Q: What are the three main levels of biological information flow?
A: 1. Molecule → Molecule (DNA → RNA → Protein) 2. Cell → Cell (Mitosis) 3. Generation → Generation (Meiosis + Fertilization)
Q: What is genetic variation?
A: Differences in DNA sequences among individuals that lead to diverse traits and drive evolution.
Q: What are the main sources of genetic variation?
A: Mutations recombination (crossing over), random chromosome assortment, and fertilization.
Q: How do identical and fraternal twins differ genetically?
A: Identical twins come from one fertilized egg that splits, fraternal twins from two separate eggs. Variation arises from meiosis and recombination.
Q: During asexual reproduction what causes genetic differences between daughter cells?
A: Random mutations during DNA replication.
Q: During sexual reproduction what mechanisms increase variation?
A: Mutations, recombination and random chromosome sorting during meiosis.
Q: What is a mutation?
A permanent change in the DNA sequence.
Q: What causes mutations?
A: DNA replication errors, UV light, chemical and radiation
Q: What does UV light do to DNA?
A: It creates thymine or cytosine dimers that distort DNA and cause replication errors.
Q: Which types of mutations can change protein function?
Missense, nonsense, and frameshift mutations. Silent mutations do not change protein function.
Q: How can UV exposure lead to skin cancer?
UV light damages DNA in skin cells, leading to mutations that cause uncontrolled cell growth.
Q: Are skin-cancer mutations inherited by children?
No, they occur in somatic cells, not in germline cells.
Q: Which type of mutation can be passed to offspring?
A: Mutations in germline (egg/sperm) cells.
Q: If one skin cell mutates which cells carry that mutation after mitosis?
A: Only the daughter cells of that original cell.
Q: What’s the difference between somatic and germline mutations?
A: Somatic mutations affect body cells (not heritable); germline mutations affect reproductive cells (heritable)
Q: Why is mutation location important?
A: Only mutations in reproductive cell DNA can be inherited by offspring.
Q: What process shuffles DNA between chromosomes?
A: Recombination (crossing over) during meiosis.
Q: What type of mutation results from a single base change without amino acid change?
A: Silent substitution.
Q: Which mechanism directly creates new alleles?
A: Mutations.
Q: Why is genetic diversity essential to evolution?
A: It provides the differences natural selection acts on driving adaptation and speciation.
