9.9 A celery stalk was placed into a beaker of blue dye. When the dye reached the leaves, the stalk was taken out and a section was cut, as shown in the diagram     Right-click on the blue button to open Fig 9.9(a)         Which diagram shows the appearance of the cut end of the stalk? (1)   Right-click on the blue button to open Fig 9.9(b) to see your options.      

  TOTAL QUESTION 1 

7.1.1 What type of blood vessel is vessel A? (1)

5.3.1 light (2)

2.2 Describe how the structure of veins ensures the flow of blood in one direction only. (1)

1 The cardiac cycle describes the sequence of events taking place in the heart to bring about changes in blood pressure.     The graph below shows the changes in blood pressure in the aorta, left ventricle, and left atrium.     Right-click on the blue button to open Figure 1.1        

6. Liposomes are spherical structures composed of phospholipids. They can be made by adding phospholipids to water. Liposomes can be used to study membrane permeability.     The diagram shows a liposome.     Right-click on the blue button to open Fig 6.1        

5.2 The diagram shows the structure of thymine and four other bases, P, Q, R and S. Bases P and S can form three hydrogen bonds each and bases Q and R can form two hydrogen bonds each.     Explain which of the four bases P, Q, R or S is adenine. (2)   Right-click on the blue button to open Fig 5.2        

2.1.1 Using the information in the graph, state which of the vessels A and B is an artery and which is a vein.   Vessel A…… Vessel B ………. (1)

6.2.3 The phospholipid bilayer plays an important role in this control of movement of molecules. Explain why the phospholipid molecules form a bilayer. (3)