MCAT
ANATOMY
BIOCHEM
SYSTEMS
GENETICS/ETHICS
100
Which organelle in a plant cell is responsible for photosynthesis?
A) Mitochondria
B) Nucleus
C) Chloroplast
D) Ribosome
C) Chloroplast
100
The trachea (windpipe) splits into two smaller tubes that go to the lungs. What are these two tubes called?
A) Bronchi
B) Alveoli
C) Diaphragm
D) Esophagus
A) Bronchi
100
A 16-year-old boy is brought to the emergency department after eating a large amount of candy. He feels shaky, sweaty, and confused. Blood glucose is measured at 65 mg/dL. Which of the following best explains why his blood sugar dropped?
A) Increased insulin release after high sugar intake
B) Decreased insulin release
C) Increased glucagon release
D) Decreased enzyme activity in the liver
A) Increased insulin release after high sugar intake
100
A 55-year-old man suddenly feels severe chest pain that spreads to his left arm. He is sweating and feels nauseous. Which of the following body systems is most likely affected?
A) Respiratory system
B) Cardiovascular system
C) Digestive system
D) Nervous system
B) Cardiovascular system
100
During a severe influenza outbreak, a hospital has only one remaining ventilator. Two patients need it immediately:
• Patient A: 34-year-old mother of two with no chronic conditions
• Patient B: 68-year-old retired physician with mild COPD
Which of the following factors should be the primary consideration when deciding who receives the ventilator?
A) The patient who is younger and has dependent children
B) The patient who has contributed more to society (physician vs. mother)
C) First-come, first-served basis
D) Likelihood of survival and expected duration of benefit from the ventilator
D) Likelihood of survival and expected duration of benefit from the ventilator
200
Chronic granulomatous disease (CGD) is a primary immunodeficiency defect of NADPH oxidase in which the body is unable to create free radicals to cause oxygen-dependent killing of pathogens. Which of the following is true?
A) Providing bacterial catalase will resolve the problem
B) Providing O₂ will resolve the problem
C) Providing H₂O₂ will resolve the problem
D) Providing NADH will resolve the problem
C) Providing H₂O₂ will resolve the problem
200
Which of the following organs is protected by the rib cage and located on the left side of the body?
A) Liver
B) Spleen
C) Stomach
D) Kidney
B) Spleen
200
A 24-year-old woman is diagnosed with lactose intolerance. She experiences bloating and diarrhea after drinking milk. Which of the following is most directly responsible for her symptoms?
A) Deficiency of the enzyme that breaks down lactose into glucose and galactose
B) Overproduction of the enzyme that digests proteins
C) Lack of the transport protein for fatty acids
D) Deficiency of the enzyme that breaks down starch
A) Deficiency of the enzyme that breaks down lactose into glucose and galactose
200
A 14-year-old girl with asthma suddenly has trouble breathing after playing soccer. Her airways become narrow and produce extra mucus. Which of the following best describes what is happening in her respiratory system?
A) Her lungs are filling with fluid
B) Her bronchi are constricting (getting narrower)
C) Her heart is beating too fast
D) Her diaphragm is not moving properly
B) Her bronchi are constricting (getting narrower)
200
A 45-year-old man is diagnosed with terminal pancreatic cancer. His wife begs the physician, “Please don’t tell him he is dying. It will destroy him.” The patient has previously told the physician he wants to know everything about his condition. The physician should:
A) Respect the wife’s wishes and withhold the diagnosis
B) Tell the patient the diagnosis because he has a right to know
C) Tell the patient only if he directly asks about his prognosis
D) Ask the hospital ethics committee to mediate
B) Tell the patient the diagnosis because he has a right to know
300
A ball is dropped from a height of 20 meters on Earth. Ignoring air resistance, which of the following is true about its motion? (Acceleration due to gravity = 10 m/s²)
A) The ball’s speed increases by 10 m/s every second
B) The ball’s speed stays constant at 20 m/s
C) The ball accelerates at 20 m/s²
D) The ball’s acceleration decreases as it falls
A) The ball’s speed increases by 10 m/s every second
300
A student breaks their forearm bone on the thumb side. Which of the following structures is located right next to this bone in the forearm?
A) Femur
B) Ulna
C) Radius
D) Humerus
B) Ulna
300
A 7-year-old boy is found to have sickle cell disease. His red blood cells become misshapen and get stuck in small blood vessels. This disease is caused by a change in the amino acid sequence of hemoglobin. Which level of protein structure is primarily affected in this condition?
A) Primary structure
B) Secondary structure
C) Tertiary structure
D) Quaternary structure
A) Primary structure
300
A 17-year-old girl is complaining of pain with menses. The physician knows that prostaglandin production, causing uterine spasm, is the cause of her pain. Which drug should the physician prescribe to inhibit the production of prostaglandins?
A) Morphine
B) Lisinopril
C) Ibuprofen
D) Diazepam
C) Ibuprofen
300
A 4-year-old boy is brought in because he bruises easily and has had several episodes of prolonged bleeding after minor injuries. His maternal grandfather had the same problem, but his mother and two sisters are unaffected. Which of the following is the most likely inheritance pattern of this disorder?
A) Autosomal dominant
B) Autosomal recessive
C) X-linked dominant
D) X-linked recessive
D) X-linked recessive
400
A student adds baking soda (sodium bicarbonate) to vinegar (acetic acid) and observes fizzing. Which of the following best explains the observation?
A) A physical change occurred with no new substances formed
B) An acid-base reaction produced carbon dioxide gas
C) The baking soda dissolved without reacting
D) The temperature of the mixture decreased significantly
B) An acid-base reaction produced carbon dioxide gas
400
During a sports injury, a player is hit hard in the front of the neck. Which of the following structures is most likely to be injured, causing difficulty breathing or speaking?
A) Spinal cord
B) Thyroid gland
C) Larynx (voice box)
D) Carotid artery
C) Larynx (voice box)
400
A 32-year-old man who is a strict vegetarian for many years presents with fatigue and tingling in his hands and feet. Laboratory tests show large, immature red blood cells (macrocytic anemia). Which of the following biochemical processes is most likely impaired due to his dietary deficiency?
A) Glycolysis
B) DNA synthesis
C) Protein digestion
D) Oxygen transport in blood
B) DNA synthesis
400
A patient has a stroke in the area indicated by the arrow
Which function would be impaired?
A) vision
B) hearing
C) personality
D) language
C) personality
400
A couple has a child with cystic fibrosis, an autosomal recessive disorder. They are both carriers. They now have a second child who is healthy. What is the probability that this healthy child is also a carrier of the cystic fibrosis mutation?
A) 1/4
B) 1/2
C) 2/3
D) 1
C) 2/3
500
Scientists studied the effect of temperature on enzyme activity using catalase (an enzyme found in potatoes that breaks down hydrogen peroxide into water and oxygen). They measured the rate of oxygen gas production at different temperatures.
Results:
- At 0°C: very slow reaction
- At 37°C: fastest reaction
- At 60°C: very slow reaction again
Which of the following is the best explanation of these results?
A) The enzyme works best at very high temperatures because heat provides more energy
B) At 37°C the enzyme has its optimal shape; too low or too high temperatures change the enzyme’s shape and reduce its activity
C) The reaction slows at high temperatures because there is less oxygen available in the air
D) Catalase only works in cold conditions and is destroyed by warmth
B) At 37°C the enzyme has its optimal shape; too low or too high temperatures change the enzyme’s shape and reduce its activity
500
A 19-year-old college football player is tackled and lands directly on his right shoulder. He is unable to abduct his arm beyond 15 degrees and has numbness over the lateral aspect of his upper arm. Imaging confirms a fracture of the surgical neck of the humerus. Which of the following structures has most likely been injured?
A) Axillary nerve
B) Suprascapular nerve
C) Radial nerve
D) Musculocutaneous nerve
A) Axillary nerve
500
A 19-year-old college student is studying late at night and drinks several energy drinks containing high amounts of caffeine. Caffeine inhibits the breakdown of cyclic AMP (cAMP) inside cells. Which of the following is the most likely result of increased cAMP levels in liver cells?
A) Decreased protein synthesis
B) Increased storage of glucose as glycogen
C) Decreased fat breakdown
D) Increased breakdown of glycogen to release glucose into the blood
D) Increased breakdown of glycogen to release glucose into the blood
500
A 10-year-old boy gets a deep cut on his hand while playing outside. The area becomes red, warm, and swollen after two days. Which of the following best describes the body’s response in this situation?
A) The immune system is sending white blood cells to fight a possible infection
B) The nervous system is causing increased pain signals
C) The digestive system is releasing extra enzymes
D) The circulatory system is shutting down blood flow to the area
A) The immune system is sending white blood cells to fight a possible infection
500
A newborn girl is noted to have slanted palpebral fissures, a single palmar crease, and a gap between her first and second toes. She is diagnosed with Trisomy 21. Which of the following best explains the mechanism of this condition?
A) Point mutation in a single gene
B) Nondisjunction during meiosis
C) Deletion of a segment of a chromosome
D) Trinucleotide repeat expansion
B) Nondisjunction during meiosis