ATI TEAS 7
Science TEAS Practice Test
1. What type of bond connects sugar and phosphate in DNA?
- A. Hydrogen
- B. Ionic
- C. Covalent
- D. Overt
Correct answer: C
Rationale: The correct answer is Covalent (C). In DNA, a covalent bond connects sugar and phosphate molecules. This bond involves the sharing of electron pairs between the atoms, providing stability to the DNA structure. Hydrogen bonds are important in DNA structure but are not the primary bond connecting sugar and phosphate. Ionic bonds involve the transfer of electrons, and 'overt' is not a term related to the bond connecting sugar and phosphate in DNA.
2. How many bones are there in the adult human skeleton?
- A. 126
- B. 206
- C. 300
- D. 525
Correct answer: B
Rationale: The correct answer is B: 206. The adult human skeleton consists of 206 bones. These bones are categorized into the axial skeleton, which includes the skull, vertebral column, and rib cage, and the appendicular skeleton, comprising the bones of the limbs and girdles. Each bone has a specific function in providing structure and support to the body. Choices A, C, and D are incorrect because they do not represent the accurate number of bones in the adult human skeleton. It is essential to remember the correct number of bones in the human skeleton for a better understanding of the skeletal system.
3. What is an isotope? For any given element, it is an atom with which of the following?
- A. a different atomic number
- B. a different number of protons
- C. a different number of electrons
- D. a different mass number
Correct answer: D
Rationale: An isotope of an element is an atom with a different number of neutrons, resulting in a different mass number. Isotopes of the same element have the same number of protons (which determines the element's identity) but differ in the number of neutrons, leading to variations in mass numbers. Choice A is incorrect because isotopes of the same element have the same atomic number. Choice B is incorrect because isotopes of the same element have the same number of protons. Choice C is incorrect because isotopes of the same element have the same number of electrons.
4. Which of the following is NOT a source of genetic variation in a population?
- A. Mutations in genes
- B. Genetic drift (random fluctuations in allele frequencies)
- C. Gene flow (movement of genes between populations)
- D. Blending inheritance (traits of parents are averaged in offspring)
Correct answer: D
Rationale: Rationale: A) Mutations in genes: Mutations are changes in the DNA sequence that can introduce new alleles into a population, leading to genetic variation. B) Genetic drift (random fluctuations in allele frequencies): Genetic drift refers to random changes in allele frequencies in a population, which can lead to genetic variation through chance events. C) Gene flow (movement of genes between populations): Gene flow occurs when individuals move between populations, bringing new alleles with them and increasing genetic variation within populations. D) Blending inheritance (traits of parents are averaged in offspring): Blending inheritance was a historical theory that suggested offspring inherit a blend of traits from their parents, leading to a reduction in genetic variation over time. However, this concept has been disproven by the understanding of Mendelian genetics, where traits are inherited independently and do not blend together. Therefore, blending inheritance does not contribute
5. Which gas is the most abundant in Earth's atmosphere?
- A. Nitrogen
- B. Oxygen
- C. Carbon dioxide
- D. Argon
Correct answer: A
Rationale: Nitrogen is the most abundant gas in Earth's atmosphere, constituting approximately 78% of the air we breathe. It is essential for various biological processes, including plant growth and nitrogen fixation. Moreover, nitrogen is a key component of the greenhouse effect, playing a crucial role in regulating the planet's temperature. Oxygen, while important for respiration, comprises about 21% of the atmosphere. Carbon dioxide, though vital for photosynthesis and a greenhouse gas, is present in much lower concentrations than nitrogen. Argon, an inert gas, is a minor component of the atmosphere.
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