Answer choice C is true because glucose and amino acids are picked up by the blood while fats are picked up by lacteals, which are special vessels that connect with the lymphatic system.
Trang 1MCAT Subject Tests
Dear Future Doctor,
The following Subject Test and explanations contains questions not in test format and should be used to practice and to assess your mastery of the foundation content necessary for success on the MCAT Simply memorizing facts is not sufficient to achieve high scores; however, an incomplete understanding of basic science knowledge will limit your ability to think critically Think of building your content knowledge as learning the vocabulary and practicing MCAT-like questions as actually speaking
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Sincerely,
Albert Chen
Executive Director, Pre-Health Research and Development
Kaplan Test Prep
© 2003 Kaplan, Inc
All rights reserved No part of this book may be reproduced in any form, by Photostat, microfilm, xerography or any other means, or incorporated into any information retrieval system, electronic
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distributed or resold, pursuant to the terms of your Kaplan Enrollment Agreement
Trang 2Biology Subject Test 3
1 Which enzyme changes disaccharides to
monosaccharides?
A Lactase
B Kinase
C Zymogen
D Lipase
E Phosphorylase
2 A heart beat is initiated by the pacemaker, which is
A also known as the atrioventricular (AV) node
B also known as the sinoatrial node
C located in the wall of the right ventricle
D functionally dependent upon nervous
stimulation
E located in the brain
3 In the digestive system, all of the following are true
except
A digestive enzymes from the pancreas are released
via a duct into the duodenum
B peristalsis is a wave of smooth muscle
contraction that proceeds along the digestive
tract
C in the small intestine, villi absorb nutrients into
both the lymphatic and circulatory systems
D the low pH of the stomach is essential for the
function of carbohydrate digestive enzymes
E the release of bile from the gall bladder is
triggered by the hormone cholecystokinin
4 In the kidney
A nephrons are located only in the cortex of the
organ
B ammonia is converted to urea
C both glucose and water are actively reabsorbed
from the glomerular filtrate
D antidiuretic hormone causes the reabsorption of
water from the collecting tubule
E filtration of the blood begins at the glomerulus
and ends at the loop of Henle
5 Which of the following statements about blood is false?
A Mature red blood cells are not nucleated
B Blood platelets are involved in the clotting process
C The adult spleen is a site of red blood cell development
D White blood cells are capable of phagocytosing foreign matter
E New red blood cells are constantly developing in the bone marrow
6 In the nervous system
A myelination of nerves permits faster rates of impulse conductance
B an excitatory neurotransmitter causes hyperpolarization of the post-synaptic membrane
C the autonomic nervous system mediates voluntary functions
D during an action potential, first K+ rushes in
E during an action potential, first K+ rushes out of the cell and then Na+ rushes in
7 Which of the following is a normal pathway of blood flow?
A Right ventricle to aorta
B Pulmonary veins to left atrium
C Inferior vena cava to left atrium
D Pulmonary veins to left ventricle
E Left ventricle to pulmonary artery
8 Which of the following associations of brain structure and function is false?
A Hypothalamus : appetite
B Cerebellum : motor coordination
C Cerebral cortex : higher intellectual function
D Reticular activating system : sensory processing
E Medulla : basic emotional drives
Trang 39 Which pairing of digestive enzyme and type of
substrate is incorrect?
A Ptyalin (salivary amylase) : proteins
B Chymotrypsin : proteins
C Carboxypeptidase : proteins
D Pancreatic amylase : carbohydrates
E Pancreatic lipase : fats
10 Which of the following statements about muscles is
false?
A During isometric contraction the length of the
muscle is constant
B During isotonic contraction the length of the
muscle shortens
C In a resting muscle there is complete relaxation
D Tonus is the state of partial contraction that
occurs in the resting muscle
E Tetanus is a condition of sustained contraction
due to an overlap of twitch impulses
11 Which statement about the respiratory system is NOT
true?
A Ciliated nasal membranes warm, moisten, and
filter inspired air
B Contraction of the diaphragm enlarges the
thoracic cavity
C When the thoracic cavity enlarges, the pressure
of air within the lungs falls
D When the pressure of air within the lungs is less
than the atmospheric pressure, air will flow out
of the lungs
E The respiratory process consists of inspiratory
and expiratory acts following one another
12 All of the following statements about hormones are
true EXCEPT
A they are transported by the circulatory system
B they bind to receptors on target cells
C they must be present in large quantities to have
an effect
D they are secreted by endocrine glands
E they can affect organs of the body that are far
removed from their site of synthesis
13 Which statement about the menstrual cycle is false?
A FSH causes the development of the primary follicle
B LH causes the graafian follicle to undergo ovulation
C The corpus luteum develops from the remains of the post-ovulatory graafian follicle
D As a follicle develops, it produces estrogen
E FSH and LH are both posterior pituitary secretions
14 Which statement about pancreatic endocrine function
is FALSE?
A Glucagon and insulin are both produced by islets
of Langerhans cells
B Glucagon and insulin are mutually antagonistic
in their behavior
C Glucagon and insulin both cause glucose to be removed from the bloodstream and stored as glycogen
D Glucagon causes an elevation in the level of serum glucose
E Insulin causes a decrease in the level of serum glucose
15 Which of the following is an incorrect pairing of an endocrine gland and hormone secretion?
A Posterior pituitary : LH
B Adrenal cortex : aldosterone
C Anterior pituitary : TSH
D Adrenal medulla : epinephrine
E Hypothalamus : FSH-releasing factor
16 What is the correct order that the body uses energy sources?
A glucose ∅ fats ∅ proteins ∅ other carbohydrates
B glucose ∅ other carbohydrates ∅ proteins ∅ fats
C glucose ∅ other carbohydrates ∅ fats ∅ proteins
D fats ∅ glucose ∅ other carbohydrates ∅ proteins
E fats ∅ proteins ∅ glucose ∅ other carbohydrates
Trang 417 Which statement about human gamete production is
false?
A In the testes, sperm develop in the seminiferous
tubules
B In the ovaries, eggs develop in the ovarian
follicles
C FSH stimulates gamete production in both sexes
D Gametes arise via meiosis
E The result of meiosis in females is the
production of four egg cells
18 Which of the following statements about evolution is
correct?
A Lamarck's theory of use and disuse adequately
describes why giraffes have long necks
B Darwin's theory of natural selection relies solely
on genetic mutation
C Darwin's theory explains the evolution of man
from present day apes
D Darwin's theory of natural selection relies solely
on environmental conditions
E Natural selection is the process in which random
mutations are selected for survival by the
environment
19 Where are amino acids absorbed?
A small intestine
B large intestine
C gall bladder
D stomach
E rectum
20 The hormone progesterone
A stimulates follicle growth
B shuts off FSH production
C prepares the uterus for implantation of the
zygotes
D is solely responsible for the maintenance of
secondary sex characteristics
E is produced by the anterior pituitary
21 To ensure survival of their species, animals that do not care for their young must
A have the ability to live in water and on land
B lay eggs
C produce many offspring
D have protective coloring
E have internal fertilization
22 Cerebellum damage will most likely
A impair memory
B impair coordination and equilibrium
C impair sense perception
D impair pituitary function
E impair breathing function
23 Basal metabolism disorders are most likely caused most directly by
A impairment of the pituitary
B impairment of the gonads
C impairment of the thyroid
D impairment of the thymus
E impairment of the parathyroid
24 In the adult man, red blood cells are
A non-nucleated and cannot repair themselves
B replaced in the liver
C outnumbered by white blood cells in the circulation
D made in the spleen
E sites of rapid protein synthesis
25 Which of the following is NOT reabsorbed from the glomerular filtrate?
A glucose
B Na+
C Cl
-D K+
E amino acids
Trang 526 Estrogen
A maintains female secondary sex characteristics
B promotes development of the follicle
C induces the ruptured follicle to develop into the
corpus luteum
D lowers blood glucose
E stimulates testosterone synthesis in males
27 You've just been stopped for going 90mph in a 55mph
zone and this tickets means your license will be
suspended As the police officer approaches your car,
which of the following is NOT occurring?
A Increased blood pressure
B Increased heart rate
C Dilated bronchioles
D Release of acetylcholine into the blood
E Increased pupil diameter
28 The oxygen content is greatest in the fluid in which
of the following structures?
A Pulmonary artery
B Thoracic duct
C Right atrium
D Left ventricle
E Inferior vena cava
29 What is the correct sequence of passages that air
travels through during exhalation?
A alveoli ∅ bronchi ∅ bronchioles ∅ trachea
∅ pharynx
B alveoli ∅ bronchi ∅ lungs ∅ trachea ∅ pharynx
C alveoli ∅ trachea ∅ bronchi ∅ larynx ∅ pharynx
D alveoli ∅ bronchi ∅ trachea ∅ larynx ∅ pharynx
E alveoli ∅ bronchi ∅ trachea ∅ pharynx ∅ larynx
30 The rate of breathing is controlled by involuntary
centers in the
A cerebrum
B cerebellum
C medulla oblongata
D spinal cord
E hypothalamus
31 Bones are connected to each other by connective tissue known as
A sockets
B tendons
C ligaments
D synovia
E muscles
32 Examples of environmental factors affecting the way
a gene is expressed include all of the following except
A Drosophila with a given set of genes have
crooked wings at low temperatures and straight wings at high temperatures
B the change in hair color of the Himalayan hare after cooling the naturally warm portions
C the production of heat shock proteins in a cell after an increase in temperature
D a decrease in temperature causing shivering
E All of the above
33 Which of the following is not a disorder of the eye?
A Myopia
B Hypermetropia
C Glaucoma
D Cataracts
E All of the above are disorders of the eye
34 Which statement concerning the pituitary gland is false?
A The anterior pituitary secretes hormones involved
in the menstrual cycle
B The posterior pituitary directs the action of the thyroid gland
C The hypothalamus secretes factors that cause the release of anterior pituitary hormones
D Growth hormone is an anterior pituitary secretion
E The posterior pituitary can affect blood pressure
35 Which of the following is not a lipid derivative?
A Waxes
B Steroids
C Carotenoids
D Albumins
E Lecithin
Trang 636 Which of the following statements about viruses is
NOT true?
A The genetic material may be DNA or RNA
B The virus may replicate in a bacterial host
C The virus may replicate in a eukaryotic host
D The virus may replicate autonomously in the
absence of a host
E The protein coat of the virus does not enter a
host bacterial cell
37 In the kidney, blood filtered through the glomerulus
does not normally contain
A glucose
B amino acids
C blood cells
D sodium ions
E potassium ions
38 According to Starling's hypothesis of capillary
physiology, which of the following is true?
A The hydrostatic pressure is lower at the arteriolar
end
B The osmotic pressure tends to keep fluid out of
the vessel
C Filtration occurs where the hydrostatic pressure
is less than the osmotic pressure
D The ultrafiltrate is returned to the bloodstream
by the lymphatic system
E None of the above
39 Renin is a polypeptide produced
A in response to decreased blood pressure
B in response to increased blood volume
C in response to a concentrated urine
D which acts on the pituitary gland
E in the proximal convoluted tubules of the kidney
40 Which statement about acetylcholine (ACh) is NOT true?
A ACh is released at the neuromuscular junction
B ACh binds to specific receptors on the post-synaptic membrane
C In a synaptic cleft there are enzymes that degrade ACh
D ACh diffuses through the pre-synaptic membrane after its synthesis
E A synapse that is subjected to many action potentials may be depleted of ACh granules
STOP! END OF TEST
Trang 7BIOLOGY SUBJECT TEST 3
ANSWER KEY
1 A
2 B
3 D
4 D
5 C
6 A
7 B
8 E
9 A
10 C
11 D
12 C
13 E
14 C
15 A
16 C
17 E
18 E
19 A
20 C
21 C
22 B
23 C
24 A
25 D
26 A
27 D
28 D
29 D
30 C
31 C
32 D
33 E
34 B
35 D
36 D
37 C
38 D
39 A
40 D
Trang 8EXPLANATIONS
Lactase breaks lactose into glucose and galactose Answer choice B is incorrect because kinase is an enzyme that phosphorylates its substrate Answer choice C is incorrect because zymogen is an enzyme that is secreted in an inactive form The zymogen is cleaved under certain physiological conditions to the active form of the enzyme Important
examples of zymogens include pepsinogen, trypsinogen, and chymotrypsinogen, which are cleaved in the digestive tract to yield the active enzymes pepsin, trypsin, and chymotrypsin Answer choice D is incorrect because lipase breaks down lipids into free fatty acids Answer choice E is incorrect because phosphorylase removes a phosphate from its substrate
The heartbeat is initiated by the sinoatrial (SA) node located in the wall of the right atrium and travels through the atria It is regulated but not controlled by the accelerator nerve (sympathetic) and the vagus nerve (parasympathetic) It is then picked up by the AV node which signals the bundle of His (AV bundle) which transports the contraction through the ventricles via the Purkinje fibers Answer choice A is incorrect because while the AV node does have contractile ability and controls the contraction of the ventricles, it does not control the contraction of the entire heart and is not as regular as the signal from the SA node Answer choices C and D are not correct because the SA node is located in the wall of the right atrium and is not functionally dependent upon nervous stimulation as this tissue initiates the heartbeat although it can be modified by the nervous system
The low pH of the stomach is essential for the function of the enzymes that break down proteins into their amino acids Answer choice A is true: amylases, lipases, and bicarbonate are released through the pancreatic duct Answer choice B is true: peristalsis propels food and waste through the system Answer choice C is true because glucose and amino acids are picked up by the blood while fats are picked up by lacteals, which are special vessels that connect with the lymphatic system Answer choice E is true because cholecystokinin is a hormone released by the wall of the small
intestine due to the presence of acidic chyme from the stomach It stimulates the gall bladder to release bile and the pancreas to release digestive enzymes Both secretions are released into the duodenum
ADH is released by the posterior pituitary gland and causes the collecting tubule to be more permeable to water Therefore, more water is absorbed and urine becomes more concentrated Answer choice A is incorrect because in the nephrons, the glomerulus, Bowman's capsule, and the proximal and distal convoluted tubule are in the cortex while the loop of Henle and the collecting tubule are in the medulla Answer choice B is incorrect because ammonia is transformed into urea in the liver and excreted by the kidney Answer choice C is incorrect because salts, glucose, and amino acids are reabsorbed by active transport while water is reabsorbed by diffusion Answer choice E is incorrect because filtration only occurs at the glomerulus and Bowman's capsule
In the adult, all hematopoiesis occurs in the bone marrow In the fetus, hematopoiesis occurs in the fetal liver The spleen acts as a reservoir for red blood cells and filters the blood Answer choice A is true because mature red blood cells are not nucleated in order to create more space for hemoglobin Answer choice B is incorrect because blood platelets are crucial for the clotting of blood, and answer choice D is incorrect because certain white blood cells such as macrophages and neutrophils engulf foreign matter, and answer choice E is incorrect because new blood cells are continually being produced in the bone marrow to replace the cells after their life span of 120 days has ended
Trang 96 A
Myelin is a fatty compound that surrounds the axons and has been compared to insulation on a wire It speeds conduction along the nerve cell, and is produced by Schwann cells Answer choice B is incorrect because depolarization actually occurs after release of an excitatory neurotransmitter Hyperpolarization actually makes it more difficult for an action potential to occur Answer choice C is incorrect because the autonomic nervous system is made up of the
sympathetic and parasympathetic nervous systems and regulates involuntary actions with opposing results Answer choices D and E are incorrect because sodium channels open first and Na+ rushes in, then K+ channels open and release potassium out of the cell
Blood traveling from the left ventricle will flow into the aorta, then go to all areas of the body except the lungs For example, blood in the brachiocephalic artery will travel to the head and the shoulders, and blood in the renal artery will travel to the kidney to be filtered Blood will go from these arteries into arterioles, then capillaries, where food, waste, and energy will be exchanged Then the blood will go into venules and collect in veins, and will be transported to the superior and inferior vena cavae This makes up the systemic circulation Then the blood will enter the right atrium and flow into the right ventricle After this it will be transported to the lungs via the pulmonary artery where capillary beds will
surround the alveoli so gas exchange can occur Then the pulmonary veins will bring it back to the left atrium to start the process over again This is known as pulmonary circulation Looking at the answer choices, only B follows this flow chart
The medulla monitors blood carbon dioxide levels and pH, and adjusts breathing, temperature, and heart rate It is also the center for reflex activities such as coughing, sneezing, and swallowing Answer choice A is true because the hypothalamus is the center that controls thirst, hunger, sleep, blood pressure, and water balance Answer choice B is true because the cerebellum controls muscle coordination and tone, and maintains posture Answer choice C is true because the cerebral cortex is the center for vision, hearing, smell, voluntary movement, and memory Answer choice D is true because the reticular activating system receives and sorts sensory input
Salivary amylase digests starch into maltose All the other enzymes are correctly paired with their substrates
Even in resting muscles there is a slight contraction known as tonus Answer choice A is true because in isometric contraction, there is constant length and an increase in muscle tension Answer choice B is true because in isotonic contraction, the muscle shortens while the tension remains constant Answer choice D is true because tonus is the partial sustained contraction in relaxed muscles Answer choice E is true because in tetanus, there is no complete recovery before the next sustained contraction This will cause muscle contraction until fatigue because of lack of energy or a build up of waste occurs
Answer choice D is false and therefore the correct answer because when the pressure of air within the lungs is less than atmospheric, air actually rushes into the lungs Answer choices B and C are correct because there is low pressure inside the thoracic cavity due to the expansion of the thoracic volume when the diaphragm contracts Answer choice A is true because when this pressure drops, air rushes in and the ciliated membranes warm, moisten, and filter the inspired air Air then travels through the bronchi, into the bronchioles and finally into the alveoli where diffusion occurs to oxygenate the blood and release CO2 carried back from the tissue
Trang 1012 C
Hormones are capable of being effective at picomolar concentrations Answer choices A and D are true because they are transported by the circulatory system after being secreted by the endocrine (ductless) glands Answer choice E is true because they may travel far from their site of synthesis to have an effect on their target organ Answer choice B is true because cells will respond to hormones only if they have the appropriate receptor on their cell surface in the case of peptide hormones, or inside their cytoplasm in the case of steroid hormones
FSH and LH are secreted by the anterior pituitary, and affect the maturation of the follicle FSH stimulates the production of estrogen, and aids in the maturation of the primary follicle LH causes the corpus luteum to secrete
progesterone, which causes the uterine lining to thicken to prepare for implantation
The pancreas is a dual organ with both endocrine and exocrine functions Its exocrine function is to release digestive enzymes and bicarbonate into the small intestine via the pancreatic duct Its endocrine function is to release insulin, produced by the b cells in the islets of Langerhans, and glucagon, produced by a cells, into the bloodstream These
antagonistic molecules work together to regulate levels of blood glucose Insulin causes a decrease of blood glucose by stimulating the formation of glycogen Glucagon causes an increase in blood glucose by catabolizing the breakdown of glycogen into glucose
The posterior pituitary only secretes ADH and oxytocin Answer choice B is correct because the adrenal cortex does secrete aldosterone, which is a mineral cortisone that causes the increase of absorption of Na+ Answer choice C is correct because the anterior pituitary does secrete TSH, which stimulates thyroid production of thyroxin, which raises the basal metabolic rate Answer choice D is correct because the adrenal medulla does secrete epinephrine, which increases heart rate and blood pressure, and the flow of the blood to skeletal muscle Answer choice E is correct because the
hypothalamus secretes FSH-releasing factor, which stimulates the anterior pituitary
When glucose supplies run low, the body utilizes other energy sources These sources are used by the body in the following preferential order: other carbohydrates, fats, and proteins These substances are first converted to either glucose
or glucose intermediates, which can then be degraded in the glycolytic pathway and the citric acid cycle Proteins are the last resource for energy because there is no protein storage in the body Utilization of protein results in muscle wasting and connective tissue breakdown, which can be harmful in the long term
Oogenesis produces only one viable egg and two or three polar bodies This is a result of unequal distribution of the cytoplasm during meiosis Answer choice A is true because interstitial cells are stimulated by LH to produce testosterone FSH and testosterone then cause the development of sperm in the seminiferous tubules Answer choice B is true because eggs develop in follicles in the ovaries under the control of FSH Answer choice C is true because obviously FSH plays a role in gamete production in both sexes Answer choice D is true because gametes become haploid through reductional division (meiosis) in which a diploid cell gives rise to four haploid sperm or one haploid egg and two or three polar bodies