Practice Test 45 - High School Biology

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

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1. Two islands have lizards with the same two genotypes for a heat-tolerance gene: $TT$ and $tt$. On Island 1 (weak selection), survival is $TT$: 95%, $tt$: 90%. On Island 2 (strong selection), survival is $TT$: 95%, $tt$: 15%. Compared to Island 1, how will genotype frequencies change on Island 2 over the same number of generations?
2. A coding DNA sequence is ATG TCA GGC. A substitution mutation changes it to ATG TTA GGC. Which statement best describes how this mutation could affect the resulting protein and its function?
3. Two different genes control two different traits in a plant: one gene affects flower color (purple vs. white) and a separate gene affects height (tall vs. short). Which statement best reflects how genes relate to traits in this situation?
4. A person becomes very cold after getting wet in windy weather. Their body temperature drops from 37.0°C to 36.0°C. Thermoreceptors detect the drop and trigger shivering, which generates heat. However, in this situation shivering is weak and stops after a few minutes even though body temperature remains at 36.0°C. Which conclusion best explains what this suggests about homeostasis in this case?
5. A person has not had water for several hours. Their blood becomes more concentrated than normal. Osmoreceptors in the brain detect this change and cause the release of ADH, which makes the kidneys reabsorb more water, producing a smaller volume of more concentrated urine. After drinking water, blood concentration returns closer to normal and ADH release decreases. Which choice best explains why this is considered negative feedback?
6. A population of beetles has two alleles for shell color: $G$ (green) and $g$ (brown). Researchers measured allele frequencies over 25 generations in the same population. Generation 0: $f(G)=0.90$, $f(g)=0.10$ Generation 5: $f(G)=0.78$, $f(g)=0.22$ Generation 15: $f(G)=0.55$, $f(g)=0.45$ Generation 25: $f(G)=0.40$, $f(g)=0.60$ Which statement best describes what the data show?
7. Skin and hair must stay strong and flexible. Cells in these tissues continually make structural proteins such as keratin and collagen to replace proteins that wear out over time. Why is ongoing protein synthesis important in this case?
8. A wildlife survey counted tail stripe patterns in a lizard population: - No stripes: 18 - One stripe: 3 - Two stripes: 19 Which statement best describes the distribution pattern for stripe type?
9. In a plant species, smooth seeds (S) are dominant over wrinkled seeds (s). Two heterozygous plants are crossed: $Ss \times Ss$. If an offspring is known to have the dominant phenotype (smooth), what is the probability the offspring is a carrier (heterozygous $Ss$)?​
10. A potato plant makes extra glucose during photosynthesis and links many glucose molecules together to form starch, which it stores in tubers. During winter, photosynthesis slows and the plant breaks down stored starch into glucose to use in cellular respiration. How does starch synthesis connect to the plant's survival?
11. A plant cell uses glucose for two different synthesis jobs: (1) linking glucose into cellulose and (2) linking glucose into starch. Which statement correctly connects each product to its main function?
12. A fenced wildlife reserve provides enough resources for up to 900 rabbits based on food availability, up to 700 rabbits based on water availability, and up to 500 rabbits based on burrow space. Assuming these are the only limiting factors, what is the reserve's carrying capacity (K) for rabbits?
13. In a grassland food chain—grass → rabbit → fox—dead organisms and waste are broken down by fungi and bacteria. What is the main role of decomposers in matter cycling?
14. A student says: "The only reason gametes are different from each other is random mutations." Which response best corrects the student using meiosis concepts?
15. A prairie restoration project began after farmland was abandoned (Year 0). Scientists tracked plant species richness and the population size of a native grassland bird. Data: - Year 0: plant species 7; birds 2 - Year 3: plant species 19; birds 8 - Year 7: plant species 28; birds 15 - Year 12: plant species 31; birds 16 Which statement best fits the pattern of recovery shown?
16. Which comparison correctly matches each process with its main location in eukaryotic cells and its energy transformation? Photosynthesis: $6CO_2 + 6H_2O + \text{light} \rightarrow C_6H_{12}O_6 + 6O_2$ Cellular respiration: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$
17. Why do cells break down glucose in many controlled steps during cellular respiration rather than releasing all the energy at once (like burning)?
18. A student is comparing two models: Model 1 (Matter): A loop of arrows: CO$_2$ in Atmosphere → Plants → Animals → Decomposers/Soil → CO$_2$ in Atmosphere. Model 2 (Energy): One-way arrows: Sun → Plants → Animals → Decomposers, with heat arrows leaving each box. Which statement correctly compares the two models?
19. A population graph shows the population increasing to a peak above a dashed line labeled $K$ (carrying capacity), then dropping sharply to a much lower level. Which interpretation best describes what happened?
20. Two siblings (not identical twins) have different combinations of traits. Which explanation best connects this to meiosis?

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