All flashcards
Flashcard 1: Identify the correct statement: sexual reproduction vs. asexual reproduction and variation.
Answer: Sexual: high variation; asexual: low variation (mostly clones). Sexual mixes genes; asexual copies parent exactly.
Flashcard 2: What is sexual reproduction?
Answer: Production of offspring by combining gametes from two parents. Requires two parents unlike asexual reproduction.
Flashcard 3: What is genetic variation among offspring?
Answer: Differences in inherited traits caused by different gene combinations. Results from mixing parental DNA during reproduction.
Flashcard 4: What is a gamete?
Answer: A sex cell with one set of chromosomes (sperm or egg). Has half the chromosomes needed for reproduction.
Flashcard 5: What is fertilization?
Answer: Fusion of sperm and egg to form a zygote. Combines genetic material from both parents.
Flashcard 6: What is a zygote?
Answer: A fertilized egg cell with genes from both parents. Contains full chromosome set from combined gametes.
Flashcard 7: Which process makes gametes with half the usual chromosome number?
Answer: Meiosis. Reduces chromosome number from diploid to haploid.
Flashcard 8: What is the main reason meiosis increases genetic variation?
Answer: It creates gametes with new allele combinations. Shuffles genes through crossing over and independent assortment.
Flashcard 9: What is crossing over in meiosis?
Answer: Exchange of DNA between homologous chromosomes. Creates new gene combinations by swapping chromosome parts.
Flashcard 10: What is independent assortment in meiosis?
Answer: Random separation of homologous chromosome pairs into gametes. Each gamete gets random mix of maternal/paternal chromosomes.
Flashcard 11: What does random fertilization mean in sexual reproduction?
Answer: Any sperm can fertilize any egg, creating unique gene combinations. Increases variation by making offspring combinations unpredictable.
Flashcard 12: What is an allele?
Answer: A different version of the same gene. Like different flavors of the same trait (e.g., brown vs blue eyes).
Flashcard 13: What is a genotype?
Answer: The allele combination an organism has for a trait. The genetic recipe that determines traits.
Flashcard 14: What is a phenotype?
Answer: The observable traits produced by genes and environment. What you see, influenced by both genes and surroundings.
Flashcard 15: Which option best explains why siblings can look different even with same parents?
Answer: They inherit different allele combinations from meiosis and fertilization. Each child gets unique mix from same gene pool.
Flashcard 16: Choose the term: exchange of chromosome segments that increases variation in gametes.
Answer: Crossing over. Physical exchange of DNA between paired chromosomes.
Flashcard 17: Choose the term: random distribution of maternal and paternal chromosomes into gametes.
Answer: Independent assortment. Chromosomes sort randomly, not by parent origin.
Flashcard 18: Identify the key idea: How does sexual reproduction lead to variation among offspring?
Answer: It combines and reshuffles alleles from two parents into new genotypes. Meiosis and fertilization create unique combinations.
Flashcard 19: Which stage of meiosis is crossing over most associated with?
Answer: Prophase I. When homologous chromosomes pair up and exchange segments.
Flashcard 20: Identify the term for two chromosomes, one from each parent, that carry the same genes.
Answer: Homologous chromosomes. Matching pairs that can exchange segments during crossing over.
Flashcard 21: Which meiosis event increases variation by randomly separating homologous chromosome pairs?
Answer: Independent assortment. Chromosomes randomly sort into gametes during meiosis I.
Flashcard 22: Which meiosis event creates new allele combinations by swapping DNA between homologous chromosomes?
Answer: Crossing over. Exchanges genetic material between paired chromosomes during meiosis.
Flashcard 23: Choose the word that completes the statement: Meiosis produces gametes that are genetically .
Answer: different. Each gamete has a unique combination of chromosomes.
Flashcard 24: Which option best explains why siblings can look different even with the same parents?
Answer: Each sibling inherits a different combination of alleles. Random processes during meiosis create unique gametes.
Flashcard 25: What is an allele?
Answer: An alternative form of a gene. Different versions of genes create trait variations.
Flashcard 26: What is random fertilization?
Answer: Any sperm can fertilize any egg, creating many possible gene combinations. Millions of possible combinations increase genetic diversity.
Flashcard 27: What is fertilization?
Answer: Fusion of sperm and egg to form a zygote. Restores the full chromosome number by combining two gametes.
Flashcard 28: What is sexual reproduction?
Answer: Reproduction using two parents that produces genetically unique offspring. Combines genetic material from two sources, unlike asexual reproduction.
Flashcard 29: What is a gamete?
Answer: A sex cell with half the usual number of chromosomes. Produced by meiosis to ensure offspring don't have double chromosomes.
Flashcard 30: What is the main reason sexual reproduction increases variation compared with asexual reproduction?
Answer: It combines and reshuffles alleles from two parents. Each parent contributes different alleles, creating new combinations.