Cambridge IGCSE Biology - 0610 - Core Paper 3 2015 Winter Zone 1

Use the key to identify the mammals shown in Fig. 1.1.
Write the letter of each species (A to E) in the correct box beside the key.

key

| 1 (a) has visible external ears | go to 2 | letter |
| | (b) does not have visible external ears | *Eschrichtius robustus* |
| 2 (a) stands on four legs | go to 3 | |
| | (b) stands on two legs | go to 4 | |
| 3 (a) has two horns between its ears | *Antidorcas marsupialis* | |
| | (b) has two horns in front of its ears | *Diceros bicornis* | |
| 4 (a) has ears placed on top of head | *Macropus rufus* | |
| | (b) has ears placed at the side of head | *Homo sapiens* | |

(a) Define the term homeostasis.
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(b) Fig. 2.1 shows a section through the skin.


(i) Name the structures F, G and H, shown on Fig. 2.1.

F ............................................
G ............................................
H ............................................ [3]

(ii) Using Fig. 2.2, state which numbered part of the skin, 1 – 4, has the highest temperature on a cold day.



part number .............................. [1]

(c) When the body temperature rises above 37°C, two changes occur in the skin to help the temperature return to normal:

• vasodilation
• increased sweating.

Fig. 2.3 shows a simplified diagram of the skin.


(i) Describe what happens in vasodilation, and explain how this helps to lower body temperature.

Use Fig. 2.3 to help with your explanation.
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(ii) Explain how increased sweating helps to lower the body temperature.
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(iii) State two methods, other than reduced sweating, that the body uses to stop the body temperature falling below normal on a cold day.

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

(d) Name the part of the body which coordinates the changes in the skin to keep the body temperature at 37°C.
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The boxes on the left contain some genetic terms.
The boxes on the right contain definitions of genetic terms.
Draw one straight line to join each term to its correct definition.
Draw only five lines.
One example has been done for you.

term | definition
allele | a thread of DNA, made up of a string of genes
chromosome | a length of DNA that codes for a specific protein
diploid | an alternative form of a gene
gene | containing two sets of chromosomes
haploid | transmission of genetic information from generation to generation
inheritance | the physical features of an organism due to both its genotype and its environment | containing a single set of unpaired chromosomes

Fig. 4.1 shows a seed as it is starting to germinate and the same seed several days later.



(a) Explain how growth differs from development.
Use information from Fig. 4.1 to help with your explanation.

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(b) State three environmental conditions that all seeds need before they can germinate.

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

Fig. 5.1 shows the reproductive system of a man.


(a) The functions of some of the parts of the reproductive system of a man are given in Table 5.1. Complete Table 5.1 using information from Fig. 5.1. One row has been done for you:

[Table_1]
| function | letter from Fig. 5.1 | name |
|------------------------------------|---------------------|-------------------|
| produces fluid for sperm to swim in| C | prostate gland |
| produces sperm and testosterone | | |
| introduces sperm into the female body | | |
| carries sperm or urine | | |
[6]

(b) (i) Some men have an operation called a vasectomy. This involves cutting the sperm ducts. Place an X on Fig. 5.1 to show where the sperm duct would be cut. [1]

(ii) State why this operation is carried out.
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Fig. 6.1 shows a human kidney and the ureter attached to it.

(a) Two other tubes are attached to the kidney, but are not shown on Fig. 6.1.
Name these two tubes.
1 ...............................................................
2 ............................................................... [2]
(b) Kidneys excrete urea.
State one other substance that is excreted by the kidneys.
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(c)(i) State where urea is formed.
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(ii) Explain why urea has to be produced.
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(iii) State how urea travels to the kidney.
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Fig. 7.1 shows part of the carbon cycle.
The arrows represent the processes that take place in the carbon cycle.
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(a) (i) Complete Fig. 7.1 by filling in box H. [1]
(ii) State the process represented by letter C. [1]
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(iii) Draw a line with an arrow on Fig. 7.1 to represent photosynthesis.
Label this line G. [1]
(iv) State the process represented by letter B. [1]
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(b) (i) State which two letters represent respiration. [2]
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(ii) Write the word equation for aerobic respiration. [2]
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(iii) Explain why every living cell has to carry out respiration.
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(a) Explain why food has to be digested.
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Fig. 8.1 shows a section through the human body.
[Image_1: Diagram of human body with labels J, K, L, M]

(b) Identify the structures labelled on Fig. 8.1.
Write your answers in Table 8.1.

Table 8.1
\[ \begin{array}{|c|c|} \hline \text{structure} & \text{name} \\ \hline J & \\ \hline K & \\ \hline L & \\ \hline M & \\ \hline \end{array} \]
[4]

(c) In a medical investigation the number of villi in four people was compared. The results given in Table 8.2 show the average number of villi present in 1 cm$^2$ of ileum wall.

Table 8.2
\[ \begin{array}{|c|c|} \hline \text{person} & \text{average number of villi per cm}^2 \\ \hline P & 4200\\ \hline Q & 4500\\ \hline R & 3500\\ \hline S & 3250\\ \hline \end{array} \]

(i) Calculate the difference in the number of villi between person P and person S.
difference = ............................................... per cm$^2$ [1]
(ii) Further investigations showed that person Q could absorb digested food more rapidly than the other people.
Use the information in Table 8.2 to explain this result.
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Transpiration occurs in plants.
(a) Explain what is meant by the term transpiration.
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(b) Fig. 9.1 shows a healthy plant and its appearance three hours later when it has started to wilt.

State and explain two changes a student could make to the environment of the plant that would stop it wilting any further.
change to the environment ............................................................................................................................................
explanation ........................................................................................................................................................
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change to the environment ............................................................................................................................................
explanation ........................................................................................................................................................
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Some animals were introduced into a new habitat.
Fig. 10.1 shows how the number of animals in the population changed with time.
(a) Name phase A and phase B of the population growth curve shown in Fig. 10.1.

phase A ...............................................................
phase B ............................................................... [2]
(b) Fig. 10.2 shows the human population growth curve since the year 1 A.D.
(i) State and explain how the human population growth curve is different to the growth curve in Fig. 10.1.
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(ii) Suggest one social implication that might arise from the current size of the human population.
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