AB 3 Flashcards
(27 cards)
What is meiosis?
A type of cell division that halves the number of chromosomes in a cell
What are the two types of cells formed during meiosis?
Egg and sperm cells
What occurs during Prophase 1 of meiosis?
Nuclear membrane disappears, chromosomes condense and homologous chromosomes pair up
What is crossing over?
The exchange of genetic material between homologous chromosomes during Prophase 1
What happens during Metaphase 1?
Homologous chromosomes line up in pairs at the equator and spindle fibers attach to centromeres
What is the outcome of Anaphase 1?
Homologous chromosomes move towards opposite poles, centromeres do not split
What occurs during Telophase 1?
The cell divides, and a nuclear membrane forms around each group of chromosomes
What is the result of Meiosis 1?
Two cells with 46 chromosomes (diploid)
What is Maturation 2 / Division 2 in meiosis?
The process where the two cells divide to form four haploid cells
What happens during Prophase 2?
New spindles appear and cells are completely separated
What occurs during Metaphase 2?
Chromosomes line up individually on the equator
What is the outcome of Anaphase 2?
Spindle fibers pull chromatids apart
What is the final result of Telophase 2?
Four gametes formed, each with half the number of chromosomes of the parent cell
What is the chromosome count in human gametes?
23 chromosomes, genetically identical to parents
What is mitosis?
A type of cell division that results in identical cells
What is the primary function of meiosis?
To produce gametes for sexual reproduction
How many cell divisions occur in meiosis?
Two cell divisions
What is the first law of inheritance?
Law of dominance
What does the law of segregation state?
Alleles segregate during gamete formation
What is the phenotypic ratio from a cross of Aa x Aa?
3:1 ratio of dominant to recessive traits
What is the third law of inheritance?
Law of independent assortment
What is a dihybrid cross?
A cross between individuals with two different traits
What is the expected phenotypic ratio in a dihybrid cross?
9:3:3:1 ratio
What did Gregor Mendel contribute to genetics?
He established the foundational laws of inheritance
