Ecology
What is the term for a group of individuals of the same species living in a specific area?
population
What does biodiversity refer to?
The variety of life in all forms, levels, and combinations.
What is the main difference between prokaryotic and eukaryotic cells?
Eukaryotic cells have a nucleus and membrane-bound organelles; prokaryotic cells do not.
What is the difference between genotype and phenotype?
Genotype is the genetic makeup; phenotype is the physical expression.
What are the base-pairing rules in DNA?
A pairs with T, and C pairs with G.
What’s the role of decomposers in nutrient cycling?
They break down dead organisms, recycling nutrients back into the ecosystem.
Why is genetic diversity important for a population's survival?
It allows populations to adapt to environmental changes and resist diseases.
Describe the function of the mitochondria.
The mitochondria generate ATP through cellular respiration.
What does it mean for an allele to be dominant?
It masks the expression of a recessive allele in heterozygous individuals.
What enzyme is responsible for unzipping the DNA strand during replication?
Helicase
Define and give an example of a density-dependent limiting factor.
A factor that changes with population density, like disease or competition.
Name two human activities that decrease biodiversity and explain why.
Deforestation and pollution reduce habitats and kill off sensitive species.
How does the structure of the cell membrane contribute to its function?
Its phospholipid bilayer with embedded proteins allows selective permeability.
What is a dihybrid cross and what’s the expected phenotypic ratio?
A cross involving two traits; the typical F2 phenotypic ratio is 9:3:3:1.
What is the role of mRNA in protein synthesis?
It carries the genetic message from DNA to the ribosome.
Explain how energy flows and matter cycles in an ecosystem.
Energy flows in one direction and is eventually lost as heat; matter cycles through biotic and abiotic components
How do invasive species reduce biodiversity?
They outcompete native species for resources, disrupting ecosystems.
Explain why muscle cells have more mitochondria than skin cells.
Muscle cells require more energy for contraction, so they need more mitochondria for ATP production.
How can a child have a genetic disorder that neither parent visibly shows?
The disorder can be recessive, and both parents may be carriers (heterozygous).
Describe the process of transcription and where it occurs.
DNA is used to make mRNA in the nucleus.
What is ecological succession and why is it important for ecosystems?
Ecological succession is the process by which the mix of species and habitat in an area changes over time. Gradually, these communities replace one another until a “climax community”—like a mature forest—is reached, or until a disturbance, like a fire, occurs.
Explain how biodiversity loss can affect ecosystem services.
It can reduce resilience, water purification, pollination, and other essential functions ecosystems provide.
Compare passive and active transport and give an example of each.
Passive transport moves substances down the gradient without energy (e.g., diffusion), while active transport moves substances against the gradient using energy (e.g., sodium-potassium pump).
Describe the difference between incomplete dominance and codominance.
In incomplete dominance, heterozygotes show a blend; in codominance, both alleles are fully expressed.
Explain how a mutation in DNA can lead to a nonfunctional protein.
A change in DNA can alter the mRNA codon, possibly changing the amino acid sequence and protein folding.