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

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

Which statement is not correct in its description of a light microscope or an electron microscope?

The electronmicrograph shows part of an animal cell.
What will be synthesised in large quantities in this cell?
1. ATP
2. glucose
3. RNA

Which statements about a typical eukaryotic cell are correct?
1 It is smaller than 2μm.
2 It has a nucleolus.
3 It has linear DNA.
4 It only has small (70S) ribosomes.

Which animal cells would have the most Golgi apparatus?

Which diagram shows the reaction that occurs to link two monomers that form cellulose?

Which bonds will be broken when a molecule of glycogen is hydrolysed?
1 $\alpha$-1, 4
2 $\beta$-1, 4
3 $\alpha$-1, 6
4 $\beta$-1, 6

Collagen is a macromolecule with three polypeptides lying closely side by side in the form of a triple helix. Every third amino acid in each polypeptide has the shortest possible R-group or side chain (– H) to allow close packing of the polypeptides. Which is the amino acid?

The diagrams show the structures of two amino acids, each of which has two amine ($-NH_2$) groups. A peptide bond is formed between the two amino acids. Which groups form the peptide bond?

Each list, 1, 2, and 3, shows some substances found in animal tissues.
1. glucose, cholesterol, triglycerides, water.
2. glycogen, antibodies, adenine, phospholipids.
3. haemoglobin, carbon dioxide, mRNA, monosaccharides.
Which shows one or more substances that contain nitrogen atoms?

Which statements about competitive inhibitors of enzyme action are correct?
1. Increasing the concentration of the enzyme’s substrate will reduce their effect.
2. They bind to an enzyme at its active site.
3. They reduce the activation energy required for a reaction to take place.
4. They reduce the maximum rate of reaction.

An enzyme is completely denatured at 50 °C. A fixed concentration of this enzyme is added to a fixed concentration of its substrate. The time taken for completion of the reaction is measured at different temperatures.
Which graph shows the results?

Molecules 1, 2 and 3 are found in cell surface membranes.
1 glycolipids
2 glycoproteins
3 phospholipids
Which contribute to cell recognition?

What are the features of facilitated diffusion? [Table_1]

The stalk of a dandelion flower is a hollow tube. Pieces of the stalk are cut as shown and placed in sucrose solutions of different water potentials.
Which diagram shows the piece that is placed in the sucrose solution with the highest water potential?

What happens to an animal cell when it is placed in a solution with a more negative water potential?

Exposure to which of the following increases the risk of developing a cancerous growth? [Table_1]

The diagram shows an outline of the process of sexual reproduction.

Which row identifies the type of cell division occurring during stages 1 and 2 and the number of chromosomes in cells P and Q?

A short piece of DNA 19 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]

How many nucleotides containing C were present in strand 1?

Which statements about complementary base pairing are correct?
1. Cytosine forms two hydrogen bonds with guanine.
2. Purines and pyrimidines are different sizes.
3. Adenine forms the same number of hydrogen bonds with thymine and uracil.
4. The base pairs are of equal length.

What does the enzyme DNA polymerase synthesise in a cell?

The statements describe some of the properties of water.
1. requires a lot of heat energy to evaporate
2. retains a lot of heat energy
3. is able to form hydrogen bonds with other water molecules
4. is able to form hydrogen bonds with other polar and non-polar molecules
Which properties are important for transport in xylem?

Which row is correct?
[Table_1]

Which feature of xylem vessel elements allows them to have reduced resistance to water movement?

An investigation was carried out into the effect of light intensity on the rate of transpiration. All other variables were standardised. A student was asked to explain the results shown in the graph below.

Which explanation is correct?

Different substances, such as sucrose and amino acids, can move in different directions in the phloem sieve tubes. Which statement explains this?

Which reactions will be taking place in blood that is passing through active tissues?
1. $\text{HbO}_8 \rightarrow \text{Hb} + 4\text{O}_2$
2. $\text{HbO}_8 + \text{H}^+ \rightarrow \text{HHb} + 4\text{O}_2$
3. $\text{HCO}_3^- + \text{H}^+ \rightarrow \text{H}_2\text{CO}_3$
4. $\text{H}_2\text{O} + \text{CO}_2 \rightarrow \text{H}_2\text{CO}_3$

During a cardiac cycle, the pressure in the right ventricle is lower than that in the right atrium and lower than that in the pulmonary artery. Which row is correct?
[Table_1]

What correctly describes an event in the cardiac cycle that follows atrial systole?

'Heart block' is a disease which can result in a lower than normal heart rate. A doctor treating a patient suffering from heart block found that electrical impulses were initiated as normal but were not correctly conducted to the ventricles, so the rate of ventricular contraction was slowed.
Which may be functioning incorrectly in the patient?
1. atrioventricular node (AVN)
2. Purkyne tissue
3. sinoatrial node (SAN)

What correctly describes the effect of carcinogens on lung tissue?

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

Which is a correct description of part of the gas exchange system?
[Table_1]

Which is correct for TB, measles and malaria? [Table_1]

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

The photomicrograph shows human blood, with three types of white cell labelled R, S, and T.
Which row correctly identifies these white cells? [Table_1]

What are the function(s) of T-lymphocytes during an immune response?
1 destroy infected body cells
2 differentiate into memory cells
3 secrete antibodies

A student wrote down three statements about antibodies.
1 Their structure depends on peptide, hydrogen and disulfide bonds.
2 They are protein molecules with both tertiary and quaternary structure.
3 Four polypeptides provide four antigen binding sites.
Which statements are true?

An insect consumes 180 J of plant material. Of this, 95 J of energy is passed out in the insect's faeces and 58 J is used for respiration. Which percentage of the energy, in the original plant material taken in by the insect, is converted into biomass?

Decomposition of organic matter can cause the concentration of ammonia to rise in a fish tank. High concentrations of ammonia in the tank are toxic to fish. Bacteria may be added to remove the ammonia. Which type of bacteria should be added?