Genetics and Meiosis Test Flashcards
(41 cards)
Stages of Meiosis
-Prophase 1
-Metaphase 1
-Anaphase 1
-Telophase 1
—–Cytokinesis——
Prophase 2
Metaphase 2
Anaphase 2
Telophase 2
—–Cytokinesis——
Main events of Meiosis 1
-Cell goes from being diploid to haploid
-produces haploid cells because the purpose of this process is to reproduce
-Homologous chromosomes are separated from each other
-Produces two haploid cells
Main events of Meiosis 2
-Exactly like Mitosis
-Sister chromatids are separated from each other
-Produces four haploid cells
Prophase 1
*Crossing over happens
-Nuclear envelope breaks down
-Chromatin is condensed into chromosomes
-Spindle forms
Metaphase 1
-Homologous chromosomes line up with their pair in the middle (metaphoric plate)
Anaphase 1
-Homologous chromosomes are pulled apart and separated
Telophase 1
-Chromosomes break down into chromatin
-Nuclear envelope reforms
-Spindle detaches
Cytokinesis 1
-Forms two new cells
Prophase 2
-Spindle forms
-Nuclear envelope breaks down
-Chromatin is condensed into chromosomes
Metaphase 2
-Chromosomes line up in the middle (metaphoric plate)
Anaphase 2
-Sister chromatids separate (pulled apart by spindle)
Telophase 2
-Nuclear envelope reforms
-Spindle dissolves
-Chromosomes turn into chromatin
Meiosis
Cell division to create gametes
Zygote
A fertilized egg
Diploid
A cell that contains two sets of homologous chromosomes
Haploid
A cell that contains only a single set of genes
Homologous
-The type of chromosomes which one set comes from male part and the other coms from female part
-Crossing over and independent assortment = genetic variation
Summary of Mendel’s Principles
-The inheritance of biological characteristics is determined by individual units called genes
-When two or more forms (alleles) of a gene for a single trait exist, some alleles may be dominant and others may be recessive
-In most sexually reproducing organisms, each adult has two copies for each gene - one from each parent. These genes segregate from each other when gametes are formed
-Alleles for different genes usually segregate independently of each other
Gregor Mendel’s two conclusions from experiment
1) An individuals characteristics are determined by factors that are passed from one parental generation to the next
2) Some alleles are dominant and others are recessive. An organism will exhibit dominant over recessive
Probability
The likelihood that a particular event will occur
Independent assortment
How different genes independently separate from one another when reproducing cells develop
Segregation
The separation of alleles during the formation of gametes so each gamete only has one allele of each gene
Codominance
Both alleles are fully expressed
Incomplete Dominance
Neither allele is expressed (phenotype is blend)
