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🧬 10 questions · answers and rationales · free

TEAS biology practice questions

Free TEAS-style biology questions: cells and organelles, mitosis and meiosis, DNA to protein, Punnett squares, macromolecules and microorganisms, each with a worked rationale.

Tap an answer to check it, or open "Show the answer and rationale" under each question.

Question 1 of 10 · Biology

A cell releases insulin by fusing vesicles with its plasma membrane and emptying them outside. This process is called what?

  1. Osmosis
  2. Pinocytosis
  3. Endocytosis
  4. Exocytosis
Show the answer and rationale

Answer: D

Exocytosis is the export of material when vesicles fuse with the plasma membrane. Endocytosis and its form pinocytosis bring material into the cell, and osmosis is the movement of water across a membrane.

📚 Learn it: Levels of organization and cell transport

Question 2 of 10 · Biology · Select all that apply

Which processes are forms of PASSIVE transport? Select all that apply.

  1. Phagocytosis of a bacterium
  2. The sodium-potassium pump
  3. Facilitated diffusion through a channel protein
  4. Simple diffusion of carbon dioxide
  5. Osmosis
Show the answer and rationale

Answer: C, D, E

Simple diffusion, osmosis and facilitated diffusion all move substances down their gradients without ATP, so they are passive. The sodium-potassium pump is active transport, and phagocytosis is a form of endocytosis that requires energy.

📚 Learn it: Levels of organization and cell transport

Question 3 of 10 · Biology

A DNA template strand reads 3'-TACCGA-5'. What mRNA sequence (written 5' to 3') will be transcribed from it?

  1. UACCGA
  2. TACCGA
  3. ATGGCT
  4. AUGGCU
Show the answer and rationale

Answer: D

RNA polymerase pairs each template base with its complement and uses uracil in place of thymine: T→A, A→U, C→G, C→G, G→C, A→U, giving AUGGCU. ATGGCT is the complementary DNA, not RNA, and the other choices copy the template instead of pairing with it.

Step by step

  1. Pair each base: T→A, A→U, C→G, G→C.
  2. TACCGA becomes A U G G C U.
  3. mRNA = AUGGCU.

📚 Learn it: DNA, RNA and protein synthesis

Question 4 of 10 · Biology

During which stage of the cell cycle is DNA replicated?

  1. G1 phase
  2. S phase
  3. Metaphase
  4. Cytokinesis
Show the answer and rationale

Answer: B

DNA is copied during the S (synthesis) phase of interphase. G1 is a growth phase before replication, metaphase is a stage of mitosis after replication is complete, and cytokinesis divides the cytoplasm.

📚 Learn it: Mitosis and meiosis

Question 5 of 10 · Biology

What is the role of transfer RNA (tRNA) during translation?

  1. It brings specific amino acids to the ribosome
  2. It unwinds DNA before replication
  3. It carries the genetic code out of the nucleus
  4. It forms the double helix in chromosomes
Show the answer and rationale

Answer: A

Each tRNA carries one amino acid and has an anticodon that matches an mRNA codon, delivering amino acids to the ribosome in order. Messenger RNA carries the code out of the nucleus, DNA forms the double helix, and helicase unwinds DNA.

📚 Learn it: DNA, RNA and protein synthesis

Question 6 of 10 · Biology

In which phase of mitosis are sister chromatids pulled toward opposite poles of the cell?

  1. Telophase
  2. Anaphase
  3. Metaphase
  4. Prophase
Show the answer and rationale

Answer: B

In anaphase the centromeres split and spindle fibers pull sister chromatids to opposite poles. Prophase condenses chromosomes, metaphase lines them up at the equator, and telophase re-forms the nuclei.

📚 Learn it: Mitosis and meiosis

Question 7 of 10 · Biology

Which comparison of prokaryotic and eukaryotic cells is accurate?

  1. Eukaryotes store all of their DNA in small plasmids
  2. Eukaryotes lack both ribosomes and a cell membrane
  3. Prokaryotes are smaller and lack membrane-bound organelles
  4. Prokaryotes are usually larger and contain many nuclei
Show the answer and rationale

Answer: C

Prokaryotic cells are typically about 0.1 to 5 micrometers across, much smaller than most eukaryotic cells, and they lack membrane-bound organelles. Eukaryotes do have ribosomes and membranes, and plasmids are small DNA rings typical of bacteria, not the main eukaryotic DNA.

📚 Learn it: Cell structure and organelles

Question 8 of 10 · Biology · Select all that apply

Which structures are found in a typical plant cell? Select all that apply.

  1. Large central vacuole
  2. Mitochondria
  3. Nucleoid in place of a nucleus
  4. Cell wall
  5. Chloroplasts
Show the answer and rationale

Answer: A, B, D, E

Plant cells have a cellulose cell wall, chloroplasts for photosynthesis, mitochondria for cellular respiration and a large central vacuole. A nucleoid instead of a nucleus is a prokaryotic feature; plant cells are eukaryotes with a true nucleus.

📚 Learn it: Cell structure and organelles

Question 9 of 10 · Biology

Measles spreads when an infected person coughs and tiny particles stay suspended in room air for a long time. This route of transmission is called what?

  1. Foodborne
  2. Direct contact
  3. Airborne
  4. Vector-borne
Show the answer and rationale

Answer: C

Airborne transmission involves tiny particles that stay in the air and can be inhaled by others at a distance, as with measles. Vector-borne spread needs a carrier such as a mosquito, direct contact needs touch, and foodborne spread comes from contaminated food.

📚 Learn it: Microorganisms and disease

Question 10 of 10 · Biology

Which bond links amino acids together in a protein?

  1. Hydrogen bond
  2. Ester bond
  3. Peptide bond
  4. Glycosidic bond
Show the answer and rationale

Answer: C

Amino acids are joined by covalent peptide bonds formed by dehydration synthesis. Glycosidic bonds link sugars, ester bonds link fatty acids to glycerol, and hydrogen bonds help hold a protein's folded shape but do not join the chain.

📚 Learn it: Macromolecules: carbohydrates, lipids, proteins and nucleic acids

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