Structure and Function
What is the correct order of processes that explains how the DNA sequence of a gene results in the formation of a protein?
Transcription of DNA into mRNA (happens in the nucleus)
mRNA leaves the nucleus and reaches a ribosome
Translation of mRNA into amino acids (happens in a ribosome)
Amino acids fold into a protein with a specific shape
Create a labeled diagram or written explanation to describe how photosynthesis transforms light energy into stored chemical energy. Be sure to include the reactants, products, and the location in the plant where photosynthesis takes place.
Occurs in chloroplasts
Reactants: carbon dioxide (CO₂), water (H₂O), and sunlight
Products: glucose (C₆H₁₂O₆) and oxygen (O₂)
Energy from sunlight is used to break the bonds of the input molecules and is ultimately stored as chemical energy in the bonds of glucose
Describe how both biotic and abiotic factors influence the carrying capacity of a freshwater lake ecosystem. Include an example of how a change in one abiotic and one biotic factor could affect the population of a fish species in the lake.
Abiotic factors: temperature, oxygen levels, water availability
Biotic factors: availability of food, predators, competition
Example: A drop in dissolved oxygen (abiotic) or increase in predators (biotic) can reduce fish population
Carrying capacity is the maximum number the ecosystem can support sustainably
Use a diagram or written explanation to model the basics of the process of mitosis. Then, explain how differentiation results in specialized cells like muscle or nerve cells, even though they all contain the same DNA.
DNA must first be replicated; then mitosis results in two genetically identical daughter cells with the same number of chromosomes (diploid 46 --> diploid 46 + diploid 46)
Differentiation is caused by the activation/deactivation of specific genes (genes turned on or off) in different cell types
Explain how different types of scientific evidence support the idea that all species share a common ancestor. Include at least two types of evidence in your answer
Examples: similarity in DNA between species; homologous structures like the forelimbs of humans, cats, and whales; similar stages of embryo development; fossil record
The idea that these similarities suggest descent from a common ancestor
DNA and protein evidence is stronger than physical appearance alone
List the correct order, from smallest to largest, of structures in the human body, starting with the atom, and going all the way up to the whole organism.
Atom --> Molecule --> Organelle --> Cell --> Tissue --> Organ --> Organ System --> Organism
Explain how atoms from sugar molecules can be rearranged and combined with other elements to form molecules such as proteins, DNA, or fats. In your explanation, include what additional elements are required and how this demonstrates the transformation of matter in an organism.
Sugar molecules provide carbon, hydrogen, and oxygen
Other elements such as sulfur, phosphorus, and nitrogen are needed to form biomolecules such as proteins, DNA, and fats
Atoms are rearranged through chemical reactions to form these molecules
Matter is conserved; atoms are not created or destroyed, only rearranged
A student collected data on two ecosystems: one with high biodiversity and one with low biodiversity. After a drought, the student observed that species in the more diverse ecosystem were more stable in number. Explain why biodiversity helps ecosystems remain stable.
Biodiverse ecosystems have more interdependent species = more resilience. Easier to fill lost niches. More options for sources of food as needed.
A student learns that only part of the DNA in a chromosome actually codes for proteins.
Ask two questions that could help the student better understand how both coding and noncoding regions of DNA contribute to inherited traits. Then, answer one of your questions based on what you know about gene expression.
How does noncoding DNA control when a gene is turned on or off?
Can mutations in noncoding DNA affect how traits are expressed?
What happens if a coding region of a gene gets deleted or changed?
Describe how natural selection works using the example of a species of beetle where some individuals are green and others are brown. Brown beetles are harder for predators to see in their environment.
1. Species produce more offspring than can survive (overproduction)
Over time, brown coloration becomes more common in the population
A mutation changes the DNA sequence in a gene. What is the most likely effect on the protein that is produced?
A change in DNA changes mRNA and ultimately the amino acid sequence, resulting in a protein with a different shape and function (or no function at all).
Create a model or written explanation that describes how anaerobic cellular respiration breaks down food molecules and releases energy. Be sure to include the reactants and products of the process and describe what happens to the energy that is released.
Occurs in cytoplasm
Reactant: glucose (C₆H₁₂O₆)
Products: lactic acid, ATP (or ethanol, CO2, and ATP)
A wildfire burns through a forest, destroying plant life and displacing most animal species.
Evaluate the claim: "Ecosystems return to their original state after any disturbance."
Use evidence from ecological succession and reasoning about biodiversity to support or refute the claim.
Reference to primary or secondary succession
Some ecosystems may recover partially or change permanently
Species composition may change; biodiversity may increase or decrease over time
Support/refute based on resilience and severity of disturbance
Make a claim about one way that genetic variation can occur in a population. Defend your claim using scientific evidence.
Options for ways that genetic variation can occur:
(1) genetic recombination during meiosis,
(2) errors in DNA replication,
(3) mutations caused by the environment, or
(4) genetic engineering
Clearly stated claim (e.g., Genetic recombination during meiosis increases variation)
Supporting evidence: crossing over, independent assortment, DNA replication errors, or environmental examples (e.g., UV radiation)
Genetic engineering examples: CRISPR, recombinant DNA
Must show that changes can be inherited if they occur in gametes
In a population of rabbits, some have long legs that help them escape predators, and others have short legs. Over 10 generations, scientists observe that the number of rabbits with long legs increases from 40% to 75%.
Use this information to explain how probability and natural selection can lead to a change in the frequency of a helpful trait in a population.
Individuals with long legs have a survival advantage → more likely to reproduce
Offspring inherit the long-leg trait → frequency of long-leg allele increases
Over generations, probability favors the survival and reproduction of long-legged rabbits
This is a shift in allele frequency due to natural selection
A student creates a model showing how the respiratory and circulatory systems work together to maintain homeostasis during exercise. Describe what they should include in their model.
Lungs breathe faster to get more oxygen into the bloodstream; heart pumps faster to bring oxygen to cells faster and move carbon dioxide back to the lungs faster; lungs breathe out carbon dioxide faster
Construct an explanation for how both matter and energy move through an ecosystem. Use producers and consumers as examples. Then, describe how this explanation would change if decomposers were removed from the system.
Producers (plants) convert sunlight to stored energy in food
Consumers eat producers and other consumers, transferring energy and matter
Energy is used for life processes, and 90% is lost as heat
Matter (like carbon and nitrogen) is reused but must be recycled by decomposers
Without decomposers, matter would not be returned to the soil/air for reuse
Design a solution to reduce the impact of one human activity (e.g., deforestation, pollution, introduction of invasive species) on a local ecosystem. Describe how your solution would protect biodiversity, and evaluate the strengths and limitations of your solution.
Identify specific human impact (e.g., plastic pollution, overfishing)
Design solution: e.g., local policy, habitat restoration, public education, new technology
Strengths: measurable impact, feasibility, scalability
Limitations: cost, community buy-in, unintended consequences
In a population of 100 people, 9 individuals have attached earlobes and 91 have detached earlobes.
(1) Determine which trait is likely recessive and which is likely dominant
(2) Identify the genotype(s) that cause each phenotype
(3) Share a reasonable estimate of the probability of having the heterozygous genotype within this population
(4) Explain how both genes and environment can affect whether a trait is expressed.
Recognition that attached earlobes are recessive: people with the trait must have two recessive alleles (aa)
AA genotype = homozygous dominant; detached earlobes phenotype
Estimate: carriers = people who have one dominant and one recessive allele (don’t show the trait, but can pass it on)
If 9% are aa, a larger number could be Aa—maybe 30–40%
Environmental effects: Not all traits are strictly genetic; some traits (like height or weight) are influenced by both genes and lifestyle factors; environment can also change gene expression through epigenetic tags
Early Earth had very little oxygen in its atmosphere. After the evolution of autotrophs such as cyanobacteria, oxygen levels began to rise.
Construct an argument, using scientific evidence, to explain how the evolution of autotrophs changed Earth’s atmosphere and made new types of life possible.
In your response, be sure to:
Describe the role of photosynthesis in changing the atmosphere
Explain how this change affected the evolution of other organisms
Support your argument with at least one piece of scientific evidence
Fossil stromatolites as evidence of early autotrophs
Changes in the types of organisms in the fossil record after oxygen levels increased
A scientist conducts an experiment to test how the human body maintains blood sugar levels after eating. Describe a proper experimental setup.
Measure blood sugar levels in a control group (no food) and an experimental group (with food) over several hours with measurements taken at regular intervals with well-tested equipment by trained professionals. Have a large number of healthy participants in each group. Perform multiple trials on different days. Control all variables except for food/no food.
Develop a model (diagram or written) that illustrates how carbon moves through the biosphere, atmosphere, hydrosphere, and geosphere. Include at least three processes that move carbon and explain how human activities have altered this natural cycle.
Photosynthesis moves carbon from atmosphere → biosphere
Respiration and decomposition return carbon to atmosphere
Combustion (burning fossil fuels) adds carbon to atmosphere
Carbon moves into oceans (hydrosphere) via acidification and can be stored in rocks (geosphere) via sedimentation
Human impact: increased combustion = increased CO₂ = climate change
Explain how group behaviors, such as flocking, schooling, or hunting in packs, can increase the survival and reproductive success of individuals in a species. Provide at least two examples and evaluate how these behaviors might influence natural selection over generations.
Example 1: Wolves hunting in packs increases hunting efficiency and food availability
Example 2: Fish schooling reduces individual chance of predation
Group behavior improves survival = greater chance to reproduce
Traits that favor cooperation may become more common through natural selection
Illustrate (in a diagram or written explanation) how the male and female reproductive systems work together to maintain the continuity of life. Include the role of testes, ovaries, and placenta, and explain how these organs support fertilization and/or the development of the fetus.
Testes produce and deliver sperm; ovaries release eggs
Fertilization occurs in the fallopian tube
Placenta allows for exchange of nutrients and waste between mother and fetus
Systems work together to ensure successful reproduction and embryonic development
After a volcanic eruption changes the climate of an island, scientists observe that:
A heat-tolerant plant species becomes more abundant
A new type of lizard appears with heat-resistant skin
Several species of amphibians disappear completely
Use evidence and reasoning to evaluate how environmental changes can lead to the increase, appearance, or extinction of species over time.
Increased temperature selects for heat-tolerant traits → species with those traits increase
New traits in lizards suggest adaptation or possibly speciation over time
Amphibians go extinct due to inability to tolerate new conditions
Shifting environmental pressures change which alleles are favored
Supports the idea that natural selection is dynamic and responsive to environmental change