Cambridge IGCSE Biology - 0610 - Core Paper 3 2021 Winter Zone 1

(a) Fig. 1.1 is a diagram of part of the human circulatory system.

(i) Identify and label on Fig. 1.1 in the spaces provided:

• the left ventricle

• the right atrium

• the septum

• a valve [4]

(ii) Complete the flow chart of the circulatory system by writing the correct blood vessels from the list, in the spaces provided.

The arrows show the direction of blood flow.

Each word or phrase may be used once, more than once or not at all.

aorta, pulmonary artery, pulmonary vein, renal artery, renal vein, vena cava

(b) A healthy diet is recommended to reduce the risk of coronary heart disease (CHD).

State three other risk factors for CHD.

(a) Fig. 2.1 shows some of the processes involved in the water cycle.
[Image_1: Fig. 2.1]
(i) Identify the processes labelled A to D in Fig. 2.1.
A ...................................................
B ...................................................
C ...................................................
D ...................................................
[4]
(ii) Describe the process that occurs at E in Fig. 2.1.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
[3]

(b) Some animals can only live in clean water that has a high concentration of dissolved oxygen.
Some animals can live in polluted water.
A student investigated which animal species lived in different locations in a river.
Fig. 2.2 is a diagram of the river. The numbers are the locations of where the student counted how many of each animal species were present.
[Image_2: Fig. 2.2]
The number of each animal species present is shown in Table 2.1.
[Table_1: Table 2.1]
(i) State which location has the most animals present.
..........................................................................................................................
[1]
(ii) Using the information in Fig. 2.2 and Table 2.1, suggest which animal species is unable to survive in polluted water. Give reasons for your choice.
species ...................................................
reasons ............................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
[3]
(iii) Suggest which animal species in Table 2.1 indicates that the water is polluted when it is present.
..........................................................................................................................
[1]
(iv) Calculate the percentage change in the freshwater shrimp numbers between location 2 and location 3.
Give your answer to one decimal place.
Space for working.
............................................................... %
[3]

Enzymes help to digest food in humans and are produced by different parts of the alimentary canal.

(a) The box on the left contains a sentence beginning.

The boxes on the right contain some sentence endings.

Draw two lines to make two correct sentences about enzymes.



[2]

(b) Fig. 3.1 is a diagram showing an enzyme and several different substrate molecules.



State the letter of the molecule that is most likely to be the substrate for this enzyme.
....................
[1]

(c) Enzymes are involved in chemical digestion in humans.

Define the term chemical digestion.

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

(d) Fig. 3.2 is a graph showing the effect of changes in pH on the activity of four different enzymes, U to X.



The pH values in different parts of the alimentary canal were measured.

Table 3.1 shows the pH values found in the different parts of the alimentary canal.

(i) Use the information in Fig. 3.2 to state the letter of the enzyme that would be most active in each part of the alimentary canal.

[Table_1]

[2]

(ii) The duodenum and ileum are part of the small intestine.

State the name of one part of the large intestine.
........................................................................................................
[1]

(e) The acid in gastric juice provides an acid pH for enzymes.

(i) State one other function of the acid in gastric juice.
........................................................................................................
........................................................................................................
[1]

(ii) State the name of the acid that is found in gastric juice.
........................................................................................................
[1]

(f) Table 3.2 shows the names of some enzymes, the substrate they act on and the products of the reaction they are involved in. It also shows the organ that secretes the enzyme.

Complete Table 3.2.

[Table_2]

[6]

[Total: 16]

(a) Place ticks (\(\checkmark\)) in the boxes that describe anaerobic respiration.

• a chemical reaction in a cell []
• breaks down nutrient molecules []
• coordinates and regulates body functions []
• does not use oxygen []
• affects reaction times and self-control []
• produces alcohol and carbon dioxide in yeast []
• uses carbon dioxide []
• uses oxygen []

(a) Complete the sentences using the words or phrases from the list.
Each word or phrase may be used once, more than once or not at all.

different from   divide   embryo   gamete   fuse
fetus   identical to   meiosis   mitosis   zygote

In sexual reproduction, each parent organism produces a sex cell called a
....................................................... . These cells are produced by a type of cell division called
....................................................... .

The nuclei of two sex cells .......................................................... to form a
....................................................... in a process called fertilisation.

The offspring are genetically ....................................................... each other and their parents.

(b) Fig. 5.1 shows four examples of reproduction in living organisms.



Fig. 5.1

State the two letters in Fig. 5.1 that identify examples of asexual reproduction.
....................................................... and .......................................................

(c) Fig. 5.2 is a diagram showing all of the chromosome pairs in a cell from a human male. The twenty-third pair of chromosomes are the sex chromosomes.



Fig. 5.2

Describe how the chromosomes in a human female differ from those shown in Fig. 5.2. ..............................................................................................................................................................................
..............................................................................................................................................................................

(d) Describe how insect-pollinated flowers are adapted for pollination.
..............................................................................................................................................................................
..............................................................................................................................................................................
..............................................................................................................................................................................
..............................................................................................................................................................................

(a) (i) State the word equation for photosynthesis.
............................................................................................................................ [2]
(ii) State the source of energy for photosynthesis.
............................................................................................................................ [1]
(iii) State the name of the structure in a cell where photosynthesis takes place.
............................................................................................................................ [1]

(b) The effect of carbon dioxide concentration on the rate of photosynthesis in an aquatic plant was investigated.
- 10 test-tubes were prepared. Each contained water, an aquatic plant and a different concentration of carbon dioxide.
- Each test-tube was placed next to a lamp and the temperature in the test-tubes was maintained at 20 °C.
- The number of bubbles produced by each aquatic plant in one minute was counted.

Fig. 6.1 shows the apparatus that was used.


The results of the investigation are shown in Fig. 6.2.


(i) State the maximum number of bubbles produced in one minute.
............................................................ [1]
(ii) The investigator concluded that 0.10 arbitrary units was the optimum (best) concentration of carbon dioxide for photosynthesis in this investigation.
Describe the evidence shown in Fig. 6.2 that supports the investigator’s conclusion.
............................................................................................................................
............................................................................................................................
............................................................................................................................
............................................................................................................................ [2]
(iii) The investigation described in 6(b) was repeated but the temperature was reduced from 20 °C to 10 °C.
Predict the effect of reducing the temperature on the number of bubbles produced and explain your answer.
prediction ............................................................................................................................
............................................................................................................................
explanation ............................................................................................................................
............................................................................................................................
............................................................................................................................ [2]

(c) Carbon dioxide is a greenhouse gas.
State the name of one other greenhouse gas.
............................................................................................................................ [1]

(a) State the term used to describe the maintenance of a constant internal environment.
.......................................................................................................................................................... [1]

(b) Mammals can maintain a constant body temperature.
Complete the sentences by circling the correct word in each group of three words that are shown in bold.
Circle five words.

When a mammal becomes too cold the effectors / hormones / receptors detect a low body temperature and send information to the brain.
The brain coordinates the response. The effectors / hormones / receptors respond by raising body hairs to trap a layer of air / oil / sweat around the body to insulate it.
During shivering, the blood / muscle / skin cells contract and respire more, releasing heat.
Sweat production decreases so that heat transfer to the environment decreases / increases / stays the same.
[5]

(c) Drugs can alter the chemical reactions in the body.
State the names of two drugs that can act as depressants.
1 ............................................................................................................................................................
2 ............................................................................................................................................................
[2]