Ecology
What is a producer?
Organism that makes its own food (plants)
What is an independent variable? Dependent?
Independent = changed (manipulated) dependent = measured (observed)
What causes Down syndrome?
extra copy of chromosome 21
What is the base-pairing rule in DNA?
A-T and C-G
A mutation occurs in a DNA sequence, but the organism shows no change in traits.
The mutation may be silent (does not change the amino acid), occur in non-coding DNA, or not significantly affect protein function.
What is the role of decomposers?
Break down dead organisms and recycle nutrients
Why should an experiment be repeated multiple times?
To increase reliability and reduce the impact of random error.
What is nondisjunction?
Failure of chromosomes to separate properly during meiosis
What is the difference between genotype and phenotype?
Genotype = genes; Phenotype = physical traits
Two populations of the same species become geographically separated. Over time, they develop different traits.
Geographic isolation leads to different environmental pressures and genetic changes over time, resulting in reproductive isolation and speciation.
What happens when energy moves up a food chain?
Energy decreases
A student tests enzyme activity at different temperatures and records the rate of reaction. The rate increases until 40°C, then rapidly decreases.
Enzyme activity increases with temperature until optimal conditions, then enzymes denature at high temperatures and lose function.
A DNA sequence changes but does not affect the protein produced.
Silent Mutation
Why is the cell membrane described as “selectively permeable”?
It allows some substances to enter/exit while blocking others
Analyze how human activity impacts biodiversity and ecosystem stability.
Reduced biodiversity makes ecosystems less stable, less productive, and less able to recover from disturbances (like natural disasters or disease).
What is carrying capacity?
Maximum population an environment can support
A scientist is testing a new fertilizer on plant growth but does not include a control group. Why is this a problem?
There is no baseline for comparison, so the scientist cannot determine if the fertilizer actually caused any change.
Why are insertion and deletion mutations often more harmful than substitutions?
They cause a frameshift, changing all downstream amino acids
Why is the shape in Biology so important?
Shape tells the item what processes/jobs to do or become
Predict what would happen if enzymes stopped functioning in a cell.
Without enzymes, life processes stop—and the cell cannot survive.
How much energy is lost at every level?
10%
A student tests how different amounts of sunlight affect plant growth. All plants receive the same amount of water and soil.
What is the difference between a gene mutation and a chromosomal mutation?
Gene mutation = change in DNA sequence
Chromosomal mutation = change in chromosome number or structure
What is the difference between primary and secondary succession?
Primary = no soil
Secondary = already has soil
A scientist places identical plant cells in two different solutions. One cell becomes rigid, and the other shrinks.
The rigid cell is in a hypotonic solution (water enters the cell), and the shrinking cell is in a hypertonic solution (water leaves the cell). This is due to osmosis and differences in solute concentration.