Practice Test 48 - High School Biology

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

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1. In aerobic cellular respiration, a muscle cell uses glucose from food and oxygen from breathing to make ATP. Which pair of substances must be used up (consumed) for aerobic cellular respiration to occur?
2. A DNA strand has the sequence CCGTA. What is the complementary sequence on the other strand?
3. Red blood cells are specialized for transporting oxygen. Compared with many other cells, mature red blood cells lack a nucleus and are packed with hemoglobin. What does this best illustrate about differentiation?
4. A gene for flower color has two alleles: R (functional enzyme makes red pigment) and r (nonfunctional enzyme makes no red pigment). Which statement best describes how alleles can lead to different phenotypes?
5. In a mouse population, fur color is influenced by alleles $D$ and $d$. Predation is higher on light-colored mice. Survival probabilities are: $DD$: 85%, $Dd$: 50%, $dd$: 15%. Which outcome is most likely after several generations?
6. A student says, "If two DNA segments have the same number of A, T, G, and C bases, they must contain the same genetic information." Which response best corrects the student?
7. A class compares two statements about adaptations: Statement 1: "An adaptation is a heritable trait that increases survival or reproduction in a specific environment and becomes common in a population over many generations." Statement 2: "An adaptation is a change an individual makes during its lifetime in response to the environment." Which choice correctly evaluates these statements?
8. A population of insects has no heritable variation for resistance to a new pesticide (all individuals are genetically susceptible). The pesticide is applied repeatedly. Which outcome is most consistent with natural selection?
9. Producers in an ecosystem contain 70,000 units of energy. Tertiary consumers contain 70 units of energy. What percentage of the producer energy reaches the tertiary consumers?
10. A piece of fruit starts to ripen and releases a gas that speeds up ripening. Faster ripening causes the fruit to release more of the gas, which speeds ripening even more until the fruit is fully ripe. Which type of feedback is described?
11. Over several decades, average spring temperatures in a mountain region increase. Some plant species begin flowering earlier, but a key pollinator insect still emerges at the same time as before. Seed production in those plants declines. What is the best explanation for this ecosystem change?
12. A forest with 30 tree species is hit by an insect that feeds mainly on one tree species. A nearby plantation has only 1 tree species (the insect's preferred food). How does biodiversity affect population stability of trees in these two forests during the outbreak?
13. A student draws a concept map for oxygen delivery during exercise with three boxes: Respiratory system, Circulatory system, Muscular system. Which set of arrow labels and directions is most appropriate?
14. A student claims: "Natural selection happens because organisms evolve the traits they need in order to survive." Which response best corrects this claim using the mechanism of natural selection?
15. A deer population in a forest increased for several years. After a series of harsh winters, many deer died and fewer fawns were born the next spring. Rangers observed that most shrubs and young trees had been eaten down to the bark, while water sources and space in the forest remained plentiful. Which factor is most likely limiting the deer population's growth (determining carrying capacity, K) in this scenario?
16. In a desert ecosystem, cactus plants capture sunlight and make sugars. Kangaroo rats eat cactus seeds, and snakes eat kangaroo rats. If all producers (like the cactus) were removed, what would most likely happen first?
17. An arctic fox population lives in a region that becomes snow-covered for most of the year. Fur color varies due to heritable differences: a few foxes are very light-colored while most are darker. Predators more easily spot foxes that contrast with the snow. Over many generations, what is the most accurate explanation for how white fur can become an adaptation in this environment?
18. A desert area is being damaged by off-road vehicle (ORV) use, which crushes fragile soil crusts and plants, increasing erosion. Managers propose: Plan A: Fence the most sensitive areas and create a few designated ORV trails on more durable ground. Plan B: Re-seed native plants each year in areas damaged by ORVs, but keep the entire area open to ORV use. Which plan is more likely to be effective and sustainable, and what is the best reason?
19. In a certain plant, tall (T) is dominant over short (t). A homozygous tall plant is crossed with a heterozygous tall plant: $TT \times Tt$. What is the probability that an offspring will be short (tt)?
20. A wetland supports a frog population. In one year, the wetland produces enough insect prey to support 1,200 frogs, and it has enough clean water to support 900 frogs. However, it only has enough safe breeding sites to support 600 frogs. Assuming these are the only limiting factors, what is the wetland's carrying capacity (K) for frogs?

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