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Practice Test 26 - High School Biology

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

  1. A bacterial population grows in a petri dish with plenty of nutrients at first. As the dish becomes crowded, a contagious virus that infects the bacteria spreads quickly from cell to cell, and the bacterial population stops increasing due to higher death rates. Which statement best describes this limiting factor?
  2. In an energy-flow model, a box labeled "Glucose (stored chemical energy)" has two outgoing arrows: one to "Cellular respiration (ATP released)" and one to "Storage as starch." What does this branching best represent?
  3. A bacterial population contains two types: antibiotic-resistant (R) and susceptible (S). Before treatment, only 10% are resistant. During antibiotic treatment, 95% of susceptible bacteria die, but only 5% of resistant bacteria die. After treatment, what happens to the frequency of resistant bacteria among the survivors?
  4. A group of plants grows in a field where sunlight and water are plentiful. Soil tests show that nitrogen is very low. The plants remain small and produce fewer seeds. When farmers add nitrogen fertilizer, the plants grow taller and produce many more seeds. Which factor was the primary limiting factor for the plant population before fertilizer was added?
  5. A plant uses glucose produced by photosynthesis to build cellulose for cell walls. Which statement best connects glucose to the macromolecule cellulose?​
  6. A student watches a flock of small birds feeding on the ground. When a hawk appears, one bird gives an alarm call and the whole flock takes off. Compared with a single bird feeding alone, what is a main advantage of feeding in a flock in this situation?
  7. A student compares two mutations in the coding region of the same gene: Mutation 1 (substitution): ATG GAA CCT → ATG GAG CCT Mutation 2 (insertion): ATG GAA CCT → ATG GCA ACC T... (one base inserted after ATG) Which comparison is most accurate about their likely effects on the protein?
  8. DNA stores genetic information using a four-letter "alphabet" of bases: A, T, G, and C. Two short DNA segments are shown: Segment 1: ATGCCG and Segment 2: GCATCG. Why can these two segments carry different genetic information even though they use the same four bases?
  9. A student says, "If a population is exposed to a new environment, it will adapt right away because natural selection makes the needed traits appear." Which response best corrects the student using natural selection and the idea that adaptations take time?
  10. A trophic transfer goes from 4,000 kJ at the primary consumer level to 400 kJ at the secondary consumer level. What percentage of energy was transferred to the next level?
  11. A student says, "Resilience and stability mean the same thing: ecosystems that are stable always bounce back after a disturbance." Which response best corrects the student using the ideas of stability and resilience?
  12. In aerobic cellular respiration, cells break down glucose using oxygen to make usable energy. Which list shows the main products (outputs) of cellular respiration?
  13. A cell continually synthesizes proteins, including enzymes like amylase and ATP synthase. Why is ongoing protein synthesis essential for cell survival?
  14. A plant makes glucose during the day and can still grow at night when there is no sunlight. Which statement best explains how photosynthesis makes this possible?
  15. Over several decades, average temperatures rise in a mountain region. A cold-adapted plant species is found at higher elevations than before, and populations at lower elevations shrink because conditions become too warm. Which climate-change impact does this illustrate?
  16. In a general homeostasis model, sensors detect the current value of a condition (like temperature), a control center compares it to a set point, and effectors carry out a response. If the internal condition is below the set point, what should a homeostatic response generally do?
  17. In DNA, the sugar and phosphate parts are the same in every nucleotide, but one part varies and carries the information in the sequence. Which part varies from one nucleotide to another?
  18. During childbirth, the baby's head stretches the cervix. Stretch receptors send signals that lead to the release of oxytocin, which strengthens uterine contractions. Stronger contractions increase cervical stretch even more, leading to more oxytocin release. This cycle continues until the baby is delivered. Which statement best explains why this process does not continue indefinitely?
  19. Claim: A population of weeds evolved resistance to Herbicide H in a farm field. Evidence to evaluate: 1) In 2015, 9% of weeds survived spraying; in 2023, 64% survived the same dose. 2) A nearby unsprayed field has 10% survival in 2023. 3) In 2023, the farm harvested more corn than in 2015. 4) A greenhouse test shows that when seeds from 2023 survivors are grown and sprayed, 60% of their offspring survive. Which choice best evaluates the evidence for evolution of herbicide resistance?
  20. A student is learning that transcription makes an mRNA copy of a gene. The DNA stays protected in the nucleus, while the mRNA can move to where proteins are made later. Where does transcription occur in a typical eukaryotic cell, and what is made?

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