AS & A Level Biology - 9700 Paper 1 2016 Summer Zone 2

A student was presented with a photomicrograph of a cell organelle. The magnification of the photomicrograph is known. Which calculation of the actual length of the organelle in \( \mu m \) is correct?

Which statements about both mitochondria and chloroplasts are correct?
1. They contain 80S ribosomes.
2. They contain circular DNA molecules.
3. They produce ATP.

Which range of sizes would include most eukaryotic cells?

A scientist carried out an experiment to separate the organelles in an animal cell by mass. The scientist mixed the cells with a buffer solution which had the same water potential as the cells. He then broke the cells open with a blender to release the organelles. The extracted mixture was filtered and then spun in a centrifuge at a speed that separates the heaviest organelle. This organelle sank to the bottom, forming a solid pellet, 1. The liquid above pellet 1 was poured into a clean centrifuge tube and spun in the centrifuge at a higher speed to separate the next heaviest organelle. This organelle sank to the bottom, forming a solid pellet, 2. He repeated this procedure twice more to obtain pellet 3 and pellet 4, each containing a single organelle. What is the function of the organelle extracted in pellet 4?

Which row shows the monomer and type of bond that form the polymer?
[Table_1]

Which biological molecules always contain the element nitrogen?

Which statement about the quaternary structure of proteins is correct?

Which set of statements correctly describes haemoglobin?

The diagrams show different types of bond found in biological molecules. Which bonds are found in proteins with a tertiary structure?

In two investigations, the rate of an enzyme-catalysed reaction was measured in the presence of either a competitive inhibitor or a non-competitive inhibitor. What could be the effect of increasing the substrate concentration on each rate of reaction? [Table_1]

Two enzymes, X and Y, were used in an experiment.
Enzyme X was from bacteria that live in rivers and lakes at temperatures from 5°C to 20°C.
Enzyme Y was from bacteria that live in hot water springs at temperatures from 40°C to 85°C.
The experiment measured the concentration of product produced by each enzyme at temperatures between 0°C and 100°C after 5 minutes.
Which graph shows the results?

What is a function of the cholesterol in a cell surface membrane?

Which roles of the cell surface membrane are a result of the properties of the phospholipids?
1. to allow cytokinesis to occur in mitotic cell division
2. to allow entry and exit of oxygen and carbon dioxide
3. to allow the phagocytosis of a bacterium into a cell

Which statements about active transport are always correct?
1 It does not require a membrane.
2 It occurs against the concentration gradient.
3 It moves oxygen molecules.

There is a high concentration of molecule X outside the cell which enters the cell by facilitated diffusion. The results of measuring the concentration of X inside the cell at 30 s intervals are shown by the graph.
Why does the concentration of X inside the cell remain constant after 150 s?

The photomicrographs show cells in various stages of the cell cycle.

Which cells contain twice as many DNA molecules as a cell from the same organism after cytokinesis?

A group of chemicals used to treat cancer prevents the formation of the spindle during mitosis. Which phase of mitosis is the first to be affected?

Mitosis is an important process for organisms. Which features of mitosis are important for single-celled organisms?
1. asexual reproduction
2. growth
3. production of genetically identical cells

Which statements about complementary base pairing are correct?
1. Cytosine forms three hydrogen bonds with guanine.
2. Purines and pyrimidines are different sizes.
3. It allows transcription to occur.
4. The base pairs are of different lengths.

Bacteria were grown in a medium containing $^{15}\text{N}$. After several generations, all of the DNA contained $^{15}\text{N}$. Some of these bacteria were transferred to a medium containing the common isotope of nitrogen, $^{14}\text{N}$. The bacteria were allowed to divide once. The DNA of some of these bacteria was extracted and analysed. This DNA was all hybrid DNA containing equal amounts of $^{14}\text{N}$ and $^{15}\text{N}$.

The remaining bacteria were left in the medium with $^{14}\text{N}$ and allowed to divide one more time. The DNA of some of these bacteria was extracted and analysed.

What is the composition of this DNA?

Which statements about tRNA are correct?
1. It contains base pairing.
2. It contains hydrogen bonds.
3. It contains uracil.
4. It is single stranded.

The diagram shows the nucleotide sequence of a small section of a gene which is transcribed.
TTCTTCCCGTTC
The table shows the amino acids coded for by 10 mRNA codons.
[Table_1] mRNA codon - amino acid
AAG - Lys
ACG - Thr
CGG CGC CGU - Arg
CCG - Pro
GCC GCG - Ala
GGC - Gly
UGC - Cys
What is the order of the four amino acids in the polypeptide translated from this small section of a gene?

The graph shows the diameter of a tree trunk at different times.
Which statement is correct?

Some plant species can take up toxic heavy metal ions that are dissolved in water in the soil. These ions accumulate in the aerial parts of the plant, which can be harvested and disposed of safely.
An investigation was carried out into the ability of a plant species to remove a heavy metal ion from soil. This produced the following observations:
• some heavy metal ions accumulated in the cells of the root cortex
• within these cells, most of these ions were in the vacuole
• in the roots and leaves, the ions were transported dissolved in water.
Which suggestions about the transport and accumulation of heavy metals are valid?
1. After initial entry into the root, some of the ions can pass through the tonoplast.
2. In the roots and leaves, the ions pass through a symplastic or apoplastic pathway but at the endodermis they must take a symplastic pathway.
3. In xylem vessels, the ions pass through an apoplastic pathway only.

The diagram shows the results of an experiment on transpiration using two different leaves. Each leaf was left on a balance in daylight in a closed room and its mass recorded at 1 hour intervals.



Which conclusions could be correct?

1. The loss of mass is mainly due to evaporation of water.
2. Most stomata close in both leaves after 1 hour.
3. Leaf 1 has a larger surface area than leaf 2.
4. Leaf 1 has a thicker cuticle than leaf 2.

Which statement about the transport of sucrose is correct?

Which of the tissue types below are present in the walls of all blood vessels?
1. collagen
2. elastic
3. endothelial
4. smooth muscle

Which components of blood are present in tissue fluid?
[Table_1]

The graph shows changes in percentage saturation of haemoglobin with oxygen in the blood of a human and of another animal. The partial pressure of carbon dioxide remains constant at 1.0 kPa and the temperature is constant at 25°C.



Which conclusion is supported by the graph?

Which statements about the formation of haemoglobinic acid are correct?
1. It can only occur with the dissociation of oxygen from haemoglobin.
2. It acts to prevent excess hydrogen ions causing acidity in blood.
3. It depends on the release of hydrogen ions by the action of carbonic anhydrase.

The photograph shows a type of blood cell.
Which statements about these cells are correct?
1. Oxygen diffuses through the phospholipid bilayer.
2. Sodium ions diffuse through the phospholipid bilayer.
3. Water passes in and out of these cells by osmosis.

A student was asked to describe the differences between four microscope slides of sections taken from different parts of the gas exchange system.

slide 1
not present: cartilage, glands
present: few goblet cells, ciliated epithelial cells, smooth muscle

slide 2
present: incomplete cartilage rings, glands, goblet cells, ciliated epithelial cells, smooth muscle

slide 3
not present: cartilage, glands, goblet cells, smooth muscle
present: squamous epithelial cells

slide 4
present: plates of cartilage, glands, goblet cells, ciliated epithelial cells, smooth muscle

Which is the correct identification of the parts of the gas exchange system?
[Table_1]

Which components of the human gas exchange system help to reduce the effects of carcinogens in tar?

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

The table shows the names of five pathogens.
Which row matches the pathogens with the diseases they cause?
[Table_1]

Which disease exhibits all the following features?
• It can be transmitted by animals to other animals, including humans.
• One mode of transmission is by transfusion with contaminated blood.
• The causative organism can show multiple drug resistance.
• The majority of humans who die from the disease are children.

The proportion of the local population who have malaria in area R is higher than the proportion in area S. Which factor causes this difference?

Which statement describes how passive natural immunity is obtained?

What describes a non-specific immune response?

What explains why monoclonal antibodies can be used to target cancer cells?