STAAR EOC Biology — Practice Test 1

Cell Structure

Choose the best answer.

1. Which organelle is primarily responsible for producing ATP through cellular respiration?

2. Ribosomes are the cellular structures that:

3. Which structure is found in a typical PLANT cell but NOT in an animal cell?

4. A scientist observes a single-celled organism that has no membrane-bound nucleus and no membrane-bound organelles. This organism is best classified as a:

5. The endoplasmic reticulum (ER) and Golgi apparatus work together to:

6. The nucleus of a eukaryotic cell is best described as the location where:

7. A mature plant cell typically has one large central vacuole. The MAIN function of this vacuole is to:

Cell Processes & Transport

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8. A red blood cell is placed in a HYPERTONIC solution (higher solute concentration outside the cell than inside). What will happen to the cell?

9. Which transport process requires the cell to use ATP energy?

10. Diffusion is BEST described as the movement of particles from an area of:

11. During which phase of mitosis do sister chromatids separate and move to opposite poles of the cell?

12. One of the major roles of the cell cycle (and mitosis) in a multicellular organism is to:

13. Which statement is part of the modern CELL THEORY?

14. A plant root cell is placed in pure (distilled) water. Compared to the cell's interior, the surrounding water is HYPOTONIC. What will happen?

DNA & Protein Synthesis

Choose the best answer or type the correct response.

15. In a DNA molecule, adenine (A) always pairs with which base?

16. During TRANSCRIPTION, a DNA template strand reads 3'-T-A-C-3'. Which mRNA codon is produced (remember mRNA uses U instead of T)?

17. Which statement BEST distinguishes transcription from translation?

18. Use this simplified codon table to answer:

Codon	Amino acid
AUG	Met (start)
UUU	Phe
GCA	Ala
UAA	Stop

An mRNA strand reads AUG-UUU-GCA-UAA. The protein produced will contain how many amino acids (not counting the stop signal)?

19. Using the table from the previous question, what is the FIRST amino acid coded by the mRNA strand AUG-UUU-GCA-UAA? (Type the three-letter abbreviation, e.g. "Phe".)

20. A mutation changes a single DNA base, which changes one codon and one amino acid in the resulting protein. The rest of the protein is built normally. This type of mutation is BEST described as:

21. Inserting one extra DNA base near the start of a gene shifts the reading frame for every codon downstream. This is BEST classified as:

Inheritance & Punnett Squares

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22. In pea plants, purple flower color (P) is dominant over white (p). Two heterozygous parents (Pp × Pp) are crossed. What fraction of offspring are predicted to have WHITE flowers?

23. An organism's GENOTYPE is best described as:

24. A pea plant with the genotype TT (homozygous tall) is crossed with a tt (homozygous short) plant, where T is dominant. What fraction of the F1 offspring will be TALL?

25. A heterozygous individual for a single trait is one who:

26. Two purple-flowered heterozygous pea plants (Pp × Pp) are crossed. What PERCENTAGE of the offspring are predicted to be heterozygous (Pp)? (Type a number only — e.g. 25.)

27. In a standard pedigree chart, a FILLED-IN circle most commonly represents:

28. A dihybrid cross involving two heterozygous parents (RrYy × RrYy) is performed in pea plants, where R = round (dominant) and Y = yellow (dominant). The classical PHENOTYPE ratio of the offspring is approximately:

Evolution & Classification

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29. In an English forest before the Industrial Revolution, light-colored peppered moths blended in with lichen-covered trees and were rarely eaten by birds. After pollution darkened the trees, dark-colored moths became more common. This change is BEST explained by:

30. The forelimbs of a human, a whale, and a bat have very different functions but share a similar underlying bone structure. These limbs are an example of:

31. A bird wing and an insect wing both allow flight but evolved independently and have completely different internal structures. These wings are an example of:

32. In undisturbed sedimentary rock, fossils found in DEEPER layers are generally:

33. The scientific name of the modern human is Homo sapiens. In binomial nomenclature, "Homo" represents the:

34. A dichotomous key is used in biology to:

35. On a cladogram, two species share a recent COMMON ANCESTOR if they:

Body Systems & Homeostasis

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36. Which body system is primarily responsible for transporting oxygen from the lungs to body cells and returning carbon dioxide back to the lungs?

37. The MAIN function of the digestive system is to:

38. The nervous system communicates with the rest of the body MAINLY by sending:

39. The endocrine system uses hormones to regulate body functions. Compared to nervous-system signals, hormonal signals are typically:

40. Homeostasis is BEST defined as:

41. When body temperature rises above normal, you sweat, which cools your skin and lowers your temperature back toward 37 °C. This is an example of:

42. After a meal, blood-glucose levels rise. The pancreas releases insulin, which lowers blood glucose by helping cells take it in. This is an example of homeostasis controlled by the:

Photosynthesis, Respiration & Plants

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43. The overall balanced equation for photosynthesis is:

44. Cellular respiration in animal cells primarily takes place in which organelle?

45. ATP is BEST described as:

46. The light-dependent reactions of photosynthesis take place in the chloroplast structures called:

47. In a vascular plant, XYLEM tissue mainly transports:

48. Phloem tissue in a plant primarily transports:

49. A student says, "Photosynthesis and cellular respiration are essentially opposite reactions." Which observation BEST supports this claim?

Ecosystems & Biogeochemical Cycles

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50. In an energy pyramid, only about 10% of the energy at one trophic level is passed on to the next. The remaining energy is mostly:

51. A food web shows hawks eating snakes, snakes eating mice, and mice eating grass seeds. If the snake population is suddenly removed, what is the MOST LIKELY short-term effect?

52. Which process is part of the CARBON cycle?

53. In the NITROGEN cycle, soil bacteria play an essential role by:

54. A volcanic eruption creates a new island made of bare rock with no soil and no living things. Lichens and mosses are the first species to colonize it. This is an example of:

55. A clownfish lives among the stinging tentacles of a sea anemone. The clownfish gains protection, and the anemone gets cleaning and small bits of food from the clownfish. This relationship is BEST classified as:

56. An invasive species is introduced into a Texas lake and quickly out-competes a native fish. The MOST LIKELY long-term consequence is:

Cell Structure

Cell Processes & Transport

DNA & Protein Synthesis

Inheritance & Punnett Squares

Evolution & Classification

Body Systems & Homeostasis

Photosynthesis, Respiration & Plants

Ecosystems & Biogeochemical Cycles

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