Download Support worksheet – Chapter 3 - Cambridge Resources for the IB

Cambridge Biology for the IB Diploma
Support worksheet – Chapter 3
1
a
Copy and complete the following table, which shows some elements needed by living
organisms.
(4)
Element
Use in organisms
calcium
phosphorus
iron
sodium
b
2
Water is important in organisms because of its solvent properties.
i
What is a solvent?
(1)
ii
Why is this property of water so important to organisms?
(1)
Identify these molecules and give one use for each.
a
3
(4)
b
Copy this paragraph about DNA structure and fill in the spaces with suitable words.
(7)
A DNA molecule is made up of ________________ sugars, phosphate groups and four types of
base. Within the DNA molecule, bases are held together in pairs by ________________ bonds.
Guanine is always paired with ________________ and thymine is always paired with
________________. This arrangement is known as ________________ base pairing. The two
strands of nucleotides coil around one another to form a ________________
________________.
4
Copy and complete the information in this table to compare the structures of DNA and RNA. (3)
DNA
RNA
a double stranded molecule
contains ribose sugar
contains adenine, guanine, cytosine and
thymine bases
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Cambridge Biology for the IB Diploma
5
Transcription and translation are processes necessary for protein synthesis. Arrange
these sentences in the correct order to explain the sequence of events.
A
B
C
D
E
F
G
H
I
J
6
7
(10)
RNA polymerase forms an mRNA strand that is complementary to DNA.
A chain of amino acids linked together is known as a polypeptide.
The mRNA molecule consists of a series of triplets of bases known as codons.
The ribosome travels along the mRNA.
Amino acids are joined by peptide bonds.
One codon codes for one amino acid.
mRNA moves into the cytoplasm from the nucleus.
tRNA brings amino acids to the ribosome.
Each tRNA molecule corresponds to one codon and can carry the appropriate amino
acid.
A ribosome attaches to the mRNA.
The graph below shows the rate of an enzyme-catalysed reaction at different temperatures.
Describe the events that are taking place at points A, B and C on the graph. Use the terms
‘molecular collisions’, ‘active site’ and ‘denaturation’.
(6)
The table below summarises the results of an experiment in which light of different intensities
was shone onto a sample of Canadian pondweed and the rate of oxygen released was measured.
The experiment was conducted at two different carbon dioxide concentrations, which were
achieved by enriching the water with sodium hydrogencarbonate. The different light intensities
were obtained by placing a lamp at different distances from the container of pondweed.
2.00
1.50
1.00
0.75
0.50
0.25
–1
0.2
0.4
0.7
1.4
1.4
1.4
Rate of oxygen release / mm3 min–1
0.6
0.8
1.1
1.6
1.8
1.8
Distance of lamp from plant / m
3
Rate of oxygen release / mm min
1% CO2
2% CO2
a
Plot the results on graph paper using the same axes for both curves.
b
Use the 2% CO2 line on your graph to outline the relationship between light intensity and
the rate of photosynthesis.
(2)
c
Explain how and why the rates of photosynthesis at 1% CO2 and 2% CO2 are different. (2)
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(4)
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