Oct/Nov 2015

What ribosome size is present in chloroplasts and in typical prokaryotic cells?

Protein synthesis

A solution that contains equal masses of amylose and amylopectin is fully hydrolysed. Which molecules would be present after the hydrolysis?

Carbohydrates and lipids

As a lake starts to freeze, which properties of water allow fish to stay alive? 1. Water has a high surface tension. 2. Water has a high latent heat of vaporisation. 3. Water has a high thermal capacity. 4. Water has its maximum density at $4\,^{\circ}\text{C}$.

Water

The graph illustrates the energy levels in an enzyme-catalysed reaction. Substrate molecules X and Y join together to form product Z. Which arrow indicates the decrease in activation energy caused by the enzyme?

Mode of action of enzymes

Which of the following statements concerning enzyme inhibitors are correct?

Factors that affect enzyme action

A constant volume of the enzyme catalase was combined with a constant volume of hydrogen peroxide solution. The diagram illustrates how the quantity of product varied as the reaction proceeded. What explains the form of this graph?

Mode of action of enzymes

Which statements about transport across cell surface membranes are correct?

Movement into and out of cells

The statements are about the differences between endocytosis and exocytosis. What number of the statements is correct?

Movement into and out of cells

The diagram shows apparatus arranged to examine the effect of placing a $10\%$ glucose solution inside a selectively permeable bag (Visking tubing) and immersing it in water. Samples of the surrounding water were tested using Benedict’s solution after $10$ minutes and again after $20$ minutes. The change in the volume of the glucose solution was recorded after $20$ minutes. Which row is correct?

Movement into and out of cells

The photomicrograph shows a cell in mitosis. What is occurring in this cell?

Chromosome behaviour in mitosis

The diagram shows stages in the life cycle of an organism. Which arrow indicates a process that produces haploid cells, and which arrow indicates mitosis?

Replication and division of nuclei and cells

Pancreatic cells measure $35\,\mu\text{m}$ across. Red blood cells measure $7000\,\text{nm}$ across. Which statement is correct?

The microscope in cell studies

Some nuclear acids are described by the statements below. 1 transport an amino acid to a ribosome 2 move a genetic code sequence out of the nucleus 3 transport a genetic code sequence to a ribosome Which functions are carried out only by mRNA?

Proteins

The antibiotic chloramphenicol prevents prokaryotes from reproducing by blocking the enzyme that catalyses peptide bond formation during translation. What will be prevented by the action of this antibiotic?

Proteins

In a DNA molecule, which row contains two pairs of nucleotide bases?

The microscope in cell studies

Through which process does sucrose travel in phloem sieve tube elements?

Movement into and out of cells

The diagram displays the findings from an experiment carried out with leaves of equal surface area taken from two different species. Each leaf was placed on a balance in daylight inside a closed room, and its mass was measured at $1$ hour intervals. What could account for these results?

Movement into and out of cells

Which statement describing how water moves through a leaf is not correct?

Movement into and out of cells

What changes happen to the water potential and the volume of liquid in the phloem when carbohydrate is transferred out of a root into phloem sieve tubes?

Movement into and out of cells

Which reactions occur in a capillary within the lungs?

Movement into and out of cells

Red blood cells can contain a molecule called 2,3-bisphosphoglycerate (2,3BPG). When 2,3BPG binds to haemoglobin, a greater partial pressure of oxygen is required to cause $50\%$ saturation of haemoglobin with oxygen. Which of these statements about the effect of 2,3BPG are correct?

Proteins

Which of the statements about arteries are correct?

The microscope in cell studies

Which process takes place in a mature red blood cell?

Transport of oxygen and carbon dioxide

The graph illustrates how pressure changes on the left side of the heart during one cardiac cycle. Determine the heart rate in beats per minute.

The heart

Which of the following statements are correct?

Cells as the basic units of living organisms

What might be observed in a photomicrograph of the trachea wall?

The gas exchange system

What process results in atherosclerosis?

Carbohydrates and lipids

A list of some symptoms of chronic obstructive pulmonary disease (COPD) is given. Which of these are also symptoms of emphysema?

The microscope in cell studies

The diagram illustrates one method of investigating the effect of an antibiotic on bacteria. The table presents the outcomes of tests on five different types of bacteria. Zones of less than $13\,\text{mm}$ indicate that resistant bacteria are present. Which statement can be supported by this data?

Antibiotics

What best identifies a function of a macrophage?

The immune system

The number of whooping cough cases has risen. A pregnant woman is immunised against whooping cough to help protect her newborn baby from this disease. How does the mother’s immune response protect a newborn baby from whooping cough?

The microscope in cell studies

A tree carries out photosynthesis and supplies organic compounds to other organisms in a forest. It removes carbon dioxide from the atmosphere and gives oxygen back to the atmosphere. It absorbs water from the soil through its roots and its leaves lose water to the atmosphere. Many other organisms live on the tree. Which term describes the tree?

Transport mechanisms

The diagram illustrates how energy flows through a food chain. Figures are given in $\text{kJ m}^{-2}\,\text{year}^{-1}$. What percentage of light energy is available to the herbivore?

Transport mechanisms

Which structures can be found in a $\textit{Vibrio cholerae}$ cell?

Cells as the basic units of living organisms

Why does applying nitrate fertilisers result in increased crop production?

Proteins

Which characteristics of microvilli and root hairs are correct?

Cells as the basic units of living organisms

What is the correct sequence of organelles when a protein is made and then secreted?

Protein synthesis

Which diagram represents the bond that joins the individual units of both glycogen and amylose?

Carbohydrates and lipids

Biological molecule tests were performed on three solutions, and the outcomes were recorded as follows. solution 1: Benedict’s test - blue to orange solution 2: Benedict’s test after acid hydrolysis - blue to red solution 3: biuret test - blue to purple Which observations would identify the solutions that contained sucrose and amylase?

Testing for biological molecules

Which row gives the description of a triglyceride?

Carbohydrates and lipids

Which ribosome size occurs in mitochondria?

Protein synthesis

The diagrams illustrate the amino acid serine. Which circled section is different in every other amino acid?

Proteins

As a frozen lake thaws after a cold winter, mineral nutrients are carried up to the surface. Which properties of water are responsible for this process?

Water

Which statements describe certain actions of enzymes?

Mode of action of enzymes

The diagram illustrates the mass of product formed over time in three reactions that use the same substrate and enzyme. The volumes of substrate and enzyme, together with the temperature, were kept the same in each reaction. Which statement accounts for the difference in these reactions?

Factors that affect enzyme action

Tyrosinase is an enzyme that speeds up the transformation of the amino acid tyrosine into the black pigment melanin. It causes the black fur colour seen in some rabbits. When one set of rabbits was maintained at $30^{\circ}\text{C}$, $90\%$ of them had light fur colour. When a different set of rabbits was kept at $10^{\circ}\text{C}$, $90\%$ of them had black fur colour. Which hypothesis do these results support?

Factors that affect enzyme action

Which statements describe transport across cell surface membranes correctly?

Movement into and out of cells

The steps in an investigation involving plant tissue are shown below. A freshly cut piece of plant tissue was rinsed with distilled water, blotted dry and weighed. This piece was then placed in a solution with a water potential of $-4$ arbitrary units for thirty minutes. It was taken out of the solution, dried and weighed again. Its mass was unchanged from its original mass. What conclusions may be made from this investigation?

Movement into and out of cells

What accounts for the effect on a red blood cell when it is placed in pure water?

Movement into and out of cells

Which of the following statements about a diploid cell are correct?

Chromosome behaviour in mitosis

Which metabolic processes would be highly active in a cell that has just finished cytokinesis?

Replication and division of nuclei and cells

A range of units is used when measuring biological specimens. Which measurement in mm has not been converted correctly into both $\mu\text{m}$ and nm?

The microscope in cell studies

What takes place in DNA replication, transcription and translation?

Replication and division of nuclei and cells

Ricin is a toxic protein that makes ribosomes inactive. What effect will this have on protein synthesis?

Protein synthesis

Which row identifies two pairs of nucleotide bases in a DNA molecule?

Structure of nucleic acids and replication of DNA

What does the Casparian strip do?

Movement into and out of cells

Via transport proteins and plasmodesmata, sucrose enters companion cells and phloem sieve tube elements by active transport and diffusion. Which row identifies the way sucrose is loaded?

Movement into and out of cells

What changes happen to the water potential and the volume of liquid in the phloem when sucrose moves from leaves into phloem sieve tubes for transport to a sink?

Movement into and out of cells

The diagram presents the findings of an experiment that used leaves with the same surface area from two different species. Each leaf was placed on a balance in daylight in a closed room, and its mass was measured at 1 hour intervals. Which features of leaf X could account for these results?

Movement into and out of cells

Which blood components are present in tissue fluid?

Movement into and out of cells

In a capillary within an active tissue, which reactions occur?

Movement into and out of cells

How do the atrioventricular valves and the semilunar valves behave during atrial systole and ventricular systole?

The heart

Which of the following features of microvilli and root hairs is correct?

Movement into and out of cells

Red blood cells can contain a molecule called 2,3-bisphosphoglycerate (2,3BPG). When 2,3BPG attaches to haemoglobin, a greater partial pressure of oxygen is required to achieve 50% saturation of haemoglobin with oxygen. Which statements concerning the effect of 2,3BPG are correct?

Proteins

Which row correctly describes the human gas exchange system?

Movement into and out of cells

Which of the following effects are brought about by inhaling both carbon monoxide and nicotine in cigarette smoke?

Transport of oxygen and carbon dioxide

Which of the following statements about chronic obstructive pulmonary disease (COPD) are correct?

Movement into and out of cells

Why must a person who has a bacterial infection take antibiotics at regular, evenly spaced intervals?

Factors that affect enzyme action

Which of the following statements is correct about a neutrophil?

The immune system

What is meant by artificial passive immunity?

Antibodies and vaccination

Which statements accurately describe lymphocytes?

The immune system

Which group could count as a population?

Infectious diseases

The diagram illustrates how energy passes along a food chain. Sunlight supplies $1 \times 10^{6}\ \text{kJ m}^{-2}\ \text{y}^{-1}$ to green plants. The green plants have $27\,000\ \text{kJ m}^{-2}\ \text{y}^{-1}$, and $3000\ \text{kJ m}^{-2}\ \text{y}^{-1}$ is dissipated as energy. What percentage of the energy is used by the green plants for photosynthesis?

Cells as the basic units of living organisms

Since lysosomes vary in shape and size, they can be hard to identify. What is a lysosome?

Cells as the basic units of living organisms

Large populations of anaerobic bacteria are present in waterlogged soils. How does this affect soil fertility, and why?

Infectious diseases

Radioactively-labelled amino acids were placed in a tracheal cell that uses them to produce mucus (a glycoprotein). What pathway will the amino acids follow?

Protein synthesis

What structures can be found in a $\textit{Vibrio cholerae}$ cell?

Cells as the basic units of living organisms

A positive Benedict’s test turns this colour because copper oxide is formed. The amount of copper oxide is directly proportional to the amount of reducing sugar present. Fruit juice samples were examined for reducing sugars and non-reducing sugars by means of the Benedict’s test. The findings give the mass of copper oxide after boiling with Benedict’s solution, and after acid hydrolysis followed by boiling with Benedict’s solution. Which sample had the greatest amount of non-reducing sugar?

Testing for biological molecules

Which diagram represents the bond that joins the individual units in both cellulose and glycogen?

Carbohydrates and lipids

Which row gives the description of a triglyceride?

Carbohydrates and lipids

What size of ribosome is present in chloroplasts?

Protein synthesis

Large concentrations of urea disrupt every bond except covalent bonds in protein molecules. Which level of protein structure would stay unchanged when a protein is exposed to urea?

Proteins

Haemoglobin, which is a globular protein, is made up of four polypeptide chains: two alpha chains and two beta chains. In people without the condition, the DNA that codes for each beta chain has a sixth triplet that specifies glutamic acid. In people with sickle cell anaemia, this base triplet mutates so that it codes for valine. What does this mutation alter in the haemoglobin molecule?

Proteins

The graph illustrates the concentration of one substance taking part in an enzyme-catalysed reaction. Which substance is represented by line X?

Mode of action of enzymes

Which description best explains the induced fit mode of action of an enzyme?

Mode of action of enzymes

Line X shows how an enzyme-catalysed reaction proceeds under optimum conditions. Line Y illustrates the action of the same enzyme on the same substrate, but with one variable altered: substrate concentration or pH or temperature. Which changes to the variables could produce the result shown by line Y?

Factors that affect enzyme action

Which statements about transport through cell surface membranes are correct?

Movement into and out of cells

Which of the following statements about the fluid mosaic model of a membrane are correct?

Fluid mosaic membranes

The diagram shows apparatus arranged to investigate diffusion. What indicates net diffusion of glucose and water molecules?

Movement into and out of cells

The photomicrograph depicts a cell as it undergoes mitosis. What is taking place in this cell?

Chromosome behaviour in mitosis

Which row indicates the products of mitosis, reduction division (meiosis) and fertilisation?

Replication and division of nuclei and cells

Biological specimens can be measured using different units. In which rows are the same measurements correctly given in each of the units named in the column headings?

The microscope in cell studies

Which of the statements below describe how a gene mutation can produce a non-functional protein?

Proteins

Certain antibiotics kill prokaryotes by attaching to RNA polymerase. What effect would this have on protein synthesis?

Proteins

Which row gives the correct description of cytosine?

Structure of nucleic acids and replication of DNA

In the photomicrograph, a transverse section of a leaf is shown. Which cell has the water potential that is least negative?

Movement into and out of cells

The diagram displays the findings from a transpiration experiment involving two different leaves. Each leaf was placed on a balance in daylight inside a closed room, and its mass was measured at 1 hour intervals. Which conclusions may be correct?

Movement into and out of cells

What processes take part in the transport of sucrose in plants?

Movement into and out of cells

What changes occur in the water potential and the volume of liquid in the phloem when carbohydrate is transferred from phloem sieve tubes into a sink?

Movement into and out of cells

Which reactions occur in a capillary within an active tissue?

Movement into and out of cells

What substance is found in the blood within human veins?

Transport of oxygen and carbon dioxide

The diagram shows the electrical activity in cardiac muscle during one heartbeat. What is occurring at each of the labelled stages in the cardiac cycle?

Movement into and out of cells

Which characteristics of cilia and root hairs are correct?

Cells as the basic units of living organisms

Which statement regarding the pulmonary artery is correct?

The circulatory system

Some red blood cells contain a molecule called 2,3-bisphosphoglycerate (2,3BPG). If 2,3BPG attaches to haemoglobin, a greater partial pressure of oxygen is required to cause $50\%$ saturation of haemoglobin with oxygen. Which statement correctly describes the effect of 2,3BPG?

Proteins

Where are cartilage and smooth muscle correctly located in the human gas exchange system?

The gas exchange system

Which factors keep the diffusion gradient for carbon dioxide at the surface of the alveoli maintained?

Movement into and out of cells

The surface tension in the liquid coating the alveoli pulls their walls inwards, so the alveoli could collapse. Which statements may account for how this is prevented?

Carbohydrates and lipids

The data illustrates how the number of human deaths due to the bacterium Staphylococcus aureus has changed across a five-year period. Methicillin is an antibiotic used to treat a disease caused by S. aureus. MRSA is methicillin-resistant S. aureus. Which statement is not supported by this data?

The microscope in cell studies

What is meant by natural active immunity?

The immune system

The bacterium that causes tetanus releases a toxin which functions as an antigen. The graph shows the concentration of an antibody in the blood of two people, G and H. On day $0$, G was given antibodies to the tetanus toxin and H was given the tetanus vaccine. What would be the outcome after G and H were infected with the tetanus bacteria on day $20$?

Antibodies and vaccination

What term is used for all the organisms of the same species that live in a particular area?

Cells as the basic units of living organisms

The table gives the findings from a field study on four species in a woodland food chain. What is the energy flow in this food chain?

Transport mechanisms

The diagram depicts a typical animal cell. Each labelled structure is associated with the synthesis of biological molecules. In which structures are glycoproteins, proteins and steroids synthesised?

Protein synthesis

The diagram illustrates a simplified nitrogen cycle. Which arrow indicates the activity of nitrogen-fixing bacteria?

Cells as the basic units of living organisms

What structures are found inside a $\textit{Vibrio cholerae}$ cell?

Cells as the basic units of living organisms

Which statement is correct for a typical prokaryotic cell?

Cells as the basic units of living organisms

The table gives the outcomes of tests done on a sample of biological molecules. Which row shows the kinds of molecules present in the sample?

Testing for biological molecules

The synthesis of biological molecules involves the formation of bonds. Which row is correct?

The microscope in cell studies

Which row gives the description of a triglyceride?

Carbohydrates and lipids