AS & A Level Biology - 9700 Paper 1 2017 Winter Zone 3

Which statement about the light microscope is correct?

The diagram shows a stage micrometer scale viewed with an eyepiece graticule, using a magnification of $\times 200$.



Using the same magnification, a chloroplast is measured as 4 eyepiece graticule divisions long.

How long is the chloroplast?

A cell was supplied with cytosine labelled with radioactive carbon.
In which cell structure would radioactivity be detected first?

The diagram shows some similarities between chloroplasts, mitochondria and typical prokaryotes.

Which row is correct?

Which statement supports the fact that mature plant cells can carry out the same role as lysosomes?

A student carried out four tests for biological molecules on a sample of milk.
The tests and their results were as follows.
• Heating to 80°C with Benedict's solution gave a green colour.
• Adding Biuret solution gave a purple colour.
• Adding iodine solution gave an orange colour.
• Boiling with acid, followed by neutralisation, then heating to 80°C with Benedict's solution gave a brick red colour.
Which conclusion about these results is correct?

The diagrams show four monosaccharides with the formula $C_6H_{12}O_6$.
Which diagrams show glucose molecules?

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

The diagram shows the amino acids in a polypeptide.
An enzyme catalyses the hydrolysis of any peptide bond between a non-polar amino acid and any polar amino acid.
How many small peptides and single amino acids will be formed by the action of this enzyme?

A person with diabetes is unable to make enough of the protein insulin.
Some forms of diabetes can be treated by using insulin produced by animals. Scientists have compared the amino acids in insulin produced by animals to human insulin.
Which level of protein structure were the scientists studying?

The diagrams show four fatty acids, each with a chain of 18 carbon atoms.
Which fatty acid, as part of a phospholipid molecule, would contribute most to the fluidity of a cell surface membrane?

Which levels of protein structure are maintained by disulfide bonds?

An experiment was conducted to investigate the effect of temperature on the activity of the enzyme $\beta$-glucosidase. The enzyme was tested when in solution (free) and when immobilised in alginate beads.
The results are shown in the graph below.

Which statement about the effect of immobilisation of $\beta$-glucosidase is correct?

An investigation was carried out into the effect of an increasing concentration of substrate molecules on the rate of an enzyme-catalysed reaction. All other variables were standardised. Which statement is correct?

Which features are correct for a competitive inhibitor of an enzyme-catalysed reaction? [Table_1]

Liver cells contain membrane-bound organelles called peroxisomes, which contain the enzyme catalase. This enzyme hydrolyses hydrogen peroxide into water and oxygen gas.
A student cut two identical sized pieces of liver and placed one in a refrigerator at 5\(^{\circ}\)C and the other in a freezer at -18\(^{\circ}\)C.
After 12 hours both pieces were raised to room temperature and placed in equal volumes of hydrogen peroxide.
The liver that had been at -18\(^{\circ}\)C produced bubbles of oxygen more rapidly than the liver that had been at 5\(^{\circ}\)C.
Which statement explains why the liver that had been at -18\(^{\circ}\)C produced bubbles of oxygen more rapidly than the liver that had been at 5\(^{\circ}\)C?

Which of these processes allow movement in both directions across cell surface membranes?
1. active transport
2. diffusion
3. facilitated diffusion
4. osmosis

The diagram shows an experiment in which two different cell surface membranes were joined to form a single large membrane.
The outer surface of one membrane contained molecules of protein P and the outer surface of the other membrane contained molecules of protein Q.
The positions of the two proteins in each membrane were observed just before they were joined together and 1 hour after they were joined.

Which statements are correct?
1. This provides evidence for the fluid mosaic model of cell membranes.
2. This shows that proteins can move freely in cell membranes.
3. This shows that the membrane is fluid but the proteins are not.

Which row describes osmosis across a cell surface membrane? [Table_1]

What describes a telomere?

Uncontrolled cell division can form tumours.
Which statement is correct for tumour cells only?

Which of these events are part of mitosis?
1 interphase
2 anaphase
3 cytokinesis

Rifampicin is an antibiotic used to treat tuberculosis.
It works by inhibiting RNA polymerase in bacteria.
Which of these processes are prevented by this antibiotic?

1. DNA replication
2. transcription
3. translation

A gene codes for the sequence of amino acids in a single polypeptide. Haemoglobin consists of two \( \alpha \)-globins and two \( \beta \)-globins.
How many genes are needed to code for a single haemoglobin molecule?

A single substitution in an allele of the gene coding for haemoglobin results in sickle cell haemoglobin.
The mRNA sequence for three amino acids for normal haemoglobin is shown.
CCUGAAGAG
The mRNA sequence for sickle cell haemoglobin is shown.
CCUGUAGAG
The table shows some of the triplet codes for two amino acids.
[Table_1]

Which row is correct for the substituted DNA nucleotide of the allele and the substituted amino acid of the protein?
[Table_2]

What is the minimum number of hydrogen bonds in a length of DNA containing 700 base pairs?

The photomicrograph is a section through a plant organ. Which label identifies the xylem vessels?

Which of these statements correctly describe transport pathways in dicotyledonous plants?
1. In the apoplast pathway, water may move through plasmodesmata.
2. In the symplast pathway, water may move through intercellular spaces.
3. The apoplast pathway may be blocked by the Casparian strip.

Mass flow is the bulk movement of materials from one place to another.
Which vessels carry fluids by mass flow?

Amino acids move from a phloem sieve tube element into a root cell.
Which changes to the water potential and the volume of liquid in the phloem sieve tube element are correct?

The table shows the volume of water taken up over a 10 minute period for two species of plant, X and Y.

[Table_1]

Both plants were tested at the same time, in the same room and using identical potometers. A student concluded that Y was a xerophyte so lost less water.

What feature of the experiment could bring this conclusion into doubt?

What happens during left ventricular systole?

The photograph shows blood cells as seen using a high power light microscope.
Which row correctly identifies the different types of white blood cell?

Which of these processes are responsible for the Bohr shift?
1. Carbon dioxide reacts with haemoglobin to form carbaminohaemoglobin.
2. Carbon dioxide reacts with water to form carbonic acid.
3. Haemoglobinic acid is formed from the dissociation of carbonic acid.

The photomicrograph shows a cross-section through a bronchus.
What is the function of the tissues X and Y?

Which flow diagram correctly describes the effect of tar entering the lungs?

The antibiotic penicillin prevents the formation of cross-links between peptidoglycans during bacterial cell wall synthesis by blocking the enzyme transpeptidase.
Which statements describe the action of penicillin on bacteria?
1 It is an enzyme inhibitor.
2 It weakens the bacterial cell wall.
3 It will work at any stage during the bacterial life cycle.

Which pathogens are spread by droplet infection?
1. *Mycobacterium tuberculosis*
2. *Vibrio cholerae*
3. *Morbillivirus*

The flow diagram shows the events following activation of a T-lymphocyte by binding to antigens on an infected cell.



Which row correctly identifies X, Y and Z?

Smallpox was eradicated from the human population by a worldwide preventative programme. Which type of immunity was triggered in people who were treated as part of this programme?