All Flashcards
What are the three main ways meiosis creates genetic variation?
Crossing over, independent assortment, and random fertilization.
Briefly outline the Law of Segregation.
During gamete formation, allele pairs separate so each gamete only gets one allele.
Describe the process of crossing over.
Homologous chromosomes exchange bits of DNA during meiosis, creating new combinations of genes.
What happens during independent assortment?
Chromosomes line up randomly during meiosis, mixing up maternal and paternal chromosomes.
What occurs during random fertilization?
The chance union of any sperm and egg further increases genetic variation.
What are the key differences between meiosis and mitosis?
Meiosis: Two rounds of cell division, creates 4 genetically unique haploid cells. Mitosis: One round of cell division, creates 2 identical diploid cells.
Differentiate between incomplete dominance and co-dominance.
Incomplete dominance: Neither allele is fully dominant, resulting in a blended phenotype. Co-dominance: Both alleles are expressed equally.
Compare dominant and recessive alleles.
Dominant allele: Expresses its trait in a heterozygote. Recessive allele: Masked by the dominant allele in a heterozygote.
Contrast haploid and diploid cells.
Haploid: Contains one set of chromosomes (n). Diploid: Contains two sets of chromosomes (2n).
Compare genotype and phenotype.
Genotype: Genetic makeup of an organism. Phenotype: Physical traits of an organism resulting from the genotype and environmental factors.
What is the effect of crossing over during meiosis?
Increased genetic variation due to the exchange of DNA between homologous chromosomes.
What is the effect of independent assortment during meiosis?
Increased genetic variation due to the random alignment of chromosomes.
What is the effect of random fertilization?
Further increased genetic variation due to the chance union of sperm and egg.
What is the effect of a dominant allele?
The dominant trait is expressed in the phenotype.
What is the effect of a mutation in DNA?
A change in the DNA sequence, potentially leading to altered protein production and phenotypic changes.
What is the effect of nondisjunction during meiosis?
Failure of chromosomes to separate properly, leading to gametes with an abnormal number of chromosomes.