Practice Test 61 - High School Biology

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

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1. A leaf cell contains both chloroplasts and mitochondria. Which statement best describes what processes this plant cell can perform and where? Photosynthesis: $6CO_2 + 6H_2O +$ light $\rightarrow C_6H_{12}O_6 + 6O_2$ Cellular respiration: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O +$ ATP
2. A cell is building a long carbohydrate chain by repeatedly adding glucose monomers. During each linking step, the reaction is endergonic (requires energy). Which statement best describes why energy is needed?​
3. In a finch population, beak size varies and is heritable. A drought causes mostly large, tough seeds to remain available for many years. Birds with larger beaks crack these seeds more efficiently and produce more offspring. Which statement best explains how the population becomes adapted to eating tough seeds?
4. Claim: Living in groups reduces per-individual predation risk ("safety in numbers"). Experiment in a controlled outdoor enclosure with identical habitat and equal predator exposure. Researchers released prey insects either alone or in groups, then measured the percent eaten after 24 hours: - Solitary (1 per enclosure): 62% eaten. - Small groups (5 per enclosure): 38% eaten. - Large groups (20 per enclosure): 21% eaten. Which choice best supports the claim using these results?
5. A plant absorbs water ($H_2O$) needed for photosynthesis. Which pathway correctly describes how the water usually reaches the leaves?
6. Why does separating homologous chromosomes during meiosis help create genetically varied gametes?
7. Which choice best describes what a single human chromosome is made of?
8. Which option best describes the main energy transformation that occurs during cellular respiration?
9. A bacterial population contains two types: antibiotic-resistant (R) and antibiotic-susceptible (S). Before treatment, most bacteria are S. During antibiotic treatment, 90% of R bacteria survive, but only 5% of S bacteria survive. After treatment, what will most likely happen to the frequency of resistance in the population that regrows?
10. A biology class discusses "reaction norms," meaning the range of phenotypes that a single genotype can produce across different environments. Which situation best matches the idea of a reaction norm?
11. An invasive plant is spreading in a grassland and reducing native wildflowers used by pollinators. Managers consider three approaches: A) Apply a broad-spectrum herbicide over the entire area. B) Introduce an insect from another country that eats the invasive plant. C) Manually remove invasive plants in priority patches and replant natives. Which approach is generally most likely to be effective with the fewest unintended ecological side effects, assuming enough volunteers/staff are available?
12. A population of bacteria contains heritable variation: most cells are susceptible to antibiotic X, but a few have a mutation that makes them resistant. A patient takes antibiotic X for several days. Which option best explains how natural selection can cause the bacterial population in the patient to change over the next few generations?
13. Which option correctly identifies what ATP represents in the cellular respiration equation $\mathrm{C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP}$?
14. A grass species grows in two fields with similar sunlight and rainfall. In Field 1, the soil is low in nitrogen and the grass remains short and produces few seeds. In Field 2, the soil has higher nitrogen and the grass grows taller and produces many seeds. Which factor most likely limits the grass population growth in Field 1?
15. A diagram summarizes a simplified fossil sequence for horses over time: earlier fossils are small with multiple toes; later fossils are larger with fewer toes and teeth adapted for grazing. Which conclusion best uses this fossil evidence to support evolution?
16. After drinking a sugary sports drink, a student's blood glucose rises and then returns closer to normal within an hour. Which model best includes the key interactions among the digestive, circulatory, and endocrine systems involved in this change?
17. A student says, "Cytokinesis is the stage of mitosis when chromosomes line up in the center." Which correction is accurate?​
18. A cell is performing aerobic cellular respiration. Which substances must be available for the process to proceed as written in $\mathrm{C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP}$?
19. During transcription of a gene, what happens to the DNA and the newly made RNA? Choose the option that best matches the simplified sequence of events: DNA opens in the gene region, one strand is used as a template, RNA is built by base pairing (U instead of T), then the RNA leaves.
20. Claim: Cooperation improves hunting success. Evidence from an experiment in which researchers formed temporary hunting groups and released the same number of prey items into identical enclosures: - Solitary hunters (n = 30 trials): captured prey in 11 of 30 trials. - Pairs (n = 30 trials): captured prey in 18 of 30 trials. - Groups of 4 (n = 30 trials): captured prey in 24 of 30 trials. Which choice is the strongest support for the claim based on the evidence provided?

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