AS & A Level Biology - 9700 Paper 1 2014 Summer Zone 2

At approximately which magnification is light microscopy not suitable because the resolution becomes too low?

The diagram shows a stage micrometer viewed with an eyepiece graticule scale, using a magnification of \times 400.

Using the same magnification, a chloroplast is measured and found to be 4 eyepiece graticule divisions long.
How long is the chloroplast?

Which organelle does not contain a partially permeable membrane?

The diagram shows an electron micrograph of a plant cell.
What do structures X, Y, and Z contain?

An amino acid enters a cell and is then used to synthesise an enzyme secreted by the cell.
What is the sequence of cell structures involved in the synthesis of the enzyme?
[Table_1]

The diagram shows some similarities between chloroplasts, mitochondria, and typical prokaryotes.
Which row is correct?

Which shows the basic unit of glycogen? [Image]

Four sugar solutions were tested with Benedict’s solution. The table shows the colour of the solutions after testing.

[Table_1]

What is the best interpretation of the results?

Which features adapt a cellulose molecule for its function?
1. Long chains of glucose molecules coil into a helix.
2. Many hydrogen bonds form between adjacent chains.
3. It is insoluble in water.

The structure of phospholipids and triglycerides include the following.
1. glycerol linked to fatty acids
2. hydrophobic fatty acid chains
3. saturated fatty acid chains
Which structures enable the formation of a lipid bilayer in cell surface membranes?

Which molecule contains a glycosidic bond?

The diagrams show the structures of two amino acids, each of which has two carboxylic acid (–COOH) groups.

A peptide bond is formed between the two amino acids.
Which groups form the peptide bond?

The drug ritonavir is sometimes used in the treatment of HIV/AIDS.
Ritonavir consists of three amino acids and is a competitive inhibitor of HIV protease. HIV causes this protease to be made inside human cells.
Ritonavir produces many side effects as it interferes with many metabolic processes in human cells.
Which statements about ritonavir are correct?
1. Ritonavir has a shape complementary to the active site of HIV protease.
2. Ritonavir will enter human cells directly through the lipid bilayer and not require any transport proteins.
3. Ritonavir is likely to inhibit many of the enzymes of human cells.
4. Complete hydrolysis of ritonavir would require the addition of three water molecules.

The diagram shows the fluid mosaic model of a section of a cell surface membrane.

What is the role of each of the components labelled 1 to 3?

Proteins in the cell surface membranes of human cells and mouse cells were labelled with red and green fluorescent dyes respectively. When a human cell and a mouse cell were fused together the red and green fluorescent labels were at first found in different regions of the cell surface membrane of the hybrid cell, but after 40 minutes they were evenly distributed in the entire cell surface membrane. What explains this observation?

The diagram shows a plant cell. The plant cell is put into a solution with a water potential less negative than the cell contents. What will happen to the appearance of the cell?

The cell cycle includes mitosis. Which are features of nuclear division?
1. forms cells of equal size to the parent cell
2. forms genetically identical cells
3. semi-conservative replication of DNA

Which is the correct statement concerning cell and nuclear division?

Diploid (2n) organisms that reproduce sexually produce haploid (n) gametes. Some plants, such as wheat, can produce diploid or haploid gametes. These gametes can fertilise other diploid or haploid gametes. Which statements are correct for plants like these?
1. Diploid gametes may be produced by a fault in the reduction division (meiosis).
2. The offspring will always show an increased chromosome number.
3. The offspring could be either 2n, 3n or 4n.
4. The chromosome number could, in theory, increase with each generation.

Which nucleic acid bases are pyrimidines?

What is the correct sequence for the processes involved in the formation of an enzyme in a cell?

A short piece of DNA fifteen base pairs long was analysed to find the number of nucleotide bases in each of the polynucleotide strands. Some of the results are shown below.
[Table_1] number of nucleotide bases
| | A | C | G | T |
|------|---|---|---|---|
|strand 1 | 6 | | 3 | |
|strand 2 | | x | 4 | |
How many nucleotides containing adenine (A) were present in strand 2?

Which feature of xylem vessel elements helps adhesion during transpiration?

The diagram represents part of the phloem pathway, with adjacent cells, from leaf to root in a plant.

Which process is occurring between 1 to 2 and what is the effect on the water potential at 2?

Which xerophytic adaptations reduce the water potential gradient?

What is not a factor influencing blood pressure?

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

The graph shows the percentage saturation of haemoglobin with oxygen at different partial pressures of oxygen and two different concentrations of carbon dioxide.
What is the effect of increasing the concentration of carbon dioxide?

Some babies are born with a hole between the right and left atria. These babies are found to have an increased number of red blood cells.
What is the reason for this increase?

In the lungs, oxygen and carbon dioxide pass through cell membranes by diffusion. Which row is correct?
[Table_1]

Which describes how substances in cigarette smoke increase the risk of developing atherosclerosis?
1. Carbon monoxide damages the endothelium of the arteries.
2. Nicotine makes platelets sticky.
3. Nicotine stimulates the release of adrenaline.

Which flow diagram correctly describes the effect of tar entering the lungs?

Which could directly reduce the surface area available for gas exchange in human lungs?
1. emphysema
2. lung cancer
3. smoking

The malarial parasite, \textit{Plasmodium}, infects red blood cells and breaks down haemoglobin. Free haem groups are toxic to \textit{Plasmodium} and the parasite converts them into non-toxic, crystalline haemozoin, using an enzyme, HDP, which is found in all species of \textit{Plasmodium}.
What will be the long term result of giving patients with malaria a drug which inhibits HDP?

During a primary immune response, the following events occur:
1 Some B-lymphocytes form plasma cells.
2 B-lymphocytes with the specific cell surface receptors divide repeatedly by mitosis.
3 Specific antibody is produced.
4 T-helper cells secrete cytokines.
5 T-helper cells identify a specific antigen.
In which order will the events occur?

Which statement concerning the defence in the body against infectious disease is not correct?

An antiserum to a snake toxin can be obtained by injecting the toxin into a horse. The antiserum is made from blood plasma taken from the horse a few weeks later. The antiserum is injected into a person who has been bitten by the same species of snake.
Which type of immunity occurs as a result of using this antiserum?

The flow of nutrients in an ecosystem is shown in the diagram.
Which letter represents decomposers?

An insect eats only the leaves of grass. This insect is eaten by carnivorous beetles. Which ecological terms are described in this information about the insect?

A gardener has a waterlogged garden showing poor growth. He decides to drain it in an attempt to reduce the numbers of some harmful bacteria.
Which type of bacteria would he be attempting to reduce in number?