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QUESTION 1.

Topic: 1.1 (The microscope in cell studies)

An eyepiece graticule can be calibrated using a stage micrometer.
What is the correct reason why an eyepiece graticule is calibrated?
(A) An eyepiece graticule can be used to make measurements.
(B) An eyepiece graticule is magnified by the objective lens.
(C) An eyepiece graticule magnifies the specimen.
(D) An eyepiece graticule makes comparisons.

▶️Answer/Explanation

Ans:- A

QUESTION 2.

Topic: 1.1 (The microscope in cell studies)

The image is an electron micrograph of a typical eukaryotic cell. What can be concluded about the eukaryotic cell from the electron micrograph?
(A) It is an animal cell because it does not have a cell wall.
(B) It is an animal cell because it contains a permanent vacuole.
(C) It is a plant cell because it contains many chloroplasts.
(D) It is a plant cell because it contains many lysosomes.

▶️Answer/Explanation

Ans:- A

QUESTION 3.

Topic: 1.2 (Cells as the basic units of living organisms)

Which features are found in typical eukaryotes and also in typical bacteria?

▶️Answer/Explanation

Ans:- C

QUESTION 4.

Topic: 1.2 (Cells as the basic units of living organisms)

Which type of cell will have the highest proportion of its volume taken up with cell structures bound by a single membrane?
(A) ciliated epithelial cell
(B) goblet cell
(C) red blood cell
(D) companion cell

▶️Answer/Explanation

Ans:- B

QUESTION 5.

Topic: 2.2 (Carbohydrates and lipids)

What causes the phosphate heads of phospholipids to become polar?
(A) The phosphate heads are joined to water molecules by hydrogen bonds.
(B) The phosphate heads are insoluble in water.
(C) The phosphate heads become ionised in water.
(D) The phosphate heads are joined to water molecules by covalent bonds.

▶️Answer/Explanation

Ans:- C

QUESTION 6.

Topic: 2.2 (Carbohydrates and lipids)

Which statements describe features of cellulose that adapt it for its function in plant cells?
1. Three cellulose molecules coil around each other to form a triple helix structure.
2. Many hydrogen bonds form between adjacent cellulose molecules.
3. Covalent bonds form between adjacent cellulose molecules.
(A) 1, 2 and 3

(B) 1 and 3 only

(D) 2 only

▶️Answer/Explanation

Ans:- D

QUESTION 7.

Topic: 2.2 (Carbohydrates and lipids)

Which structure shows α-glucose?

▶️Answer/Explanation

Ans:- B

QUESTION 8.

Topic: 2.2 (Carbohydrates and lipids)

What cannot occur as a result of a condensation reaction?
(A) breaking of a glycosidic bond
(B) formation of a disaccharide
(C) joining together of two amino acids
(D) production of a molecule of water

▶️Answer/Explanation

Ans:- A

QUESTION 9.

Topic: 2.3 (Proteins)

Which fact about the quaternary structure of proteins is correct?
(A) consists of four polypeptides
(B) depends on the presence of metal ions
(C) depends on the primary structure of the polypeptides
(D) is made of α and β polypeptides

▶️Answer/Explanation

Ans:- C

QUESTION 10.

Topic: 3.1 (Mode of action of enzymes)

The diagram shows different molecules in a solution.

Which statement could explain what happens when some of the molecules are mixed together?
(A) Molecule P forms an enzyme-substrate complex with the non-competitive inhibitor molecule Q.
(B) Molecule Q binds to molecule P, increasing the activation energy.
(C) Molecules R and S bind to the active site of molecule P.
(D) Molecules S and R are the products of the breakdown of molecule P.

▶️Answer/Explanation

Ans:- C

QUESTION 11.

Topic: 3.1 (Mode of action of enzymes)

The effect of substrate concentration on an enzyme-catalysed reaction was measured in three different conditions:
● without an inhibitor
● with a competitive inhibitor
● with a noncompetitive inhibitor.
The graph shows the results.

Which row is correct?

▶️Answer/Explanation

Ans:- A

QUESTION 12.

Topic: 3.2 (Factors that affect enzyme action)

Which aspect of enzyme activity can be compared by the Michaelis-Menten constant?
(A) activation energy of a reaction with or without an enzyme
(B) affinity of different enzymes for their substrates
(C) affinity of an enzyme at different substrate concentrations
(D) maximum rate of reaction (Vmax) at different temperatures

▶️Answer/Explanation

Ans:- B

QUESTION 13.

Topic: 3.2 (Factors that affect enzyme action)

The number of substrate molecules one enzyme molecule can convert to product in a second is
called the turnover number. This number is obtained when all conditions are optimum for the specific enzyme-catalysed reaction.

How many times faster at converting substrate to product is catalase compared to phosphatase?
(A) 29

(B) 288

(D) 28 836

▶️Answer/Explanation

Ans:- C

QUESTION 14.

Topic: 4.2 (Movement into and out of cells)

A red indicator solution was mixed with agar, and the resulting solid was cut into small cuboid
blocks. The blocks were placed in an acid which turns the indicator yellow, and all other variables
were kept constant. The dimensions of the three blocks used are shown.
block 1 3 mm × 3 mm × 3 mm
block 2 8 mm× 8 mm × 8 mm
block 3 11 mm× 11 mm × 11 mm
Which row shows the correct surface area (SA) to volume (V) ratio for each block, and the time taken for the block to turn yellow?

▶️Answer/Explanation

Ans:- C

QUESTION 15.

Topic: 4.2 (Movement into and out of cells)

The statements describe some events in the process of exocytosis of glycoprotein molecules.

1. Membrane of the Golgi body folds around glycoprotein molecules.
2. Vesicle binds to and fuses with the cell surface membrane.
3. Vesicle attached to microtubules moves through the cytoplasm.
4. Secretory vesicle forms.
What is the correct order of events for exocytosis?
(A) 1 → 4 → 2 → 3
(B) 1 → 4 → 3 → 2
(C) 2 → 3 → 1 → 4
(D) 4 → 1 → 3 → 2

▶️Answer/Explanation

Ans:- B

QUESTION 16.

Topic: 4.2 (Movement into and out of cells)

Four cylinders that were identical in size, A, B, C and D, were cut from potatoes that had been stored for different lengths of time.
The cylinders were weighed, immersed in 10% salt solution for 45 minutes and then reweighed. The percentage change in mass was then calculated. Which cylinder had a water potential similar to the 10% salt solution?

▶️Answer/Explanation

Ans:- C

QUESTION 17.

Topic: 5.1 (Replication and division of nuclei and cells)

The contents of a daughter cell are compared to the parent cell after one cell cycle. Which row is correct?

▶️Answer/Explanation

Ans:- D

QUESTION 18.

Topic: 5.1 (Replication and division of nuclei and cells)

A high-power photomicrograph shows a cell in a stage of mitosis. The chromosomes are visible and lined up along the cell equator but there is no nuclear envelope.Which stage of mitosis is shown by the photomicrograph?
(A) prophase
(B) metaphase
(C) anaphase
(D) telophase

▶️Answer/Explanation

Ans:- B

QUESTION 19.

Topic: 5.1 (Replication and division of nuclei and cells)

Which statements about the cell cycle are correct?
1. The cell cycle includes interphase and mitosis.
2. DNA replication takes place in interphase.
3. A cell can remain in interphase for several months.
(A) 1, 2 and 3

(B) 1 and 2 only

(D) 2 and 3 only

▶️Answer/Explanation

Ans:- A

QUESTION 20.

Topic: 5.2 (Chromosome behaviour in mitosis)

A scientist stains the chromosomes of a plant cell with a fluorescent dye to observe the telomeres. This cell has 38 chromosomes.
How many telomeres will the scientist observe in one of the nuclei during telophase of mitosis?
(A) 38

(B) 76

(D) 152

▶️Answer/Explanation

Ans:- B

QUESTION 21.

Topic: 6.1 (Structure of nucleic acids and replication of DNA)

During the semi-conservative replication of DNA, the double helix is unwound by an enzyme. Which diagram shows how the strands are copied?

▶️Answer/Explanation

Ans:- D

QUESTION 22.

Topic: 6.2 (Protein synthesis)

A transcription error results in the deletion of one nucleotide from the middle of a primary transcript. mRNA forms from the primary transcript.
Which statement describes one possible effect of this deletion on the protein translated from this mRNA?
(A) The protein will be unchanged as the same amino acids can be coded by another codon formed by the deletion.
(B) The tertiary structure of the protein is not affected as only one amino acid has been changed by the deletion.
(C) Only one amino acid has been changed by the deletion but this changes the quaternary structure of the protein.
(D) The sequence of amino acids in the protein will be different as all the codons from the deletion onwards are changed.

▶️Answer/Explanation

Ans:- D

QUESTION 23.

Topic: 6.2 (Protein synthesis)

Which statements correctly describe the process of translation?

(1) The nucleotide sequence on an mRNA molecule is used to produce a specific amino acid chain.
(2) A section of DNA is copied into an mRNA molecule by RNA polymerase.
(3) A polypeptide is produced because anticodons on tRNA molecules attach to mRNA codons through peptide bonds.

(A) 1 and 2

(B) 1 and 3

(D) 2 and 3

▶️Answer/Explanation

Ans:- C

QUESTION 24.

Topic: 6.2 (Protein synthesis)

A molecule of mRNA was used in translation. Part of its sequence is shown.

GAU CUG UAA CGG

There were no introns present in the section of DNA that was transcribed to make this mRNA.
What is the sequence of the non-transcribed DNA strand for this section?
(A) CTA GAC ATT GCC
(B) CUA GAC AUU GCC
(C) GAT CTG TAA CGG
(D) GAU CUG UAA CGG

▶️Answer/Explanation

Ans:- C

QUESTION 25.

Topic: 2.4 (Water)

Which properties of water are dependent on hydrogen bonding between water molecules?

▶️Answer/Explanation

Ans:- B

QUESTION 26.

Topic: 7.2 (Transport mechanisms)

Which substances in xylem tissue are impermeable to water and prevent the collapse of the vessels?

▶️Answer/Explanation

Ans:- D

QUESTION 27.

Topic: 7.1 (Structure of transport tissues)

The electron micrograph shows a longitudinal section through phloem tissue.

Which student’s drawing of a sieve tube element is correctly drawn and labelled?

▶️Answer/Explanation

Ans:- A

QUESTION 28.

Topic: 7.2 (Transport mechanisms)

Carrier proteins in the cell surface membranes of companion cells are involved in the transfer of
assimilates to phloem sieve tubes. The diagram represents the use of two types of carrier protein
in this process.

What are the substances labelled X and Y?

▶️Answer/Explanation

Ans:- A

QUESTION 29.

Topic: 8.3 (The heart)

The diagram shows pressure changes during two cardiac cycles. Which arrow indicates atrial systole?

▶️Answer/Explanation

Ans:- B

QUESTION 30.

Topic: 8.3 (The heart)

An irregular heartbeat may be the result of ineffective electrical stimulation of the atria. Which area of the heart could be damaged, causing this irregular heartbeat?
(A) atrioventricular node
(B) septum
(C) Purkyne tissue
(D) sinoatrial node

▶️Answer/Explanation

Ans:- D

QUESTION 31.

Topic: 8.2 (Transport of oxygen and carbon dioxide)

The diagram shows the effect of three different concentrations of carbon dioxide on the oxygen dissociation curve for human haemoglobin.

Which effect does increasing carbon dioxide concentration have on haemoglobin?
(A) It makes haemoglobin less efficient at taking up oxygen and less efficient at releasing oxygen.
(B) It makes haemoglobin less efficient at taking up oxygen and more efficient at releasing oxygen.
(C) It makes haemoglobin more efficient at taking up oxygen and less efficient at releasing oxygen.
(D) It makes haemoglobin more efficient at taking up oxygen and more efficient at releasing oxygen.

▶️Answer/Explanation

Ans:- B

QUESTION 32.

Topic: 8.2 (Transport of oxygen and carbon dioxide)

Which reactions will be taking place in blood in a capillary that is next to an alveolus?

$1. Hb+4O_{2}\to HbO_{8}$ Key Hb=haemoglobin

$2. H_{2}O+CO_{2}\to H_{2}CO_{8}$

$3. H_{2}CO_{3}+H^{+}\to HCO_{3}^{-}$

(A) 1 and 2

(B) 1 only

(D) 2 only

▶️Answer/Explanation

Ans:- B

QUESTION 33.

Topic: 9.1 (The gas exchange system)

Which structure of the gas exchange system always contains cartilage?

(A) alveoli
(B) bronchiole
(C) capillary
(D) bronchus

▶️Answer/Explanation

Ans:- D

QUESTION 34.

Topic: 9.1 (The gas exchange system)

Exchange of carbon dioxide and oxygen occurs between air in the alveoli and blood in the capillaries of the lung.
Which partial pressures of the gases will allow gaseous exchange to occur?

▶️Answer/Explanation

Ans:- B

QUESTION 35.

Topic: 9.1 (The gas exchange system)

The plan diagram shows a cross-section of a trachea. Which labelled tissue prevents the trachea from collapsing?

▶️Answer/Explanation

Ans:- A

QUESTION 36.

Topic: 9.1 (The gas exchange system)

Which layers of cells does an oxygen molecule diffuse through when moving from an alveolus into an alveolar capillary?

▶️Answer/Explanation

Ans:- C

QUESTION 37.

Topic: 10.2 (Antibiotics)

Bacteria may be classified according to differences in cell wall structure. The differences are shown by using the Gram stain.
The diagram shows part of a Gram-positive bacterium and part of a Gram-negative bacterium, drawn to the same scale.

The antibiotic penicillin kills bacteria by inhibiting the synthesis of the cell walls during bacterial cell growth.
Which type of bacteria will be killed by penicillin more easily and why?
(A) Gram-positive bacteria because the peptidoglycan layer is exposed to penicillin directly
(B) Gram-positive bacteria because it has a thinner layer surrounding the cell membrane overall
(C) Gram-negative bacteria because the thin peptidoglycan layer can be broken down faster
(D) Gram-negative bacteria because there is more periplasm available, which gives a weaker structure

▶️Answer/Explanation

Ans:- A

QUESTION 38.

Topic: 10.1 (Infectious diseases)

Which facts relate to the disease TB or its pathogen?
1. Viruses change their antigens to a limited extent.
2. TB is caused by only one species of pathogen.
3. HIV/AIDS makes the bacterial infection worse.
4. The pathogen may be transmitted by ingestion.
5. The pathogen may be transmitted from animals.
6. Multi-drug resistance occurs.
(A) 1, 4, 5 and 6
(B) 1, 2 and 6
(C) 2, 3 and 5
(D) 3, 4, 5 and 6

▶️Answer/Explanation

Ans:- D

QUESTION 39.

Topic: 11.1 (The immune response)

The events listed occur during the primary immune response to a specific pathogen.
1. activation of B-lymphocyte to produce plasma cells and memory cells
2. phagocytosis of invading pathogens by macrophages
3. T-helper cell activation and production of T-killer cells
4. expression of antigens on phagocyte cell surface
5. production and release of antibodies
Which row identifies a correct sequence of events?

▶️Answer/Explanation

Ans:- B

QUESTION 40.

Topic: 11.1 (The immune response)

Influenza is an infectious disease caused by a virus It is possible to have influenza more than once.
Which statements explain why it is possible to have influenza more than once?
1. The viral antigen change as a result of mutations.
2. The immune system may be weak and make few B-memory cells.
3. Untreated HIV infection has resulted in a low T-helper cell count.
(A) 1, 2 and 3

(B) 1 and 2 only

(D) 2 and 3 only

▶️Answer/Explanation

Ans:- A

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