Which of the following is a mechanism that the body uses to regulate blood pH levels?
A. Increased respiration rate to remove excess CO2.
B. Decreased respiration rate to retain CO2.
C. Increased water intake to dilute the blood.
D. Decreased water intake to concentrate the blood.
The correct answer is choice A.
Increased respiration rate to remove excess CO2.
The body regulates blood pH through several mechanisms, including chemical buffers, the respiratory system, and the urinary system.
The respiratory system can adjust blood pH by changing the rate of respiration to remove or retain CO2.
When there is excess acid in the blood, the respiratory rate increases to remove more CO2, which helps to raise blood pH.
Choice B is incorrect because decreasing the respiration rate would retain CO2, which would lower blood pH.
Choice C is incorrect because increased water intake would not directly affect blood pH levels.
Choice D is incorrect because decreased water intake would not directly affect blood pH levels.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: What is the relationship between atomic mass and mass number?
A. They are the same.
B. Atomic mass is always greater than mass number.
C. Atomic mass and mass number are not related.
D. Atomic mass is very close to mass number but with some deviation in the decimal places.
Answer Explanation
Atomic mass is very close to mass number but with some deviation in the decimal places.
Atomic mass is also known as atomic weight and is the weighted average mass of an atom of an element based on the relative natural abundance of that element’s isotopes.
The mass number, on the other hand, is a count of the total number of protons and neutrons in an atom’s nucleus.
Choice A is incorrect because atomic mass and mass number do not mean the same thing.
Choice B is incorrect because atomic mass is not always greater than mass number.
Choice C is incorrect because atomic mass and mass number are related.
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Q #2: Which gland, located in the mediastinum, plays a key role in the development and maturation of T-lymphocytes?
A. Thymus
B. Parathyroid
C. Adrenal
D. Pituitary
Answer Explanation
The correct answer is choice A. Thymus.
The thymus is a primary lymphoid organ located in the mediastinum.
It plays a key role in the maturation and differentiation of T-lymphocytes.
Choice B.
Parathyroid is incorrect because the parathyroid glands are small endocrine glands located in the neck that produce parathyroid hormone, which regulates calcium levels in the blood.
Choice C.
Adrenal is incorrect because the adrenal glands are endocrine glands located above the kidneys that produce hormones such as cortisol and adrenaline.
Choice D.
Pituitary is incorrect because the pituitary gland is an endocrine gland located at the base of the brain that produces hormones that regulate growth, metabolism, and reproductive functions.
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Q #3: 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.
Answer Explanation
Hydrogen bonding is an interaction involving a hydrogen atom located between a pair of other atoms having a high affinity for electrons.
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.
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Q #4: Which process involves the fusion of male and female gametes resulting in the formation of a zygote?
A. Oogenesis.
B. Fertilization.
C. Meiosis.
D. Mitosis.
Answer Explanation
Fertilization.
Fertilization is the process by which male and female gametes fuse to form a zygote.
Oogenesis (choice A) is the process by which female gametes, or eggs, are produced.
Meiosis (choice C) is a type of cell division that results in the formation of gametes.
Mitosis (choice D) is a type of cell division that results in the formation of two identical daughter cells.
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Q #5: How does the use of a catalyst affect the activation energy of a chemical reaction?
A. It increases the activation energy required for the reaction.
B. It decreases the activation energy required for the reaction.
C. It has no effect on the activation energy required for the reaction.
D. It increases the rate of reaction but has no effect on the activation energy.
Answer Explanation
The correct answer is choice B.
It decreases the activation energy required for the reaction.
A catalyst provides a new reaction pathway in which a lower activation energy is offered.
This allows more reactant molecules to collide with enough energy to surmount the smaller energy barrier, increasing the rate of reaction 2.
Choice A, It increases the activation energy required for the reaction, is not the correct answer because it describes the opposite effect of a catalyst.
Choice C, It has no effect on the activation energy required for the reaction, is not the correct answer because a catalyst does have an effect on activation energy.
Choice D, It increases the rate of reaction but has no effect on the activation energy, is not the correct answer because a catalyst increases the rate of reaction by decreasing the activation energy.
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Q #6: 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 #7: Why is water sometimes called the "universal solvent"?.
A. Because water dissolves all solutes equally well.
B. Because water is a nonpolar solvent.
C. Because water is good at dissolving ions and polar molecules.
D. Because water is poor at dissolving nonpolar molecules.
Answer Explanation
Water is sometimes called the “universal solvent” because it dissolves more substances than any other liquid.
This is due to its polarity and ability to form hydrogen bonds, which allows it to dissolve ions and polar molecules.
Choice A) Because water dissolves all solutes equally well is incorrect because water does not dissolve all solutes equally well.
Choice B) Because water is a nonpolar solvent is incorrect because water is a polar solvent.
Choice D) Because water is poor at dissolving nonpolar molecules is incorrect because it does not explain why water is called the “universal solvent”.
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Q #8: Which of the following statements about bacteria and archaea is true?
A. A. Bacteria have a true nucleus while archaea do not
B. B. Archaea reproduce by spores while some bacteria reproduce by fission.
C. C. Bacteria can perform photosynthesis while archaea cannot.
D. D. Archaeal and bacterial flagella are constructed similarly.
Answer Explanation
Bacteria can perform photosynthesis while archaea cannot. Many types of bacteria can generate oxygen from sunlight through photosynthesis, while archaea cannot perform this process.
Choice A is incorrect because neither bacteria nor archaea have a true nucleus. Both are prokaryotic organisms. Choice B is incorrect because archaea reproduce by fission, fragmentation, or budding, while bacteria can produce spores and divide sexually or asexually. Choice D is incorrect because archaeal and bacterial flagella are constructed differently.
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Q #9: Which of the following hormones is responsible for regulating the body's metabolism and energy levels?
A. Estrogen
B. Progestin
C. Thyroxine
D. Androgen
Answer Explanation
The correct answer is choice C. Thyroxine.
Thyroxine (T4) is a hormone produced by the thyroid gland that controls your body’s metabolism, the process in which your body transforms the food you eat into energy.
Choice A, Estrogen, is not the correct answer because it is a hormone responsible for the development of female secondary sexual characteristics.
Choice B, Progestin, is not the correct answer because it is a synthetic form of progesterone used in hormonal birth control and hormone replacement therapy.
Choice D, Androgen, is not the correct answer because it is a hormone responsible for the development of male secondary sexual characteristics.
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Q #10: A nurse is caring for a patient who has been declared brain dead and is awaiting organ donation. Which of the following interventions is most important to preserve the viability of the organs?
A. Administering antibiotics to prevent infection.
B. Maintaining normal body temperature and blood pressure.
C. Providing emotional support to the family members.
D. Applying eye drops and ointment to prevent corneal drying.
Answer Explanation
The correct answer is choice B.
Maintaining normal body temperature and blood pressure.
Early identification and management of potential organ donors must take into consideration specific pathophysiologic changes for medical optimization 1.
The VIPPS (ventilation, infusion and pumping, pharmacological treatment, and specificities) strategy is a mnemonic method that brings together key aspects of the restoration of oxygen delivery to tissues during hemodynamic instability plus organ optimization strategies.
Choice A is incorrect because administering antibiotics to prevent infection is not the most important intervention to preserve organ viability.
Choice C is incorrect because providing emotional support to family members, while important, is not an intervention that directly affects organ viability.
Choice D is incorrect because applying eye drops and ointment to prevent corneal drying is not the most important intervention to preserve organ viability.
