All flashcards
Flashcard 1: Which gametes can a heterozygous parent (Aa) produce for that gene?
Answer: A and a. Heterozygotes produce equal amounts of both allele types.
Flashcard 2: What is the probability of aa offspring from a cross Aa × Aa?
Answer: rac{1}{4}. One in four offspring inherit both recessive alleles.
Flashcard 3: What is the probability of dominant phenotype offspring from a cross Aa × aa?
Answer: rac{1}{2}. Half the offspring (Aa) show dominant phenotype.
Flashcard 4: Identify the expected genotype ratio from a monohybrid cross Aa × Aa.
Answer: 1 AA : 2 Aa : 1 aa. Classic Mendelian ratio from heterozygous parents.
Flashcard 5: What is the expected phenotype ratio for complete dominance in Aa × Aa?
Answer: 3 dominant : 1 recessive. Three genotypes (AA, Aa, Aa) show dominant; one (aa) shows recessive.
Flashcard 6: What does heterozygous mean?
Answer: Having two different alleles (Aa). One dominant and one recessive allele create a mixed genotype.
Flashcard 7: What does homozygous mean?
Answer: Having two identical alleles (AA or aa). Both alleles are the same, either both dominant or both recessive.
Flashcard 8: What is phenotype?
Answer: The observable trait produced by genotype and environment. Phenotype results from both genetic and environmental factors.
Flashcard 9: What is a chromosome?
Answer: A DNA-protein structure carrying many genes. Chromosomes package and organize genetic information for inheritance.
Flashcard 10: What is genotype?
Answer: An organism’s allele combination for a trait. Genotype is the genetic makeup that determines potential traits.
Flashcard 11: What is a gene?
Answer: A DNA segment that codes for a trait or protein. Genes are hereditary units that determine specific characteristics.
Flashcard 12: What is the difference between dominant and recessive alleles in a model?
Answer: Dominant is expressed in Aa; recessive needs aa. Dominant masks recessive in heterozygotes; recessive appears only when homozygous.
Flashcard 13: What is a Punnett square used to model?
Answer: Possible offspring genotypes and their probabilities. This grid shows all possible genetic combinations from parent crosses.
Flashcard 14: Which statement describes meiosis in inheritance models?
Answer: It makes gametes with one allele per gene. Meiosis halves chromosome number, creating haploid gametes.
Flashcard 15: What is fertilization in inheritance models?
Answer: Fusion of two gametes to form a zygote. Gametes unite to restore the diploid chromosome number.
Flashcard 16: What fraction of an offspring’s alleles for a gene comes from each parent?
Answer: Each parent contributes rac{1}{2} of the alleles. Sexual reproduction ensures equal genetic contribution from both parents.
Flashcard 17: Identify the genotype of an offspring that must show a recessive trait.
Answer: aa. Recessive traits only appear with two recessive alleles.
Flashcard 18: What is a dominant allele in simple Mendelian inheritance?
Answer: An allele expressed in a heterozygote. It masks the recessive allele when both are present.
Flashcard 19: Identify the offspring genotype ratio for Aa × Aa using a Punnett square.
Answer: 1 AA : 2 Aa : 1 aa. Cross produces rac{1}{4} AA, rac{2}{4} Aa, rac{1}{4} aa.
Flashcard 20: What is a recessive allele in simple Mendelian inheritance?
Answer: An allele expressed only when homozygous. Hidden by dominant allele; needs two copies to show.
Flashcard 21: What is an allele in a heredity model?
Answer: An alternative form of a gene. Alleles are different versions of the same gene, like brown vs blue for eye color.
Flashcard 22: What is a gamete, and how many alleles for a gene does it carry?
Answer: A sex cell; it carries 1 allele per gene. Gametes (sperm/egg) carry half the genetic information.
Flashcard 23: What is fertilization in a heredity model?
Answer: Fusion of two gametes to form a zygote. Sperm and egg unite, combining their genetic information.
Flashcard 24: What is a zygote in a heredity model?
Answer: A fertilized egg with 2 alleles per gene. Gets one allele from each parent, restoring the full genetic set.
Flashcard 25: What model best represents that offspring receive one allele from each parent?
Answer: A Punnett square showing one allele per gamete. Shows gametes with single alleles combining at fertilization.
Flashcard 26: What is meant by segregation in models of inheritance?
Answer: Allele pairs separate into different gametes. During gamete formation, paired alleles split up.
Flashcard 27: What is a gene?
Answer: A DNA segment that codes for a trait. Genes are specific DNA sequences that determine inherited characteristics.
Flashcard 28: What is a phenotype?
Answer: The observable trait produced by genotype and environment. Phenotype is what you see, influenced by both genes and environment.
Flashcard 29: What is a genotype?
Answer: The allele combination an organism has. Genotype refers to the genetic makeup, not the visible trait.
Flashcard 30: Which gametes can a parent with genotype Aa produce in a simple model?
Answer: A and a. Each gamete gets one allele due to segregation.