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PAAET Nursing and Health Sciences Aptitude Test study materials
PAAET Nursing and Health Sciences Aptitude Test study resources

PAAET Nursing and Health Sciences Aptitude Test practice questions

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Question 1Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which organelle is the main site of ATP production in a eukaryotic cell?

  1. Mitochondrion Correct answer.
  2. Golgi apparatus
  3. Smooth endoplasmic reticulum
  4. Lysosome

Explanation

Mitochondria carry out oxidative phosphorylation, in which the electron transport chain and ATP synthase generate most of the cell's ATP. Other organelles perform synthesis, digestion or transport rather than bulk energy production.

Question 2Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

In a DNA molecule, adenine forms hydrogen bonds with which base?

  1. Guanine
  2. Thymine Correct answer.
  3. Uracil
  4. Cytosine

Explanation

DNA base pairing follows complementary rules in which adenine pairs with thymine through two hydrogen bonds and guanine pairs with cytosine through three. Uracil replaces thymine only in RNA.

Question 3Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Oxygenated blood returning from the lungs enters the heart into which chamber?

  1. Left atrium Correct answer.
  2. Left ventricle
  3. Right atrium
  4. Right ventricle

Explanation

Pulmonary veins deliver oxygenated blood to the left atrium, which passes it to the left ventricle for distribution around the body. The right side of the heart handles deoxygenated systemic venous blood.

Question 4Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which statement correctly distinguishes bacteria from viruses?

  1. Viruses are larger than bacterial cells
  2. Bacteria reproduce only inside host cells
  3. Bacteria lack nucleic acid; viruses contain it
  4. Bacteria possess ribosomes; viruses do not Correct answer.

Explanation

Bacteria are complete prokaryotic cells with their own ribosomes and metabolic machinery, so they can synthesise proteins and reproduce independently. Viruses are acellular obligate intracellular parasites with no ribosomes of their own.

Question 5Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

How many chromosomes are present in a normal human somatic cell?

  1. 46 Correct answer.
  2. 23
  3. 22
  4. 92

Explanation

Human somatic cells are diploid, containing 23 pairs of homologous chromosomes, which totals 46. Gametes are haploid and contain 23.

Question 6Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which hormone lowers the concentration of glucose in the blood?

  1. Adrenaline
  2. Glucagon
  3. Insulin Correct answer.
  4. Cortisol

Explanation

Insulin is released by pancreatic beta cells when blood glucose rises and promotes cellular uptake and storage of glucose, lowering glycaemia. The other hormones named raise or help maintain blood glucose.

Question 7Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

On which cell structure does translation of mRNA into protein take place?

  1. Vacuole
  2. Centriole
  3. Peroxisome
  4. Ribosome Correct answer.

Explanation

Ribosomes read the mRNA codon sequence and assemble the corresponding amino acids into a polypeptide chain. They may be free in the cytosol or attached to the rough endoplasmic reticulum.

Question 8Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which molecule binds and transports oxygen inside red blood cells?

  1. Albumin
  2. Haemoglobin Correct answer.
  3. Fibrinogen
  4. Collagen

Explanation

Haemoglobin contains four haem groups, each with an iron ion that reversibly binds one oxygen molecule, giving blood its oxygen-carrying capacity. The other proteins listed have unrelated functions.

Question 9Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

A red blood cell is placed in a hypertonic saline solution. What happens to the cell?

  1. It shrinks as water leaves Correct answer.
  2. It swells and then bursts
  3. It keeps its normal volume
  4. It gains water without changing

Explanation

In a hypertonic solution the surrounding fluid has a lower water potential than the cytoplasm, so water moves out of the cell by osmosis across the membrane. The resulting loss of cell water causes shrinkage.

Question 10Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

During which stage of mitosis do chromosomes line up along the equator of the cell?

  1. Prophase
  2. Anaphase
  3. Telophase
  4. Metaphase Correct answer.

Explanation

In metaphase the chromosomes become attached to spindle fibres from opposite poles and align along the metaphase plate at the cell equator. Separation of chromatids only begins afterwards.

Question 11Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Two heterozygous tall pea plants (Tt) are crossed. What phenotypic ratio is expected in the offspring?

  1. 3:1 tall to short Correct answer.
  2. 4:0 tall to short
  3. 2:1 tall to short
  4. 1:1 tall to short

Explanation

A Tt x Tt cross gives genotype frequencies of 1 TT : 2 Tt : 1 tt. Because T is dominant, both TT and Tt plants are tall, so the phenotypic ratio is three tall to one short.

Question 12Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

In the nephron, most of the filtered glucose is reabsorbed in the:

  1. Collecting duct
  2. Bowman's capsule
  3. Proximal tubule Correct answer.
  4. Loop of Henle

Explanation

The proximal convoluted tubule has abundant microvilli and sodium-linked co-transporters that recover nearly all filtered glucose, amino acids and much of the sodium and water. Distal regions handle fine-tuning of water and electrolytes.

Question 13Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

An enzyme-catalysed reaction is already limited by the amount of enzyme present. Raising the substrate concentration further will:

  1. Denature the enzyme rapidly
  2. Lower the activation energy
  3. Have little effect on the rate Correct answer.
  4. Increase the rate indefinitely

Explanation

Once all active sites are saturated, enzyme molecules are working at maximum turnover and extra substrate cannot raise the rate further. More enzyme, not more substrate, would be required to increase it.

Question 14Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

During muscle contraction, the sarcomere shortens because:

  1. Actin filaments shorten in length
  2. Myosin heads pull actin inward Correct answer.
  3. The Z-lines move further apart
  4. Myosin filaments dissolve away

Explanation

According to the sliding filament model, myosin cross-bridges bind actin and undergo a power stroke that draws the thin filaments toward the centre of the sarcomere. The filaments themselves do not change length.

Question 15Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Gram-positive bacteria retain the crystal violet stain because they possess:

  1. No cell wall at all
  2. A thin peptidoglycan layer
  3. An outer membrane rich in lipid
  4. A thick peptidoglycan layer Correct answer.

Explanation

The thick peptidoglycan wall of Gram-positive cells traps the crystal violet-iodine complex when alcohol is applied, so they remain purple. Thin-walled Gram-negative cells lose the dye and take up the counterstain.

Question 16Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which of the following is a clear example of negative feedback regulation?

  1. Oxytocin release during childbirth
  2. The clotting cascade after injury
  3. Sweating when body temperature rises Correct answer.
  4. Uterine contractions during labour

Explanation

Sweating cools the body, which reduces the initial rise in temperature and therefore reduces the stimulus for further sweating, completing a negative feedback loop. Positive feedback instead amplifies the original change.

Question 17Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

The enzyme pepsin, secreted into the stomach, digests which nutrient?

  1. Starches
  2. Proteins Correct answer.
  3. Nucleic acids
  4. Fats

Explanation

Pepsin is a protease secreted as inactive pepsinogen and activated by gastric acid; it cleaves proteins into shorter peptides. Its acidic optimum suits the gastric environment.

Question 18Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which cells are responsible for secreting large quantities of antibodies?

  1. Plasma cells Correct answer.
  2. Mast cells
  3. Neutrophils
  4. Helper T cells

Explanation

Activated B lymphocytes differentiate into plasma cells, which are specialised for high-level synthesis and release of specific immunoglobulins. T cells coordinate the response but do not secrete antibodies.

Question 19Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

A person of blood group AB carries the genotype I^A I^B. This pattern of expression is an example of:

  1. Sex linkage
  2. Codominance Correct answer.
  3. Complete dominance
  4. Epistasis

Explanation

In codominance both alleles are fully expressed in the heterozygote, so I^A I^B individuals carry both A and B antigens on their red cells. Neither allele masks the other.

Question 20Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Exchange of oxygen and carbon dioxide across the alveolar membrane occurs mainly by:

  1. Osmosis
  2. Bulk flow
  3. Simple diffusion Correct answer.
  4. Active transport

Explanation

Gas exchange depends on partial pressure gradients, so oxygen diffuses from alveolar air into the blood while carbon dioxide diffuses in the opposite direction. The thin, moist membrane and large surface area make diffusion rapid.

Question 21Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

The rapid depolarisation phase of a neuron action potential is caused by:

  1. Sodium ions entering the axon Correct answer.
  2. Potassium ions entering the axon
  3. Calcium ions leaving the axon
  4. Chloride ions entering the axon

Explanation

Opening of voltage-gated sodium channels allows a sudden inward sodium current that reverses the membrane potential towards positive values. Repolarisation then follows as potassium channels open and potassium leaves the cell.

Question 22Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

A colour-blind man marries a woman who is a carrier of the same X-linked recessive allele. What proportion of their sons is expected to be colour-blind?

  1. All of them
  2. One quarter of them
  3. None of them
  4. One half of them Correct answer.

Explanation

Sons inherit a Y chromosome from the father and one of the mother's two X chromosomes. A carrier mother transmits the affected allele to half of her sons, so half are expected to be colour-blind regardless of the father's genotype.

Question 23Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

A bacterium acquires a plasmid carrying a gene for beta-lactamase. The most immediate advantage this gives the cell is the ability to:

  1. Break down penicillin-type antibiotics Correct answer.
  2. Adhere to the host epithelium
  3. Survive in anaerobic conditions
  4. Move more quickly through tissue

Explanation

Beta-lactamase hydrolyses the beta-lactam ring of penicillins and related antibiotics, so the enzyme destroys the drug before it can inhibit cell wall synthesis. Plasmid transfer therefore spreads resistance rapidly between bacteria.

Question 24Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

A mutation inactivates the p53 gene in a cell. What is the most likely consequence?

  1. Enhanced repair of broken DNA
  2. Failure to arrest after DNA damage Correct answer.
  3. Immediate entry into mitosis
  4. Permanent exit into G0 phase

Explanation

p53 normally halts the cell cycle at the G1/S checkpoint to allow repair or to trigger apoptosis when damage is severe. Losing this function lets cells with damaged DNA continue dividing, encouraging mutation accumulation.

Question 25Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

A person hyperventilates, so blood carbon dioxide falls sharply. The immediate effect on blood pH is that it:

  1. Stays constant due to buffers
  2. Falls, as bicarbonate rises
  3. Rises, as carbonic acid falls Correct answer.
  4. Falls, as lactate accumulates

Explanation

Lower carbon dioxide shifts the carbonic anhydrase equilibrium away from carbonic acid, so fewer hydrogen ions are released and pH rises, producing respiratory alkalosis. Buffers slow the change but cannot prevent it once the respiratory drive is altered.

Question 26Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which organelle contains hydrolytic enzymes that break down worn-out cell components and engulfed material?

  1. Lysosome Correct answer.
  2. Ribosome
  3. Nucleus
  4. Golgi apparatus

Explanation

Lysosomes are membrane-bound vesicles holding acid hydrolases that digest macromolecules and damaged organelles at acidic pH. The other organelles listed have entirely different roles in the cell.

Question 27Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which type of blood vessel carries blood away from the heart?

  1. Vein
  2. Venule
  3. Artery Correct answer.
  4. Capillary

Explanation

By definition arteries are the vessels that transport blood away from the heart, regardless of whether the blood is oxygenated. Veins and venules return blood toward the heart, and capillaries are the site of exchange.

Question 28Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

How many chromosomes are present in a normal human somatic (body) cell?

  1. 46 Correct answer.
  2. 22
  3. 23
  4. 92

Explanation

Human somatic cells are diploid, containing 23 pairs of chromosomes, which totals 46. Gametes are haploid and carry only one chromosome of each pair.

Question 29Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which formed element of blood is essential for the formation of a clot?

  1. Monocyte
  2. Lymphocyte
  3. Platelet Correct answer.
  4. Erythrocyte

Explanation

Platelets are cell fragments that adhere to damaged vessel walls, aggregate and release factors that drive the clotting cascade. Red cells and white cells do not perform this haemostatic role.

Question 30Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which bacterial structure allows certain species to survive boiling and prolonged drying in a dormant state?

  1. Flagellum
  2. Endospore Correct answer.
  3. Pilus
  4. Capsule

Explanation

An endospore is a highly resistant dormant structure with a dehydrated core and tough coat that permits survival through heat, desiccation and chemical stress. The other structures serve functions unrelated to extreme environmental resistance.

Question 31Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

The knee joint, which allows movement mainly in one plane, is classified as which type of synovial joint?

  1. Pivot
  2. Saddle
  3. Hinge Correct answer.
  4. Ball-and-socket

Explanation

A hinge joint permits flexion and extension about a single transverse axis, as seen at the knee and elbow. The other joint types allow rotation or movement in additional planes.

Question 32Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which vitamin is needed by the liver for the synthesis of several clotting factors?

  1. Vitamin K Correct answer.
  2. Vitamin A
  3. Vitamin C
  4. Vitamin B12

Explanation

Vitamin K acts as a cofactor for the carboxylation of glutamate residues in clotting factors such as prothrombin, allowing them to bind calcium. Deficiency therefore prolongs clotting time.

Question 33Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which structure contains the main centres that set the rhythm of breathing?

  1. Hypothalamus
  2. Medulla oblongata Correct answer.
  3. Thalamus
  4. Cerebellum

Explanation

The medulla oblongata houses the respiratory rhythm centres whose output drives the phrenic nerve and intercostal muscles. Other brain regions modulate breathing but do not generate the basic rhythm.

Question 34Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which enzyme seals the nicks between adjacent Okazaki fragments on the lagging strand?

  1. DNA helicase
  2. DNA ligase Correct answer.
  3. DNA polymerase III
  4. Primase

Explanation

DNA ligase forms phosphodiester bonds that join the sugar-phosphate backbones of neighbouring fragments into a continuous strand. The other enzymes unwind, extend or prime DNA but do not seal nicks.

Question 35Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which enzyme catalyses the synthesis of messenger RNA from a DNA template?

  1. Aminoacyl-tRNA synthetase
  2. RNA polymerase Correct answer.
  3. DNA polymerase
  4. Reverse transcriptase

Explanation

RNA polymerase binds the promoter, unwinds the template strand and links ribonucleotides in the 5' to 3' direction to form mRNA. Each of the other enzymes acts on a different class of substrate or reaction.

Question 36Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Both parents are heterozygous carriers (Aa) of the same autosomal recessive disorder. What is the probability that their child will be affected?

  1. 50%
  2. 0%
  3. 75%
  4. 25% Correct answer.

Explanation

An Aa × Aa cross gives genotype ratios of 1 AA : 2 Aa : 1 aa, so only the aa genotype is affected, giving a probability of one in four. The remaining three quarters have at least one dominant allele and appear unaffected.

Question 37Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which heart chamber ejects oxygenated blood into the aorta?

  1. Left ventricle Correct answer.
  2. Left atrium
  3. Right ventricle
  4. Right atrium

Explanation

The left ventricle receives oxygenated blood from the left atrium and pumps it through the aortic valve into the systemic circulation. The right-sided chambers handle deoxygenated blood destined for the lungs.

Question 38Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

During quiet inspiration, contraction of the diaphragm produces which immediate change?

  1. Thoracic volume rises and intrapulmonary pressure rises
  2. Thoracic volume rises and intrapulmonary pressure falls Correct answer.
  3. Thoracic volume falls and intrapulmonary pressure rises
  4. Thoracic volume falls and intrapulmonary pressure falls

Explanation

Diaphragmatic contraction flattens the dome of the muscle and enlarges the thoracic cavity, so intrapleural and intrapulmonary pressures drop below atmospheric and air flows inward. Volume and pressure move in opposite directions because the gas laws relate them inversely.

Question 39Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Bile, which emulsifies dietary fat, is produced by which organ?

  1. Pancreas
  2. Gallbladder
  3. Liver Correct answer.
  4. Stomach

Explanation

Hepatocytes in the liver secrete bile, which is then stored and concentrated in the gallbladder before release into the duodenum. Emulsification increases the surface area available to pancreatic lipase.

Question 40Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Antidiuretic hormone increases water reabsorption mainly at which site in the nephron?

  1. Ascending limb of the loop of Henle
  2. Proximal convoluted tubule
  3. Glomerulus
  4. Collecting duct Correct answer.

Explanation

Antidiuretic hormone inserts aquaporin-2 water channels into the membranes of collecting duct cells, allowing water to move down its osmotic gradient into the medullary interstitium. This produces small volumes of concentrated urine.

Question 41Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which statement correctly describes a feature that distinguishes viruses from bacteria?

  1. They are killed by antibiotics that block bacterial ribosomes.
  2. They lack ribosomes and cannot make proteins unaided. Correct answer.
  3. They possess a rigid cell wall made of peptidoglycan.
  4. They reproduce independently by binary fission.

Explanation

A virus consists of nucleic acid enclosed in a protein coat and has no ribosomes or energy-generating machinery, so it must use a host cell to translate its genes. Bacteria are complete cells with their own protein-synthesis apparatus.

Question 42Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

In which phase of the cell cycle does DNA replication occur?

  1. S phase Correct answer.
  2. G1 phase
  3. M phase
  4. G2 phase

Explanation

The S phase of interphase is the synthetic period in which each chromosome is copied, doubling the DNA content before division. G1 and G2 are gap phases of growth and checking, and the M phase is when the chromosomes separate.

Question 43Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Which brain region coordinates posture, balance and the smooth execution of learned movements?

  1. Medulla oblongata
  2. Cerebellum Correct answer.
  3. Hypothalamus
  4. Cerebrum

Explanation

The cerebellum compares intended movement with sensory feedback and adjusts motor output, giving coordinated, balanced movement. The cerebral cortex initiates voluntary movement, while the other regions serve vital reflexes and homeostasis.

Question 44Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Facilitated diffusion of glucose across a cell membrane is best characterised as:

  1. Downhill movement through a carrier protein without ATP Correct answer.
  2. Passage through the lipid bilayer without any protein
  3. Bulk transport inside a vesicle formed from the membrane
  4. Movement against a gradient using ATP hydrolysis

Explanation

Facilitated diffusion uses specific membrane proteins to let a solute move down its concentration gradient, so no metabolic energy is spent. Energy-dependent, uphill transport is active transport, not facilitated diffusion.

Question 45Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

What is the principal action of calcitonin on blood calcium concentration?

  1. It raises calcium by stimulating osteoclast activity
  2. It lowers calcium by increasing intestinal calcium absorption
  3. It raises calcium by increasing renal reabsorption of calcium
  4. It lowers calcium by inhibiting osteoclast activity Correct answer.

Explanation

Calcitonin is secreted by thyroid C cells when calcium is high and reduces it by suppressing osteoclast-mediated bone resorption and promoting renal calcium loss. Parathyroid hormone has the opposite effect and is the main day-to-day regulator.

Question 46Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

An autosomal recessive disorder affects 1 in 10,000 newborns in a population at Hardy-Weinberg equilibrium. Approximately what proportion of the population are carriers?

  1. 1 in 10,000
  2. 1 in 200
  3. 1 in 100
  4. 1 in 50 Correct answer.

Explanation

The incidence equals q squared, so q is the square root of 0.0001, which is 0.01; p is therefore 0.99 and the carrier frequency 2pq is about 0.0198, close to 1 in 50. Carriers greatly outnumber affected individuals for rare recessive alleles.

Question 47Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

For each molecule of ATP hydrolysed, the sodium-potassium pump moves which ions across the plasma membrane?

  1. Three sodium ions in and two potassium ions out
  2. One sodium ion out and one potassium ion in
  3. Three sodium ions out and two potassium ions in Correct answer.
  4. Two sodium ions out and three potassium ions in

Explanation

Each cycle of the Na+/K+-ATPase exports three sodium ions and imports two potassium ions, both against their gradients. The unequal charge transfer makes the pump electrogenic and helps maintain the resting membrane potential.

Question 48Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

A resting adult has a heart rate of 75 beats per minute and a stroke volume of 70 mL. What is the cardiac output?

  1. 4.0 L/min
  2. 7.5 L/min
  3. 2.1 L/min
  4. 5.25 L/min Correct answer.

Explanation

Cardiac output equals heart rate multiplied by stroke volume, so 75 beats per minute times 70 mL gives 5250 mL, or about 5.25 litres per minute. This value lies within the normal resting range for an adult.

Question 49Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

A woman with a mitochondrial disorder has children with an unaffected man. Which outcome is expected for the children?

  1. None of the children can inherit the mutation
  2. All of the children may inherit the mutation Correct answer.
  3. Only the sons can inherit the mutation
  4. Only the daughters can inherit the mutation

Explanation

Mitochondrial DNA is inherited almost entirely from the mother because the zygote's mitochondria come from the oocyte, so a mother carrying a mitochondrial mutation can transmit it to both sons and daughters. An affected father does not pass the trait on through this route.

Question 50Biology (cell biology, human anatomy and physiology, genetics, basic microbiology)

Cyanide binds to cytochrome oxidase (complex IV) of the electron transport chain. What is the most direct consequence for the cell?

  1. ATP synthase is stimulated and ATP output rises sharply
  2. Glycolysis is blocked directly because hexokinase is inhibited
  3. Oxidative phosphorylation stops and ATP must come largely from glycolysis Correct answer.
  4. ATP production continues normally because ATP synthase works without the chain

Explanation

Blocking complex IV prevents electron flow and therefore the pumping of protons, so the proton gradient collapses and ATP synthase can no longer make ATP aerobically. Cells then depend on the small yield from anaerobic glycolysis.