Biology 9700 · AS & A Level
Oct/Nov 2010
120 questions from this paper, with worked solutions and instant marking.
Which cell organelle would be seen clearly under high power ($\times 400$) with a light microscope after suitable staining?
The microscope in cell studies
Water is essential to living organisms because it
Water
Which diagram shows the bond that joins the individual units in both cellulose and amylose?
Carbohydrates and lipids
Which of the following statements about amylopectin and glycogen are correct?
Carbohydrates and lipids
The graph illustrates the progression of an enzyme-catalysed reaction at $30\degree\text{C}$. What is true at time $X$?
Mode of action of enzymes
The speed of enzyme-catalysed reactions in human cells is controlled. Which of these may be part of that control?
Factors that affect enzyme action
Which molecules in the cell surface membrane possess the properties shown?
Fluid mosaic membranes
A dandelion stalk is a hollow tube. Sections of the stalk are cut as illustrated and then put into sucrose solutions with different water potentials. Which diagram shows the piece placed in the sucrose solution with the highest water potential?
Movement into and out of cells
During an investigation, four sucrose solutions were separated from one another by partially permeable membranes. 1. $1.1\ \text{mol dm}^{-3}$ 2. $0.8\ \text{mol dm}^{-3}$ 3. $0.5\ \text{mol dm}^{-3}$ 4. $0.1\ \text{mol dm}^{-3}$ Which option shows the direction that water will travel between the solutions?
Movement into and out of cells
Male bees are haploid. They arise from unfertilised eggs. Female bees are diploid. Which statements are correct?
Replication and division of nuclei and cells
Which statement describes what happens to the nuclear envelope and the cell membrane during mitosis?
Chromosome behaviour in mitosis
Which statement about the organelles shown in the table is correct?
Cells as the basic units of living organisms
DNA was extracted from the salivary glands of a fruit fly and from a human cheek cell. In what way did the DNA molecules differ?
Structure of nucleic acids and replication of DNA
Which statement explains semi-conservative DNA replication?
Replication and division of nuclei and cells
The table gives the percentages of nitrogenous bases in four nucleic acid samples. Which base is adenine?
Structure of nucleic acids and replication of DNA
The table presents the roles of four different proteins involved in DNA replication. Which option shows the function of these proteins?
Replication and division of nuclei and cells
Which diagram shows the correct arrangement of mature xylem vessel elements and phloem elements?
Structure of transport tissues
The photomicrograph presents a transverse section of a leaf. Which xerophytic leaf features can be seen in this section?
The microscope in cell studies
The diagram illustrates several neighbouring cells from the root of a plant. Which route is the apoplastic pathway for water movement?
Movement into and out of cells
Which factor controls the rate at which water is transported from the roots to the leaves?
Movement into and out of cells
The mammalian circulatory system is referred to as a closed double circulation. The diagram illustrates the circulatory system in another organism. The arrows indicate the direction in which blood moves through the vessels. How would the circulatory system in this organism be described?
The circulatory system
The diagram illustrates the valves inside the heart. When the atria are relaxed and the ventricles are contracted, which valves are open and which are closed?
The heart
Cells are measured with the graticule and stage micrometer. Which option gives the correct reason for why the graticule cratered?
The microscope in cell studies
What tissues make up the walls of a trachea and an alveolus?
The gas exchange system
In what way does nicotine in cigarette smoke raise the risk of cardiac disease?
The circulatory system
The diagram shows how the amount of air inhaled and exhaled changes when a person is breathing at rest. They breathe out as deeply as possible, then breathe in as much as possible before returning to normal breathing. Which points would you use to work out the vital capacity?
The microscope in cell studies
Which diseases can antibiotics be used to cure?
Antibiotics
What might lead to a malaria outbreak in a country where it had previously been eliminated?
Infectious diseases
The diagram illustrates a section of the immune response. What are P, Q and R?
The immune system
When a body cell becomes infected by a pathogen, which option correctly describes an immune response?
The immune system
The photomicrograph is of human blood, and three kinds of white cell have been labelled. Which row identifies these white cells correctly?
The immune system
The table presents the findings from a field study involving four species in a food chain within one area. Which pyramid of energy is correct from these data?
Transport mechanisms
The diagram shows how energy moves through a tropical rainforest ecosystem. Which set of figures shows the percentage transfer of energy between the Sun, producers, consumers and decomposers?
Cells as the basic units of living organisms
What features are typical of a prokaryotic cell?
Cells as the basic units of living organisms
A farmer cultivates a different crop in the same field each year for three years. In the fourth year, the farmer grows a leguminous crop and then ploughs it into the soil. The following year, the rotation starts once more. Which microorganisms will have increased by the time the rotation starts again?
Infectious diseases
The diagram depicts a stage micrometer, whose divisions are spaced by $0.1\,\text{mm}$, seen through an eyepiece that includes a graticule. That same eyepiece is then used to observe a blood smear. How many graticule divisions are needed to span the diameter of a white cell measuring $10\,\mu\text{m}$?
The microscope in cell studies
The equation represents a reversible reaction. $\text{sucrose} + \text{water} \rightleftharpoons \text{glucose} + \text{fructose}$ (In the presence of the enzyme sucrase) For this reaction, which molecule has an active site, and what kinds of reaction take place at 1 and 2?
Mode of action of enzymes
What characteristics do triglycerides have?
Carbohydrates and lipids
A liquid is tested and the following observations are recorded. Benedict’s test: red Biuret test: lilac Iodine in potassium iodide solution: orange Which substances are present in the liquid?
Testing for biological molecules
What linkages are present between the glucose units in cellulose?
Carbohydrates and lipids
Which steps are required to determine the actual width of a xylem vessel seen in transverse section with a \times40 objective lens? 1 Change mm to µm by multiplying by $10^{-3}$. 2 Use a stage micrometer with the \times10 objective lens to calibrate the eyepiece graticule. 3 Use an eyepiece graticule to measure the width of the xylem vessel. 4 Multiply the calibration of the eyepiece graticule by the number of eyepiece graticule units.
The microscope in cell studies
As red blood cells exit the lungs, haemoglobin is $98\%$ saturated. How many molecules of oxygen will be carried by most haemoglobin molecules?
Proteins
A fixed volume of the enzyme catalase was mixed with a fixed volume of hydrogen peroxide solution. The diagram illustrates how the reaction rate changed as the reaction proceeded. Why did the actual rate of reaction fall as time passed?
Factors that affect enzyme action
Which levels of protein structure are invariably involved when competitive and non-competitive inhibitors attach to enzymes?
Mode of action of enzymes
The diagram illustrates the movement of ions across the cell surface membrane. Within the cell, the concentration of sodium ions ($\mathrm{Na^+}$) is low and the concentration of potassium ions ($\mathrm{K^+}$) is high. Outside the cell, the concentration of $\mathrm{K^+}$ is low and the concentration of $\mathrm{Na^+}$ is high. The carrier molecule is a pump that swaps $\mathrm{Na^+}$ for $\mathrm{K^+}$ ions. Which ion movements are shown by the arrows?
Movement into and out of cells
Plant cells were placed in solutions with different water potentials and then left for one hour. Which row shows the effect of these different solutions on the plant cells?
Movement into and out of cells
Which molecules, located in cell surface membranes, are involved in cell recognition?
Fluid mosaic membranes
Mitosis is part of the cell cycle. Which of these are characteristics of nuclear division?
Replication and division of nuclei and cells
In which life process does mitosis not play an important role?
Replication and division of nuclei and cells
The diagram illustrates the chromosomes in a typical plant cell at the metaphase stage. Which row gives the description of this cell during metaphase?
Chromosome behaviour in mitosis
The table displays the percentages of bases in DNA from different cell types. What valid deduction can be made from these data?
Structure of nucleic acids and replication of DNA
A specimen is observed with a microscope by using green light of wavelength $510\text{ nm}$. If the same specimen is then observed under identical conditions, but with red light of wavelength $650\text{ nm}$ instead, how will the microscope’s magnification and resolution be affected?
The microscope in cell studies
Which row presents the correct combination?
Movement into and out of cells
All the DNA in a bacterial culture had been labelled with the heavier nitrogen isotope, $^{15}\text{N}$. A sample was removed and placed in a centrifuge. The diagram shows where the DNA band is located at Z in the centrifuge tube. The culture was then permitted to replicate using nucleotides that contained the usual nitrogen isotope, $^{14}\text{N}$. Samples were taken and centrifuged after one generation and again after two generations. Which pattern would show the DNA after the first generation and after the second generation?
Replication and division of nuclei and cells
S and T are end products of a biochemical pathway. Each stage in the pathway is catalysed by a different enzyme, which is encoded by specific genes. What may happen to the pathway if a mutation in gene 3 results in an inactive enzyme?
Mode of action of enzymes
Which processes happen in transpiration? 1 the diffusion of water vapour out through stomata 2 the mass flow of water in the xylem 3 the evaporation of water from spongy mesophyll cells 4 the evaporation of water vapour from leaves exposed to the air
Movement into and out of cells
What is the primary role of a companion cell in mature phloem tissue?
Movement into and out of cells
Water moves through leaf tissues via different pathways because of: • differences in water potential • the pull passed on by cohesive forces between water molecules. The diagram illustrates three pathways along which water may move. Which row correctly shows why water moves across leaf tissues by the different pathways?
Movement into and out of cells
The diagram depicts a transverse section through a stem. Which region is the phloem?
Structure of transport tissues
The diagram illustrates the water potential ($\Psi$) in several plant cells and in the surrounding environment. Which of the statements are correct in this situation?
Movement into and out of cells
Which of the tissue types listed below are found in the walls of every blood vessel?
The circulatory system
In mammals, some carbon dioxide is transported inside red blood cells by combining with haemoglobin. What product is formed by this combination?
Proteins
Which cell organelle does not include nucleic acid?
Cells as the basic units of living organisms
The graph illustrates pressure variations throughout one cardiac cycle. Which row correctly names W, X, Y, and Z?
The heart
A number of babies are born with an opening between the right and left atria. These newborn babies are discovered to have a larger number of red blood cells. Why does this happen?
Transport of oxygen and carbon dioxide
Which row correctly identifies the sections of the respiratory tract that contain cartilage, cilia, goblet cells and smooth muscle?
The gas exchange system
In certain cases involving a person with lung disease, the oxygen partial pressure in the pulmonary veins is lower than the oxygen partial pressure in the alveoli. Which of the following would help explain the situation described above?
Movement into and out of cells
Which of the effects in the list occur as a result of breathing in both carbon monoxide and nicotine from cigarette smoke?
Transport of oxygen and carbon dioxide
In a study of gas exchange, measurements were taken on four people. For all four people, the efficiency of gas exchange was identical. During normal breathing, which person, A, B, C or D, absorbed the greatest amount of oxygen? The figures are: A: breathing rate $14$ breaths per minute, tidal volume $0.6\,\text{dm}^3$, total lung volume $6.4\,\text{dm}^3$ B: breathing rate $15$ breaths per minute, tidal volume $0.6\,\text{dm}^3$, total lung volume $6.0\,\text{dm}^3$ C: breathing rate $16$ breaths per minute, tidal volume $0.5\,\text{dm}^3$, total lung volume $6.4\,\text{dm}^3$ D: breathing rate $17$ breaths per minute, tidal volume $0.5\,\text{dm}^3$, total lung volume $5.8\,\text{dm}^3$
Movement into and out of cells
The table illustrates how the number of human deaths linked to the bacterium $\textit{Staphylococcus aureus}$ has varied between 1997 and 2005. Methicillin is an antibiotic that is used to treat an illness caused by $S.\ aureus$. MRSA means methicillin-resistant $S.\ aureus$. Year and total number of death certificates: 1997: $S.\ aureus = 369$, MRSA $= 355$ 1999: $S.\ aureus = 452$, MRSA $= 431$ 2001: $S.\ aureus = 456$, MRSA $= 681$ 2003: $S.\ aureus = 420$, MRSA $= 890$ 2005: $S.\ aureus = 428$, MRSA $= 1512$ Which statement cannot be supported by this data?
The microscope in cell studies
An enzyme hydrolyses the two heavy polypeptide chains in an antibody molecule. This hydrolysis takes place at the hinge region and splits the antibody into three fragments. How many of these fragments can bind to antigens?
Proteins
The diagram illustrates how the immune system responds to a pathogen. Which row correctly identifies P, Q, R and S?
Proteins
The diagram shows a section of the nitrogen cycle. Which process is performed by nitrifying bacteria?
The microscope in cell studies
Cell diameters can differ greatly. Representative diameters are: - a eukaryote, such as a white blood cell: $1.5 \times 10^{1}\,\mu\text{m}$ - a prokaryote, such as Streptococcus: $7.5 \times 10^{2}\,\text{nm}$ From these measurements, determine the greatest number of each cell type that could be placed in a straight line of length $1\text{ cm}$.
The microscope in cell studies
The diagram illustrates how energy moves among organisms in an ecosystem. Which option correctly names each organism in the ecosystem?
The microscope in cell studies
Cells are made up of several different components. Which row indicates the components present (✓) in both a prokaryotic and eukaryotic cell?
Cells as the basic units of living organisms
The diagram depicts a section of a carbohydrate molecule. If every $1,4$ glycosidic bond in this molecule is hydrolysed, how many water molecules will be needed and how many individual glucose molecules will be formed?
Carbohydrates and lipids
Between atoms of which two elements does a peptide bond form?
Proteins
Which features influence the tensile strength of collagen? 1 the helix-like arrangement of collagen chains 2 the small R groups of amino acids in collagen 3 the insoluble character of collagen 4 the covalent links between collagen molecules
Proteins
An amino acid may be shown as below, in which $R$ stands for a variable side chain. Which of the following is not a possible side chain?
Proteins
The photomicrograph depicts a transverse section of a leaf. Which xerophytic leaf features can be seen in this section?
Transport mechanisms
During an investigation, four sucrose solutions were each separated from the others by partially permeable membranes. 1 $1.1\,\text{mol dm}^{-3}$ 2 $0.8\,\text{mol dm}^{-3}$ 3 $0.5\,\text{mol dm}^{-3}$ 4 $0.1\,\text{mol dm}^{-3}$ Which option indicates the direction in which water will move between the solutions?
Movement into and out of cells
The equation represents a reversible reaction. $\text{sucrose} + \text{water} \; \rightleftharpoons \; \text{glucose} + \text{fructose}$ (This occurs in the presence of sucrase.) For this reaction, which molecule has an active site, and what kind of reactions take place at 1 and 2?
Mode of action of enzymes
A liquid is tested and the following outcomes are obtained. Benedict’s test: red Biuret test: lilac iodine in potassium iodide solution: orange Which substances are contained in the liquid?
Testing for biological molecules
What linkages are present between the glucose units in cellulose?
Carbohydrates and lipids
Which diagram shows the bond that joins the individual units in both cellulose and amylose?
Carbohydrates and lipids
Which of the following statements about amylopectin and glycogen are correct?
Carbohydrates and lipids
What characteristics do triglycerides have?
Carbohydrates and lipids
The photomicrograph shows human blood, and three kinds of white cell are labelled. Which row correctly names these white cells?
The immune system
The diagram illustrates part of the immune response. What are P, Q and R?
Proteins
Which diseases are able to be cured through the use of antibiotics?
Factors that affect enzyme action
What influences the rate at which water moves from the roots to the leaves?
Movement into and out of cells
What might lead to a malaria outbreak in a country in which it had previously been eradicated?
The microscope in cell studies
If a body cell becomes infected by a pathogen, which option gives a correct immune response?
The immune system
Which cell organelle, if suitably stained, would be clearly seen using the high power ($\times 400$) setting of the light microscope?
The microscope in cell studies
Cells are measured using the graticule and stage micrometer. Which is the correct reason for calibrating the graticule?
The microscope in cell studies
The diagram depicts a stage micrometer, whose divisions are spaced 0.1 mm apart, as seen through an eyepiece containing a graticule. That same eyepiece is then used to look at a blood smear. How many graticule divisions are required to span the diameter of a white cell of $10\,\mu\text{m}$?
The microscope in cell studies
What features does a prokaryotic cell have?
Cells as the basic units of living organisms
Which statement is correct about the organelles listed in the table?
Cells as the basic units of living organisms
The graph illustrates the progress of an enzyme-catalysed reaction at $30\,^{\circ}\text{C}$. What is true at time X?
Mode of action of enzymes
The rate of enzyme-catalysed reactions in human cells is controlled. Which of these may be involved in this control?
Factors that affect enzyme action
The table lists the roles of four different proteins that take part in DNA replication. Which option shows the functions of these proteins?
Replication and division of nuclei and cells
Which diagram correctly represents the structure of mature xylem vessel elements and phloem sieve tube elements?
Structure of transport tissues
Male bees are haploid, so they arise from unfertilised eggs. Female bees are diploid. Which of the following statements are correct?
Replication and division of nuclei and cells
Which statement explains the semi-conservative replication of DNA?
Replication and division of nuclei and cells
What term describes the changes to the nuclear envelope and the cell membrane during mitosis?
Chromosome behaviour in mitosis
DNA was extracted from the salivary glands of a fruit fly and from a human cheek cell. In what way did the DNA molecules differ?
Structure of nucleic acids and replication of DNA
The table gives the percentages of nitrogenous bases in four nucleic acid samples. Which base is adenine?
Structure of nucleic acids and replication of DNA
The diagram illustrates the volume of air inhaled and exhaled while a person is at rest. They breathe out as deeply as possible and then breathe in as much as they can before returning to normal breathing. Which points would you use to work out the vital capacity?
The gas exchange system
Identify the tissues found in the walls of a trachea and an alveolus.
The gas exchange system
In what way does nicotine in cigarette smoke increase the risk of cardiac disease?
The heart
The diagram shows how energy passes through a tropical rainforest ecosystem. Which set of figures shows the percentage transfer of energy between the Sun, producers, consumers and decomposers?
Cells as the basic units of living organisms
A farmer cultivates a different crop in the same field each year for three years. In the fourth year, the farmer grows a leguminous crop and then ploughs it into the soil. The rotation then begins again in the following year. Which microorganisms will have increased by the time the rotation begins again?
Infectious diseases
The diagram illustrates several neighbouring cells from the root of a plant. Which option represents the apoplastic pathway of water movement?
Movement into and out of cells
The table presents the findings from a field study of four species in a food chain in an area. Species P: number of individuals = 10 000, biomass of one individual = 0.100 (arbitrary units), energy value per unit mass = 1.0 (arbitrary units). Species Q: number of individuals = 5, biomass of one individual = 10.000 (arbitrary units), energy value per unit mass = 2.0 (arbitrary units). Species R: number of individuals = 500, biomass of one individual = 0.002 (arbitrary units), energy value per unit mass = 1.8 (arbitrary units). Species S: number of individuals = 3, biomass of one individual = 300 000.000 (arbitrary units), energy value per unit mass = 0.5 (arbitrary units). Which pyramid of energy is correct using these data?
The microscope in cell studies
Water is vital to living organisms because it
Water
The diagram illustrates the valves within the heart. When the atria are relaxed and the ventricles are contracted, which valves are open and which are closed?
The heart
The circulatory system of mammals is referred to as a closed double circulation. The diagram depicts the circulatory system of another organism. The arrows indicate the direction in which blood moves through the vessels. How would you describe the circulatory system in this organism?
The circulatory system
Which molecules in the cell surface membrane possess the properties listed?
Fluid mosaic membranes
A dandelion stalk is a hollow tube. Sections of the stalk are cut as shown and then put into sucrose solutions with different water potentials. Which diagram shows the section that is placed in the sucrose solution with the highest water potential?
Movement into and out of cells