Cambridge IGCSE Biology - 0610 - Supplement Paper 4 2014 Winter Zone 2

(a) Name A to E.
A ..............................................................................................................
B ..............................................................................................................
C ..............................................................................................................
D ..............................................................................................................
E .............................................................................................................. [5]
[Image_1: Fig. 1.1 is a photomicrograph of a leaf of the tea plant, Camellia sinensis.]

(b) Fig. 1.2 shows a cell from region B of the leaf shown in Fig. 1.1.
Use the letters from Fig. 1.2 to complete Table 1.1.
Write one letter only in each box to identify the function. You may use each letter once, more than once or not at all.

Table 1.1
| function | letter from Fig. 1.2 |
|-----------------------------------------------------|-----------------------|
| controls movement of substances into and out of the cell | |
| exerts a pressure to help maintain the shape of the cell | |
| produces sugars using light as a source of energy | |
| withstands the internal pressure of the cell | |
| controls all the activities of the cell | |
[5]
[Image_2: Fig. 1.2 shows a cell with parts labeled F, G, H, J, K, L.]

(c) The enzyme catalase is found in lettuce leaves.
A student investigated the activity of this enzyme by grinding some lettuce leaves and adding them to a solution of hydrogen peroxide. The volume of oxygen produced was measured until the reaction stopped.
The student's results are shown in Fig. 1.3.
(i) Describe the results shown in Fig.1.3. You will gain credit if you use the data in your answer.
..............................................................................................................
..............................................................................................................
..............................................................................................................
..............................................................................................................
..............................................................................................................
.............................................................................................................. [3]
(ii) Explain the action of enzymes during a reaction.
..............................................................................................................
..............................................................................................................
..............................................................................................................
..............................................................................................................
..............................................................................................................
.............................................................................................................. [3]
[Image_3: Fig. 1.3 graph of volume of oxygen collected over time.]

(a) Define the term excretion.
.................................................................................................................................................
.................................................................................................................................................
.................................................................................................................................................
.................................................................................................................................................
.................................................................................................................................................[3]

Fig. 2.1 is a diagram of a kidney tubule and its blood supply.


(b) The concentrations of solutes in the fluids at regions 1, 2, 3 and 4 were determined. The results are shown in Table 2.1.

[Table_1]

State the substance or substances in Table 2.1 which:

(i) has molecules which are too large to be filtered;
.................................................................................................................................................[1]

(ii) has molecules which are small enough to be filtered but is completely reabsorbed from the fluid in the kidney tubule;
.................................................................................................................................................[1]

(iii) increases in concentration as fluid moves along the kidney tubule.
1 .................................................................................................................................................
2 .................................................................................................................................................[1]

(c) State three structures through which the fluid from region 4 passes as it leaves the body.
1 .................................................................................................................................................
2 .................................................................................................................................................
3 .................................................................................................................................................[3]

(d) One role of the kidney is to maintain the concentration of the blood plasma.
Name the process of maintaining constant conditions within the body.
.................................................................................................................................................[1]

(a) Explain the roles of bacteria in the aerobic digestion tank shown in Fig. 3.1.
.................................................................
.................................................................
.................................................................
.................................................................
.................................................................
.................................................................
.................................................................
.................................................................
................................................................. [5]

(b) Fig. 3.1 shows that chlorine is added to water before it leaves the sewage treatment works. Explain why chlorine is added to the water.
.................................................................
.................................................................
................................................................. [2]

Mammals have a double circulatory system. Blood flows between:
• the heart and the lungs
• the heart and the rest of the body (systemic circulation).

(a) Fig. 4.1 shows a cross-section of an artery.

Explain how the structure of an artery, as shown in Fig. 4.1, is related to its functions...........................................................[4]

(b) Fig. 4.2 shows the total cross-sectional area of the blood vessels in the systemic circulation. It also shows the changes that occur in blood pressure and the speed (velocity) of blood in the different blood vessels.

(i) State the maximum mean blood pressure in the aorta...............................................................................[1]
(ii) Describe how mean blood pressure and speed of blood change with cross-sectional area of blood vessels, as shown in Fig. 4.2.
blood pressure .................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
speed of blood .................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................
..................................................................................................................................................[3]

(c) Describe how substances move from the blood in the capillaries into the tissue fluid..........................................................................................................[3]

(d) Blood flows from arteries into arterioles before entering capillaries.
Explain the role of the arterioles in the skin when a person is very cold.........................................................................................................[3]

Fig. 5.1 is a diagram of the human immunodeficiency virus (HIV).

Fig. 5.1

(a) (i) Name the parts of the virus labelled X and Y.

X ...............................................................................................................................
Y ...............................................................................................................................[2]

(ii) State three ways in which the structure of bacteria differs from the structure of viruses.

1 ..............................................................................................................................
2 ..............................................................................................................................
3 ..............................................................................................................................[3]

(b) Sub-Saharan Africa has the highest proportion of the population living with HIV in the world. The World Health Organization estimates both the total number of people who live with HIV and the total number of people that are newly infected each year.

Fig. 5.2 shows the estimated numbers for sub-Saharan Africa between 1990 and 2010.

(i) Summarise the changes between 1990 and 2009 in the number of people living with HIV and the number of people newly infected with HIV.

number of people living with HIV ....................................................................................................
..............................................................................................................................
number of people newly infected with HIV ......................................................................................
..............................................................................................................................
..............................................................................................................................[4]

(ii) Suggest why in 2010 the number of people living with HIV increased but the number of newly infected people decreased.

..............................................................................................................................
..............................................................................................................................
..............................................................................................................................[2]

(iii) Describe three ways in which HIV is transmitted from infected to uninfected people.

1 ..............................................................................................................................
2 ..............................................................................................................................
3 ..............................................................................................................................[3]

(iv) Describe the effects of HIV on the immune system.

..............................................................................................................................
..............................................................................................................................
..............................................................................................................................[3]

(a) (i) Describe the results shown in Fig. 6.1.

.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................[3]

(ii) Suggest an explanation for the different concentrations of PCBs in the organisms of the food chain.

.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................[3]


(b) PCBs are toxic to many organisms because they bind to a protein molecule known as AHR.

The Atlantic tomcod, Microgadus tomcod, is a fish that lives in the Hudson River and other rivers nearby.

90% of the tomcod population in the Hudson River is resistant to the effects of PCBs. This is because these fish have a different type of AHR compared with other tomcod populations.

(i) Suggest how this resistance came about.

.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................[5]

(ii) Scientists predict that the proportion of fish resistant to PCBs will decrease if the concentration of PCBs in the river decreases.

Suggest reasons why the proportion of fish with the altered AHR protein might decrease.

.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................[2]

(c) Describe the problems caused by non-biodegradable plastics in the environment.

.................................................................................................................................
.................................................................................................................................
.................................................................................................................................
.................................................................................................................................[3]