Practice TEAS Science Test

Correct Answer: B

Rationale: The correct answer is B: Sebaceous gland. Sebaceous glands produce sebum, an oily substance that helps moisturize the skin and hair. The sudoriferous gland produces sweat, not oil. The hair follicle anchors the hair to the skin, it does not produce oil. Melanocytes are responsible for producing melanin, the pigment that gives skin its color, not oil. Therefore, the sebaceous gland is the structure responsible for producing oil to keep the skin and hair moisturized.

Correct Answer: C

Rationale: Natural Killer Cells produce Perforin to create pores in the target cell membrane, leading to target cell rupture. Perforin forms channels in the cell membrane, allowing for the entry of granzymes that induce apoptosis in the target cell. Interferon is produced by infected cells to inhibit viral replication. Apoptosis is a programmed cell death process. Antibodies are produced by B cells in response to antigens but are not involved in the direct lysis of target cells by Natural Killer Cells.

Correct Answer: B

Rationale: The correct answer is B: 12 NADPH and 18 ATP. In the Calvin cycle of photosynthesis, each molecule of CO2 requires 2 NADPH and 3 ATP for reduction to glucose. Therefore, to reduce 6 molecules of CO2, you would need 6 x 2 = 12 NADPH and 6 x 3 = 18 ATP. This is why choice B is the correct answer. Choices A, C, and D have incorrect combinations of NADPH and ATP that do not match the stoichiometry of the Calvin cycle for the reduction of CO2 to glucose.

Correct Answer: B

Rationale: The correct answer is B: Hydrogen bond. Water molecules are held together by hydrogen bonds, which form between the hydrogen atom of one water molecule and the oxygen atom of another. This bond is weaker than a covalent bond but still strong enough to keep water molecules attracted to each other. Covalent bonds (choice A) involve the sharing of electrons between atoms, not present in water. Ionic bonds (choice C) involve the transfer of electrons between atoms, not applicable to water. Peptide bonds (choice D) are found in proteins, not in water molecules.

Correct Answer: C

Rationale: The correct answer is C because not all macromolecules contain phosphorus. Macromolecules such as proteins, carbohydrates, and lipids contain carbon, hydrogen, and oxygen but not necessarily phosphorus. Proteins and carbohydrates can exist as single chains or be branched, so choices A and B are not characteristics that exclude a macromolecule. Choice D is also incorrect because not all macromolecules are used by the body, as some like cellulose are not digestible by humans.