Which type of bond is responsible for the unique properties of water and plays a crucial role in the structure of DNA and proteins?
A. Hydrogen bonds.
B. Covalent bonds.
C. Ionic bonds.
D. Van der Waals forces.
The correct answer is choice A. Hydrogen bonds.
Hydrogen bonds are responsible for the unique properties of water and play a crucial role in the structure of DNA and proteins.
Hydrogen bonds are weak electrostatic attractions between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.
Choice B.
Covalent bonds is incorrect because covalent bonds are strong chemical bonds formed by the sharing of electrons between two atoms.
Choice C.
Ionic bonds is incorrect because ionic bonds are chemical bonds formed by the transfer of electrons from one atom to another, resulting in the formation of ions.
Choice D.
Van der Waals forces is incorrect because Van der Waals forces are weak intermolecular forces that arise from temporary dipoles induced in atoms or molecules.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: Which subatomic particle contributes to the positive charge of an atom?
A. Proton
B. Neutron
C. Electron
D. Nucleon
Answer Explanation
Protons contribute to the positive charge of an atom.
Protons are subatomic particles with a positive charge found in the nucleus of an atom.
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.
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Q #2: What is the normal flora?
A. A variety of microbial species found in certain areas of the human body.
B. A group of infectious parasites that cause diarrheal diseases.
C. The genetic material of bacteria housed within a true nucleus.
D. The protein coat surrounding the viral genome.
Answer Explanation
The normal flora refers to the microbial community that colonizes on the skin and mucus membrane .
Normal flora can be found in many sites of the human body including the skin, respiratory tract, urinary tract, and the digestive tract.
Choice B is incorrect because normal flora does not refer to a group of infectious parasites that cause diarrheal diseases .
Choice C is incorrect because normal flora does not refer to the genetic material of bacteria housed within a true nucleus .
Choice D is incorrect because normal flora does not refer to the protein coat surrounding the viral genome .
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Q #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 .
Answer Explanation
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.
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.
