www.igexams.com
Characteristics and
Classification of
Living Organisms
Question Paper 1
Level
IGCSE
Subject
Biology
Exam Board
CIE
Topic
Characteristics and Classification of Living Organisms
Paper Type
(Extended) Theory Paper
Booklet
Question Paper 1
Time Allowed:
75 minutes
Score:
/62
Percentage:
/100
www.igexams.com
1
Fig. 2.1 is an electron micrograph showing the bacteria, Vibrio cholerae.
Fig. 2.1
(a)
(i)
Bacteria are prokaryotes.
State two distinguishing features of all prokaryotes.
Doesn't have true nucleus
1 .............................................................................................................................
Most of the prokaryot have plasmids( useful for genetic engeneering)
2 .............................................................................................................................
Unicellular organism
[2]
no cell membrane
(ii) The bacteria shown in Fig. 2.1 each have a flagellum.
Suggest the function of the flagellum in bacteria.
For movement
................................................................................................................................
................................................................................................................................
................................................................................................................................
[1]
www.igexams.com
(b) V. cholerae is the pathogen that causes cholera. Vaccination is used to control the spread of
cholera during an outbreak.
Explain how vaccination can control the spread of diseases.
Vaccination contains inactivated pathogens that cant be able to reproduce, when it is
...........................................................................................................................................
injected into the body the pathogen causes the lymphocyte trigger to produce antibodies
active
and bind into the antigen of the pathogen and this produces the memory cell provides long
...........................................................................................................................................
term immunity for the body.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[4]
(c) Many years ago scientists discovered that V. cholerae secretes a toxin. Fig. 2.2 shows the
results of an experiment to measure the flow of chloride ions out of human cells with and
without the toxin.
14
12
10
key
with toxin
without toxin
8
flow of chloride
ions / arbitrary
units
6
4
2
0
0
50
100
150
time / s
Fig. 2.2
200
250
300
www.igexams.com
(i)
Calculate the difference in flow of chloride ions between the cells with the toxin and the
cells without the toxin at 50 seconds.
Show your working and state the units in your answer.
0.4-12
11.6 arbitary units
.................................................
[2]
(ii) Use the data in Fig. 2.2 to describe the effect of the toxin on the flow of chloride ions
out of the cells.
................................................................................................................................
as
data in fig 2.2 the flow of chloride ion out of the cell with toxin is higher compared to the flow of
chloride ion out of the cell without a toxin, the time taken for flow of chloride ion with toxin is higher
................................................................................................................................
compared
to the flow of chloride ion without the toxin
The flow of chloride ions with toxin has a rapid increase at 50 sec 12 au then decrease at 5
................................................................................................................................
sec /4.6au
................................................................................................................................
The flow of chloride ion without the toxin stays the same between 125-150sec / 4.4-4.8au , it
fluctuates
................................................................................................................................
................................................................................................................................
................................................................................................................................
[3]
(iii) Chloride ions cannot move out of cells by simple diffusion.
Suggest and describe how chloride ions could move out of cells.
Active Transport
................................................................................................................................
Through the protein molecules in the cell membrane
using energy
................................................................................................................................
movement against the concentration gradient
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
[3]
www.igexams.com
(d) The loss of chloride ions from cells causes diarrhoea and dehydration in patients with cholera.
(i)
State which organ in the alimentary canal is affected by the cholera toxin.
Small Intestine
................................................................................................................................
[1]
(ii) Describe the treatment for cholera.
Oral rehydration salt
to replace loss of water
................................................................................................................................
................................................................................................................................
Antibiotics
................................................................................................................................
................................................................................................................................
................................................................................................................................
[2]
[Total: 18]
www.igexams.com
2
(a) Fig. 1.1 shows five species of mollusc.
A
C
B
D
E
Fig. 1.1
Use the key to identify each species. Write the letter of each species (A to E) in the correct
box beside the key.
Key
1 (a)
body is completely or partly covered in a shell
go to 2
body is not completely covered or partly covered in a shell
Limax flavus
shell is attached to rocks by thin threads
Mytilus edulis
shell is not attached to rocks by thin threads
go to 3
shell is a spire that comes to a point
Buccinum undatum
shell is not a spire that comes to a point
go to 4
4 (a)
animal has tentacles
Nautilus pompilius
(b)
animal has 2 tentacles
Planorbis planorbis
(b)
2 (a)
(b)
3 (a)
(b)
[3]
(b) State two features that are shown by all molluscs.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
[Total: 5]
www.igexams.com
3
Fig. 1.1 shows seven different species of amphibian.
A
B
C
D
E
F
not drawn to scale
G
Fig. 1.1
www.igexams.com
(a) Use the key to identify each species. Write the letter of each species (A to G) in the correct
box beside the key. One has been done for you.
Key
1 (a)
long, narrow body, with or without legs
go to 2
body not long and narrow, back legs are larger than
the front legs
go to 5
body without legs
Gymnopis multiplicata
body with legs which are all of the same size
go to 3
raised crest along the back of the body
Triturus cristatus
no crest along the back of the body
go to 4
4 (a)
gills present
Necturus maculosus
(b)
no gills present
Ambystoma tigrinum
5 (a)
skin is smooth
go to 6
skin is not smooth
Oreophrynella
quelchii
digits end in swellings
Polypedates
leucomystax
digits do not end in round swellings
Rana temporaria
(b)
2 (a)
(b)
3 (a)
(b)
(b)
6 (a)
(b)
B
[3]
(b) Many amphibian species throughout the world are endangered.
Suggest three reasons why many amphibian species are endangered.
1 ................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
3 ................................................................................................................................................
...................................................................................................................................................
[3]
[Total: 6]
www.igexams.com
4
Fig. 1.1 shows seven lizards that are at risk of becoming extinct.
C
A
B
E
D
F
G
www.igexams.com
(a) (i)
Name the vertebrate group that contains lizards.
reptiles
.......................................................................................................................................[1]
(ii)
Use the key to identify each species. Write the letter of each species (A to G) in the
correct box beside the key. One has been done for you.
key
1
2
3
4
5
6
(a) feet with three toes
go to 2
(b) feet with five toes
go to 3
(a) has a collar or crest on head
go to 4
(b) has no collar or crest on head
Chalcides minutus
(a) spikes along back
go to 5
(b) no spikes along back
go to 6
(a) ridges extend along back and tail
Brookesia perarmata
(b) no ridges along back or tail
Calumma parsonii
(a) blunt, rounded head
Amblyrhynchus cristatus
(b) elongated head
Cyclura lewisi
(a) large raised scales on skin
Abronia graminea
(b) scales on skin are not large or raised
Varanus komodoensis
D
[3]
(b) The effect of humans on the environment has caused the populations of the lizard species in
Fig. 1.1 to decrease.
Explain why conserving lizards is important.
Maintains food webs or chain
...................................................................................................................................................
maintain biodiversity
Food for predators of lizard
...................................................................................................................................................
reasearch in source of medicine
encourages genetic diversity
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
www.igexams.com
(c) Zookeepers report that isolated female Komodo dragons, Varanus komodoensis, have
produced offspring asexually. This is very unusual in vertebrates.
(i)
State two disadvantages of asexual reproduction.
Less variation : genetically identical offspring
...........................................................................................................................................
No evolution or adaptation of the environment
...........................................................................................................................................
...........................................................................................................................................
Reduced genetic diversity
Negative Traits passed on
...........................................................................................................................................
Less chance of surviving ina varying environment
.......................................................................................................................................[2]
(ii)
State two disadvantages of sexual reproduction.
Takes time to find a partner
Slower process than asexually
...........................................................................................................................................
Requires more energy
Requires a Partner
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(d) Sexual reproduction requires meiosis to occur.
(i)
Define the term meiosis.
Reduction division of a diploid nucleus to form a haploid
...........................................................................................................................................
Production of sexual gamate eg: sperm
...........................................................................................................................................
half number of chromosome
.......................................................................................................................................[2]
(ii)
Explain the significance of meiosis to the survival of endangered species of lizards.
Causes genetic variation
...........................................................................................................................................
Allows evolution
adaptation of new environment
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[3]
[Total: 16]
www.igexams.com
5
Myriapods are a group of arthropods that are commonly found in soil habitats in many parts of the
world. Many myriapods are very small and not easy to identify.
Fig. 6.1 shows four species of myriapod, not drawn to the same scale.
Polydesmus
denticulatus
Cylindroiulus
punctatus
Scutigera
coleoptrata
Scolopocryptops
sexspinosus
Fig. 6.1
(a) State three features of all myriapods that are visible in Fig. 6.1.
segmented body
1 ...............................................................................................................................................
...................................................................................................................................................
Has a pair of antannae
2 ...............................................................................................................................................
...................................................................................................................................................
more than 10 pairs of legs
3 ...............................................................................................................................................
.............................................................................................................................................. [3]
www.igexams.com
(b) Describe three features of myriapods that could be used to make a dichotomous key to
distinguish between the four species in Fig. 6.1.
Total number of legs
1 ...............................................................................................................................................
Length of legs
...................................................................................................................................................
Number of segments of body
2 ...............................................................................................................................................
Number of legs per segment
...................................................................................................................................................
length of the body
3 ...............................................................................................................................................
head shape
.............................................................................................................................................. [3]
(c) Mitochondria are cell structures that contain a small quantity of DNA.
Scientists are sequencing the DNA of one particular gene in mitochondria to help identify
different species of many animals including myriapods. The sequences that they find are
called ‘barcodes’.
(i)
State the part of the cell that contains most of the DNA.
Nucleus
Plasmid
...................................................................................................................................... [1]
(ii)
Suggest how DNA barcoding might be useful in the conservation of animals, such as
myriapods.
To identify the animals accurately
...........................................................................................................................................
barcoding is chaep/quick/efficient
identify previously unknown species
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
(iii)
State the function of DNA in cells.
Stores genetic information
Used to carry out protein synthesis
...........................................................................................................................................
Codes for specific protein
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
www.igexams.com
(d) A student found the following information about the feeding relationships between some
organisms in a soil habitat.
Dead organic matter, such as leaves, provides food for bacteria and soil fungi.
Earthworms eat dead leaves.
Many millipedes feed on dead plant matter and also on soil fungi.
Nematodes feed on bacteria and are eaten by springtails.
Centipedes are predators that feed on earthworms, millipedes and springtails.
(i)
Draw a food web to show the feeding relationships described above.
[4]
(ii)
Describe the roles of the soil organisms in the carbon cycle.
release Carbon dioxide
...........................................................................................................................................
decomposition
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
[Total: 17]