Biology
Chemistry
Human Physiology
Organic Chemistry
Physics
100
Organisms which can run metabolic pathways with or without the presence or absence of oxygen are called:
(a) facultative anaerobes
(b) obligate anaerobes
(c) obligate aerobes
(d) protoplasts
(a) facultative anaerobes
(b) obligate anaerobes
(c) obligate aerobes
(d) protoplasts
(a) facultative anaerobes
Explanation: Obligate anaerobes cannot function in the presence of oxygen while obligate aerobes cannot function in the absence of oxygen. Protoplasts are bacteria (or other microorganisms) which have lost their cell walls; this says nothing about their metabolic pathways.
Explanation: Obligate anaerobes cannot function in the presence of oxygen while obligate aerobes cannot function in the absence of oxygen. Protoplasts are bacteria (or other microorganisms) which have lost their cell walls; this says nothing about their metabolic pathways.
100
The concentration of hydroxide in an aqueous solution is 1x10^-3. What is the pH of the solution?
(a) 3
(b) 4
(c) 10
(d) 11
(a) 3
(b) 4
(c) 10
(d) 11
(d) 11
The equation for pOH is –log[OH-]. Inserting the concentration of OH- into the equation, you obtain pOH = 3. The pH of the solution would be 14-pOH = 11. Thus, the correct answer is (D).
The equation for pOH is –log[OH-]. Inserting the concentration of OH- into the equation, you obtain pOH = 3. The pH of the solution would be 14-pOH = 11. Thus, the correct answer is (D).
100
Aplastic anemia is a condition that results in the decreased production of blood cells by the bone marrow. One known cause of aplastic anemia is autoimmune reaction against the bone marrow. A potential treatment is a bone marrow transplant to replace the immune system. Which of the following is an inherent risk associated with such a procedure?
(a) The body will be devoid of an immune system during the transition period from one immune system to the other.
(b) It is exceedingly difficult to oxygenate the body during the transplant due to the cessation of red blood cell production.
(c) Bone integrity decreases during the transplant; this increases the risk of fractures.
(d) The new immune system may mount an autoimmune attack against other tissues of the body.
(a) The body will be devoid of an immune system during the transition period from one immune system to the other.
(b) It is exceedingly difficult to oxygenate the body during the transplant due to the cessation of red blood cell production.
(c) Bone integrity decreases during the transplant; this increases the risk of fractures.
(d) The new immune system may mount an autoimmune attack against other tissues of the body.
(d) The new immune system may mount an autoimmune attack against other tissues of the body.
Explanation: Replacing the immune system of an individual is risky in large part because the new immune system may reject the new body. During the transition period, the body is not devoid of immune system to a relevant degree. Moreover, the time frame of replacement is relatively short and does not pose a serious risk. Oxygenation of the body is also not a large risk especially with the technique of blood transfusions. If RBCs are in very low supplies, there are methods to assist oxygenation. Finally, bone integrity is not likely to decrease significantly because the structure of the bone itself is not noticeably compromised during such a procedure.
Explanation: Replacing the immune system of an individual is risky in large part because the new immune system may reject the new body. During the transition period, the body is not devoid of immune system to a relevant degree. Moreover, the time frame of replacement is relatively short and does not pose a serious risk. Oxygenation of the body is also not a large risk especially with the technique of blood transfusions. If RBCs are in very low supplies, there are methods to assist oxygenation. Finally, bone integrity is not likely to decrease significantly because the structure of the bone itself is not noticeably compromised during such a procedure.
100
The following molecule contains all of which list of functional groups?
(a) amide, ester, alcohol
(b) amine, alcohol, ether, ketone
(c) amine, amide, ketone
(d) amine, ester, alcohol
(a) amide, ester, alcohol(b) amine, alcohol, ether, ketone
(c) amine, amide, ketone
(d) amine, ester, alcohol
(d) amine, ester, alcohol
Explanation: The only nitrogen in the compound is a tertiary amine; it is bonded to three different R groups. The ester is in the center of the molecule; the -O-C=O is a single group, not an ether and ketone. The alcohol is at the top right of the molecule.
Explanation: The only nitrogen in the compound is a tertiary amine; it is bonded to three different R groups. The ester is in the center of the molecule; the -O-C=O is a single group, not an ether and ketone. The alcohol is at the top right of the molecule.
100
A pendulum moves with periodic motion. At the maximal height of motion, it is true that:
(a) Kinetic energy is at a maximum, potential energy is at a minimum
(b) Kinetic energy is at a minimum, potential energy is at a maximum
(c) Both kinetic and potential energies are at a maximum
(d) Both kinetic and potential energies are at a minimum
(a) Kinetic energy is at a maximum, potential energy is at a minimum
(b) Kinetic energy is at a minimum, potential energy is at a maximum
(c) Both kinetic and potential energies are at a maximum
(d) Both kinetic and potential energies are at a minimum
(b) Kinetic energy is at a minimum, potential energy is at a maximum
Explanation: At the maximal height of motion, the pendulum is not moving, thus we see that kinetic energy is zero, and since kinetic energy cannot be negative, it is at a minimum. All of the energy is in the form of potential because the pendulum is at maximal height. At the bottom of motion of the pendulum, i.e. zero displacement, the pendulum has maximal velocity and zero potential energy.
Explanation: At the maximal height of motion, the pendulum is not moving, thus we see that kinetic energy is zero, and since kinetic energy cannot be negative, it is at a minimum. All of the energy is in the form of potential because the pendulum is at maximal height. At the bottom of motion of the pendulum, i.e. zero displacement, the pendulum has maximal velocity and zero potential energy.
200
Which of the following is(are) NOT an example of codominance?
I. a cross between a homozygous long beet and a homozygous round beet producing oval beets
II. a cross between a homozygous red flower and a homozygous white flower producing a spotted white and red flower
III. a cross between a homozygous blue-eyed person with a heterozygous brown-eyed person producing offspring with blue eyes
(a) I only
(b) II only
(c) I and II only
(d) I and III only
I. a cross between a homozygous long beet and a homozygous round beet producing oval beets
II. a cross between a homozygous red flower and a homozygous white flower producing a spotted white and red flower
III. a cross between a homozygous blue-eyed person with a heterozygous brown-eyed person producing offspring with blue eyes
(a) I only
(b) II only
(c) I and II only
(d) I and III only
(d) I and III only
Explanation: A cross between a long beet and a round beet producing oval beets is an example of incomplete dominance since an intermediate between the two alleles is present. The red and white flower producing a spotted flower is an example of codominance since both alleles are present. The blue- and brown-eyed people producing a blue-eyed child is an example of simple or complete dominance.
Explanation: A cross between a long beet and a round beet producing oval beets is an example of incomplete dominance since an intermediate between the two alleles is present. The red and white flower producing a spotted flower is an example of codominance since both alleles are present. The blue- and brown-eyed people producing a blue-eyed child is an example of simple or complete dominance.
200
Under which conditions are gases most soluble in water?
(a) high pressure and high temperature
(b) high pressure and low temperature
(c) low pressure and high temperature
(d) low pressure and low temperature
(a) high pressure and high temperature
(b) high pressure and low temperature
(c) low pressure and high temperature
(d) low pressure and low temperature
(b) high pressure and low temperature
Explanation: Recall Henry's Law that the solubility of a gas is directly proportional to the partial pressure of the gas above the solvent. Hence under high pressure, more gas is dissolved. Note also that Henry's Law involves a constant which is temperature-dependent. Under high temperatures, less gas is dissolved whereas under low temperatures, more gas is dissolved. Alternatively, you can think of a can of soda. The contents are under pressure and if you shake the can before opening, the soda fizzes out all over as you open it. So the higher the pressure, the more gas or more CO2 can be dissolved in the drink. Eliminate choices 3 and 4. Now focus on the temperature. Soda goes flat (loses carbonation or gas) as it warms up. Soda is usually served cold because more of the carbonation or CO2 stays in the drink when the soda is cold.
Explanation: Recall Henry's Law that the solubility of a gas is directly proportional to the partial pressure of the gas above the solvent. Hence under high pressure, more gas is dissolved. Note also that Henry's Law involves a constant which is temperature-dependent. Under high temperatures, less gas is dissolved whereas under low temperatures, more gas is dissolved. Alternatively, you can think of a can of soda. The contents are under pressure and if you shake the can before opening, the soda fizzes out all over as you open it. So the higher the pressure, the more gas or more CO2 can be dissolved in the drink. Eliminate choices 3 and 4. Now focus on the temperature. Soda goes flat (loses carbonation or gas) as it warms up. Soda is usually served cold because more of the carbonation or CO2 stays in the drink when the soda is cold.
200
Which of the following is not a component of a nephron, the functional unit of the kidney?
(a) Loop of Henle
(b) Bowman's Capsule
(c) Distal convoluted tubule
(d) Ureter
(a) Loop of Henle
(b) Bowman's Capsule
(c) Distal convoluted tubule
(d) Ureter
(d) Ureter
Explanation: The ureter leads from the kidneys in to the bladder, but is not part of the nephron. The nephron consists of the Bowman's Capsule, the proximal convoluted tubule, the Loop of Henle, and the distal convoluted tubule.
Explanation: The ureter leads from the kidneys in to the bladder, but is not part of the nephron. The nephron consists of the Bowman's Capsule, the proximal convoluted tubule, the Loop of Henle, and the distal convoluted tubule.
200
The reduction of a 3° alcohol produces what type of structure?
(a) an aldehyde
(b) an alkyne
(c) an alkane
(d) a 2° alcohol
(a) an aldehyde
(b) an alkyne
(c) an alkane
(d) a 2° alcohol
(c) an alkane
Explanation: As a general rule, reduction can involve the loss of oxygen and the gain of hydrogen. A 3° alcohol has carbon that holds the hydroxyl group and three substituted carbon groups. The reduced form of this structure would replace the hydroxyl group with hydrogen, producing an alkane. Thus, the correct answer is (C).
Explanation: As a general rule, reduction can involve the loss of oxygen and the gain of hydrogen. A 3° alcohol has carbon that holds the hydroxyl group and three substituted carbon groups. The reduced form of this structure would replace the hydroxyl group with hydrogen, producing an alkane. Thus, the correct answer is (C).
200
The gravitational force between planets X and Y is F. If both planets double in mass, and the distance between them triples, what is the force between them?
(a) 1/3 F
(b) 4/9 F
(c) 4/3 F
(d) 2/3 F
(a) 1/3 F
(b) 4/9 F
(c) 4/3 F
(d) 2/3 F
b) 4/9 F
Explanation: Using the equation F=Gm1m2/r2, we see that if both masses double, then the force increases 4 times, but if the distance between them is tripled, then the force decreases 9 times, thus 4/9 F is the correct answer.
Explanation: Using the equation F=Gm1m2/r2, we see that if both masses double, then the force increases 4 times, but if the distance between them is tripled, then the force decreases 9 times, thus 4/9 F is the correct answer.
300
RNA can expected to have lower stability as a molecule than DNA due to its
(a) Highly angular conformation
(b) Additional hydroxyl group
(c) Inherent instability of uracil
(d) Differentials in hydrogen bonding between bases.
(a) Highly angular conformation
(b) Additional hydroxyl group
(c) Inherent instability of uracil
(d) Differentials in hydrogen bonding between bases.
(b) Additional hydroxyl group
Explanation: RNA has an additional hydroxyl group in comparison to DNA. This hydroxyl group can participate in a variety of reactions, and thus contributes to the relative instability of RNA when compared to DNA.
Explanation: RNA has an additional hydroxyl group in comparison to DNA. This hydroxyl group can participate in a variety of reactions, and thus contributes to the relative instability of RNA when compared to DNA.
300
A buffer is made for an experiment to a pH of 7.5. The scientist realizes that the volume of the buffer is 5 mL too low, and adds 5 mL of water. What will be the pH of the subsequent solution?
(a) pH < 7
(b) 7 < pH < 7.5
(c) pH = 7.5
(d) pH > 7.5
(a) pH < 7
(b) 7 < pH < 7.5
(c) pH = 7.5
(d) pH > 7.5
(b) 7 < pH < 7.5
Explanation: Water has a pH of 7, i.e. it has a hydronium ion concentration of 10^-7 M. When you add water, you are adding hydronium ions, and while the buffer will be quite successful at maintaining the pH around 7.5, the pH will drop slightly. An easy way to solve this problem is to think hypothetically what would happen if you added a very large amount of water, say 1000 gallons. Then the pH of the solution will be just about 7, the pH of water.
Explanation: Water has a pH of 7, i.e. it has a hydronium ion concentration of 10^-7 M. When you add water, you are adding hydronium ions, and while the buffer will be quite successful at maintaining the pH around 7.5, the pH will drop slightly. An easy way to solve this problem is to think hypothetically what would happen if you added a very large amount of water, say 1000 gallons. Then the pH of the solution will be just about 7, the pH of water.
300
A swimmer holds her breath underwater and swims as far and fast as she can before resurfacing to breathe. At the end of this physical exertion, her blood will
(a) have a lower pH
(b) have a higher pH
(c) have a lower nitrogen concentration
(d) have a lower carbon dioxide concentration
(a) have a lower pH
(b) have a higher pH
(c) have a lower nitrogen concentration
(d) have a lower carbon dioxide concentration
(a) have a lower pH
Explanation: After vigorous exercise and the inability to replenish oxygen in the body, carbon dioxide will build up in the bloodstream. This dissolved CO2 forms a carbonic acid buffer, lowering the pH of the blood.
Explanation: After vigorous exercise and the inability to replenish oxygen in the body, carbon dioxide will build up in the bloodstream. This dissolved CO2 forms a carbonic acid buffer, lowering the pH of the blood.
300
The oxidation of primary alcohols can produce which of the following pairs of products, depending on the reaction?
(a) aldehydes and carboxylic acids
(b) ketones and carboxylic acids
(c) aldehydes and ketones
(d) ketones only
(a) aldehydes and carboxylic acids
(b) ketones and carboxylic acids
(c) aldehydes and ketones
(d) ketones only
(a) aldehydes and carboxylic acids
Explanation: Primary acohols have the formula -CH2OH. Because they do not have two carbons attached to the same carbon as the -OH, they cannot form ketones. The removal of the hydrogen from -OH and formation of a double bond to the carbon will form -CHO which is an aldehyde. Oxidation can also include the removal of the two hydrogens from -CH2OH and their replacement with an oxygen, turning the -CH2OH into -COOH (carboxylic acid).
Explanation: Primary acohols have the formula -CH2OH. Because they do not have two carbons attached to the same carbon as the -OH, they cannot form ketones. The removal of the hydrogen from -OH and formation of a double bond to the carbon will form -CHO which is an aldehyde. Oxidation can also include the removal of the two hydrogens from -CH2OH and their replacement with an oxygen, turning the -CH2OH into -COOH (carboxylic acid).
300
What is the period of a wave if 50 crests pass an unmoving point over the course of 20 seconds?
(a) 1000 seconds
(b) 2.5 seconds
(c) 0.4 seconds
(d) 1/1000 seconds
(a) 1000 seconds
(b) 2.5 seconds
(c) 0.4 seconds
(d) 1/1000 seconds
(c) 0.4 seconds
Explanation: Recall that T = 1/f where T is the period (in seconds) and f is the frequency (in Hz). We divide 50 crests by 20 seconds to get 2.5 crests per second (2.5 Hz). Hence the period is 1/2.5; 0.4 seconds.
Explanation: Recall that T = 1/f where T is the period (in seconds) and f is the frequency (in Hz). We divide 50 crests by 20 seconds to get 2.5 crests per second (2.5 Hz). Hence the period is 1/2.5; 0.4 seconds.
400
Cytotoxic T cells are also known as CD8+ T cells, denoting the presence of CD8. CD8 is a
(a) co-receptor for the T cell receptor (TCR)
(b) analog of the T cell receptor (TCR)
(c) protein that cytotoxic T cells recognize when inducing death in infected target cells
(d) protein that cytotoxic T cells secrete to kill infected target cells
(a) co-receptor for the T cell receptor (TCR)
(b) analog of the T cell receptor (TCR)
(c) protein that cytotoxic T cells recognize when inducing death in infected target cells
(d) protein that cytotoxic T cells secrete to kill infected target cells
(a) co-receptor for the T cell receptor (TCR)
Explanation: CD8 is a transmembrane glycoprotein which is a co-receptor of the TCR (T cell receptor). CD8 helps the receptor recognize target antigens in their environment. The protein is neither an analog of the TCR (as it is one of the components that join the TCR during antigen recognition), nor is it secreted into the environment (since it is a transmembrane protein).
Explanation: CD8 is a transmembrane glycoprotein which is a co-receptor of the TCR (T cell receptor). CD8 helps the receptor recognize target antigens in their environment. The protein is neither an analog of the TCR (as it is one of the components that join the TCR during antigen recognition), nor is it secreted into the environment (since it is a transmembrane protein).
400
A sample of calcium carbonate is immersed in water and does not dissolve. A scientist adds calcium carbonate to 0.1 M NaOH and still the calcium carbonate is insoluble. In 0.1 M HCl, however, the salt dissolves. After neutralization with an equal volume of 0.1 M NaOH, however, the calcium carbonate does not reform.
Which of the following is a product of the reaction of CaCO3 and HCl?
(a) CaCl
(b) H2O
(c) Ca2C
(d) CO
Which of the following is a product of the reaction of CaCO3 and HCl?
(a) CaCl
(b) H2O
(c) Ca2C
(d) CO
(b) H2O
Explanation: Calcium carbonate acts as a base reacting with HCl, an acid. This forms a salt and water. The unbalanced reaction is shown below:
CaCO3 + HCl → CaCl2 + CO2 + H2O
Explanation: Calcium carbonate acts as a base reacting with HCl, an acid. This forms a salt and water. The unbalanced reaction is shown below:
CaCO3 + HCl → CaCl2 + CO2 + H2O
400
Which of the following organs/glands is ventral to the heart in the human body?
(a) Liver
(b) Thymus
(c) Brain
(d) Stomach
(a) Liver
(b) Thymus
(c) Brain
(d) Stomach
(b) Thymus
Explanation: Ventral is equivalent to the front (as opposed to dorsal which refers to the back) on the abdominal plane of the body. Anterior refers to closer to the head or forward end of the body while posterior refers to the rear end of the body. In the human body, the thymus sits behind the sternum. Behind the thymus lies the heart. Hence the heart is dorsal to the thymus; the thymus is ventral to the heart.
Explanation: Ventral is equivalent to the front (as opposed to dorsal which refers to the back) on the abdominal plane of the body. Anterior refers to closer to the head or forward end of the body while posterior refers to the rear end of the body. In the human body, the thymus sits behind the sternum. Behind the thymus lies the heart. Hence the heart is dorsal to the thymus; the thymus is ventral to the heart.
400
Passage: A scientist hypothesizes the existence of the molecule shown below:
Question 2: Treatment of alcohols with Na2CrO7 oxidizes them to ketones and carboxylic acids. Which hydrogens will be removed from the molecule shown above to produce a ketone?
(a) I only
(b) II only
(c) III only
(d) I and III only
Question 2: Treatment of alcohols with Na2CrO7 oxidizes them to ketones and carboxylic acids. Which hydrogens will be removed from the molecule shown above to produce a ketone?
(a) I only
(b) II only
(c) III only
(d) I and III only
(b) II only
Explanation: The oxidation of an alcohol to a ketone involves the replacement of an C-H bond with another C-O bond, yielding a C=O bond. The only hydrogen attached to the same carbon as the -OH group is the II hydrogen.
Explanation: The oxidation of an alcohol to a ketone involves the replacement of an C-H bond with another C-O bond, yielding a C=O bond. The only hydrogen attached to the same carbon as the -OH group is the II hydrogen.
400
A person pushes a 200N cart filled with a 40N weight. After one minute of pushing, the cart has traveled 10 meters. What was the power output of the person?
(a) 20 W
(b) 24 W
(c) 36 W
(d) 40 W
(a) 20 W
(b) 24 W
(c) 36 W
(d) 40 W
(d) 40 W
Explanation: Power = work/time = (force*distance)/time = [(200 N + 40 N)*10 m]/ 60 sec = 40 watts
Explanation: Power = work/time = (force*distance)/time = [(200 N + 40 N)*10 m]/ 60 sec = 40 watts
500
In a distant planet, organisms only contain 5 amino acids and there are only three nucleotides. A codon is composed of five nucleic acids signify an amino acid during translation. In a string of fifteen nucleic acids, how many amino acid strings are possible? Assume that all of the amino acids are different.
(a) 125
(b) 153
(c) 60
(d) 155
(a) 125
(b) 153
(c) 60
(d) 155
(c) 60
Explanation: Fifteen nucleic acids signifies three codons, therefore three amino acids can be coded for. Since all of the amino acids are different, there are a total of 5*4*3 combinations.
Explanation: Fifteen nucleic acids signifies three codons, therefore three amino acids can be coded for. Since all of the amino acids are different, there are a total of 5*4*3 combinations.
500
Which of the following substance would you expect to have the lowest melting point?
(a) H2O
(b) NaCl
(c) Ar
(d) Hg
(a) H2O
(b) NaCl
(c) Ar
(d) Hg
(c) Ar
Explanation: You should be able to answer this question from experience. Consider at STP, Hg and H2O are both liquids. Ar is a gas, and NaCl is a solid. The substance with the lowest melting point, therefore, should be the one that is least organized: the gas (Argon). Hence (C) is the correct answer.
Explanation: You should be able to answer this question from experience. Consider at STP, Hg and H2O are both liquids. Ar is a gas, and NaCl is a solid. The substance with the lowest melting point, therefore, should be the one that is least organized: the gas (Argon). Hence (C) is the correct answer.
500
How many of the following are important factors in blood clotting?
Platelets
Thrombin
Aspirin
Dicumarol
Calcium ions
Fibrin
Basophils
(a) all of the above
(b) none of the above
(c) 3 of the above
(d) 4 of the above
Platelets
Thrombin
Aspirin
Dicumarol
Calcium ions
Fibrin
Basophils
(a) all of the above
(b) none of the above
(c) 3 of the above
(d) 4 of the above
(d) 4 of the above
Explanation: Blood clotting involves the actions of platelets, thrombin, calcium ions, and fibrin. Aspirin and dicumarol are both anti-coagulant agents. Basophils are leukocytes that contain heparin, which slows blood clotting.
Explanation: Blood clotting involves the actions of platelets, thrombin, calcium ions, and fibrin. Aspirin and dicumarol are both anti-coagulant agents. Basophils are leukocytes that contain heparin, which slows blood clotting.
500
Which of the following is most reactive with HCl?
(a) trans but-2-ene
(b) prop-1-ene
(c) cis but-2-ene
(d) but-1-ene
(a) trans but-2-ene
(b) prop-1-ene
(c) cis but-2-ene
(d) but-1-ene
(b) prop-1-ene
Explanation: Each choice is an alkene. HCl would undergo electrophilic addition with each of the alkenes. However, according to Markovnikov’s rule, the most stable carbocation intermediate would be formed when the hydrogen from HCl adds to the least substituted carbon in the alkene double bond. Choices (B) and (D) both contain a carbon containing 2 hydrogens. However, the reaction with (B) would occur faster because the ethyl group of the carbocation would be smaller (than the propyl of the carbocation from (D)), thus create less resistance for the addition of Cl-. Thus, the correct answer is (B).
Explanation: Each choice is an alkene. HCl would undergo electrophilic addition with each of the alkenes. However, according to Markovnikov’s rule, the most stable carbocation intermediate would be formed when the hydrogen from HCl adds to the least substituted carbon in the alkene double bond. Choices (B) and (D) both contain a carbon containing 2 hydrogens. However, the reaction with (B) would occur faster because the ethyl group of the carbocation would be smaller (than the propyl of the carbocation from (D)), thus create less resistance for the addition of Cl-. Thus, the correct answer is (B).
500
On which of the following surfaces would a moving sled encounter the least friction?
I. Coefficient of static friction: 0.60
Coefficient of kinetic friction: 0.40
II. Coefficient of static friction: 0.40
Coefficient of kinetic friction: 0.40
III. Coefficient of static friction: 0.50
Coefficient of kinetic friction: 0.50
(a) I only
(b) II only
(c) I and II
(d) I, II, and III
I. Coefficient of static friction: 0.60
Coefficient of kinetic friction: 0.40
II. Coefficient of static friction: 0.40
Coefficient of kinetic friction: 0.40
III. Coefficient of static friction: 0.50
Coefficient of kinetic friction: 0.50
(a) I only
(b) II only
(c) I and II
(d) I, II, and III
(c) I and II
Explanation: Since the sled is moving, the important number is the coefficient of kinetic friction. Since I and II have the same coefficient of kinetic friction, we would expect them to give the same friction the sled is in motion.
Explanation: Since the sled is moving, the important number is the coefficient of kinetic friction. Since I and II have the same coefficient of kinetic friction, we would expect them to give the same friction the sled is in motion.