AS & A Level Biology - 9700 Paper 1 2014 Summer Zone 3

The eyepiece lens of a microscope is fitted with an eyepiece graticule. Which statements about the graticule are correct?
1. It allows you to measure the actual length of cells.
2. It allows you to draw cells with correct proportions.
3. It changes in size as the objective lens changes from ×10 to ×40.

The diameter of living cells varies considerably.
The diameter of a typical eukaryotic cell is $1.5 \times 10^1 \mu m$.
The diameter of a typical prokaryotic cell is $7.5 \times 10^2$ nm.
Using these measurements, what is the maximum number of each cell type which could fit along a line 1 cm long?
[Table_1]

In order to complete the sentence below, what is the correct process and cell structure?
Cells which have a high rate of ......1...... will have many ......2....... .
[Table_1]

A cell secreting glycoproteins is supplied with radioactively-labelled glucose which is detected in the cytoplasm first.
In which organelle would radioactively-labelled glucose be detected next?

The diagram shows some similarities between chloroplasts, mitochondria and typical prokaryotes.

Which row is correct?

A student carried out four tests for biological molecules on a solution. The results are shown in the table.

[Table_1]

Which molecules are present in this solution?

Which bonds will be broken when a molecule of amylose is hydrolysed?

Which statement describes how the molecular structure of starch is suited to its function?

Which comparative statements concerning biological molecules are correct?
1. A collagen molecule is a fibrous protein that contains many amino acids with hydrophobic R-groups whereas a haemoglobin molecule is a globular protein with no amino acids with hydrophobic R-groups.
2. Sucrose hydrolysis results in glycosidic bond breakage and the production of equal proportions of fructose and $\alpha$-glucose molecules, whereas cellulose hydrolysis results in only $\beta$-glucose molecules.
3. The glycosidic bonds of glycogen have been formed between two $\alpha$-glucose molecules, whereas with amylopectin, the bonds have been formed between an $\alpha$-glucose molecule and a $\beta$-glucose molecule.

In triglyceride molecules, where are double bonds located?

The diagram represents an amino acid.

R represents a variable side chain.
Which is not a possible side chain?

Which of the statements describe some roles of enzymes?
1. catalyse the breakdown of larger molecules into smaller ones
2. lower the activation energy required to start a reaction
3. increase the number of collisions between molecules
4. supply the activation energy required to start a reaction

The graph shows the rate of activity of the enzyme sucrase plotted against the concentration of sucrose.

Why does the rate of enzyme activity remain constant from 80–90 g dm$^{-3}$?

Which graph represents the action of a non-competitive inhibitor?

The diagram shows part of a cell surface membrane.
Which molecules have both hydrophobic and hydrophilic regions?

One type of antigen is formed by a reaction between two different molecules.
Apart from oxygen, which other elements are found in this antigen?

What are the features of facilitated diffusion?
1. It uses protein channels in the membrane and is driven by the energy from ATP.
2. It moves molecules from regions of higher concentration to lower concentration and is driven by the kinetic energy of the molecules which are diffusing.
3. It uses protein channels in the membrane, and the maximum rate of diffusion depends on the number of these channels.

Single-celled animals that live in fresh water have a vacuole that contracts regularly to remove excess water. Single-celled plants that live in fresh water do not have a similar vacuole. Which statement explains why these animals need this vacuole but plants do not?

During which process does only mitosis occur?

The photomicrograph shows cells in different stages of mitosis.

In which order do these stages occur?

The statements are about genes and proteins involved in breast cancer.
• The protein coded by the BRAC1 gene inhibits the growth of breast cancer cells.
• The protein coded by the RAD51 gene is required for the repair of damaged DNA.
Which combination of genes is most likely to result in breast cancer?
[Table_1]

The diagram shows some relationships between different nucleic acid bases.

Which row is correct?

The diagram shows the structures of some drugs that have a similar structure to nucleotides. The presence of these drugs reduces nucleic acid synthesis. Which statement explains how these drugs reduce nucleic acid synthesis?

What terminates the formation of a polypeptide chain during protein synthesis in cells?

In which combination of environmental conditions are the stomata of a plant most likely to close?
[Table_1]

The diagrams show some tissue types in plant organs. Which row identifies the tissue types?

Which features apply to both sieve tube elements and xylem vessel elements?
1. no cytoplasm
2. no end walls
3. no nucleus

What changes occur to the water potential and the volume of liquid in the phloem when carbohydrate is moved into a sink? [Table_1]

Some plant species can take up heavy metal contaminants that are dissolved in soil water and then transport them within the plant. Within plant cells, the heavy metals accumulate mainly in the vacuole.

Which are valid suggestions about the transport and accumulation of heavy metals?

1. After initial entry into the root, some of the heavy metals can pass through the tonoplast to be stored in the vacuole of cortical cells.
2. The heavy metals take an apoplastic pathway in the xylem but at the endodermis must take a symplastic pathway.
3. The rate of accumulation of the heavy metals in leaf cells will be faster at night, when photosynthesis is not occurring, than during the day.
4. The presence of the heavy metal will inhibit active transport, causing the transpiration stream to slow down and reduce the rate of transpiration.

Which process can be carried out by a mature red blood cell?

Which is not a correct statement about phagocytes?

Which of the following are found in blood and lymph and tissue fluid?
1. carbon dioxide
2. glucose
3. white blood cells
4. fatty acids

The diagram shows a section through a type of epithelium.

Where is this type of epithelium found in the respiratory system?
[Table_1]

The diagram shows a magnified section of part of the lungs containing specialised tissues.



Where are there a high proportion of carbonic anhydrase, $\text{HCO}_3^-$ ions and lysosomes?

Which row correctly identifies the effects of carbon monoxide, nicotine and tar?
[Table with effects: raises blood pressure, causes gene mutation, reduces oxygenation of blood]

Which factors may increase the risk of cholera in refugee camps?
1. no refrigeration of food
2. increase in the number of people
3. lack of hand washing facilities

What are antigens?

A total of $3 \times 10^6$ kJ m$^{-2}$ yr$^{-1}$ is available from the producers in an ecosystem.
In theory, how much of this energy would be available to tertiary consumers?

In a food chain, which link involves the \textit{least} efficient energy transfer?

The growth of crop plants is often limited by the availability of nitrogen in the soil.
The graph shows the results of an investigation into the yield of a crop plant, with increasing levels of nitrogen supplied.

Which of the following best explains the shape of this curve?