS AND THEIR NATURAL HABITAT

(ii) Describe briefly a technique for sampling organisms in the pond.

Complete Table 2 to match EACH organism with its natural habitat.

TABLE 2: ORGANISMS AND THEIR NATURAL HABITAT

Describe briefly a technique for sampling organisms in the pond.

Harry plants tomato seedlings 10 cm apart and Karen plants the same variety 30 cm apart. The plots of land are identical in size and are located next to each other. The plants in both plots receive the same amount of water and fertilizer. At harvest, Karen reaps many more tomatoes, which are larger and healthier than Harry’s tomatoes.

Explain THREE factors that may have caused a lower yield of tomatoes in Harry’s plot.

Suggest THREE ways by which human activity could adversely affect an oyster population living in a mangrove swamp.