AS & A Level Biology - 9700 Paper 1 2013 Winter Zone 2

Which structure is measured in the units shown using a light microscope?

structure       unit
A   cell surface membrane   nm
B   cell wall           nm
C   chloroplast        μm
D   ribosome         μm

A student studied two photographs, at the same magnification, of a palisade mesophyll cell, one using a light microscope and the other using an electron microscope.

The student observed:
1. the cisternae of the Golgi apparatus
2. the grana in the chloroplasts
3. the two membranes of the nuclear envelope
4. the vacuole enclosed by a tonoplast.

Which features can only be seen because of the higher resolution of the electron microscope?

A piece of mammalian tissue was homogenised and centrifuged. The biochemical activity of four subcellular fractions was investigated. Which diagram indicates the fraction with maximum synthesis of messenger RNA?

Which row shows features of a typical eukaryotic cell?
[Table_1]

Many single-celled animals, living in fresh water, possess vacuoles which contract regularly, expelling excess water.
Why do the cells of plants living in fresh water not require such vacuoles?

Which shows $\beta$-glucose?

Which row is correct when one molecule of sucrose is hydrolysed? [Table_1]

The formation of glycosidic and peptide bonds is responsible for polymerisation in some biological molecules.
Which bonds are found in which molecules? [Table_1]

The diagrams show the structures of two amino acids, each of which has more than one amine (−NH\(_2\)) group.



A peptide bond is formed between the two amino acids.

Which groups form the peptide bond?

Which explains why haemoglobin is able to carry oxygen?

Which is correct for a non-competitive inhibitor of enzyme action?
1. Increasing the concentration of the enzyme’s substrate will reduce its effect.
2. It reduces the activation energy required for a reaction to take place.
3. It reduces the maximum rate of reaction.

The enzyme lysozyme secreted from tear glands forms deposits on contact lenses.
Which ingredient would be effective in a contact lens cleaner for removing these deposits?

Which is correct for components of a cell surface membrane?
[Table_1]
| increases membrane fluidity | allows recognition of cell |
|-----------------------------|---------------------------|
| A | cholesterol | glycoproteins |
| B | glycolipids | phospholipids |
| C | glycoproteins | glycolipids |
| D | phospholipids | cholesterol |

A method called freeze-fracture can be used to study the structure of cell membranes. The membrane is frozen and then split down the middle, separating the two layers of phospholipids from each other. Any proteins contained within one layer remain in that layer. Proteins which span the membrane can be found in either layer after freeze-fracture, depending on the protein's properties.
Which statement(s) about the results of freeze-fracture studies are correct?
1. It provides evidence for the bilayer nature of membranes.
2. It provides evidence for the arrangement of proteins.
3. It shows that the proteins in the membrane do not contribute to its strength.

Which statements are descriptions of both facilitated diffusion and active transport?
1 moves substances against a concentration gradient
2 requires ATP
3 transports charged ions across the cell surface membrane
4 uses proteins

Which statement about the fluid mosaic model of membrane structure is correct?

Which statements about cancer are correct?
1. Exposure to UV light from the sun always causes skin cancer.
2. Some viruses can cause cancer.
3. The mutation of genes controlling the cell cycle may cause cancer.

The diagram represents the life cycle of a sexually reproducing animal.

Which row correctly identifies meiosis and mitosis?
[Table_1]

The following statements describe events that take place during DNA replication and transcription.
Which row is not correct?

Which statements about complementary base pairing are correct?
1. Purines and pyrimidines are different sizes.
2. It occurs during translation.
3. The base pairs are of different length.
4. Uracil forms two hydrogen bonds with adenine.

What is the minimum number of base substitutions required to change the nucleotide sequence of the HbA (normal) allele to the HbS (sickle cell) allele?

Which feature of a plant cell is an adaptation for water uptake from the soil solution?

A student used a potometer to measure the rate of water loss from a plant by transpiration. The internal diameter of the capillary tube and the distance moved by the bubble in 30 seconds were recorded. The results are shown in the table.
[Table_1]
The volume of water moved = $\pi r^2 \times \text{distance moved by the bubble}$.
Which calculation correctly shows how to determine the rate of transpiration in mm³s⁻¹?

Which feature of xylem vessel elements helps the cohesion of water?

What determines the rate of water movement from the roots to the leaves?

The photomicrograph shows a transverse section through a leaf.
Which features of a xerophytic leaf are visible in this section?
1. sunken stomata
2. two layers of epithelium
3. thick cuticle
4. small surface area to volume

The graph represents data on blood vessels and blood flow.

Which row correctly identifies the curves?

What occurs during ventricular systole in a mammalian heart?
1. aortic pressure increases
2. atrial pressure does not change
3. ventricular pressure increases

The diagram shows a defect in the walls between the atria.
What effect would this defect have on the blood circulatory system?

Which will not be formed in the plasma in capillaries surrounding active tissue?

Goblet cells are found in the trachea.
Which organelles would be found in large numbers in a goblet cell?
1 lysosomes
2 mitochondria
3 rough endoplasmic reticulum
4 secretory vesicles

Which tissues are present in a bronchus?
[Table_1]
Key: ✓ present, ✗ absent

Which statements are correct effects of tar in tobacco smoke on the human gas exchange system?
[Table_1]

The diagram shows the relationship between cholera, measles and TB.
Which is correct? [Table_1]

New-born babies have natural passive immunity.
What is the correct explanation for this?
[Table_1]

Which is a correct description of different types of immunity? [Table_1]

The World Health Organization (WHO) set a target to eradicate polio, using vaccination, by the year 2000. However, cases are still being reported in some parts of the world after this date.
What explains these new cases of polio?
1 Some parts of countries are difficult to reach because of poor transport or wars.
2 There is not enough research to develop more effective vaccines.
3 Records of vaccinated and unvaccinated people are incomplete.

The graph shows the annual changes of the following factors in a lake:
intensity of light per day
numbers of producers
numbers of primary consumers
quantity of nutrients
Which curve represents the numbers of producers?

Which events can occur in the nitrogen cycle?
1. Inorganic nitrogen in the atmosphere undergoes denitrification by specific prokaryotes.
2. Nitrate concentrations in the soil are increased by nitrifying bacteria in waterlogged soil.
3. Organic nitrogen in legumes passes into the soil where deamination and ammonification occurs.
4. Saprotrophic fungi living in the soil decompose organic nitrogen in faeces.

Two different ecosystems of the same size, X and Y, were compared. Both ecosystems have the same climate. The results of the comparison are shown.
[Table_1]
Using the information in the table, which statement is not a valid suggestion concerning X and Y?