General Certificate of Education
Advanced Subsidiary Examination
June 2009
Mark
1
2
3
Biology
Unit 2
BIOL2
4
5
The variety of living organisms
6
Thursday 4 June 2009
1.30 pm to 3.15 pm
7
8
9
For this paper you must have:
G a ruler with millimetre measurements.
You may use a calculator.
TOTAL
Time allowed
G
1 hour 45 minutes
Instructions
G
G
G
G
G
G
Use black ink or black ball-point pen.
Fill in the boxes at the top of this page.
Answer all questions.
You must answer the questions in the spaces provided. Answers written in margins or on blank pages will not be marked.
You may ask for extra paper. Extra paper must be secured to this booklet. Do all rough work in this book. Cross through any work you do not want to be marked.
Information
G
G
G
G
The maximum mark for this paper is 85.
The marks for questions are shown in brackets.
Quality of Written Communication will be assessed in all answers.
You will be marked on your ability to:
– use good English
– organise information clearly
– use accurate scientific vocabulary where appropriate.
(JUN09BIOL201)
APW/Jun09/BIOL2
BIOL2
2
Areas outside the box will not be scanned for marking
Answer all questions in the spaces provided.
1 The diagram shows some of the large blood vessels in a mammal.
A
E
Heart
C
B
Liver
D
Small intestine 1 (a)
Add arrows to the diagram to show the direction of blood flow in each of the blood vessels A to E.
(1 mark)
1 (b)
(i)
Which of blood vessels A to E is the hepatic portal vein?
(1 mark)
1 (b)
(ii)
Which of blood vessels A to E contains blood at the lowest pressure?
(1 mark)
(02)
APW/Jun09/BIOL2
3
1 (c)
Areas outside the box will not be scanned for marking
Complete the table to show two differences between the structure of vessel C and the structure of vessel E.
Structural feature
Vessel C
Vessel E
(2 marks)
1 (d)
Blood vessel B contains smooth muscle in its walls. Explain how this muscle may reduce the blood flow to the small intestine.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
1 (e)
Elastic tissue in the walls of blood vessel A helps to even out the pressure of blood through this vessel. Explain how.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
Turn over
(03)
APW/Jun09/BIOL2
9
4
Areas outside the box will not be scanned for marking
2 The diagram shows part of a DNA molecule.
M
ATT C A GT ACGAT
T AAGT CA T GC T A
2 (a)
Name the two components of the part of the DNA molecule labelled M.
1 .........................................................................................................................................
2 .........................................................................................................................................
(2 marks)
2 (b)
What is the maximum number of amino acids for which this piece of DNA could code? (1 mark)
(04)
APW/Jun09/BIOL2
5
Areas outside the box will not be scanned for marking
2 (c)
Scientists calculated the percentage of different bases in the DNA from a species of bacterium. They found that 14% of the bases were guanine.
2 (c)
(i)
What percentage of the bases in this species of bacterium was cytosine?
The scientists found that, in a second species of bacterium, 29% of the bases were guanine. Explain the difference in the percentage of guanine bases in the two species of bacterium. .............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
Turn over
(05)
APW/Jun09/BIOL2
7
6
3 (a)
Areas outside the box will not be scanned for marking
Give one way in which a DNA molecule in a prokaryote, such as a bacterium, is different from a DNA molecule in a eukaryote.
.............................................................................................................................................
.............................................................................................................................................
(1 mark)
Species X and Y are bacteria. The diagram shows gene transfer between bacteria in these two species. The bacteria that are shaded are resistant to the antibiotic penicillin.
Species X
Species Y
A
B
3 (b)
(i)
C
Use the diagram to explain why bacterium A is resistant to penicillin.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(3 marks)
(Extra space) .............................................................................................................
...................................................................................................................................
...................................................................................................................................
(06)
APW/Jun09/BIOL2
7
3 (b)
(ii)
Areas outside the box will not be scanned for marking
Use the diagram to explain why bacteria B and C are resistant to penicillin.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(2 marks)
(Extra space) .............................................................................................................
...................................................................................................................................
3 (c)
A person is infected with bacteria of species Y. Some of these bacteria are resistant to penicillin. A doctor gives the person a course of penicillin.
What would happen to the proportion of species Y bacteria that are resistant to penicillin? Explain your answer.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
Turn over
(07)
APW/Jun09/BIOL2
8
8
Areas outside the box will not be scanned for marking
4 The diagram shows a cell cycle.
Key
Mitosis
P
P prophase
M metaphase
M
A
A anaphase
T
T telophase
Interphase
4 (a)
The table shows the number of chromosomes and the mass of DNA in different nuclei.
All the nuclei come from the same animal. Complete this table.
Nucleus
At prophase of mitosis
Number of chromosomes
26
Mass of DNA / arbitrary units
60
At telophase of mitosis
From a sperm cell
(4 marks)
(08)
APW/Jun09/BIOL2
9
4 (b)
Areas outside the box will not be scanned for marking
If the DNA of the cell is damaged, a protein called p53 stops the cell cycle.
Mutation in the gene for p53 could cause cancer to develop. Explain how.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(3 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
4 (c)
Drugs are used to treat cancer. At what phase in the cell cycle would each of the following drugs act?
4 (c)
(i)
A drug that prevents DNA replication
...................................................................................................................................
(1 mark)
4 (c)
(ii)
A drug that prevents spindle fibres shortening
...................................................................................................................................
(1 mark)
9
Turn over
(09)
APW/Jun09/BIOL2
10
Areas outside the box will not be scanned for marking
There are no questions printed on this page
DO NOT WRITE ON THIS PAGE
ANSWER IN THE SPACES PROVIDED
(10)
APW/Jun09/BIOL2
11
5 (a)
Areas outside the box will not be scanned for marking
What is a tissue?
.............................................................................................................................................
.............................................................................................................................................
(1 mark)
5 (b)
A student cut a thin section of tissue from a potato and examined it with an optical microscope.
5 (b)
(i)
Starch was present in the cells of this tissue. Describe how the student could find out where in the cells the starch was present.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(2 marks)
5 (b)
(ii)
The student cut a thin section of the tissue. Explain why it was important that the section was thin.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(2 marks)
5 (c)
The cell walls of potato cells contain cellulose. Cellulose and starch are both carbohydrates. Describe two ways in which molecules of cellulose are similar to molecules of starch.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
Turn over
(11)
APW/Jun09/BIOL2
7
12
6 (a)
Areas outside the box will not be scanned for marking
An order is a taxonomic group. All seals belong to the same order. Name one other taxonomic group to which all seals belong.
.............................................................................................................................................
(1 mark)
6 (b)
The diagram shows how some species of seal are classified.
Mirounga angustirostris
Mirounga leonina
Monachus tropicalis
Phocidae
How many different genera are shown in this diagram?
(1 mark)
6 (b)
(ii)
All the seals shown in the diagram are members of the Phocidae. Phocidae is an example of a taxonomic group. Of which taxonomic group is it an example?
...................................................................................................................................
(1 mark)
6 (b)
(iii) The diagram is based on the evolutionary history of the seals. What does the information in the diagram suggest about the common ancestors of Mirounga angustirostris, Mirounga leonina and Monachus tropicalis?
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(1 mark)
(12)
APW/Jun09/BIOL2
13
6 (c)
Areas outside the box will not be scanned for marking
A species of seal shows genetic diversity. Explain what is meant by genetic diversity. .............................................................................................................................................
.............................................................................................................................................
(1 mark)
6 (d)
In the late 18th century, the population of northern elephant seals was estimated to be about 150 000. These seals lived in different colonies in different places. The seals were then hunted. By 1910, the total population had fallen to under 100. All these seals lived in a single colony on one island. Hunting then stopped. Numbers increased and there are now approximately 150 000 seals living in many different colonies. Use this information to explain
6 (d)
(i)
what is meant by a genetic bottleneck
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(2 marks)
(Extra space) .............................................................................................................
...................................................................................................................................
6 (d)
(ii)
how you would expect the founder effect to have influenced the genetic diversity of northern elephant seals after 1910.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(2 marks)
(Extra space) .............................................................................................................
...................................................................................................................................
Turn over
(13)
APW/Jun09/BIOL2
9
14
Areas outside the box will not be scanned for marking
7 Mole crickets are insects that live underground. At night, a male cricket produces a courtship song. A female cricket is attracted by this song and mates with the male.
Scientists investigated courtship in two species of mole cricket. They found that female mole crickets were only attracted to the song produced by a male of the same species.
The charts show recordings of typical songs of two species of mole cricket.
Start of song Start of song Species F
Species G
0.5 s
7 (a)
The song of species F is repeated at regular intervals. The arrows on the chart show the beginning of each song.
Calculate the rate of singing in songs per minute.
Answer.......................................songs per minute (1 mark)
(14)
APW/Jun09/BIOL2
15
7 (b)
Areas outside the box will not be scanned for marking
Explain why courtship song is an important part of species recognition in mole crickets. .............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
7 (c)
The scientists produced hybrids between the two crickets by fertilising eggs from one species with sperms from the other. The male hybrids had songs that had some features of one parent species and some features of the other. Suggest why the male hybrids were not able to reproduce.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
Turn over for the next question
Turn over
(15)
APW/Jun09/BIOL2
6
16
8 (a)
Areas outside the box will not be scanned for marking
A fish uses its gills to absorb oxygen from water. Explain how the gills of a fish are adapted for efficient gas exchange.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(6 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(16)
APW/Jun09/BIOL2
17
Areas outside the box will not be scanned for marking
Mackerel live in the surface waters of the sea. Toadfish live on the seabed in deep water.
8 (b)
The concentration of oxygen is higher in the surface waters than it is in water close to the seabed. Suggest why.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
Question 8 continues on the next page
Turn over
(17)
APW/Jun09/BIOL2
18
8 (c)
Areas outside the box will not be scanned for marking
The graph shows oxygen dissociation curves for toadfish haemoglobin and for mackerel haemoglobin.
100
Toadfish
80
Mackerel
60
Explain how the shape of the curve for toadfish haemoglobin is related to where the toadfish is normally found.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
(18)
APW/Jun09/BIOL2
19
8 (d)
Areas outside the box will not be scanned for marking
Scientists analysed the sequence of amino acids in one polypeptide chain in the haemoglobin of four different species of ape. The only difference they found affected the amino acids at three positions in the polypeptide chain. Their results are shown in the table. The letters are abbreviations for particular amino acids.
Species
Position 87
Position 104
Position 125
Chimpanzee
R
P
Bonobo
T
R
P
Gorilla
T
K
P
Orang utan
8 (d)
T
K
R
Q
(i)
What information do the data in the table suggest about the relationships between the chimpanzee, the bonobo and the gorilla? Explain your answer.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(2 marks)
8 (d)
(ii)
Hybrid DNA was made from the gene for chimpanzee haemoglobin and the genes for the haemoglobin of the other three species of ape. Which of the three samples of hybrid DNA would separate into two strands at the lowest temperature? Explain your answer.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(3 marks)
(Extra space) .............................................................................................................
...................................................................................................................................
...................................................................................................................................
Turn over
(19)
APW/Jun09/BIOL2
15
20
9 (a)
Areas outside the box will not be scanned for marking
In the USA, members of the public found many frogs with deformed legs. Scientists investigated this. They collected samples of the frogs. They wanted to get reliable data. Give one feature of the sample, other than a large sample size, that would help to make sure that their data were reliable.
.............................................................................................................................................
.............................................................................................................................................
(1 mark)
The team of scientists then investigated frogs in ponds. The team measured many different factors and then analysed their results. The graph shows the relationship between the percentage of frogs with deformed legs and the mean number of parasitic worms found in the frogs.
50
40
30
Percentage
of frogs with deformed legs
Pond A
20
10
0
0.0
9 (b)
1.0
2.0
3.0
4.0
Mean number of parasitic worms per frog
5.0
The scientists collected a sample of three frogs from pond A. What was the total number of parastic worms found in these three frogs?
(1 mark)
(20)
APW/Jun09/BIOL2
21
9 (c)
Areas outside the box will not be scanned for marking
One scientist suggested that the parasites caused the deformed legs found in frogs.
Does the graph support this suggestion? Explain your answer.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(4 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
9 (d)
The scientists wrote a paper. In their discussion they wrote that they found very few ponds that were free from human influence. The few that they did find were only in mountainous areas.
The scientists could not draw any reliable conclusions about whether human influence contributed to the frogs’ deformed legs. Explain why each of the following meant that they could not draw reliable conclusions.
9 (d)
(i)
There were very few ponds free from human influence.
...................................................................................................................................
...................................................................................................................................
(1 mark)
Question 9 continues on the next page
Turn over
(21)
APW/Jun09/BIOL2
22
9
(d)
Areas outside the box will not be scanned for marking
(ii) The ponds free from human influence were found only in mountainous areas.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(2 marks)
(Extra space) ............................................................................................................
...................................................................................................................................
In a second investigation, another research team investigated deformed legs in frogs in a different way.
G
They chose six ponds, all of which contained parasitic worms. Three of the ponds were close to fields and received agricultural run-off from these fields. The other three ponds did not receive agricultural run-off.
G
They built two cages in each of the six ponds. One cage in each pond allowed parasitic worms to enter and one cage did not.
G
They put frogs that were not infected with parasitic worms into all twelve cages.
The table shows the results of this second investigation.
Percentage of frogs with deformed limbs
Ponds with agricultural run-off
Ponds with no agricultural run-off
Pond number 1
2
3
4
5
6
Cage with mean mesh diameter of
500 µm
22
27
24
3
4
7
Cage with mean mesh diameter of
75 µm
0
0
0
0
0
0
(22)
APW/Jun09/BIOL2
23
9 (e)
Areas outside the box will not be scanned for marking
One of the boxes in the table has been shaded. Describe the information given in the shaded box.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(2 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
9 (f)
What conclusions can you draw from the data in the table about the factors causing deformed leg in frogs? Explain your answer.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
(4 marks)
(Extra space) .......................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
END OF QUESTIONS
(23)
APW/Jun09/BIOL2
15
24
There are no questions printed on this page
DO NOT WRITE ON THIS PAGE
ANSWER IN THE SPACES PROVIDED
