Practice Test 51 - High School Biology

20 questions. Answer them in any order, then submit to see your score and every explanation.

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1. Cells use ATP to power processes like active transport and muscle contraction. What is the best description of ATP's role in relation to glucose during cellular respiration?
2. A lake has declining native fish diversity. Investigators find an invasive predatory fish was introduced and now eats juvenile native fish. Managers consider three actions: (1) remove the invasive fish using targeted netting, (2) do nothing but add more native fish from hatcheries each year, or (3) ban all fishing by people. Which action most directly addresses the root cause of the biodiversity loss in this lake?
3. Water can move through an ecosystem as: lake water → plant roots → plant leaves → water vapor in air → rain → lake. Which statement best describes this movement of water?
4. An mRNA sequence is read by a ribosome as codons (3 bases each). If the mRNA sequence changes, what is the most likely effect on the protein made during translation?
5. Consider the food chain: algae → insect larva → fish → heron. When the heron produces waste or dies, decomposers break it down. What is the main role of decomposers in matter cycling in this ecosystem?
6. A student compares the elements in different macromolecules made by a plant. Carbohydrates contain C, H, and O. Proteins contain C, H, O, and N. Which statement best explains why proteins require an additional environmental source compared with carbohydrates?
7. A person drinks a large amount of water quickly. Later, the body adjusts to keep internal water balance near its usual level. Which statement best describes homeostasis in this situation?
8. During development, cells in different locations of an embryo receive different signals. Some become skin cells that form a protective barrier, while others become muscle cells that contract to produce movement. Which statement best connects these signals to differentiation?
9. Which of the following is an output of cellular respiration that cells can use immediately to power cellular work (like muscle contraction or active transport)?
10. A bird species shows heritable variation in body size. Population A lives in a cold climate with long winters. Population B lives in a hot climate with very warm summers. Which pairing best describes which body size is likely to be favored in each environment due to climate-related selection pressures?
11. A population of mice lives in a barn. Grain (food) is stored in open bins, and water is available from a leaky pipe. Over time, the mice population increases until nearly all hiding places (small wall cavities and hay-bale tunnels) are occupied. After that, many young mice are eaten by cats because they cannot find cover, and fewer survive to adulthood. What is the most direct limiting factor for the mouse population at this point?
12. In a cooperative breeding bird species, a breeding pair has chicks in a nest. Two additional adult birds (helpers) bring food to the chicks and help chase away predators near the nest. Which option best describes a likely benefit of this communal care?
13. Two wheat fields experience the same fungal disease. Field X is planted with a single genetically uniform wheat variety. Field Y is planted with a mix of wheat plants that have higher genetic diversity (some are more disease-resistant than others). After the outbreak, Field Y still has many surviving plants, but Field X loses nearly all plants. How does genetic diversity affect population stability in this case?
14. A herd of deer lives in a forest preserve. During spring and summer, grasses and shrubs grow quickly and the deer population increases. After several years, the deer population stops increasing and stays about the same each winter. Rangers notice that by late winter, most shrubs have been eaten down and many deer have low body mass, even though there is still plenty of space in the preserve. Which factor is most directly limiting the deer population size (carrying capacity, K) in late winter?
15. A forest produces about 12,000 kg of acorns each year. A squirrel needs about 80 kg of acorns per year. However, there are only 110 suitable tree cavities for nesting, and each squirrel needs one cavity. What is the carrying capacity (K) for squirrels in this forest?
16. In rabbits, black fur (B) is dominant over white fur (b). A heterozygous black rabbit is crossed with a white rabbit: $Bb \times bb$. What is the probability an offspring will have genotype $Bb$?
17. A population of moths has two color phenotypes: light and dark. The percentage of each phenotype was recorded over time in the same region. 1900: 92% light, 8% dark 1930: 65% light, 35% dark 1960: 28% light, 72% dark 1990: 18% light, 82% dark Based on these data, which statement is best supported?
18. During meiosis, homologous chromosomes can exchange segments of DNA. What is this process called, and why does it increase genetic diversity?
19. Which statement correctly describes what happens to key substances in cellular respiration (glucose + oxygen → carbon dioxide + water + ATP)?
20. A small river experienced a fertilizer spill from a nearby farm in Year 0. Biologists measured dissolved oxygen (DO) and counted a common fish species (minnows) at the same 200 m stretch each year. Data: - Pre-spill (Year -1): DO = 8.1 mg/L; minnows = 520 - Year 0 (1 week after spill): DO = 2.3 mg/L; minnows = 60 - Year 1: DO = 4.7 mg/L; minnows = 210 - Year 3: DO = 6.9 mg/L; minnows = 410 - Year 5: DO = 7.8 mg/L; minnows = 495 Which conclusion is best supported by the evidence about ecosystem recovery at this site by Year 5?

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