All flashcards
Flashcard 1: What is a mutation?
Answer: A heritable change in DNA nucleotide sequence. Can be passed to offspring and affect protein function.
Flashcard 2: Which two meiosis-related mechanisms create recombination without creating new alleles?
Answer: Crossing over and independent assortment. Both processes occur during meiosis I.
Flashcard 3: What is a locus?
Answer: A gene’s specific location on a chromosome. Each gene has a fixed chromosomal address.
Flashcard 4: Which meiotic stage directly produces independent assortment of chromosomes?
Answer: Metaphase I. When homologous pairs align randomly at cell equator.
Flashcard 5: What is random fertilization as a source of genetic variation?
Answer: Any sperm can fertilize any egg, creating new genotypes. Combines genetic material from two different parents.
Flashcard 6: Which genetic process can introduce alleles from one population into another?
Answer: Gene flow. Migration connects previously isolated gene pools.
Flashcard 7: What is independent assortment?
Answer: Random orientation of homologous pairs in meiosis I. Each homolog can go to either pole during division.
Flashcard 8: What is polyploidy?
Answer: More than two complete sets of chromosomes. Often results from errors in meiosis or mitosis.
Flashcard 9: During which meiotic phase does crossing over typically occur?
Answer: Prophase I. When chromosomes pair and exchange genetic material.
Flashcard 10: Which meiotic event creates new allele combinations by exchanging DNA between homologs?
Answer: Crossing over (homologous recombination). Occurs between paired homologous chromosomes in meiosis.
Flashcard 11: Which process produces gametes and increases genetic variation in sexually reproducing organisms?
Answer: Meiosis. Combines crossing over and independent assortment for variation.
Flashcard 12: What is nondisjunction in meiosis?
Answer: Failure of homologs or sister chromatids to separate. Results in gametes with incorrect chromosome numbers.
Flashcard 13: Which chromosomal mutation moves a segment to a nonhomologous chromosome?
Answer: Translocation. Transfers genetic material between different chromosomes.
Flashcard 14: Which chromosomal mutation reverses a segment within a chromosome?
Answer: Inversion. Flips gene order but keeps genes on same chromosome.
Flashcard 15: Which chromosomal mutation repeats a segment of a chromosome?
Answer: Duplication. Creates extra copies of genes within a chromosome.
Flashcard 16: Which broad category of mutations affects an entire chromosome segment?
Answer: Chromosomal mutation (structural rearrangement). Involves large-scale DNA changes beyond single nucleotides.
Flashcard 17: Which mutation changes a codon but not the amino acid it codes for?
Answer: Silent mutation. Due to genetic code redundancy, protein remains unchanged.
Flashcard 18: Which mutation creates a premature stop codon?
Answer: Nonsense mutation. Truncates protein synthesis early, often affecting function.
Flashcard 19: Which mutation changes an amino acid in a protein sequence?
Answer: Missense mutation. Results in a different amino acid in the protein product.
Flashcard 20: What is a frameshift mutation?
Answer: Insertion or deletion that shifts the reading frame. Changes how codons are read downstream from mutation site.
Flashcard 21: Which mutation removes one or more nucleotides from a DNA sequence?
Answer: Deletion. Removes genetic material from the DNA sequence.
Flashcard 22: Which mutation adds one or more nucleotides to a DNA sequence?
Answer: Insertion. Adds extra genetic material to the DNA strand.
Flashcard 23: Which source of variation is described: new alleles are created rather than reshuffled?
Answer: Mutation. Only mutation introduces completely novel genetic material.
Flashcard 24: What is genetic recombination?
Answer: Formation of new allele combinations in offspring. Shuffles existing alleles into new arrangements.
Flashcard 25: Which two meiosis-related mechanisms create recombination without creating new alleles?
Answer: Crossing over and independent assortment. Both processes occur during meiosis I.
Flashcard 26: What is the difference between mutation and recombination as sources of variation?
Answer: Mutation creates new alleles; recombination reshuffles alleles. Mutation adds novelty; recombination rearranges existing material.
Flashcard 27: Which point mutation replaces one nucleotide with another?
Answer: Substitution. One of three types of point mutations affecting single bases.
Flashcard 28: Which type of mutation changes a single nucleotide in DNA?
Answer: Point mutation. Affects only one DNA base position at a time.
Flashcard 29: What is a mutation?
Answer: A heritable change in DNA nucleotide sequence. Can be passed to offspring and affect protein function.
Flashcard 30: What is the primary genetic source of new alleles in a population?
Answer: Mutation. Creates entirely new alleles that didn't exist before.