CAIE
A Level
9700
Biology 2025 · Oct/Nov
40 Questions
Q&A Available
Questions & Model Answers 40 Qs
Q1
MCQ
1 mark
A student observed some cells using a microscope with an eyepiece graticule. 0 10 20 30 40 50 60 70 They then replaced the slide containing the cells with a stage micrometer with a millimetre scale, and lined up the eyepiece graticule as shown. 0 10 20 30 40 graticule 0 0.1 0.2 stage micrometer What is the maximum diameter of the cell labelled X? A 0.0066
A
student observed some cells using a microscope with an eyepiece graticule.
A
0.0066
Q2
Short Answer
1 mark
Which structures will be present in a cell that causes cholera? 1 circular DNA 2 cytoplasmic DNA 3 70S ribosomes A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only
Q3
Short Answer
1 mark
Which organelles have a partially permeable membrane? 1 Golgi apparatus 2 lysosome 3 mitochondrion 4 ribosome A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4
Q4
Short Answer
1 mark
Mouse cells were grown in a dish containing a growth medium. Radioactively labelled amino acids were added to the growth medium. The table shows the time taken for the radioactively labelled amino acids to appear in three different organelles, R, S and T. organelle time taken for radioactivity to appear / min T 35 Which row correctly identifies the organelles? R S T Golgi body lysosome rough endoplasmic reticulum Golgi body rough endoplasmic reticulum lysosome rough endoplasmic reticulum Golgi body lysosome rough endoplasmic reticulum lysosome Golgi body
Q5
MCQ
1 mark
The electron micrograph shows a section through a cell. What would be present in this type of cell? mitochondria peptidoglycan cell wall histone proteins A 3 3 7 key B 3 7 3 3 = present C 7 3 7 7 = not present D 7 7 3
A
3 3 7 key
B
3 7 3 3 = present
C
7 3 7 7 = not present
D
7 7 3
Q6
MCQ
1 mark
A student carried out four tests for biological molecules. The observations are shown in the table. test observations iodine orange biuret purple Benedict's orange emulsion clear The diagrams show molecules or parts of molecules. Which pair is present in the solution? CCHCCHCHO CO RH CO RH PO ORH OHHO2OHC C2OHO C2OH A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4
A
student carried out four tests for biological molecules. The observations are shown in the table.
A
1 and 2 B 1 and 3 C 2 and 3 D 3 and 4
Q7
MCQ
1 mark
The diagram shows some relationships between features of carbohydrates. 1 3 α-glucose 1,4 bonds highly branched Which row correctly matches the carbohydrate with some of its features? 1 2 3 A amylopectin glycogen amylose B amylose amylopectin cellulose C cellulose glycogen sucrose D glycogen amylose amylopectin
A
amylopectin glycogen amylose
B
amylose amylopectin cellulose
C
cellulose glycogen sucrose
D
glycogen amylose amylopectin
Q8
MCQ
1 mark
The diagram shows a triglyceride molecule. COCH COCH COCH Which statement is correct for the structure and function of this triglyceride? A The glycerol head forms hydrogen bonds with water in cytoplasm to produce oil droplets. B The hydrophobic fatty acids allow only small molecules to pass through the cell surface membrane. C It packs closely with identical triglyceride molecules to form energy reserves in lysosomes. D It has long hydrocarbon chains that release high energy output per unit mass when oxidised.
A
The glycerol head forms hydrogen bonds with water in cytoplasm to produce oil droplets.
B
The hydrophobic fatty acids allow only small molecules to pass through the cell surface
C
It packs closely with identical triglyceride molecules to form energy reserves in lysosomes.
D
It has long hydrocarbon chains that release high energy output per unit mass when oxidised.
Q9
MCQ
1 mark
Enzyme P has been found in a tropical grass. sugars. of amylose. Which row describes the actions of enzyme P? reaction catalysed reaction inhibited A hydrolysis of glycosidic bonds condensation of glycosidic bonds B hydrolysis of glycosidic bonds hydrolysis of glycosidic bonds C hydrolysis of peptide bonds condensation of glycosidic bonds D hydrolysis of peptide bonds hydrolysis of glycosidic bonds
A
hydrolysis of glycosidic bonds condensation of glycosidic bonds
B
hydrolysis of glycosidic bonds hydrolysis of glycosidic bonds
C
hydrolysis of peptide bonds condensation of glycosidic bonds
D
hydrolysis of peptide bonds hydrolysis of glycosidic bonds
Q10
MCQ
1 mark
Which bonds between amino acids hold the shape of the secondary structure and also the tertiary structure of proteins? A peptide bonds B disulfide bonds C hydrogen bonds D ionic bonds
A
peptide bonds
B
disulfide bonds
C
hydrogen bonds
D
ionic bonds
Q11
Short Answer
1 mark
Resilin is a protein found in the wings of insects. It is an elastic, fibrous protein and scientists have suggested that it may have an important role in allowing the wings of an insect to fold and unfold without damage. Peptidyl transferase is an enzyme which catalyses the condensation of amino acids during translation to form resilin. Which statements are correct? 1 Peptidyl transferase and resilin have structural roles in the insect. 2 Peptidyl transferase is a globular protein. 3 Peptidyl transferase is soluble in water. A 1 and 2 B 1 and 3 C 1 only D 2 and 3
Q12
MCQ
1 mark
Collagen is a protein that helps to strengthen and increase the elasticity and hydration of the skin. Aging can lead to dry skin and the formation of wrinkles, due to the body producing less collagen. Which row is correct for the structure of collagen in the skin? every fourth amino acid is glycine fibrous protein A 7 7 key B 3 3 3 = correct C 7 3 7 = not correct D 3 7
A
7 7 key
B
3 3 3 = correct
C
7 3 7 = not correct
D
3 7
Q13
MCQ
1 mark
What is the effect of an enzyme in an enzyme-catalysed reaction? A decreases the activation energy and decreases the energy yield B decreases the activation energy and has no effect on the energy yield C increases the activation energy and increases the energy yield D decreases the activation energy and increases the energy yield
A
decreases the activation energy and decreases the energy yield
B
decreases the activation energy and has no effect on the energy yield
C
increases the activation energy and increases the energy yield
D
decreases the activation energy and increases the energy yield
Q14
MCQ
1 mark
How is the Michaelis-Menten constant (K m) used? A to determine the number of collisions between the enzyme and substrate B to compare the affinity of enzymes for their substrates C to find the maximum velocity of an enzyme (V max) D to find the optimum rate of reaction
A
to determine the number of collisions between the enzyme and substrate
B
to compare the affinity of enzymes for their substrates
C
to find the maximum velocity of an enzyme (V
D
to find the optimum rate of reaction
Q15
Short Answer
1 mark
Some students investigated the effect of pH on the rate of starch digestion by amylase at 20 °C. of a 1% amylase solution and 1 cm of pH 4 buffer to a test-tube. of a starch solution, containing 0.02 g of starch, to the test-tube. The students then repeated these steps with pH 5, pH 6, pH 7 and pH 8 buffers. The table shows the results. time taken for starch to be digested / minutes 4 4.0 5 1.5 6 1.0 7 2.5 8 6.0 Which graph is correct for these data? rate of starch digestion by amylase minutes rate of starch digestion by amylase seconds rate of starch digestion by amylase mg min rate of starch digestion by amylase mg s
Q16
Short Answer
1 mark
Which statements are correct for a non-competitive inhibitor of enzyme action? 1 Increasing the concentration of the enzyme's substrate will reduce its effect. 2 It reduces the activation energy required for a reaction to take place. 3 It reduces the maximum rate of reaction. A 1 and 3 B 1 only C 2 and 3 D 3 only
Q17
Short Answer
1 mark
What can increase the fluidity of the cell surface membrane at low temperatures? 1 double bonds between carbon atoms in the fatty acid chains 2 cholesterol 3 fatty acids having shorter chains A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only
Q18
Short Answer
1 mark
Which statements about the proteins and glycoproteins in cell surface membranes are correct? 1 They can allow cells to bond together to form tissues. 2 They can recognise messenger molecules like hormones. 3 They can be antigens and allow cell-to-cell recognition. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only
Q19
MCQ
1 mark
In an experiment, four different-sized cubes of colourless agar were placed into a blue dye. The time taken for each cube to turn blue was recorded. Which row shows the surface area and volume of the cube that took the longest time to turn completely blue? surface area volume / cm A 6.0 1 B 9.5 2 C 12.5 3 D 38.0 16
A
6.0 1
B
9.5 2
C
12.5 3
D
38.0 16
Q20
Short Answer
1 mark
The stalk of a dandelion flower is a hollow tube called a scape. Pieces of the scape are cut as shown by the dotted lines and placed in sucrose solutions of different water potentials. hollow centre of scape outer cells inner cells cuts Which diagram shows the piece that is placed in the sucrose solution with the highest water potential? C D outer cells inner cells outer cells inner cells outer cells inner cells outer cells inner cells
Q21
MCQ
1 mark
Telomeres prevent the loss of genes during DNA replication. Which row correctly shows cell types that contain telomeres? typical animal cell typical plant cell typical bacterial cell A 3 3 3 key B 3 3 7 3 = present C 7 7 3 7 = not present D 3 7 7
A
3 3 3 key
B
3 3 7 3 = present
C
7 7 3 7 = not present
D
3 7 7
Q22
Short Answer
1 mark
Which events listed are part of mitosis? 1 interphase 2 prophase 3 cytokinesis A 1, 2 and 3 B 1 and 2 only C 1 only D 2 only
Q23
MCQ
1 mark
The photomicrograph shows 17 cells in different stages of the mitotic cell cycle. cell 1 Which row is correct for this photomicrograph? the role of a centromere in cell 1 the proportion of the cells in the photomicrograph in telophase attaches daughter chromosomes to spindle fibres > 0.2 B holds sister chromatids together > 0.2 attaches daughter chromosomes to spindle fibres < 0.2 D holds sister chromatids together < 0.2
B
holds sister chromatids together > 0.2
D
holds sister chromatids together < 0.2
Q24
Short Answer
1 mark
The flow diagram shows some of the stages in the replication of a lagging strand of DNA. Which stage of DNA replication uses the enzyme DNA ligase? The DNA double helix begins to unwind. The single strands of DNA are exposed. New complementary DNA fragments are synthesised The fragments of newly formed DNA are linked together. AB C D
Q25
MCQ
1 mark
In a gene, the 20 common amino acids are each coded for by thr ee bases in adjacent nucleotides. Why is there a difference between the number of amino acids and the number of possible triplet codes? A 44 triplets have no functions. B Some amino acids are coded for by more than one triplet. C Some triplets have unknown functions. D There are 44 'start' and 'stop' triplets.
A
44 triplets have no functions.
B
Some amino acids are coded for by more than one triplet.
C
Some triplets have unknown functions.
D
There are 44 'start' and 'stop' triplets.
Q26
MCQ
1 mark
How is a primary transcript modified to form mRNA? A It becomes longer as exons are joined together. B It becomes shorter as exons are removed. C It becomes longer as introns are joined together. D It becomes shorter as introns are removed.
A
It becomes longer as exons are joined together.
B
It becomes shorter as exons are removed.
C
It becomes longer as introns are joined together.
D
It becomes shorter as introns are removed.
Q27
MCQ
1 mark
The diagram shows protein synthesis in a prokaryote. tRNA 1 tRNA 2 AUG-CCU-AAG-UUG-CCC-DNA cell wall mRNA NOT TO SCALE Which row is correct for molecule X, structure Y and the anticodon of tRNA 1? molecule X structure Y anticodon of tRNA 1 A amino acid 80S ribosome AAC B polypeptide 80S ribosome UUG C polypeptide 70S ribosome AAC D protein 70S ribosome UUG
A
amino acid 80S ribosome AAC
B
polypeptide 80S ribosome UUG
C
polypeptide 70S ribosome AAC
D
protein 70S ribosome UUG
Q28
Short Answer
1 mark
The photomicrographs show sections of two organs of a plant. Which letter identifies a cell found with companion cells in a tissue in a root?
Q29
MCQ
1 mark
Which row correctly describes the pressure in the xylem and the water potential in the root hair cells used in the transport of water in a transpiring plant? pressure in the xylem water potential in root hair cells A positive negative B positive positive C negative negative D negative positive
A
positive negative
B
positive positive
C
negative negative
D
negative positive
Q30
MCQ
1 mark
Which row correctly identifies the definitions for each of the key terms used in transpiration? attraction between water molecules and walls of the xylem vessel effect created by evaporation of water from the surface of the leaf A cohesion adhesion B adhesion tension C cohesion tension D tension cohesion
A
cohesion adhesion
B
adhesion tension
C
cohesion tension
D
tension cohesion
Q31
MCQ
1 mark
Which combination of features is characteristic of a phloem sieve tube element immediately after it is loaded from a source? water potential of the phloem sieve tube element lignification of the cell wall A higher than source not present B higher than source present C lower than source not present D lower than source present
A
higher than source not present
B
higher than source present
C
lower than source not present
D
lower than source present
Q32
MCQ
1 mark
Which blood vessel carries blood with the lowest pressure? A aorta B pulmonary artery C pulmonary vein D vena cava
A
aorta
B
pulmonary artery
C
pulmonary vein
D
vena cava
Q33
MCQ
1 mark
The photomicrograph shows cells found in mammalian blood. What is cell P? A lymphocyte B monocyte C neutrophil D red blood cell
A
lymphocyte
B
monocyte
C
neutrophil
D
red blood cell
Q34
MCQ
1 mark
The diagram shows the Bohr shift in actively respiring cells. 0246810 partial pressure of oxygen / kPa percentage saturation of haemoglobin with oxygen What causes the shift from L to M? A Carbonic acid dissociates to release protons that bind to oxyhaemoglobin, affecting the conformation of haemoglobin to reduce its affinity for oxygen. B Hydrogencarbonate ions produced by carbonic anhydrase alter th e charge of oxyhaemoglobin, reducing its ability to bind oxygen. C Hydrogen ions combine with chloride ions in tissue fluid to produce hydrochloric acid, distorting oxyhaemoglobin and causing it to lose bound oxygen. D A low concentration of oxygen in actively respiring cells causes oxyhaemoglobin to release oxygen more quickly down the concentration gradient.
A
Carbonic acid dissociates to release protons that bind to oxyhaemoglobin, affecting the
B
Hydrogencarbonate ions produced by carbonic anhydrase alter th e charge of
C
Hydrogen ions combine with chloride ions in tissue fluid to produce hydrochloric acid,
D
A low concentration of oxygen in actively respiring cells causes oxyhaemoglobin to release
Q35
MCQ
1 mark
The bar chart shows the mean thickness of the walls of the main chambers in a mammalian heart. mean wall thickness heart chamber PQRS Which row correctly identifies the heart chambers? right atrium left atrium right ventricle left ventricle A R Q S P B Q S R P C R Q P S D Q R S P
A
R Q S P
B
Q S R P
C
R Q P S
D
Q R S P
Q36
Short Answer
1 mark
The diagram shows parts of the gas exchange system in humans and the associated cells or structures. alveolus bronchiole bronchus trachea ciliated cells squamous epithelial cells C-shaped rings of cartilage ciliated cells and goblet cells Which diagram shows the lines that correctly match the parts to their cells or structures? A BC D
Q37
MCQ
1 mark
The photomicrograph shows the wall of a bronchus as seen with a light microscope. Which row correctly identifies the structures labelled? X Y Z A epithelium elastic fibres bronchiole B endothelium smooth muscle bronchiole C epithelium smooth muscle blood vessel D endothelium elastic fibres blood vessel
A
epithelium elastic fibres bronchiole
B
endothelium smooth muscle bronchiole
C
epithelium smooth muscle blood vessel
D
endothelium elastic fibres blood vessel
Q38
MCQ
1 mark
Which factors affect the global pattern of distribution of malaria? 1 the disease is mainly restricted to tropical and subtropical environments 2 the effective vaccine has eradicated the disease in many countries 3 the vector required for transmission of malaria parasites 1 2 3 A 3 3 7 key B 3 3 3 3 = effect C 3 7 3 7 = not an effect D 7 3 3
A
3 3 7 key
B
3 3 3 3 = effect
C
3 7 3 7 = not an effect
D
7 3 3
Q39
MCQ
1 mark
Which molecule could be a self antigen? A a viral capsid protein B a phospholipid in a viral envelope C a toxin released by a pathogen D a glycoprotein on the surface of a macrophage
A
a viral capsid protein
B
a phospholipid in a viral envelope
C
a toxin released by a pathogen
D
a glycoprotein on the surface of a macrophage
Q40
MCQ
1 mark
The diagram shows an antibody molecule with some parts labelled. Which row is correct about the parts that form an antigen-binding site and have identical amino acid sequences? form an antigen-binding site have identical amino acid sequences A P and Q R and S B Q and V P and S C R and S U and V D U and V Q and R Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.
A
P and Q R and S
B
Q and V P and S
C
R and S U and V
D
U and V Q and R
Paper Details
| Board | CAIE |
| Level | A Level |
| Subject | Biology |
| Code | 9700 |
| Year | 2025 |
| Session | Oct/Nov |
| Q&A | 40 questions |
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