AS & A Level Biology - 9700 Paper 1 2009 Winter Zone 2

Which cell structure can be seen only with an electron microscope?

Which is a feature of all prokaryotic cells?

A lymphocyte has a diameter of $1 \times 10^{-2}$ millimetres (mm).
What is the diameter in nanometres (nm)?

Which plan diagram of a transverse section of a leaf correctly shows the position of xylem and phloem as well as the fact that the palisade mesophyll is twice as thick as the spongy mesophyll?

The photomicrograph of a cell has a 2 cm scale line labelled 5 µm.

What is the magnification of the photomicrograph?

What is a function of the smooth endoplasmic reticulum?

Which combination of bond types correctly shows the weak and strong bonds that hold a molecule of protein in shape?
[Table showing types of bond: hydrogen, disulfide, ionic with options A-D]

Which statement is true for cellulose, but not true for protein?

The diagram shows a triglyceride molecule that has been partially hydrolysed.
What will be the products of the total hydrolysis of the molecule shown?

The diagram shows a tripeptide molecule.
At which two points will hydrolysis occur to release three amino acids?

Which combination of procedures would not be used in a food test?
[Table_1]

HIV-1 protease is an enzyme produced by the HIV virus.
Two identical chains of 99 amino acids form the enzyme. In each chain, amino acids 25, 26 and 27 in the sequence form part of the active site.
Which orders of protein structure control the shape of the active site?

Which features of collagen result in it having high tensile strength?
1. covalent bonds form between adjacent molecules
2. each three-stranded molecule is held together by hydrogen bonds
3. every third amino acid in the polypeptide is small
4. the primary structure is held together by peptide bonds

The diagram shows a red blood cell and the concentrations of ions, in mmol dm^-3, in the plasma and in the cell.

Which ions are actively transported into and out of the cell?

Diagrams 1 and 2 show how the transverse section through a leaf changes when moved from one solution W to a different solution Y.

How has the water potential changed in diagram 2?

In an experiment, 5 cm$^3$ of 1 % salivary amylase are added to 100 cm$^3$ of different concentrations of starch.
Which graph shows the results of plotting the initial rate of reaction (y-axis) against the concentration of substrate (x-axis)?

Cystic fibrosis is a disease where $\text{Cl}^-$ ions are unable to be transported into cells.
Which structure in the cell surface membrane is faulty?

Cancer cells divide out of control, forming tumours.
Which statement describes the difference between a cancer cell and a normal cell?

Which statement describes a cell that is capable of reproduction and belonging to a haploid organism?

During which stage of the mitotic cell cycle is DNA replicated?

What does the enzyme DNA polymerase synthesise in a cell?

The following statements describe events that take place during DNA replication and transcription.
Which statement is not correct?
[Table_1]

A peptide consists of ten amino acids of four different kinds.
What is the theoretical minimum number of tRNA molecules required to translate the mRNA for this peptide?

Which diagram shows the semi-conservative replication of a section of a molecule of DNA?

What is the sequence of events in the translocation of assimilates?

Which description states some of the features of xylem vessels?

The diagram shows the changes in pressure potential ($\Psi_p$), solute potential ($\Psi_s$), and water potential ($\Psi$) when a plasmolysed plant cell is placed in pure water.



Which shows the correct curves for each potential?

The graph shows the percentage saturation of haemoglobin with oxygen at different partial pressures of oxygen.
Which range of partial pressures of oxygen produces the greatest change of percentage saturation of haemoglobin per unit oxygen tension?

When stained, which features, visible under the light microscope, are part of the cells of the plant tissues listed in the table? [Table_1]

A disease damages alveoli.
Which effect does this have on the gas exchange surface area and volume of the lungs?
[Table_1]

An oxygen molecule diffuses directly from the air in an alveolus to haemoglobin in a red blood cell.
What is the minimum number of cell surface membranes through which this molecule must pass?

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

Below are correct statements comparing blood, tissue fluid and lymph in a capillary bed.
• W lacks large plasma proteins and red blood cells and has a higher water potential than Z.
• X is at a lower pressure than Y and contains red blood cells and large plasma proteins.
• Y is at a higher pressure than W and contains red blood cells and large plasma proteins.
• Z is at a lower pressure than Y and lacks red blood cells.

Which correctly identifies W, X, Y and Z?
[Table_1]

After an immune response, memory cells remain in the blood for a long time.
What is the function of memory cells?

What are produced by B-lymphocytes?
[Table_1]

Scientists are concerned that avian (bird) flu caused by the H5N1 virus, could infect humans and cause a pandemic.
If this occurs, which factors could help prevent humans spreading the disease?
1. killing all poultry
2. reducing all air flights
3. taking a course of antibiotics

A country has fewer than 2.5 deaths per 100 000 people from TB in one year and the next year this rose to 25 deaths per 100 000.
What may have contributed to this change?
1. decrease in contact tracing
2. increase in refugee camps
3. water supply contaminated by sewage

The diagram shows an arctic ecosystem.

How many trophic levels are represented?

A tree carries out photosynthesis and provides organic compounds for other organisms in a forest. It takes carbon dioxide from and returns oxygen to the atmosphere. It takes water from the soil into its roots and its leaves lose water to the atmosphere. Many other organisms live in the tree.
Which term applies to the description of the tree?

In an investigation, discs of 2.5 cm diameter were cut from leaves. Fifty discs were put into three identical bags with different net sizes and buried in newly dug soil at a depth of 3 cm.
At 60 day intervals the bags were dug up and the leaf discs measured to see how much of the leaf area had disappeared.
The table shows the percentage of leaf discs remaining in each bag.

[Table_1]

Which organisms are most important for breaking down the leaves?