TEAS Biology and Chemistry Practice
Updated October 27, 2026
Besides anatomy and physiology, the ATI TEAS 7 Science section covers biology and chemistry. Biology questions focus on cells, DNA, genetics and microorganisms; chemistry questions cover atoms, the periodic table, reactions, and acids and bases. Here’s a quick review, followed by free practice questions.
Biology essentials
- Cells: the nucleus holds DNA; mitochondria make energy (ATP); ribosomes make proteins; plant cells also have cell walls and chloroplasts.
- DNA: a double helix of nucleotides. The bases pair A with T and C with G. In RNA, uracil (U) replaces thymine.
- Cell division: mitosis makes two identical body cells; meiosis makes sex cells (gametes) with half the chromosomes.
- Genetics: a dominant allele shows its trait when present; a recessive trait shows only with two recessive alleles.
Chemistry essentials
- Atoms: protons (positive) and neutrons (no charge) are in the nucleus; electrons (negative) surround it. The atomic number is the number of protons.
- Bonds: ionic bonds transfer electrons; covalent bonds share them.
- pH: below 7 is acidic, 7 is neutral, above 7 is basic.
- Reactions: in a balanced equation, atoms are neither created nor destroyed.
Free TEAS biology and chemistry questions
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In DNA, adenine pairs with:Answer: BIn DNA, adenine pairs with thymine and cytosine pairs with guanine. In RNA, adenine pairs with uracil.
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Which type of cell division produces sex cells with half the number of chromosomes?Answer: CMeiosis produces gametes (sperm and egg cells) with half the usual number of chromosomes. Mitosis makes identical body cells.
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The atomic number of an element equals its number of:Answer: DThe atomic number is the number of protons in the nucleus, which defines the element.
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A solution with a pH of 10 is:Answer: AA pH above 7 is basic (alkaline). Below 7 is acidic, and 7 is neutral.
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Two parents each carry one dominant and one recessive allele (Bb). What fraction of their children are expected to show the recessive trait?Answer: BA Punnett square for Bb × Bb gives BB, Bb, Bb and bb. Only bb shows the recessive trait, so 1 in 4 children are expected to.
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Which type of bond forms when atoms share electrons?Answer: CIn a covalent bond, atoms share electrons. In an ionic bond, electrons are transferred from one atom to another.
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Which organelle makes proteins?Answer: DRibosomes build proteins. Mitochondria make energy, lysosomes break down waste, and the nucleus holds the DNA.
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Which molecule carries amino acids to the ribosome during protein synthesis?Answer: CTransfer RNA (tRNA) brings specific amino acids to the ribosome, matching them to codons on the messenger RNA (mRNA).
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In mitosis, how many daughter cells are produced, and how do they compare with the parent cell?Answer: AMitosis produces two genetically identical daughter cells with the same number of chromosomes as the parent. Meiosis produces four cells with half the number.
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An element has 11 protons and 12 neutrons. What is its mass number?Answer: DMass number = protons + neutrons = 11 + 12 = 23. The atomic number is 11 (sodium).
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Which type of chemical reaction breaks one compound into simpler substances?Answer: BA decomposition reaction breaks one compound into two or more simpler substances, the opposite of synthesis.
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Which is an example of a physical change?Answer: CMelting changes only the state of water, not its chemical identity, so it's a physical change. Burning, rusting and souring make new substances.
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A trait shows only when an organism has two copies of its allele. The allele is:Answer: AA recessive allele is expressed only when two copies are present (homozygous recessive). A dominant allele shows with just one copy.
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What is the main function of enzymes?Answer: BEnzymes are biological catalysts. They lower the energy needed for reactions, speeding them up, and aren't consumed.
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Which subatomic particles determine how an atom bonds with other atoms?Answer: DValence electrons, in the outermost shell, are gained, lost or shared in chemical bonds.
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