Which factor is primarily responsible for the movement of water across cell membranes in osmosis?
A. Hydrostatic pressure of the solution.
B. Concentration of solute particles in the solution.
C. Temperature of the solution.
D. Kinetic energy of liquid water molecules .
Concentration of solute particles in the solution.
Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.
The concentration of solute particles in the solution is the primary factor that determines the movement of water across cell membranes in osmosis.
Hydrostatic pressure (choice A) can affect the movement of water across cell membranes but is not the primary factor responsible for osmosis.
Temperature (choice C) can affect the rate of osmosis but is not the primary factor responsible for osmosis.
Kinetic energy of liquid water molecules (choice D) can affect the rate of osmosis but is not the primary factor responsible for osmosis.
Therefore, the Correct Answer is B.
More Questions on TEAS 7 Science
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Q #1: A nurse is conducting a research study to compare the effects of two different pain medications on postoperative patients. The nurse randomly assigns the patients to either receive medication A or medication B. Which of the following is the best way to ensure that the study is valid and reliable?
A. Use a large sample size and a standardized procedure for administering the medications.
B. Use a placebo group and a double-blind technique for giving the medications.
C. Use a matched-pairs design and a crossover technique for switching the medications.
D. Use a convenience sample and a pretest-posttest design for measuring the pain levels.
Answer Explanation
The correct answer is choice B.
Using a placebo group and a double-blind technique for giving the medications is the best way to ensure that the study is valid and reliable.
A placebo group helps control for the placebo effect, which can influence the results of a study.
A double-blind technique means that neither the patients nor the researchers know which medication is being given, reducing bias.
Choice A is not the best answer because while a large sample size and standardized procedure can increase reliability, they do not address validity.
Choice C is not the best answer because a matched-pairs design and crossover technique are useful for reducing variability but do not address validity.
Choice D is not the best answer because a convenience sample may not be representative and a pretest-posttest design does not control for extraneous variables.
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Q #2: What is a primer in DNA sequencing?
A. A short piece of double-stranded DNA that binds to the template DNA and acts as a "starter" for the polymerase.
B. A short piece of double-stranded DNA that binds to the primer and acts as a "starter" for the template.
C. A short piece of single-stranded DNA that binds to the template DNA and acts as a "starter" for the polymerase.
D. A short piece of single-stranded DNA that binds to the polymerase and acts as a "starter" for the template.
Answer Explanation
A primer is a short single-stranded DNA fragment used in certain laboratory techniques, such as the polymerase chain reaction (PCR).
In the PCR method, a pair of primers hybridizes with the sample DNA and defines the region that will be amplified.
Choice A) A short piece of double-stranded DNA that binds to the template DNA and acts as a “starter” for the polymerase is incorrect because primers are single-stranded, not double-stranded.
Choice B) A short piece of double-stranded DNA that binds to the primer and acts as a “starter” for the template is incorrect because it does not make sense for a primer to bind to itself.
Choice D) A short piece of single-stranded DNA that binds to the polymerase and acts as a “starter” for the template is incorrect because primers bind to the template DNA, not to the polymerase.
Note: DNA primers are used instead of RNA primers in DNA sequencing and PCR because DNA is more stable, specific, and compatible with the enzymes and processes involved in these techniques.
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Q #3: What is the hallmark of adaptive immunity?
A. Rapid recruitment of immune cells to sites of infection and inflammation
B. Antigen-independent defense mechanism
C. Immunologic memory
D. Non-specific host-defense mechanisms .
Answer Explanation
Immunologic memory is the hallmark of adaptive immunity.
Immunologic memory enables the host to mount a more rapid and efficient immune response upon subsequent exposure to the antigen.
Choice A is incorrect because rapid recruitment of immune cells to sites of infection and inflammation is a characteristic of innate immunity.
Choice B is incorrect because antigen-independent defense mechanisms are characteristic of innate immunity.
Choice D is incorrect because non-specific host-defense mechanisms are characteristic of innate immunity.
