Meiosis and Genetics Flashcards
(29 cards)
What occurs during Prophase 1
The chromosomes condense and the nuclear envelope breaks down.
What occurs during Prophase 2
A new spindle forms around the chromosomes.
What occurs during Metaphase 1
Pairs of homologous chromosomes meet at the equator of the cell.
What occurs during Metaphase 2
Chromosomes line up at the equator.
What occurs during Anaphase 1
Homologous chromosomes move to the opposite poles of the cell.
What occurs during Anaphase 2
Centromeres divide, chromatids move to opposite poles of the cell.
What occurs during Telophase 1
Chromosomes gather at the poles of the cells and the cytoplasm seperates.
What occurs during Telophase 2
A new nuclear envelope forms around the chromaids, and the cytoplasm seperates.
Describe crossing over
During prophase 1, homologous chromosomes pair up to form a tetrad. Bits of non-sister chromatids are swapped at “random” locations. Crossing over creates more combinations of DNA than would otherwise be possible
Describe independent assortment
During metaphase 1, homologous chromosomes line up together across the middle. Then, they are randomly sorted into different cells
Describe random fertilization
What is the probability that any one sperm will fertilize any particular egg? 1 out of 64 trillion.
Compare/Contrast Mitosis vs Meiosis
Mitosis: Growth, Repair, creates two genetically identical diploid daughter cells.
Meiosis: Sexual Reproduction, creates four genetically different Haploid cells
How is genetic information from both parents combined in the fertilized egg to produce a new combination of genes and traits.
Half the genetic information for the offspring comes from the father and the other half comes from the mother, out of all the sperm cells and all the eggs there is a huge variety of the genetic combination that can be shown in the offspring.
What is dominant vs recessive
Two “factors” control a trait, one is dominant and the other recessive. For the recessive trait to show both factors must be recessive, often shown by a lower case letter “a” however for the dominant trait to show there only needs to be one because it “dominates” recessive gene often shown with an uppercase letter “A”
What is a phenotype
A phenotype is the observable characteristics of an individual resulting from its genotype
What is a genotype
A genotype is the genetic makeup of a cell and contributes to its phenotype. Shown by a set of two letters “AA” that represents one of the two alleles in a genotype.
What is an allele and what is its function
An allele is one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome. The one that produces the protein is usually the dominant one and the one that doesn’t produce a protein is recessive.
What is the law of segregation
The two alleles of the parent separate during meiosis so that each gamete contains only one allele
What is incomplete dominance
In complete dominance occurs when the dominant allele doesn’t fully mask the recessive one. So, for example if the color red was dominant for flower petals and white is recessive and there is incomplete dominance than the flower petals would be pink.
What is co-dominance
Co-dominance occurs when both Alleles are dominant resulting in a mix of both colors like a speckled chicken shown by two uppercase letters “AB” this occurs because alleles produce the protein.
What is multiple allele inheritance
Multiple allele inheritance is a situation where a gene is controlled by more than two allele Ex: Blood type (A, B, AB, and O) from 3 alleles (i, Ia, Ib)
What is a polygenic trait
trait controlled by more than one gene, often deals with size, shape, form , color. For example in skin color each dominant allele makes melanin and darkens the skin by a certain amount.
Compare/Contrast Polygenic inheritance and single gene inheritance
Polygenic inheritance results from multiple alleles and has a wide variety of phenotypes. Single gene inheritance results from one set of alleles and usually only has two outcomes
How to you show someone who is affects by a trait on a pedigree
A shaded shape
