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Which of the cell organelles, when appropriately stained, will be clearly visible under the high power ($\times400$) of the light microscope?
[Table_1]
Which is correct about the organelles listed in the table?
[Table_1]
The graticule and stage micrometer are used to measure cells. Which is the correct reason why the graticule calibrated?
What are the characteristics of a prokaryotic cell? [Table_1]
The diagram shows a stage micrometer, with divisions 0.1 mm apart, viewed through an eyepiece containing a graticule.
The same eyepiece is now used to examine a blood smear.
How many graticule divisions will cover the diameter of a white cell of 10 μm?
The equation shows a reversible reaction.
\[ \text{sucrose + water} \xrightarrow{\text{sucrase } 1} \text{glucose + fructose} \xleftarrow{2} \]
In this reaction, on which molecule does an active site occur and what types of reaction occur at 1 and 2?
[Table_1]
What are the features of triglycerides?
[Table_1]
Tests on a liquid give these results:
[Table_1]
What are present in the liquid?
Which linkages are found between the glucose units in cellulose?
Water is important to living organisms because it
Which diagram shows the bond linking the individual units of both cellulose and amylose?
Which statements about amylopectin and glycogen are correct?
1. both contain 1-4 glycosidic bonds
2. amylopectin contains $\beta$-glucose
3. glycogen contains more 1-6 branches than amylopectin
The graph shows the course of an enzyme-catalysed reaction at 30°C.
What is true at time X?
The rate of enzyme-catalysed reactions in human cells is regulated.
Which may be involved in such regulation?
1 a change in enzyme concentration
2 a change in substrate concentration
3 inhibition by the final product of the reaction
Which molecules, found in the cell surface membrane, have the properties listed? [Table 1]
The stalk of a dandelion is a hollow tube. Pieces of the stalk are cut as shown and placed in sucrose solutions of different water potentials.
Which diagram shows the piece that is placed in the sucrose solution with the highest water potential?
In an investigation, four sucrose solutions were separated from each other by partially permeable membranes.
1 1.1 mol dm-3
2 0.8 mol dm-3
3 0.5 mol dm-3
4 0.1 mol dm-3
Which shows the direction in which water will move between the solutions?
Male bees are haploid. They develop from unfertilised eggs. Female bees are diploid.
Which statements are correct?
1. All male bees are genetically identical.
2. Male bee sperm cells are produced by mitosis.
3. New combinations of genes only occur in female bees.
What describes the behaviour of the nuclear envelope and the cell membrane during mitosis?
DNA was extracted from the salivary glands of a fruit fly and a human cheek cell. In which way did the DNA molecules differ?
Which statement describes the semi-conservative replication of DNA?
The table shows the percentages of nitrogenous bases in four samples of nucleic acids.
Which base is adenine?
[Table_1]
Table 1: percentage of nitrogenous bases
\[
\begin{array}{|c|c|c|c|c|c|}
\hline
\text{sample} & \text{A} & \text{B} & \text{C} & \text{D} & \text{uracil} \\
\hline
1 & 19 & 31 & 30 & 19 & \text{nil} \\
2 & 27 & 23 & 24 & 26 & \text{nil} \\
3 & 25 & 25 & \text{nil} & 25 & 25 \\
4 & 17 & 32 & 33 & 18 & \text{nil} \\
\hline
\end{array}
\]
The table shows the role of four different proteins involved in DNA replication.
[Table_1]
Which shows the function of these proteins?
Which shows the correct structure of mature xylem vessel elements and phloem sieve tube elements? [Table_1]
The photomicrograph shows a transverse section through a leaf.
1. sunken stomata
2. two layers of epithelium
3. thick cuticle
4. small surface area to volume
Which features of a xerophytic leaf are visible in this section?
The diagram shows some adjacent cells from the root of a plant. Which is the apoplastic pathway of water movement?
What determines the rate of water movement from the roots to the leaves?
The mammalian circulatory system is described as a closed double circulation.
The diagram shows the circulatory system in a different organism. The arrows show the direction of blood flow in the vessels.
How is the circulatory system in this organism described?
The diagram shows the valves inside the heart.
Which valves are open or closed when the atria are relaxed and the ventricles contracted?
Which tissues are present in the walls of a trachea and an alveolus? [Table_1]
How does nicotine in cigarette smoke increase the risk of cardiac disease?
The diagram shows the volume of air breathed in and out while a person is breathing normally when at rest.
They breathe out the deepest breath they can and then breathe in as much as they can before breathing normally again.
Which points would you use to calculate the vital capacity?
Which diseases can be cured by the use of antibiotics?
What could cause an outbreak of malaria in a country where it had been eliminated?
1. mosquitoes became resistant to insecticides
2. migration of population due to war
3. malarial parasites became resistant to quinine
The diagram shows part of the immune response.
What are P, Q and R?
When a body cell is infected by a pathogen, which describes a correct immune response?
The photomicrograph shows human blood, with three types of white cell labelled.
Which row correctly identifies these white cells?
The table shows the results of a field study of four species in a food chain in an area of woodland.
[Table_1]
Which is the correct pyramid of energy from these data?
The diagram represents the flow of energy through a tropical rainforest ecosystem.
Which set of figures identifies the percentage transfer of energy between the Sun, producers, consumers and decomposers?
A farmer grows a different crop in a field each year for three years. In the fourth year the farmer plants a leguminous crop and then ploughs this into the soil. The next year the rotation starts again. Which microorganisms will increase by the time the rotation starts again?
1 denitrifying bacteria
2 nitrifying bacteria
3 nitrogen-fixing bacteria
4 decomposing bacteria