ATI TEAS Science Test Practice (2025)

The correct answer is A) Sacrum.

Let's break down each option with a detailed answer explanation:

A) Sacrum: This is the correct answer. The sacrum is an irregularly shaped bone at the base of the spine, between the two hip bones. It has a unique triangular shape and is formed by the fusion of five vertebrae. Its irregular shape allows it to fit perfectly between the hip bones and support the weight of the upper body.

B) Fibula: This is a long bone found in the lower leg, running parallel to the larger tibia. It has a regular, slender cylindrical shape typical of long bones.

C) Sternum: Also known as the breastbone, the sternum is a flat bone in the center of the chest. While it has a somewhat unique shape, it's generally classified as a flat bone rather than an irregular bone.

D) Incus: This is one of the three small bones found in the middle ear. While it has a distinctive anvil-like shape, it's classified as an auditory ossicle rather than an irregular bone due to its specialized function and location.

The correct answer is (C).

Let's break down each option with a detailed answer explanation:

To calculate glucose excretion rates, the following equation should be used: Urinary excretion rate = filtration rate– (reabsorption rate + secretion rate). In answer (C), the places of the filtration rate and reabsorption rate are changed.
Answer (A) describes a correct statement because glucose is transported through a symporter, conjugated to the transport of sodium. This is correct. Glucose reabsorption in the proximal tubule occurs via sodium-glucose cotransporters (SGLT1 and SGLT2), which rely on the sodium gradient maintained by the Na+/K+ ATPase pump.

Answer (B) presents a true statement. Increased glucose delivery to the tubules causes them to reabsorb excess sodium along with glucose. This, in turn, decreases delivery of sodium chloride to the macula densa, activating a tubuloglomerular feedback which subsequently increases the renal blood flow and GFR.

Answer (D) states a true statement, since both intestinal and renal glucose transports are mediated by the same type of symport proteins.

Therefore, answer (C) contains an incorrect statement- Glucose is not secreted by the renal tubules; it is only filtered and reabsorbed. Therefore, the correct relationship for urinary glucose excretion is the amount of glucose filtered minus the amount reabsorbed. There is no secretion of glucose into the tubular lumen to consider in this equation

The correct answer is (A).

The levels of hemoglobin within erythrocytes do not directly affect the binding affinity of oxygen to hemoglobin. The affinity of hemoglobin for oxygen is mainly influenced by various physiological and chemical factors, but its concentration does not alter its intrinsic affinity for oxygen.

Let’s break down each option with a detailed answer explanation:

Why do the other options affect oxygen binding affinity:

B) The allosteric regulation of hemoglobin: This factor does affect oxygen binding affinity. Allosteric regulation involves the binding of molecules to sites other than the oxygen-binding site, which can alter hemoglobin's structure and its affinity for oxygen. For example, 2,3-diphosphoglycerate (2,3-DPG) is an allosteric regulator that shifts the oxygen dissociation curve to the right, decreasing hemoglobin's affinity for oxygen.

C) The pH level: pH significantly affects hemoglobin's oxygen affinity through the Bohr effect. As mentioned in the search results, "Decreases in pH shift the curve to the right, while increases shift the curve to the left". This means that in more acidic conditions (lower pH), hemoglobin's affinity for oxygen decreases, facilitating oxygen release to tissues.

D) The partial pressure of oxygen: The partial pressure of oxygen (PaO2) is a crucial factor in determining hemoglobin's oxygen saturation. The oxyhemoglobin dissociation curve describes the relationship between PaO2 and hemoglobin saturation. As PaO2 increases, more oxygen binds to hemoglobin until saturation is reached.

The correct answer is (C).

The Question: Which disease is caused by a vitamin C deficiency?

The Correct Answer: C. Scurvy

• Vitamin C's Role: Vitamin C is essential for making collagen. Think of collagen as the "glue" that holds your body together. It's crucial for healthy skin, blood vessels, bones, and cartilage.
• What Happens When You're Deficient? Without enough vitamin C, your body can't produce enough collagen. This leads to the symptoms of scurvy:
  • Weak connective tissue: This causes problems like bleeding gums (because the tissue holding your teeth weakens), slow wound healing, and easy bruising.
  • Lethargy (tiredness): Vitamin C is also involved in energy production, so deficiency can cause fatigue.
  • Edema (swelling): Fluid can build up in tissues.
• Historical Context: You might have heard about scurvy in stories about sailors. Long sea voyages meant no fresh fruits or vegetables (which are rich in vitamin C), so scurvy was a common problem.

Why the Other Answers are Incorrect:

• A. Rickets: Rickets is caused by a vitamin D deficiency. Vitamin D is crucial for absorbing calcium and phosphorus, which are essential for strong bones. A lack of vitamin D leads to weak bones, especially in children, causing them to become soft and bendy. Sunlight helps your body produce vitamin D, which explains why rickets was more common in areas with limited sunlight exposure (like during the Industrial Revolution).

• B. Beriberi: Beriberi is caused by a vitamin B1 (thiamine) deficiency. Vitamin B1 is vital for energy metabolism, especially in the nervous system and heart. A deficiency can cause problems with nerve function, heart problems, and digestive issues. Beriberi was historically common in populations whose diets were primarily polished white rice, which is low in thiamine.

• D. Anemia: Anemia isn't caused by a single vitamin deficiency, although certain vitamin deficiencies can contribute to it. Anemia is a condition where you don't have enough healthy red blood cells or hemoglobin (the protein in red blood cells that carries oxygen). Several factors can cause anemia, including:

  • Iron deficiency: Iron is needed to make hemoglobin.
  • Vitamin B12 or folate deficiency: These vitamins are needed for red blood cell production.
  • Other factors: Chronic diseases, genetic conditions, and blood loss can also cause anemia.

Key Takeaway: It's important to remember which vitamin is associated with each disease. This explanation breaks down the "why" behind the connection, which will help you remember the information better and apply it to future questions. Focus on the function of each vitamin and what happens when that function is disrupted due to a deficiency.

The correct answer is (B).

Answer -The correct answer is (B). 

Let's break down each option with a detailed answer explanation:

The reaction can be represented by the following chemical equation:

NaOH+ CH₃COOH→ CH₃COONa + H₂O

In this reaction, sodium hydroxide, a strong base, reacts with acetic acid, a weak acid, to form sodium acetate (CH₃COONa) and water (H₂O).

A) Neutral:

This option would be correct if the strong base completely neutralized the weak acid, resulting in a neutral solution. However, because acetic acid is a weak acid and does not fully dissociate, the resulting solution will not be neutral.

B) Basic:

This is the correct answer. When NaOH is added to acetic acid, the resulting solution will be basic. This is because sodium acetate (CH₃COONa) is a salt that, when dissolved in water, hydrolyzes to form OH⁻ ions, making the solution basic.

C) Depends on the amount of added NaOH:

While the pH of the resulting solution can vary depending on the amount of NaOH added, the solution's nature (basic) remains the same if there is an excess of NaOH or equal moles of NaOH and acetic acid.

D) Depends on the acid’s pH prior to the addition of NaOH:

The initial pH of the acetic acid solution does not determine its final nature. The nature of the resulting solution depends on the products formed after the reaction, which will be basic due to the presence of sodium acetate

The correct answer is D:

There are two intermediates and three transition states in the overall reaction.

Let's analyze each option and explain why D is correct:

A) The overall reaction is endothermic. This is incorrect. The reaction profile shows that the energy of the final product D is lower than the initial reactant A. This indicates an exothermic reaction, not endothermic.

B) The reaction B → C is the fastest step of the overall reaction. This is incorrect. The fastest step would be the one with the lowest activation energy barrier. From the diagram, the step B → C actually has the highest energy barrier, making it the slowest step, not the fastest.

C) The reaction B → C is the rate-determining step of the overall reaction. While this step does have the highest energy barrier, making it the slowest step, we can't definitively say it's the rate-determining step without more information about the reversibility of the steps. Therefore, this statement isn't necessarily true.

D) There are two intermediates and three transition states in the overall reaction. This is correct.

Let's break it down:

• Intermediates: These are the relatively stable species between reactants and products. In the diagram, we see two local minima (B and C) between A and D. These represent the two intermediates.
• Transition states: These are the highest energy points between stable species. We can see three peaks in the energy profile, which represent the three transition states.

The reaction profile clearly shows:

• Starting material A
• First transition state
• First intermediate B
• Second transition state (highest point)
• Second intermediate C
• Third transition state
• Final product D

This matches exactly with the description in option D, making it the correct answer.

The correct answer is (B).

The correct answer is (B).

The Question: Mg + 2HCl → MgCl₂ + H₂

Which statement correctly describes what happens in this reaction?

The Correct Answer: B. The magnesium has been oxidized and the hydrogen has been reduced.

To understand this, we need to understand oxidation and reduction. A helpful mnemonic is OIL RIG:

• Oxidation Is Loss (of electrons)
• Reduction Is Gain (of electrons)

Let's look at what happens to each element in the reaction:

1. Magnesium (Mg):

   • On the left side of the equation (reactants), magnesium is by itself, with a neutral charge (0).
   • On the right side (products), magnesium is part of MgCl₂, where it has a +2 charge (Mg²⁺).
   • To go from 0 to +2, magnesium loses two electrons.
   • Loss of electrons is oxidation. Therefore, magnesium is oxidized.

2. Hydrogen (H):

   • On the left side, hydrogen is part of HCl, where it has a +1 charge (H⁺).
   • On the right side, hydrogen is H₂, a neutral molecule with a charge of 0.
   • To go from +1 to 0, each hydrogen atom gains an electron.
   • Gain of electrons is reduction. Therefore, hydrogen is reduced.

3. Chlorine (Cl):

   • Chlorine starts as Cl⁻ in HCl and ends as Cl⁻ in MgCl₂. Its charge remains -1 throughout the reaction.
   • Since there's no change in charge, chlorine is neither oxidized nor reduced. It's called a spectator ion.

Why the Other Answers are Incorrect:

• A. The chlorine has been oxidized and the hydrogen has been reduced: Chlorine's charge doesn't change, so it's not oxidized.

• C. The magnesium has been reduced and the chlorine has been oxidized: Magnesium loses electrons (oxidized), not gains (reduced). Chlorine's charge doesn't change.

• D. The magnesium and chlorine have been reduced: Magnesium loses electrons (oxidized), not gains (reduced). Chlorine's charge doesn't change.

In Simple Terms: In this reaction, magnesium gives away electrons (gets oxidized), and hydrogen takes those electrons (gets reduced). Remember OIL RIG to help you remember which is which.

Answer –The correct answer is A

Let's break down each option with a detailed answer explanation:

A) The mother cell divides once into two daughter cells:

• This occurs in mitosis but not in meiosis.
• In mitosis, one cell division results in two daughter cells.
• In meiosis, there are two cell divisions, resulting in four daughter cells.

B) DNA replication:

• This occurs in both mitosis and meiosis.
• DNA replication happens during the S phase of interphase, before either type of cell division begins.

C) Cross-over in homologous chromosomes:

• This occurs in meiosis but not in mitosis.
• Crossing over happens during prophase I of meiosis, contributing to genetic diversity.

D) Divides from a reproductive cell:

• This is not a characteristic of either mitosis or meiosis.
• Mitosis occurs in somatic (body) cells, while meiosis occurs in gamete-producing cells.

Answer & Explanation

The correct answer is A) Histones.

Let's break down each option with a detailed answer and explanation:

A) Histones: This is the correct answer. Histones are proteins found in eukaryotic cells that help package DNA into a compact structure called chromatin. Prokaryotes do not have histones or a nucleus to contain their DNA.

B) Ribosomes: Both eukaryotes and prokaryotes have ribosomes. These are essential for protein synthesis in all living cells.

C) Genetic recombination: This process occurs in both eukaryotes and prokaryotes. It's a mechanism for exchanging genetic material and creating genetic diversity.

D) Flagella: While the structure and composition of flagella differ between eukaryotes and prokaryotes, both can possess these structures for movement.

Detailed answer explanations: The key to this question is identifying a feature unique to eukaryotes. Histones are the only option that fits this criterion. They play a crucial role in DNA organization within the eukaryotic nucleus, a structure absent in prokaryotes.

The correct answer is (B)

Answer -Both C and D are true.

Let's break down each option with a detailed answer explanation:

A) The dependent variable is what the researchers measure to see the effect of the independent variable.

In this experiment, the researchers are measuring the change in blood pressure after the treatment. Therefore, the dependent variable is the blood pressure difference (before and after treatment), not just the blood pressure after the treatment.

Verdict: False

B) The purpose of the second group is to examine a placebo effect.

Explanation: The second group took the old medicine, not a placebo. The group taking a pill without any active ingredient (the third group) is the one used to examine the placebo effect.

Verdict: False

C) The independent variable is the treatment type.

Explanation: The independent variable is what the researchers manipulate to observe its effect on the dependent variable. In this case, the treatment type (new medicine, old medicine, placebo, or no treatment) is what is being manipulated.

Verdict: True

D) The fourth group is a control group.

Explanation: A control group is used as a baseline to compare the effects of the treatments. The fourth group, which received no treatment, serves as a control group to help determine the natural changes in blood pressure without any intervention.

Verdict: True

Summary

The true statements regarding the experiment are:

• The independent variable is the treatment type.
• The fourth group is a control group.

Answer & Explanation

The correct answer is C.

Correct Answer: C) Volumetric pipette

Explanation:

Graduated Cylinder: While it can measure volumes, it's typically used for larger volumes and isn't as precise for small volumes like 2 mL.

Thermometer: This is used for measuring temperature, not volume.

Volumetric Pipette: This is the correct tool for precisely measuring and transferring small volumes of liquids. It's designed to deliver a specific volume with high accuracy.

Meter Stick: This is used for measuring length, not volume.

A volumetric pipette is the most appropriate tool for this task because:

• It's designed for precise measurement of small liquid volumes.
• It can accurately transfer exactly 2 mL of solution.
• It's commonly used in chemistry labs for tasks requiring high precision.