Which of the following types of cells produce and release antibodies?
A. Natural killer cells
B. Cytotoxic T-cells
C. Plasma B cells
D. Helper T-cells
Plasma B cells.
Antibodies are produced by specialized white blood cells called B lymphocytes (or B cells).
When an antigen binds to the B-cell surface, it stimulates the B cell to divide and mature into a group of identical cells called a clone.
The mature B cells, called plasma cells, secrete millions of antibodies into the bloodstream and lymphatic system.
Choice A, Natural killer cells, is not the correct answer because natural killer cells are a type of white blood cell that play a major role in the host-rejection of both tumors and virally infected cells.
Choice B, Cytotoxic T-cells, is not the correct answer because cytotoxic T-cells are a type of white blood cell that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways.
Choice D, Helper T-cells, is not the correct answer because helper T-cells are a type of white blood cell that play an important role in the immune system by helping other white blood cells fight infections.
Therefore, the Correct Answer is C.
More Questions on TEAS 7 Science
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Q #1: Which of the following is the atomic number of an atom that has 12 protons and 12 neutrons?
A. 24
B. 12
C. 1
D. 144
Answer Explanation
The atomic number of an atom is equal to the number of protons in its nucleus.
In this case, the atom has 12 protons, so its atomic number is 12.
Choice A, 24, is not the correct answer because it represents the sum of the number of protons and neutrons in the atom’s nucleus, which is known as the mass number.
Choice C, 1, is not the correct answer because it does not represent the number of protons in the atom’s nucleus.
Choice D, 144, is not the correct answer because it represents the square of the mass number and does not represent any property of the atom.
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Q #2: Which of the following is the structure through which blood exits the glomerulus?
A. Efferent arteriole
B. Proximal tubule
C. Distal tubule
D. Afferent arteriole
Answer Explanation
The glomerulus is the main filtering unit of the kidney.
It is formed by a network of small blood vessels (capillaries) enclosed within a sac called the Bowman’s capsule.
The blood supply to the glomerulus is provided via the afferent arteriole.
The blood then flows through the capillary network, where it gets filtered, and then leaves the glomerulus via the efferent arteriole.
Choice B.
Proximal tubule is not correct because it is where the ultrafiltrate collected in the Bowman’s space drains directly into.
Choice C.
Distal tubule is not correct because it is not mentioned in relation to blood exiting the glomerulus.
Choice D.
Afferent arteriole is not correct because it provides blood supply to the glomerulus.
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Q #3: To separate genomic DNA fragments by size, which of these laboratory methods is most useful?
A. Titration
B. Electrophoresis
C. Filtration
D. Spectrophotometry
Answer Explanation
Electrophoresis is the most useful laboratory method for separating genomic DNA fragments by size.
Electrophoresis is a technique that uses an electric field to separate charged molecules, such as DNA fragments, based on their size and charge.
Choice A is not correct because titration is a laboratory method used to determine the concentration of a solution.
Choice C is not correct because filtration is a laboratory method used to separate solids from liquids.
Choice D is not correct because spectrophotometry is a laboratory method used to measure the absorbance of light by a solution.
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Q #4: Hikers who found a human body at high altitude in the Italian Alps thought the man had died recently, but tests indicated he was shot with an arrow more than 5,300 years ago. Which of the following would be the best reason for prolonged preservation of the body? .
A. The food that the person ate contained toxins that killed the bacteria that would have otherwise destroyed the body
B. The arrow wound caused blood to flow out of the body, which led the enzymes that would break down tissue to be cleared from the body
C. The body was frozen in the cold temperature of the Alps shortly after he died and remained frozen until it was found
D. The ultraviolet rays at such a high altitude caused all the body's molecules to be preserved.
Answer Explanation
The best reason for the prolonged preservation of the body is that it was frozen in the cold temperature of the Alps shortly after he died and remained frozen until it was found.
Freezing can preserve a body by slowing down or stopping the decomposition process.
Choice A is not correct because the food that the person ate would not have contained toxins that killed the bacteria that would have otherwise destroyed the body.
Choice B is not correct because the arrow wound would not have caused blood to flow out of the body in a way that would have cleared enzymes that break down tissue from the body.
Choice D is not correct because ultraviolet rays at high altitude would not have caused all of the body’s molecules to be preserved.
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Q #5: In a hypertonic solution, water flows through aquaporins embedded in the plasma membrane of the cell. This type of transport is best known as which of the following?
A. Facilitated diffusion
B. Active transport
C. Osmosis
D. Diffusion
Answer Explanation
Osmosis is the movement of water molecules across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.
In a hypertonic solution, the concentration of solutes outside the cell is higher than inside the cell, so water flows out of the cell through aquaporins embedded in the plasma membrane to balance the concentration gradient.
Choice A.
Facilitated diffusion is not correct because it is a type of passive transport that involves the movement of molecules across a membrane through specific transport proteins, but it does not specifically refer to the movement of water molecules.
Choice B.
Active transport is not correct because it is a type of transport that involves the movement of molecules against their concentration gradient and requires energy in the form of ATP, but osmosis is a passive process that does not require energy.
Choice D.
Diffusion is not correct because it refers to the movement of molecules from an area of higher concentration to an area of lower concentration, but it does not specifically refer to the movement of water molecules.
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Q #6: Which of the following can lead to a tsunami?
A. Sunspot activity
B. Lightning strikes.
C. Earthquakes
D. Flooding.
Answer Explanation
A tsunami is a catastrophic ocean wave that is usually caused by a submarine earthquake.
It can also be caused by an underwater or coastal landslide, the eruption of a volcano, or the impact of a meteor or comet in a body of water.
Choice A is not correct because sunspot activity does not cause tsunamis.
Choice B is not correct because lightning strikes do not cause tsunamis.
Choice D is not correct because flooding does not cause tsunamis.
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Q #7: A myocardial infarction affects which of the following blood vessels of the heart?
A. Coronary
B. Aorta
C. Pulmonary
D. Vena cava
Answer Explanation
A myocardial infarction affects the coronary blood vessels of the heart.
A myocardial infarction, commonly known as a heart attack, occurs when blood flow decreases or stops in the coronary artery of the heart, causing damage to the heart muscle 1.
Choice B is incorrect because the aorta is not a blood vessel of the heart.
The aorta is the main artery that carries oxygenated blood from the heart to the rest of the body.
Choice C is incorrect because the pulmonary blood vessels are not affected by a myocardial infarction.
The pulmonary blood vessels carry deoxygenated blood from the heart to the lungs.
Choice D is incorrect because the vena cava is not a blood vessel of the heart.
The vena cava is a large vein that carries deoxygenated blood from the body to the heart.
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Q #8: In a phase diagram, which of the following is the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously?
A. Triple point
B. Critical temperature
C. Critical point
D. Absolute zero
Answer Explanation
Triple point.
In a phase diagram, the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously is the triple point.
The triple point is a unique point on a phase diagram where the three states of matter (solid, liquid, and gas) can coexist in equilibrium.
At the triple point, the temperature and pressure of the substance are fixed.
Option B, critical temperature, is the temperature at which a gas cannot be liquefied, regardless of the pressure applied.
It is a characteristic property of a substance and is typically higher than the boiling point of the liquid at standard pressure.
Option C, critical point, is the point on a phase diagram where the liquid and gas phases of a substance become indistinguishable.
At the critical point, the distinction between the liquid and gas phases disappears, and the substance becomes a supercritical fluid.
Option D, absolute zero, is the theoretical temperature at which all matter has zero thermal energy.
At absolute zero, all substances are in their solid state, but it is not relevant to a phase diagram, as it is a temperature where no transitions between states occur.
In summary, the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously in a phase diagram is the triple point, whereas the other options provided are not relevant or are characteristic properties of substances in different contexts.
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Q #9: Parasitic worm infestation is hypothesized to be damaging to the host. However, scientists have recently discovered that worm infestation can relieve the effects of certain autoimmune disorders. In which of the following ways should the hypothesis be modified, given the new findings?
A. Worm infestation prevents the body from immune malfunction
B. Worm infestation reduces the severity of certain autoimmune disorders
C. Worm infestations exacerbate the body's immune reactions
D. Lack of worm infestations is the cause of some autoimmune disorders
Answer Explanation
The hypothesis should be modified to include the new findings that worm infestation can relieve the effects of certain autoimmune disorders.
A possible modification could be: “Parasitic worm infestation can have both damaging and beneficial effects on the host.
While it can cause harm, it has also been found to reduce the severity of certain autoimmune disorders.”
Choice A.
Worm infestation prevents the body from immune malfunction is not correct because it overstates the findings and implies that worm infestation completely prevents immune malfunction, which is not supported by the evidence.
Choice C.
Worm infestations exacerbate the body’s immune reactions is not correct because it contradicts the new findings that worm infestation can relieve the effects of certain autoimmune disorders.
Choice D.
Lack of worm infestations is the cause of some autoimmune disorders is not correct because it overstates the findings and implies a causal relationship between lack of worm infestations and autoimmune disorders, which is not supported by the evidence.
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Q #10: Which of the following indicates the function of sodium bicarbonate secreted by the pancreas?
A. Sodium bicarbonate is a protease that digests carbohydrates.
B. Sodium bicarbonate stimulates the pyloric sphincter.
C. Sodium bicarbonate inhibits peristalsis.
D. Sodium bicarbonate neutralizes the acidity of chyme.
Answer Explanation
Sodium bicarbonate neutralizes the acidity of chyme.
The pancreas secretes large amounts of sodium bicarbonate, which protects the duodenum by neutralizing the acid that comes from the stomach.
This compound helps neutralize stomach acid generated during the digestive process.
Choice A is incorrect because sodium bicarbonate is not a protease that digests carbohydrates.
Proteases are enzymes that break down proteins, while sodium bicarbonate is a chemical compound that helps neutralize stomach acid.
Choice B is incorrect because sodium bicarbonate does not stimulate the pyloric sphincter.
The pyloric sphincter is a ring of smooth muscle that separates the stomach from the duodenum and regulates the passage of partially digested food (chyme) into the small intestine.
Choice C is incorrect because sodium bicarbonate does not inhibit peristalsis.
Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract.
