AS & A Level Biology - 9700 Paper 1 2012 Winter Zone 3

Which feature is found in both prokaryotic and plant cells?

What leaves the nucleus through the pores in the nuclear envelope?
1 DNA
2 mRNA
3 ribosomes

The same plant cells were viewed by a student using an electron microscope and a light microscope.
The electron microscope used a magnification of ×1000.
The light microscope used a ×10 eyepiece lens and a ×100 objective lens.
The student concluded that the image of the plant cell obtained using the electron microscope was clearer and more detailed than the image obtained using the light microscope.
Which explanation supports this conclusion?

The diagram shows an organelle drawn at a magnification of ×20,000.
What is the maximum length of the organelle?

When drawing a plan diagram of a transverse section of a dicotyledonous leaf, which feature should not be included?

What is the general formula for starch?

Which bonds are the last to break when an enzyme is heated?

Which molecules have a structural formula that contains C=O bonds?
1. amino acids
2. glucose
3. glycerol
4. protein

Which of the statements about polysaccharides can be used to describe both starch and cellulose?
1 adjacent glucose molecules are rotated by 180°
2 contains glycosidic bonds
3 polymer of α-glucose

Five biochemical tests were carried out on four unknown substances, A, B, C, and D.
Following the tests, it was possible to determine the presence or absence of each of the biochemicals in each substance.
Which substance contains glucose, fat, and protein?
[Table_1]

What describes a globular protein that is not soluble in water?

Polymers of molecule X or polymers of molecule Y can be formed using glycosidic bonds.
Which statement is correct?

The diagrams show where an inhibitor becomes attached to an enzyme and whether this is permanent or temporary.

Which diagrams represent a non-competitive inhibitor?

The diagrams show two molecules found in cell surface membranes. Which part affects the fluidity of the membrane?

The graph shows how the rate of entry of glucose into a cell changes as the concentration of glucose outside the cell changes.
What is the cause of the plateau at X?
1. All the carrier proteins are saturated with glucose.
2. The cell has used up its supply of ATP.
3. The concentrations of glucose inside and outside the cell are equal.

The following are all processes by which substances can enter cells.
1. phagocytosis
2. active transport
3. facilitated diffusion
Which processes require ATP?

Which diagram represents a cell undergoing metaphase of mitosis?

Colchicine is a substance which inhibits the formation of spindle fibres. At which stage is the cell cycle interrupted?

The sequence of nucleotides in DNA in a gene that controls the synthesis of a protein is arranged in triplets, each coding for specific amino acids. The table shows three examples of these triplets.
[Table 1]

Which are the correct codon and anticodon?

Enzymes are ......1...... proteins, made up of polypeptides.
A gene is a sequence of ......2......, which are parts of a ......3...... molecule coding for a polypeptide.
Which words correctly complete gaps 1, 2 and 3 in the sentences?

Which process does \textit{not} occur during the formation of messenger RNA?

Which correctly matches the structure and function of sieve tube elements?

How do single-celled organisms survive without a specialised transport system?

The photomicrograph shows a transverse section of a leaf.
Which cell has the least negative water potential?

What occurs during the movement of water through the apoplast pathway?
1. water enters cell wall
2. water enters cytoplasm through plasma membrane
3. water enters vacuoles
4. water moves from cell to cell through plasmodesmata
5. water moves from cell wall to cell wall through intercellular spaces

Why does the red blood cell count of humans increase when they remain at high altitudes?

Which row correctly shows all the blood vessels that have the features in the table below? [Table_1]

The graph shows the dissociation of oxygen from haemoglobin at two different pHs. Which curve represents the lower pH and in which tissue might the data have been recorded?

The diagram shows changes in pressure in the left side of the heart during the cardiac cycle.

Which statement about the heart valves is correct?

When a person suffers an asthma attack, the tubes of the gas exchange system narrow and extra mucus is produced.
Which of these changes occur during an asthma attack?

1. Activity of ciliated epithelium increases.
2. Endocytosis in goblet cells increases.
3. Smooth muscles more active.

Which symptoms may be seen in a person affected by chronic obstructive pulmonary disease (COPD)?

1. persistent cough
2. less elastic alveoli
3. increased risk of lung infection
4. shortness of breath

Which row shows the effects of chronic bronchitis? [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?

For some diseases, one of the most effective measures for prevention and control is tracing people who have been in contact with infected people.
For which disease would tracing the contacts of infected people help in its prevention and control?

A child is vaccinated against a viral disease. A few weeks later she is exposed to the same virus.
What is the expected response to this exposure?

Why has it proved difficult to develop an effective vaccine against malaria?

Which statement describes a role of lymphocytes in the immune response?

The diagram shows some of the processes that are involved in the cycling of nitrogen in an ecosystem. Which type of bacterium is found at X?

The diagram shows the flow of energy through a food chain.

What percentage of the energy is used by the green plants for photosynthesis?

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 describes the tree?