AS & A Level Biology - 9700 Paper 1 2012 Summer Zone 3

What is the ecological definition of the term community?

The table shows the results of a field study of four species in a food chain in an area of woodland.
[Table_1]
What is the energy flow in the food chain?

The diagram shows the flow of energy through an ecosystem. Photosynthesis is the gross productivity. Producers lose some energy in respiration and the energy left is the net productivity.
This can also be expressed as an equation:
\( \text{net productivity} = \text{gross productivity} - \text{respiration} \)
Some of the net productivity passes to herbivores.

Which calculation gives the proportion of net productivity passing to herbivores?

What are always present in prokaryote cells?

The following are all features of eukaryotic cells.
1 chloroplast
2 endoplasmic reticulum
3 lysosome
4 mitochondrion
5 nucleus
Which of these have a double membrane?

Which group of structures are visible in a suitably stained plant cell using a high power (x400) light microscope?
[Table_1]

A microscope has a resolution of 200 nm. Which of the following organelles would not be resolved using this microscope?

The magnification of the photomicrograph is ×4000.

What is the actual size of the nucleolus?

The diagram shows the fluid mosaic model of membrane structure. Which would enable a hormone to recognise its target cell?

Which of the following ways of moving substances across cell surface membranes allows movement in both directions?
1. active transport
2. diffusion
3. facilitated diffusion
4. osmosis

The graphs show the rate of uptake of sugars by a culture of animal cells, under different conditions.
How are the sugars taken up by the cells when air is bubbled through the culture?

Which molecule in the key is sucrose?

Tests were performed on samples from a mixture of biological molecules.
When iodine in potassium iodide solution was added to a sample, the mixture turned black.
When the biuret test was carried out on another sample, the mixture turned purple.
Which biological molecules were in the mixture?

Which of the statements about polysaccharides can be used to describe both amylopectin and cellulose?
1. adjacent glucose molecules are rotated by 180°
2. contains 1,4 glycosidic bonds
3. polymer of α-glucose

Which substances contain carbon, hydrogen, oxygen and nitrogen?
1. collagen
2. amylopectin
3. deoxyribonucleic acid

Which molecules have a structural formula that contains C=O bonds?
1. fatty acids
2. glucose
3. glycerol

Which level of protein structure maintains the globular shapes of enzymes?

Catalase is an enzyme that catalyses the conversion of hydrogen peroxide into water and oxygen.
Two students investigated the effect of enzyme concentration on the rate of reaction of the enzyme catalase. The students predicted their results would show the same trend. The graphs show the rates obtained by each student.

Which statement explains the different trend shown by student 2’s results?

The graph shows the progress of a reaction in the presence and absence of an enzyme.
What is the activation energy of the reaction in the presence of the enzyme?

For organisms undergoing sexual reproduction, a reduction division occurs before fertilisation.
Which reasons explain why this is necessary?
1. increase genetic variation
2. prevent doubling of the chromosome number
3. reduce the chances of mutation

What occurs during metaphase of mitosis?

What are the conditions in a human cell just before the cell enters prophase?
[Table_1]

A length of double-stranded DNA contains 120 nucleotides and codes for polypeptide X.
What is the maximum length of polypeptide X?

Which statement describes a process that occurs during protein synthesis?

During semi-conservative replication of DNA in eukaryotic cells, the following processes occur:
1. Free nucleotides are hydrogen bonded to those on the exposed strand.
2. Hydrogen bonds are broken between the complementary base pairs.
3. The cell receives the signal to begin to divide.
4. Covalent bonds form between adjacent nucleotides on the same strand.
5. The DNA double helix is unwound.
Which shows the correct order of some of the processes?

During transpiration, from where does the evaporation of water occur?

When transpiration is at a maximum rate, tree trunks decrease in diameter. Which statement explains this?

The graph shows stomatal opening and closing in the leaves of a species of Pelargonium, during a 24 hour period.
What can be concluded?

Which statement explains how mass flow arises in sieve tube elements?

The diagram shows a model to demonstrate the mass flow hypothesis of translocation.



In a plant, what are the structures W, X, Y and Z and what is the direction of flow of solution along W?

Which of the following increases the risk of contracting cholera?
1. drinking unpasteurised milk
2. eating shellfish which have fed on raw sewage
3. living in overcrowded conditions

Which cells become memory cells in the immune response?
1. B-lymphocytes
2. T-lymphocytes
3. phagocytes

Which describes a T-helper lymphocyte?

Antibodies can act in a number of ways to protect the body from pathogenic bacteria. Which event will not occur following antigen-antibody binding?

The graph shows the pressure in three parts of the heart during one cycle. At 0.2 seconds, which part of the heart is responding to the excitatory stimulus?

Each set of graphs represents data for blood vessels in the sequence: art (artery), a (arterioles), c (capillaries), v (venules), vein (veins).
Which set is correct?
(Graphs labeled A, B, C, D showing total cross-sectional area, velocity, wall thickness, and pressure)

Which is correct about the affinity between haemoglobin and the gases carbon dioxide, carbon monoxide and oxygen?
[Table_1]

An increase in carbon dioxide in human blood shifts the oxyhaemoglobin dissociation curve to the right.
What is the explanation for this effect?

What would be seen in an electron micrograph of a bronchus wall?
1 cartilage cells
2 ciliated cells
3 exocytotic vesicles

The photomicrographs show transverse sections of arteries from a non-smoker and a smoker.

From the evidence above, which disease is most likely to occur in the smoker?