What is hydrogen bonding?
A. The attraction between the relatively positive areas of one molecule and the relatively negative areas of another molecule.
B. The repulsion between the positive and negative charges of two molecules.
C. The attraction between two nonpolar molecules.
D. The attraction between two ionic molecules.
This question was extracted from the actual TEAS 7 Exam. Get access to the actual TEAS 7 Exams (past and recent) on ExamGates.
Hydrogen bonding is an interaction involving a hydrogen atom located between a pair of other atoms having a high affinity for electrons.
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One atom of the pair (the donor), generally a fluorine, nitrogen, or oxygen atom, is covalently bonded to a hydrogen atom, whose electrons it shares unequally; its high electron affinity causes the hydrogen to take on a slight positive charge.
The other atom of the pair (the acceptor), also typically F, N, or O, has an unshared electron pair, which gives it a slight negative charge.
Mainly through electrostatic attraction, the donor atom effectively shares its hydrogen with the acceptor atom, forming a bond.
Choice B) The repulsion between the positive and negative charges of two molecules is incorrect because hydrogen bonding involves attraction, not repulsion.
Choice C) The attraction between two nonpolar molecules is incorrect because hydrogen bonding involves polar molecules.
Choice D) The attraction between two ionic molecules is incorrect because hydrogen bonding involves polar molecules and not ionic molecules.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science Test 4
Question 1:
Which of the following represents the first line of defense to an intruding pathogen?
A. Adaptive immunity
B. Antibodies
C. Innate immunity
D. T cells .
The Correct Answer is C.Innate immunity represents the first line of defense to an intruding pathogen.
The innate immune system is a series of nonspecific defenses that make up the innate immune system.
These defenses are not directed against any one pathogen but instead provide a guard against all infection.
Choice A is incorrect because adaptive immunity is activated when pathogens are able to bypass innate immune defenses.
Choice B is incorrect because antibodies are part of the adaptive immune system and are produced by B cells.
Choice D is incorrect because T cells are part of the adaptive immune system and assist B cells or directly kill infected cells.
Question 2:
Which subatomic particle contributes to the positive charge of an atom?
A. Proton
B. Neutron
C. Electron
D. Nucleon
The Correct Answer is A.Protons contribute to the positive charge of an atom.
Protons are subatomic particles with a positive charge found in the nucleus of an atom.
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Choice B is incorrect because neutrons are neutral and do not have a charge. Choice C is incorrect because electrons have a negative charge.
Choice D is incorrect because nucleons refer to both protons and neutrons, but only protons contribute to the positive charge of an atom.
Question 3:
Which of the following allows a limited range of immune cells to detect and respond rapidly to a wide range of pathogens that share common structures?
A. Pattern recognition receptors (PRRs)
B. Cytokines
C. Chemokines
D. T cells .
The Correct Answer is A.Pattern recognition receptors (PRRs) are a class of receptors that can directly recognize the specific molecular structures on the surface of pathogens.
PRRs play a crucial role in the proper function of the innate immune system and are germline-encoded host sensors, which detect molecules typical for the pathogens.
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Choice B is incorrect because cytokines are not receptors but rather signaling molecules that regulate immunity.
Choice C is incorrect because chemokines are not receptors but rather signaling molecules that attract immune cells to sites of infection.
Choice D is incorrect because T cells are not receptors but rather white blood cells that assist B cells or directly kill infected cells.
Question 4:
What is a control group used for in scientific studies?
A. To establish causality by isolating the effect of an independent variable.
B. To establish the effect of a dependent variable on an independent variable.
C. To control the impact of extraneous variables on the dependent variable.
D. To control the impact of extraneous variables on the independent variable.
The Correct Answer is A.A control group is used in scientific studies to establish causality by isolating the effect of an independent variable.
The control group serves as a baseline or comparison group that does not receive the treatment or intervention being tested.
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By comparing the results of the control group to the experimental group, researchers can determine if any observed changes are due to the independent variable or if they are due to chance or other factors.
Choice B is incorrect because a control group is not used to establish the effect of a dependent variable on an independent variable.
Choice C is incorrect because while a control group can help control for the impact of extraneous variables on the dependent variable, its primary purpose is to isolate the effect of the independent variable.
Choice D is incorrect because a control group is not used to control for the impact of extraneous variables on the independent variable.
Question 5:
What is the function of the neuromuscular junction?
A. To connect muscle fibers to motor neurons
B. To bind acetylcholine to nAChRs
C. To depolarize the muscle cell membrane D.
D. To activate voltage-gated sodium channels on the muscle membrane .
The Correct Answer is A.The neuromuscular junction is a type of synapse where neuronal signals from the brain or spinal cord interact with skeletal muscle fibers, causing them to contract.
The activation of many muscle fibers together causes muscles to contract, which in turn can produce movement.
Choice B is incorrect because binding acetylcholine to nAChRs is a process that occurs at the neuromuscular junction, but it is not the function of the neuromuscular junction itself.
Choice C is incorrect because depolarizing the muscle cell membrane is a result of the function of the neuromuscular junction, but it is not the function itself.
Choice D is incorrect because activating voltage-gated sodium channels on the muscle membrane is a result of the function of the neuromuscular junction, but it is not the function itself.