AS & A Level Biology - 9700 Paper 1 2022 Winter Zone 2

The diagram shows a stage micrometer, with divisions 0.10 mm apart, viewed through an eyepiece containing a graticule.

The area of the field of view of the microscope can be calculated using this formula:
$\text{area} = \pi r^2$
A student calculated the area of the field of view of the microscope using the information provided and a value for $\pi$ of 3.142.
Which answer has been rounded correctly to an appropriate number of significant figures?

Where are cisternae found in a cell?
1. endoplasmic reticulum
2. Golgi body
3. mitochondria

Which row matches the functions to the cell structures? [Table_1]

Which structures are found in prokaryotes and eukaryotes?

Which molecules are present in all viruses?
1. thymine
2. adenine
3. cytosine

The table shows the observations recorded from tests for biological molecules on four samples, A, B, C and D.
Which conclusion is correct?
[Table_1]

The diagrams show some biological molecules. Which biological molecule forms a polymer with a structural role in plants?

Which molecule is a disaccharide and a reducing sugar?

The diagram shows bonding in part of a polysaccharide.

Which type of glycosidic bond is shown at position X?

Which statements about triglycerides and phospholipids are correct?
1. Fatty acids in a triglyceride may be saturated or unsaturated but in a phospholipid they are always saturated.
2. Triglycerides and phospholipids both have a hydrophobic region.
3. Triglycerides are non-polar molecules and phospholipids are polar molecules.

Silk moth caterpillars have been genetically modified to produce a mixture of their own silk and the much stronger spider silk of the golden orb web spider.
The spider silk polypeptide chain has many repeated sequences of two amino acids, glycine and alanine, arranged in a crystalline structure.

What correctly describes the structure of spider silk?

Which property of the tertiary structure of a globular protein enables it to catalyse a metabolic reaction?

A student investigated the effect of substrate concentration on the activity of an enzyme.
The graph shows the results of this investigation.

An increase in which factors could lead to a change in the activity of the enzyme at point X on the graph?

The Michaelis–Menten constant, $K_m$, is the substrate concentration at which an enzyme works at half its maximum rate. What is correct when the $K_m$ value is low?

Which functions are performed by glycoproteins on the surface of a cell surface membrane?
1. to act as enzymes catalysing reactions in the membrane
2. to have a specific site where chemicals can bind
3. to secrete specific chemicals used for cell signalling

The diagram represents a process by which molecules move out of a cell through a cell surface membrane.
Which process does this represent?

The photomicrograph shows the appearance of onion epidermal cells after they have been soaked in solution X for one hour.
What fills the space labelled Y?

The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles.
Which cells need to transcribe telomerase enzyme?
1. cancer cells
2. stem cells
3. activated memory B-lymphocytes

Which processes that occur in the cell cycle are represented in the diagram?

A gene codes for the production of a protein, p53, that binds to damaged DNA during interphase and prevents its replication. A carcinogen in cigarette smoke mutates the gene coding for the p53 protein, preventing production of the protein. Which statement explains why this mutation may cause cancer?

Stained onion cells undergoing mitosis were observed using a microscope. Which row is correct for mitosis in plant cells? [Table_1]

How many statements about semi-conservative replication of DNA in a eukaryotic cell are correct?
1. The process takes place in the cytoplasm.
2. An adenine nucleotide will line up against uracil on the template strand.
3. Each daughter molecule will contain half of the original DNA molecule.
4. If the DNA molecule contained 40% guanine nucleotides, each daughter molecule will contain 20% guanine nucleotides.

A section of the polypeptide coding for the haemoglobin β-chain contains the following amino acids.

– Pro – Glu – Glu –

Patients with sickle cell anaemia have mutated β-polypeptide chains. The section of the mutated polypeptide contains the following amino acids.

– Pro – Val – Glu –

The table shows the possible anticodons for Val.

[Table_1]

What is the corresponding DNA triplet code for the substituted amino acid in the mutated polypeptide?

Which diagram correctly represents temporary hydrogen bonding during transcription?

The diagram shows part of the DNA sequence of a gene and a mutated sequence of the same gene.

normal DNA sequence ...CCG GAT TAT TGC GAG AAA TGG CAT TCT AGG...
mutated DNA sequence ...CCG GAT GTA TTG CGA GAA ATG CAT TCT AGG...

What are possible effects of the mutated sequence?

1 the presence of mRNA stop codons, UAG, UAA or UGA
2 a change in the sequence of amino acids
3 a non-functional protein
4 ribosomes cannot translate the mRNA

The electron micrograph shows a longitudinal section through part of a plant stem. What is X?

Sodium chloride is added to a culture solution containing freshwater single-celled plant cells. What happens to the water potential of the culture solution when the sodium chloride is added and what may happen to the plant cells after 5 minutes?
[Table showing two columns: 'water potential of the culture solution when sodium chloride added' and 'single-celled plant cells after 5 minutes']

Which 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.

Which statement about the movement of water from roots to leaves is not correct?

Which terms describe the method by which water is transported within xylem vessel elements?
1. cotransport
2. cohesion-tension
3. osmosis

What is the main function of a companion cell in phloem tissue?

The photomicrograph shows a blood smear.
Which cell is a monocyte?

The table shows some information about three blood vessels, P, Q and R, from a mammal.

[Table_1]

Which row identifies blood vessels P, Q and R?

Ventricular septal defect (VSD) is a heart defect that people can have from birth. People with VSD have a hole in the wall (septum) that separates the left and right ventricles.
What could happen in a person with VSD?
1. Blood will leak through the hole, mostly from right to left.
2. The volume of blood circulating through the lungs will be higher than in a person without VSD.
3. Less oxygen will be delivered to the body tissues.

Which statement about the structure of the heart is correct?

What can be found in the wall of an alveolus in the lungs of a human?
[Table_1]

What are the functions of cilia in the gas exchange system?

1. to move mucus
2. to trap pathogens and dust
3. to increase the surface area

| | 1 | 2 | 3 |
|---|---|---|---|
| A | ✓ | ✗ | ✗ |
| B | ✓ | ✓ | ✗ |
| C | ✗ | ✓ | ✓ |
| D | ✗ | ✗ | ✓ |

Key:
✓ = a function
✗ = not a function

Cholera and tuberculosis are infectious diseases that can spread when people have to live in overcrowded conditions. Which strategies would help control the spread of cholera and tuberculosis? 1. covering food to prevent flies landing on it 2. providing chlorinated drinking water 3. treating severe cases with antibiotics

Immunity to certain pathogens develops when a person is given a vaccination. Which effects of vaccination are correct?
1. production of antibodies to protect against future infections
2. results in artificial active immunity
3. stimulation of appropriate lymphocytes

A student wrote 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 correct?