Practice Test 5 - 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 short DNA segments are shown: Sequence 1: ATGCCG and Sequence 2: GCATCG. They contain the same four types of bases (A, T, G, C), but in a different order. Why can these two sequences store different genetic information?
2. In the nitrogen cycle diagram, decomposers connect dead organisms back to the soil. According to the arrow labels, what is the immediate product added to the soil by decomposition (ammonification)?
3. Photosynthesis and cellular respiration can be summarized by these overall equations: Photosynthesis: $6CO_2 + 6H_2O +$ light energy $\rightarrow C_6H_{12}O_6 + 6O_2$ Cellular respiration: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O +$ ATP energy Which statement best explains how these two processes are related in terms of matter and energy?
4. A population of lizards reproduces in two different ways depending on conditions. In one mode, each offspring gets DNA from two parents and siblings are usually genetically different. In the other mode, one parent produces offspring that are genetically identical to the parent. Which mode would generally produce more genetic variation in the offspring, and why?​
5. A family trait (attached earlobes) is caused by a recessive allele (a). Two parents do not have attached earlobes, but they have one child who does. Which explanation best fits the evidence?
6. A human is made up of many organ systems (such as the circulatory and digestive systems) working together. At what level of biological organization is a human classified?
7. A grassland site experienced a wildfire in Year 0. Ecologists tracked several ecosystem indicators before the fire and during recovery. Data: - Species richness (number of plant species): Pre-fire 42; Year 0: 14; Year 2: 27; Year 5: 36; Year 8: 40 - Aboveground plant biomass (g/m²): Pre-fire 520; Year 0: 110; Year 2: 310; Year 5: 470; Year 8: 500 Which conclusion is best supported by the data about ecosystem recovery by Year 8?
8. Which pair correctly matches the process with the reproduction type it is most closely associated with in basic biology?
9. Which option correctly describes what happens to the ~90% of energy that is not passed from one trophic level to the next?
10. In an ecosystem, plants and animals exchange gases. Using the overall equations: Photosynthesis: $6CO_2 + 6H_2O + \text{light} \rightarrow C_6H_{12}O_6 + 6O_2$ Respiration: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$ Which pair correctly identifies a substance produced by animals (through respiration) that plants can use for photosynthesis, and a substance produced by plants (through photosynthesis) that animals can use for respiration?
11. A gene contains the DNA sequence (coding strand) ATG CCC GAA, which helps make a protein. A mutation changes it to ATG CTC GAA. This is a substitution (one base changed). Which statement best describes the most likely effect on the protein? (You do not need to know the exact codon-to–amino acid chart.)
12. In a simple ecosystem model: producer → primary consumer → secondary consumer → tertiary consumer → decomposers. Which statement correctly describes how energy and matter move through this model?
13. In winter, emperor penguins form large colonies and huddle close together during blizzards. How does this group behavior help individual penguins compared with standing alone?
14. The fossil Tiktaalik has fish-like traits (scales, fin rays) and tetrapod-like traits (a neck and wrist-like bones that could support weight). How does Tiktaalik best support evolution by common ancestry?
15. A field is planted with young sunflower seedlings. At first, most seedlings grow quickly. As they get taller and more crowded, many smaller plants stop growing and produce fewer seeds because they are shaded by taller neighbors. Which limiting factor best explains why the sunflower population's growth and reproduction decrease as density increases?
16. A plant leaf cell contains both chloroplasts and mitochondria. Which pairing correctly matches the process to its main location in the cell and the main direction of energy change?
17. A student says, "Chromosomes only exist when a cell is dividing; when the cell is not dividing, there are no chromosomes." Which correction best matches how DNA is organized in cells?
18. A student is comparing two ideas about how macromolecules form: (1) "Monomers just clump together to make polymers," and (2) "Monomers chemically bond together during synthesis." In the context of building a polysaccharide from glucose, which statement is most accurate?
19. In a eukaryotic cell, DNA stays in the nucleus. Transcription makes an mRNA copy of a gene so the information can be used elsewhere in the cell. After transcription is complete, what happens to the newly made mRNA (basic idea)?
20. Two coastal marsh sites were monitored for recovery after an oil spill that affected only Site A in Year 0. Site B was nearby and not oiled. Scientists measured marsh grass cover (%) and counted crab burrows (an indicator of crab population) per 100 m². Year 0 (3 months after spill): - Site A: grass cover 18%; crab burrows 12 - Site B: grass cover 82%; crab burrows 64 Year 4: - Site A: grass cover 63%; crab burrows 41 - Site B: grass cover 80%; crab burrows 66 Which conclusion is best supported?

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