Study Guide

Field 706: Biology
Sample Multiple-Choice Questions

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The following reference material will be available to you during the assessment:

Testlet 300: Structures and Processes of Cells and Organisms

Competency 0001
Understand the characteristics and behavior of the atoms and molecules necessary for life.

1. Before a marathon, a runner decides to eat pasta meals every night for dinner. Which of the following statements best describes the purpose of this strategy?

  1. The pasta fills saturated fat stores to help maintain body temperature during the race.
  2. The pasta increases the long-term energy stores in fat cells so that energy can be easily accessible during the race.
  3. The pasta allows for muscle proteins to be accessible for energy during the race.
  4. The pasta becomes glycogen stored in muscles so that it can be converted readily into sugars during the race.
Answer
Correct Response: D. Consuming pasta nightly before a marathon increases dietary carbohydrate intake, which is stored as glycogen in skeletal muscle (and liver), thereby maximizing endogenous carbohydrate reserves available for endurance exercise. During the race, glycolysis supports  A T P  production during sustained running.

2. Algae are placed in culture mediums of saline and different nutrient combinations (nitrogen, phosphate, and carbon dioxide) and then placed in optimal growing conditions. After two weeks, the amount of carbohydrates and lipids measured in the cultures remained constant. However, the protein and nucleic acid levels decreased. Which of the following statements is most accurate in describing the nutrients in the cultures at the end of the experiment?

  1. There were insufficient nitrogen compounds.
  2. There was insufficient carbon dioxide and too many nitrogen compounds.
  3. There were insufficient phosphate compounds.
  4. There were insufficient phosphate compounds and too much carbon dioxide.
Answer
Correct Response: A. Proteins and nucleic acids require the most nitrogen of all the macromolecules due to nitrogen-dense amino acids in proteins and nitrogenous bases in nucleotides. A lack of nitrogen in the culture medium would therefore result in low levels of proteins and nucleic acids due to reduced synthesis of those macromolecules.
Competency 0002
Understand the components of living things.

3. Gap junctions in animal cells are different from other types of cell-to-cell signaling because the ligands are:

  1. released only when the density in adjacent cells has reached a critical level.
  2. so short lived that they are manufactured constantly within each awaiting cell.
  3. carried between neighboring cells by chemical ions rather than protein molecules.
  4. exchanged between adjoining cells due to a direct connection of cell membranes.
Answer
Correct Response: D. Gap junctions are intercellular channels formed by the docking of connexon hemichannels in the plasma membranes of two adjacent animal cells, creating a direct cytoplasm-to-cytoplasm connection that permits diffusion of ions and other small signaling molecules between the adjoining cells.

4. A student sets up a wet mount of a leaf from an aquatic plant under a light microscope. After drawing an image of the wet mount, the student adds a drop of 1.0 M salt solution to the slide. Which of the following observations is most likely to occur after the salt solution is added to the slide?

  1. The cell membrane contracts away from the cell wall, clumping chloroplasts together.
  2. The central vacuole fills with water, pushing chloroplasts against the cell wall.
  3. The whole cell, including the organelles, remains the same in size.
  4. The chloroplasts move faster around the central vacuole due to salt diffusing into the cell.
Answer
Correct Response: A. Adding a 1.0 M salt solution creates a strongly hypertonic environment around the aquatic plant cells, causing water to exit cells by osmosis. This reduces turgor pressure and causes cell contents, including the cell membrane and cytoplasm, to shrink and pull away from the rigid cell wall.
Competency 0003
Understand the flow of energy in different organisms.

5. Plants use sunlight during  C 3  photosynthesis. Which of the following statements best describes what process these organisms use at night?

  1. Plants continue to make carbohydrates through photosynthesis at night, using the fluorescence of chlorophyll.
  2. Plants proceed with only the Calvin cycle at night, taking in carbon dioxide to synthesize carbohydrates.
  3. Plants continue respiration via glycolysis at night, using the chemical energy that was generated from sunlight during the day.
  4. Plants do not process carbohydrates at night, and then restart photosynthesis once the sun appears.
Answer
Correct Response: C. In  C 3  plants, the light-dependent reactions of photosynthesis require sunlight to produce  A T P  and  N A D P H , and the Calvin cycle depends on that  A T P  and  N A D P H  to fix carbon dioxide into sugars, so carbohydrate production by photosynthesis cannot continue in darkness. At night, however, plants remain metabolically active and keep making usable cellular energy ( A T P ) by cellular respiration, which includes glycolysis and uses sugars made earlier as fuel.

6. Use the table below to answer the question that follows.

Table depicting a student's calculations of the rate of oxygen consumption in germinating and dried (non-germinating) peas
Experimental Groups Oxygen Consumption Rate
( milliliters of Oxygen per minute )
W 0.0005
Y 0.001
X 0.005
Z 0.02

Students investigating cellular respiration have calculated the rate of oxygen consumption in germinating and dried (non-germinating) peas at 10 degrees Celsius  and at 24 degrees Celsius . Based on the data in the table, which of the following groups contained germinating peas at 24 degrees Celsius ?

  1. Group W
  2. Group X
  3. Group Y
  4. Group Z
Answer
Correct Response: D. Germinating seeds require oxygen to perform cellular respiration, which breaks down food and provides energy for the seeds to grow. The significantly higher oxygen consumption rate in Group Z compared to the other groups indicates that germination is occurring in this group.
Competency 0004
Understand the homeostasis, growth, and reproduction of organisms.

7. Many plants can be propagated by making a stem cutting below a new growth node. The cell tips in the node are called meristems and will start to form roots when placed in the right conditions. Which of the following statements best describes why this is possible?

  1. The cut stem releases enzymes that trick the new cells into believing they are root cells.
  2. The node contains totipotent stem cells that differentiate into what the plant needs.
  3. The lateral stem has root cells all along it that are waiting to be activated.
  4. The meristem is made of haploid cells that can be stimulated to clone itself.
Answer
Correct Response: B. In plants, meristems are regions of actively dividing, developmentally flexible (totipotent) cells that can keep producing new cells and then differentiate into the specialized tissues required in that location, such as root tissues when a cutting is placed in rooting conditions.

8. Use the information below to answer the question that follows.

Myelodysplastic syndrome ( M D S ) is a blood disorder where blood stem cells in the marrow are unable to become mature red blood cells, white blood cells, or platelets. Current research on the disease suggests that there is a defect in the ability to repair duplication errors in  D N A  synthesis during the cell cycle. This creates abnormal cells that are unable to carry out the important functions of blood in the cardiovascular system.

Based on this information, in which of the following phases of the cell cycle should the error be repaired in a healthy cell?

  1.  G 1  phase
  2. S phase
  3.  G 2  phase
  4. M phase
Answer
Correct Response: C.  D N A  duplication happens during S phase, so replication (duplication) mistakes are typically detected after copying is finished but before the cell enters mitosis, at the  G 2  checkpoint. This checkpoint can halt the cycle to allow time for repair of damaged or incompletely/incorrectly replicated  D N A , so abnormal chromosomes are not passed to daughter cells.

Testlet 301: Ecosystem Interactions and Dynamics

Competency 0001
Understand the relationships between organisms within an ecosystem.

1. Every two to five years, oak trees produce a greater than normal abundance of acorns, which is known as masting. Acorns are a primary food for small rodents. Which of the following statements should be a direct effect of any given masting event by an oak tree?

  1. The small rodent population would increase.
  2. There will be smaller secondary consumers than normal.
  3. The acorn size will be larger than normal.
  4. There would be a decrease in the number of oak trees the next year.
Answer
Correct Response: A. Acorns are a key food resource for many small rodents; when this food suddenly becomes abundant, it directly increases food availability, which commonly boosts rodent survival and reproduction (often resulting in higher rodent numbers in the months to year following the mast).

2. The anemone shrimp hides among the sea anemones as a safe space from predators. In addition, the shrimp eats parasites and slime off the anemones. Which of the following types of symbiosis does this interaction represent?

  1. parasitism
  2. predation
  3. mutualism
  4. commensalism
Answer
Correct Response: C. This is an example of mutualism because the interaction benefits both organisms: the anemone shrimp gains protection by hiding among the anemone's stinging tentacles (a safe refuge from predators), and the sea anemone benefits when the shrimp removes parasites and other unwanted materials from its surface, which can help maintain the anemone's health.
Competency 0002
Understand how energy and matter pass through ecosystems.

3. Which of the following statements best describes the role of denitrification in the nitrogen cycle?

  1. converting atmospheric nitrogen into a usable form
  2. assimilating nitrogen compounds into plants
  3. accumulating nitrogen stores in the soil
  4. releasing nitrogen gas into the atmosphere
Answer
Correct Response: D. Denitrification is the nitrogen-cycle process in which microbes (typically under low-oxygen conditions) convert bioavailable nitrogen compounds such as nitrate into gaseous nitrogen, thereby returning nitrogen to the atmosphere and completing the cycle.

4. A student group is designing an experiment to test a hypothesis about the flow of energy in an ecosystem using plants in a small terrarium in the classroom. To simulate a limiting factor in tropical rainforest ecosystems, the amount of light the plants receive is altered. Which of the following factors is the dependent variable in this experiment?

  1. the amount of water each plant receives
  2. the type of plant used
  3. the growth rate of the plants
  4. the temperature the plants are exposed to
Answer
Correct Response: C. The dependent variable is the growth rate of the plants because the experimenter is manipulating the amount of light (the independent variable) to simulate a limiting factor, and the dependent variable is the outcome that is measured to see how it changes in response to that manipulation. In this example, the outcome is the growth rate of the plants under different light levels.
Competency 0003
Understand how humans impact ecosystems.

5. Which of the following environmental consequences is most closely associated with the use of solar panel farms?

  1. thermal pollution of nearby waterways
  2. loss of habitat due to large area requirements
  3. release of sulfur oxides into the atmosphere
  4. harm of avian populations due to collisions
Answer
Correct Response: B. Solar panel farms require substantial land area, and a widely recognized environmental impact of this land conversion is land disturbance/land-use change that can remove, fragment, or degrade existing habitat at and around the project site.

6. Which of the following methods would be the most effective at alleviating the effects of acid rain on a lake?

  1. phytoremediation
  2. carbon capture
  3. lime application
  4. membrane filtration
Answer
Correct Response: C. Acid rain harms lakes primarily by lowering water  P H  (making it more acidic). Applying lime/limestone (commonly calcium carbonate) is a well-established remediation method that neutralizes acidity and raises  P H , restoring the lake's buffering capacity and improving conditions for aquatic life.

Testlet 302: Heredity and Evolution

Competency 0001
Understand genetic inheritance.

1. In a certain variety of garden pea, round shape and yellow color are dominant traits, while wrinkled shape and green color are recessive traits. When two pea plants heterozygous for these traits are crossed, phenotypes of the offspring are observed in the following proportions.

Based on the information, these results best support which of Mendel's laws of inheritance?

  1. law of dominance
  2. law of segregation
  3. law of crossing over
  4. law of independent assortment
Answer
Correct Response: D. The alleles for seed shape and seed color assort independently into gametes during meiosis, producing four gamete types in roughly equal proportions. The 9:3:3:1 phenotypic ratio in the subsequent generation is a pattern that results directly from the law of independent assortment in a dihybrid cross such as this one.

2. The cloning of target genes is often done by using the technique of polymerase chain reaction ( P C R ) rather than using bacterial plasmids, because  P C R :

  1. can clone a wider range of target genes for any given species.
  2. is less likely to produce clones that are contaminated by nontarget  D N A .
  3. can separate out target genes from a particular species more efficiently than plasmids.
  4. is able to make larger quantities of target genes more quickly than plasmids.
Answer
Correct Response: A.  P C R  is an in vitro  D N A  amplification method that can generate millions of copies of a specific  D N A  sequence within a few hours by repeated replication cycles, whereas plasmid-based cloning generally requires multiple slower biological steps (insertion into a vector, transformation into bacteria, and growth/replication) before large amounts of the target  D N A  are obtained.
Competency 0002
Understand natural selection, adaptation, and the diversity of life.

3. Drought conditions are occurring more frequently across an island chain than in previous decades. Small-seed plant populations are decreasing in number as they succumb to the reduced water conditions and competition from the more tolerant plants with hard-cased seeds. Hard-cased seeds are consumed by a population of seed-eating birds with large, thick, cone-shaped beaks, while small seeds are eaten by a population of seed-eating birds with small, cone-shaped beaks. Based on the information, if drought becomes more severe, which of the following statements best fits the theory of natural selection for the seed-eating birds?

  1. The small-beaked birds will become generalists and begin eating other foods.
  2. The bird populations will gradually change, increasing the number of birds with large, thick, cone-shaped beaks.
  3. The small-beaked birds will begin to gradually enlarge and thicken their beaks.
  4. The bird populations will remain the same, with no change in the percentages of birds with small and larger beaks.
Answer
Correct Response: B. As drought becomes more severe in this environment, more hard-cased seeds will likely be available, and birds that already have heritable beak traits best suited to cracking those seeds are more likely to survive and reproduce. Over multiple generations the frequency of large, thick beaks will likely increase in the population (natural selection acts on existing variation and changes populations over time).

4. In a southwest Australian nature park, the koala population dwindled from 8,000 to about 150 individuals following a severe forest fire. The fire critically affected the population's ability to recover. Park ecologists raced to help preserve the species by capturing and relocating 50 individuals to start a new colony. Which of the following statements best describes what would most likely happen to the new population over time?

  1. The new colony will retain the same genetic diversity as the original colony.
  2. The new colony will be less genetically diverse than the original colony.
  3. The new colony will use new adaptations that drive genetic diversity.
  4. The new colony will not be able to adapt and will go extinct.
Answer
Correct Response: B. Relocating only 50 koalas to found a new population creates a founder effect, where a new colony starts from a small subset of the original gene pool and therefore carries only some of the original population's alleles. This reduces genetic variation over time compared to the source population.