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

The photomicrograph shows part of a plant cell.
[Image_1: Photomicrograph of plant cell]
What is the magnification of the cell?

Which row matches each organelle with its function?
[Table_1]

Where are 80S ribosomes found?
1 chloroplasts
2 cytoplasm of eukaryotes
3 mitochondria
4 cytoplasm of prokaryotes

Which feature, when present in an organism, enables it to be identified as a prokaryote?

What is the function of the nucleolus?

The diagram shows the results of a number of tests on a solution of biochemicals.

Which substances are present in the solution?

Which diagram shows the ring form of $\beta$-glucose?

Which row correctly matches the example with the type of molecule? [Table_1]

The enzyme \( \alpha \)-amylase hydrolyses amylopectin but it is not able to hydrolyse some of its glycosidic bonds.
• It only hydrolyses 1,4 glycosidic bonds.
• It is not able to hydrolyse the last bond of a chain.
• It is not able to hydrolyse the bonds in a chain of three units attached by a 1,6 glycosidic bond to another chain.
Which glycosidic bond can be hydrolysed by \( \alpha \)-amylase?

Molecule X is a lipid.

Which row is correct for molecule X and a triglyceride?
[Table_1]

Bread contains a mixture of polypeptides known as gluten.
Two of the polypeptides found in gluten are glutenin and gliadin.
Which statement describes the tertiary structure of a protein?

A student was provided with two test-tubes, one containing 10 cm³ of solution P and one containing 10 cm³ of solution Q. When these solutions were mixed together and left for 24 hours, the concentration of P decreased but the concentration of Q remained the same. The student wrote the following conclusions.
1. P may break down over time.
2. Q may be a biological catalyst.
3. P may be the substrate for Q.
Which conclusions could be supported by the information?

Which statements are correct for the lock and key hypothesis and the induced fit hypothesis of enzyme action?
1 The substrate is the same shape as the active site.
2 The substrate is held in place in the active site by temporary bonds.
3 The enzyme and sometimes the substrate change shape slightly as the substrate molecule enters the enzyme.

A student investigated the rate of enzyme activity with increasing substrate concentration. The experiment was repeated with the addition of a reversible non-competitive enzyme inhibitor. A graph was plotted to show the results. Which graph represents the results of the two experiments?

A cuboidal epithelium cell has a length of 2 \mu m.
The cell is an approximate cube shape.
What is the most accurate estimate of the surface area : volume ratio of this cuboidal epithelium cell?

Which statement is correct for facilitated diffusion and active transport?

Equal sized potato pieces were placed into a test-tube and covered with a sucrose solution. The test-tube was left for 30 minutes. All other variables were standardised.
After 30 minutes, the potato piece had not changed in size.
What can be concluded from this result?

How many of these processes produce genetically identical cells?
• growth of plant roots
• replacement of dead human skin cells
• repair of damaged muscle tissue
• asexual reproduction of coral

Which row shows the correct number of each component of a single chromosome at the end of prophase of mitosis?
[Table_1]

Which processes occur during interphase?
1. DNA replication
2. microtubule organisation
3. synthesis of ribosomes

Embryonic stem cells are able to replicate continuously.
What happens to the telomeres during repeated mitotic cell cycles of embryonic stem cells?

Which nitrogenous bases are pyrimidines?

DNA replication in bacteria was investigated. Bacteria were grown in a medium with only heavy nitrogen, $^{15}N$, until all of the bacterial DNA was heavy. These bacteria were moved from the heavy nitrogen medium and cultured in a medium with only light nitrogen, $^{14}N$. This formed the first generation. The bacteria continued to reproduce, and a sample of bacteria was collected from the second generation and the DNA analysed. Hybrid DNA contains heavy and light DNA. Which row is correct for the second generation?
[Table_1]

The sequence shows the series of bases at the start of a gene.

TAC CGA CCA CCA CAA CCA CGA...

After transcription, the mRNA was translated via tRNA into a sequence of amino acids. When this part of the polypeptide was analysed, it was found to contain the amino acids in the table.

[Table_1]

What is the sequence of amino acids in this part of the polypeptide?

The table shows the mode of action of two antibacterial drugs that can affect the synthesis of proteins.

[Table showing antibacterial drugs and their mode of action]

If bacteria are treated with the drugs rifampicin and streptomycin, what will be the immediate effects?

1. Transcription will stop but faulty proteins may continue to be synthesised.
2. If translation has started, proteins may be faulty.
3. Translation will be inhibited.

The electron micrograph shows a cross-section of a leaf vein and some neighbouring cells.
Which structure contributes to mass flow by the use of proton pumps?

The diagrams show some tissue types in plant organs. Which row identifies the tissue types?

Which description of xylem vessel elements is correct?

Which properties of lignin are important for the function of xylem vessels in the stem of a tall plant, such as a tree?
1. It is inflexible so does not bend easily.
2. It is not permeable to water.
3. It is strong to resist collapse under pressure.
4. It has weaker adhesion to water molecules than cellulose.

Which row is correct for the sucrose concentrations and the water potentials in a source and a sink in a potato plant, at 12:00 p.m.?
[Table_1]

The diagram shows one possible way in which sucrose may be loaded into a sieve tube element.
Which steps require ATP?

Which statements about arteries are correct?
1. Artery walls can resist high pressure.
2. Arteries pump blood out of the heart.
3. Blood in arteries has the same flow rate as in veins.
4. The pulse in arteries is the result of a surge in blood that causes expansion of the artery wall.
5. There are semilunar valves at the junction of arteries with the heart.

What happens during ventricular systole in a mammalian heart?
1. The atrioventricular node transmits an electrical signal to the apex of the heart.
2. The pressure in the ventricles drops below the pressure in the atria.
3. The atrioventricular valves close and the semilunar valves open.

A shortage of protein in the diet of children can lead to a disease that causes excess tissue fluid to build up in the abdomen. What explains why a build-up of excess tissue fluid can occur in this disease?

Red blood cells may contain a molecule known as 2,3-bisphosphoglycerate (2,3-BPG).
When 2,3-BPG binds to haemoglobin, a higher partial pressure of oxygen is needed to bring about 50% saturation of haemoglobin with oxygen.
Which statements about the effect of 2,3-BPG are correct?
1. 2,3-BPG in red blood cells causes the oxygen dissociation curve to shift to the right.
2. The binding of 2,3-BPG to haemoglobin reduces the Bohr effect.
3. The binding of 2,3-BPG to haemoglobin lowers the affinity of the haemoglobin for oxygen.
4. When 2,3-BPG is not present, oxyhaemoglobin is less likely to unload oxygen.

Carbon dioxide is continually produced by respiring cells. It diffuses into red blood cells and dissociates into hydrogen ions ($H^{+}$) and hydrogen carbonate ions ($HCO_{3}^{-}$). $HCO_{3}^{-}$ then diffuses out of the cell in exchange for chloride ions ($Cl^{-}$) in the chloride shift.
What is the importance of the chloride shift?

The photomicrograph shows a section through a bronchus.
Which annotated label is correct?

Penicillin is an antibiotic used to treat infections caused by bacteria.
Which events explain how bacteria become resistant to penicillin?
1 The number of bacteria with the allele for resistance to penicillin increases.
2 Resistance to penicillin is the result of a mutation in a bacterium.
3 Bacteria with the allele for resistance to penicillin pass the allele to their daughter cells.
4 The mutation for resistance to penicillin is always caused by the presence of penicillin.

Which statements explain why some vaccines can be taken by mouth but tuberculosis (TB) vaccine has to be injected?

1. Macrophages present antigens in vaccines to stimulate an immune response.
2. The TB antigens necessary to produce an immune response are proteins which would be digested in the stomach and small intestine.
3. There are no B-lymphocytes and T-lymphocytes in the stomach.

A student wrote the following statements about the production of monoclonal antibodies.
Which statement is not correct?