Biology Chapter 11 - Genetics Test Review Flashcards
Are there any exceptions to Mendel’s principles? What are some examples?
Yes;
- Some genes are neither dominant nor recessive
- Many genes have multiple alleles
- Many traits are produced by the interactions between several genes
Describe the relationship between genes and the environment.
Genes provide a plan for development, but how that plan unfolds also depends on the environment. Environmental conditions affect gene expression.
How many sets of genes do multicellular organisms inherit?
The diploid cells contain 2 copies of chromosomes and 2 sets of genes
What are chromosomes?
Strands of protein and DNA inside the cell nucleus; the carriers of genes.
What does ‘haploid’ mean? What are haploid cells?
Haploid = “one set”
Haploid cells = containing only one set of chromosomes and one set of cells
What are the main phases of meiosis? (There are 5)
- Prophase I
- Metaphase I
- Anaphase I
- Telophase I
- Prophase II
What happens in Prophase I ?
Each replicated chromosome pairs with its corresponding homologous chromosome.
What happens in Metaphase I ?
Paired homologous chromosomes line up across the center of the cell.
What happens in Anaphase I ?
Spindle fibers pull each homologous chromosome pair toward opposite ends of the cell.
What happens in Telophase I ?
A nuclear membrane forms around each cluster of chromosomes. Cytokinesis follows this phase and produces two new cells.
What happens in Prophase II ?
The cells’ chromosomes (each consisting of two chromatids) become visible.
The final four stages of Meiosis II result in what kind of cells?
Four haploid daughter cells.
What happens in Prophase I ?
Each replicated chromosome pairs with its corresponding homologous chromosome. Tetrads form. Homologous chromosomes pair up and undergo crossing-over.
What happens in Metaphase I ?
Paired homologous chromosomes line up across the center of the cell. Spindle forms and attaches itself to a tetrad.
What happens in Anaphase I ?
Spindle fibers pull each homologous chromosome pair toward opposite ends of the cell. After anaphase, the separated chromosomes cluster at opposite end of the cell.
What happens in Prophase II ?
The cells’ chromosomes (each consisting of two chromatids) become visible.
What does Meiosis I result in?
2 daughter cells that each have 4 chromatids
What stages occur in Meiosis II ?
Prophase II Metaphase II Anaphase II Telophase II Cytokinesis
What happens in Prophase II ?
Chromosomes (which each have 2 chromatids) become visible.
What happens in Metaphase II ?
Chromosomes line up at the center of the cell
What happens in Anaphase II ?
Paired chromatids separate
The ____ cells produced by meiosis II are gametes.
Haploid. (Four haploid daughter)
Fertilization generates new combinations of alleles in ___.
a zygote
How is meiosis different from mitosis?
Mitosis does not change number of chromosomes of the original cell. Meiosis reduces the number of chromosomes by half.
In mitosis, two sets of genetic material separate and each daughter cell receives one set of chromosomes. In Meiosis, homologous chromosomes line up and then move to separate daughter cells.
Mitosis results in the production of two genetically identical diploid cells whereas meiosis produces four genetically different haploid cells.
