Cell division 2 Flashcards
What terms go with asexual reproduction
One parent, all offspring are identical, each parent passes all of its DNA to the offspring
What terms go with sexual reproduction
2 parents, Each parent passes half of its DNA to the offspring
What are gametes
Sex cells (sperm and egg cells)
What is fertilization
The union of sperm+egg
What is a zygote
The product of fertilization (the first cell of the new offspring)
What are homologous chromosomes
The chromosomes in a organism that is a result of sexual reproduction, this organism will have 2 sets of homologous chromosomes
What is a diploid
A cell that contains both sets of homologous chromosomes
What will happen if a parent cell is a diploid
The 2 daughter cells will be identical
What is a haploid
A cell that only has one set of chromosomes
Why must the egg and sperm cells have half the number of chromosomes
So that when fertilization occurs the zygote will have the proper diploid number
What is the purpose of meiosis
To reduce the chromosome number in the gametes in half
How many divisions happen in meiosis
2
How many chromosomes do humans have
46
How many chromosomes are there at the end of a cycle
4 cells with 23 chromosomes each
What is the difference between mitosis and meiosis
Mitosis is the certain of body cells and meiosis is the creation of sex cells
What happens in prophase 1
The chromosomes pair with their homologous chromosome to form a tetrad (4), crossing over occurs and they recombine their DNA
What happens in metaphase 1
The tetrads attach to spindle fibers and line up in the middle of the cell
What happens in anaphase 1
The tetrads separate the homologous chromosomes move to opposite sides of the cell
What happens in telophase
Nuclear membranes form around the chromosomes
How many cells were made in meiosis 1
2
What happens in prophase ll
Sister chromatids are still attached at the centromere and spindle fibers begin to form
What happens in metaphase ll
The chromosomes line up in the middle of the cell, the centrioles are at the poles
What happens in anaphase ll
The centrioles split and sister chromosomes separate and move to opposite sides of the cell
What happens in telophase ll
Nuclear membranes form, cytokinesis happens at the same time
