Cell Biology
What organelle is known as the “powerhouse of the cell”?
mitochondria
What process converts sunlight into chemical energy?
Photosynthesis
What does DNA stand for?
Deoxyribonucleic acid
Who developed the theory of natural selection?
Charles Darwin
What organism makes its own food?
Producer (autotroph)
What structure controls what enters and leaves the cell?
Cell membrane (plasma membrane)
Where does cellular respiration mainly occur?
Mitochondria
What is the probability of offspring with genotype aa from Aa × Aa?
25%
What is natural selection?
The process where organisms with beneficial traits survive and reproduce more successfully.
What is the role of decomposers in an ecosystem?
They break down dead organisms and recycle nutrients.
What process allows water to move across a semipermeable membrane?
Osmosis
What molecule stores and transfers energy in cells?
ATP
What process produces gametes?
Meiosis
Structures with similar anatomy but different functions are called what?
Homologous structures
What is carrying capacity?
The maximum population size an environment can support.
Why do cells remain small instead of growing indefinitely?
A large surface area-to-volume ratio is needed for efficient transport of materials.
Name the two main stages of photosynthesis.
Light-dependent reactions and the Calvin cycle
What enzyme unzips DNA during replication?
helicase
What is genetic drift?
Random changes in allele frequencies due to chance events.
Only about what percentage of energy transfers between trophic levels?
About 10%
How does the structure of the phospholipid bilayer help maintain homeostasis?
The phospholipid bilayer is selectively permeable, allowing some substances to pass while blocking others, which helps regulate the cell’s internal environment.
Describe the role of the electron transport chain in cellular respiration.
The electron transport chain uses high-energy electrons to create a proton gradient that powers ATP synthase to produce ATP.
Explain the difference between independent assortment and crossing over.
Independent assortment is the random distribution of chromosomes during meiosis, while crossing over is the exchange of DNA between homologous chromosomes.
Explain how mutations contribute to evolution.
Mutations create genetic variation within populations, and beneficial mutations may increase survival and reproduction through natural selection.
Describe how removing a keystone species could affect an ecosystem.
Removing a keystone species can disrupt food webs, reduce biodiversity, and destabilize the ecosystem because many organisms depend on it.