No questions found
1. (a) The movement of molecules within an organism can occur by diffusion and active transport. Complete Table 1.1 by placing ticks (√) to show the correct features of each process.
(b) Explain why active transport is important in root hair cells. [3]
591
578
514
2. Transpiration is the loss of water vapour from the leaves of a plant.
(a) Complete the sentence describing transpiration. [2]
(b) Explain how water moves upwards in the xylem. [3]
(c) A student investigated the effect of wind speed on the rate of transpiration in a small Pachira aquatica tree.
(i) Describe and explain the results shown in Fig. 2.1. [4]
(ii) The investigation was repeated in the light with the same species of tree in an environment where the humidity was higher. Draw a line on Fig. 2.1 to predict the results in the light with increased humidity. [1]
(iii) The investigation described in 2(c) was repeated (different wind speeds in both the light and the dark). However, the tree was not given an adequate supply of water during the investigation. Predict the result and explain your prediction. [4]
540
531
577
3. Fig. 3.1 is a diagram of a section through a human heart.
(a) Draw an X on the septum in Fig. 3.1. [1]
(b) Explain the reason for the difference between the thickness of the walls at B and at C in Fig. 3.1. [2]
(c) A red blood cell enters the vena cava at A in Fig. 3.1. Explain how the red blood cell is moved from the vena cava to the aorta. [6]
(d) An athlete measured her heart rate during a running race. She recorded it before the race, during the race and during her recovery.
(i) Suggest how the athlete could monitor the activity of her heart. [1]
(ii) Calculate the percentage change in heart rate from the maximum heart rate reached during the race until the heart rate recorded at 18 minutes. Give your answer to three significant figures. [3]
(iii) Explain why heart rate must increase during exercise. [3]
536
534
590
4. (a) Urea is a waste product.
(i) Describe how urea is formed. [3]
(ii) State the component of blood that transports urea. [1]
(iii) State why urea must be excreted. [1]
(iv) State the name of the blood vessel that carries blood away from the kidney. [1]
(b) Fig. 4.1 shows a drawing of a nephron in the human kidney and associated blood vessels.
Describe how the structures labelled in Fig. 4.1 produce urine. [4]
(c) Urea can be used as a fertiliser as it is a source of nitrogen. Explain the importance of nitrate ions to plants. [1]
(d) A farmer applied fertiliser to a field next to a lake. Suggest two precautions the farmer should take when applying fertiliser to reduce the risk of eutrophication occurring in the lake. [2]
563
534
524
5. (a) Describe the role of progesterone in pregnancy. [3]
(b) Fig. 5.1 shows a drawing of a section of a human placenta. The arrows show the direction of blood flow.
Substances move across the placenta by diffusion.
(i) State the names of two useful substances that move from the blood of the mother to the blood of the fetus. [2]
(ii) Using the information in Fig. 5.1, suggest how the placenta is adapted for efficient diffusion. [3]
(c) The Rhesus (Rh) factor is a protein that is found on the surface of red blood cells in some people. If the protein is present then the individual is Rh positive. The allele for the presence of the Rh factor is dominant and is represented by the letter D. The recessive allele is represented by the letter d. If a mother is Rh negative and the fetus is Rh positive there can be problems during pregnancy. A Rh negative mother and a heterozygous Rh positive father have a child. Complete the Punnett square and determine the probability of the child being Rh positive. [3]
538
548
582
6. (a) Fig. 6.1 shows the percentage of land covered by forest in a country from 1660 until 2000.
(i) Using the information in Fig. 6.1, state which 10-year period had the highest increase in the percentage of land covered by forest. [1]
(ii) Outline how human activities could cause the change in the percentage of land covered by forest from 1660 to 1800 shown in Fig. 6.1. [3]
(b) It is estimated that 40% of plant species are at risk of extinction. Seed banks can store seeds from many species for a long time. Table 6.1 shows some information about one plant species that is stored in a seed bank.
[Table_1]
(i) Using the data shown in Table 6.1, calculate the mass of protein in one seed. [1]
(ii) Suggest why many plants can easily be conserved using seed banks. [2]
(iii) Describe why conservation projects such as seed banks are important. [5]
544
556
536
7. (a) State the name of a chemical element that is found in all proteins but not in carbohydrates or fats. [1]
(b) Table 7.1 shows the names of some biological molecules, enzymes and the organs that produce the enzymes. Complete Table 7.1.
[Table_2]
(c) State two hormones that can affect the concentration of glycogen in the liver. [2]
551
599
528
