Practice Test 38 - High School Biology

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

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1. Consider the flowchart model: Sun → light energy → Chloroplast (chlorophyll) → Photosynthesis reactions → glucose → (stored chemical energy) Which arrow in the model best represents the transfer of light energy into the plant?
2. A student compares two models of a plant and a rabbit living in the same area. Model 1: Sun → photosynthesis → glucose + O2 → rabbit respiration → CO2 + H2O (arrows stop). Model 2: Sun → photosynthesis → glucose + O2 → respiration → CO2 + H2O → photosynthesis (forms a loop for matter), plus an arrow showing heat leaving after respiration. Which statement best evaluates the models?
3. A bird species has two male types. Brightly colored males are chosen by females more often and average about 4 offspring per season, but they are also spotted by predators more often than dull males. Dull males average about 2 offspring per season and are less often attacked. Which statement best describes how bright coloration can still increase fitness?
4. A lab grows bacteria in a flask where glucose is the limiting nutrient. The flask contains 2,400 mg of usable glucose. Each bacterial cell requires about 0.8 mg of glucose to survive and reproduce over the growth period. Using $K = \frac{\text{total glucose}}{\text{glucose per cell}}$, what is the carrying capacity (K) for bacterial cells in this flask?
5. A cell is observed with condensed, X-shaped chromosomes scattered in the cell. The nuclear envelope is breaking down and spindle fibers are beginning to form. Which stage of mitosis is being described?
6. A student says, "Cells store the energy they make during cellular respiration as ATP to power cellular work." Which choice lists the correct outputs of cellular respiration that would be formed inside the cell?
7. Farmers apply large amounts of fertilizer to cornfields. After several storms, a nearby lake turns bright green with an algae bloom, and later many fish are found dead near the shore. What is the best explanation for what happened in the lake?
8. A person holds their breath underwater. After a short time, their muscles feel weaker and they must surface. Which interaction best explains why both the respiratory and circulatory systems are needed for sustained muscle activity?
9. A system is described as "stable" if, after a disturbance, it tends to return toward a target value. A system is described as "unstable" if disturbances cause it to drift farther away. Which situation best represents a stable, homeostatic system?
10. In mice, normal tail (N) is dominant over short tail (n). Two heterozygous mice are crossed: $Nn \times Nn$. What is the expected genotype ratio (NN : Nn : nn) among the offspring?​
11. In a pond food chain, primary consumers have 4,000 kcal of energy. Using the 10% rule, how much energy is available to secondary consumers?
12. A diagram description includes matter and energy labels: Inputs to photosynthesis: CO2 + H2O + light energy Outputs of photosynthesis: glucose + O2 A student says, "The arrow for CO2 shows the energy entering the plant." Which correction best fits the model?
13. A forest stand experienced a severe insect outbreak that killed many mature trees in Year 0. Ecologists measured canopy cover (percent) and understory plant biomass (g/m²). Measurements: - Pre-outbreak: canopy cover 92%; understory biomass 140 - Year 0: canopy cover 40%; understory biomass 220 - Year 5: canopy cover 55%; understory biomass 260 - Year 15: canopy cover 80%; understory biomass 170 Which interpretation best fits the recovery trajectory shown?
14. Which option lists the levels of biological organization from smallest to largest?
15. A student says, "Glucose can only be used to make carbohydrates like starch." Which choice best corrects the student's claim about how cells use glucose as a building block?
16. A student claims, "Genetic variation in offspring comes only from mutations; meiosis just reduces chromosome number." Which choice best corrects this idea?
17. A cell is performing active transport across its membrane and needs ATP. Which statement best links this ATP use to cellular respiration?
18. A diagram of DNA shows two strands twisting into a double helix. The two strands run in opposite directions (often called antiparallel). What does "antiparallel" mean in this context?
19. A student says, "Transcription makes a mobile copy of a gene so the DNA can stay protected in the nucleus." Which statement best describes what RNA polymerase does during transcription?
20. In a fish species, tolerance to polluted water is influenced by a gene with alleles $P$ (tolerant) and $p$ (not tolerant). In polluted water, survival probabilities are: $PP$: 85%, $Pp$: 80%, $pp$: 15%. If the river stays polluted for many generations, what is the most likely long-term trend?

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