TEAS 7 practice test science

Correct Answer: D

Rationale: A) Point mutation involves a change in a single nucleotide base pair within the DNA sequence. B) Frameshift mutation involves the insertion or deletion of nucleotides, causing a shift in the reading frame of the genetic code. C) Missense mutation involves a single nucleotide change that results in a codon that codes for a different amino acid. D) Aneuploidy involves a change in the number of chromosomes, where an individual may have an extra chromosome (trisomy) or a missing chromosome (monosomy). Aneuploidy can lead to genetic disorders such as Down syndrome (trisomy 21) or Turner syndrome (monosomy X). Changing the number of chromosomes is a characteristic feature of aneuploidy, making it the correct answer. Point mutation, frameshift mutation, and missense mutation do not involve a change in the number of chromosomes and are focused on alterations at the nucleotide level within the DNA sequence.

Correct Answer: B

Rationale: The correct answer is B: Hormones. The endocrine system communicates through hormones, which are chemical messengers produced by glands and released into the bloodstream to target specific cells or organs in the body. Enzymes are biological molecules that catalyze biochemical reactions, antibodies are part of the immune system, and neurons are cells that transmit nerve impulses. In this context, enzymes, antibodies, and neurons do not play roles in the endocrine system's communication process, making them incorrect choices.

Correct Answer: D

Rationale: The correct answer is D, the cell wall. The cell wall is the structure in plant cells that provides rigidity and support. It is a tough, rigid structure located outside the cell membrane. Composed primarily of cellulose, the cell wall offers structural support to the cell, helping it maintain its shape and protect it from damage. The other choices, such as the cell membrane (choice A), Golgi apparatus (choice B), and plastid (choice C) do not provide rigidity and support to plant cells. The cell membrane is a selectively permeable barrier, the Golgi apparatus is involved in processing and packaging proteins, and plastids are organelles responsible for functions like photosynthesis and storage, but they do not provide the structural support that the cell wall does.

Correct Answer: B

Rationale: Gluconeogenesis is the correct answer. It is the process of synthesizing glucose from non-carbohydrate sources, such as amino acids or glycerol. A) Glycolysis is the process of breaking down glucose into pyruvate to produce energy. C) The Krebs cycle, also known as the citric acid cycle, generates energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. D) Oxidative phosphorylation is the final stage of cellular respiration where ATP is produced using energy derived from the electron transport chain. Therefore, choices A, C, and D are not the processes involved in converting simple sugars into complex carbohydrates.

Correct Answer: B

Rationale: The correct answer is the p orbital. Each p orbital can hold a maximum of 6 electrons (2 electrons in each of the 3 p orbitals), totaling 18 possible electrons when considering all three p orbitals. The s orbital can hold a maximum of 2 electrons, the d orbital can hold a maximum of 10 electrons, and the f orbital can hold a maximum of 14 electrons. Therefore, the p orbital is the orbital that can hold a maximum of 8 electrons, making it the correct choice.