Mitosis and Meiosis Comparison
Introduction:
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell
nucleus into two identical sets, in two separate nuclei. Meiosis, is a special type of cell division
necessary for sexual reproduction in eukaryotes.
In this activity you will whiteboard the similarities and differences between Meiosis and Mitosis.
Students will present in a boardroom format.
Key Terms for Mitosis and Meiosis
Students should be able to identify and use the terms during the whiteboard boardroom meeting:
DNA (deoxyribonucleic acid): The molecule that encodes genetic information. DNA is a
double- stranded molecule held together by weak bonds between base pairs of nucleotides. The
four nucleotides in DNA contain the bases: adenine (A), guanine (G), cytosine (C), and thymine
(T). In nature, base pairs form only between A and T and between G and C; thus the base
sequence of each single strand can be deduced from that of its partner.
Gene: The fundamental physical and functional unit of heredity. A gene is an ordered sequence
of nucleotides located in a particular position on a particular chromosome that encodes a specific
functional product (i.e., a protein or RNA molecule)
Chromosome: The self- replicating genetic structure of cells containing the cellular DNA that
bears in its nucleotide sequence the linear array of genes. Eukaryotic genomes consist of a
number of chromosomes whose DNA is associated with different kinds of proteins.
Chromatid: One of the daughter strands of a chromosome that has recently been copied (during
mitosis or meiosis), and which is still connected to the other daughter strand. Upon separation
from each other, the chromatids become chromosomes.
Chromatin: Mass of genetic material composed of DNA and proteins that condense to form
chromosomes in eukaryotic cell division. Chromatin is located in the cell's nucleus.
Centromere: A specialized chromosome region to which spindle fibers attach during cell
division.
Centrosome: A small region of cytoplasm adjacent to the nucleus that contains the centrioles
and serves to organize microtubules.
Centriole: A short cylindrical organelle, found in pairs arranged at right angles to each other at
the centre of a microtubule organizing centre (MTOC) or centrosome, found in eukaryotes
(except in higher plants). The centrosome organizes formation of a spindle during mitosis or
meiosis.
Spindle Fibers: Microtubular structures that extend from the centrioles and attach to the
centromere of a chromosome during mitosis and meiosis.
Metaphase Plate: An imaginary plane perpendicular to the spindle fibers of a dividing cell,
along which chromosomes align during metaphase.
Homologous chromosomes: A pair of chromosomes containing sequences for the same genes,
each derived from one parent.
Tetrad: A four-part structure that forms during the prophase of meiosis and consists of two
homologous chromosomes, each composed of two sister chromatids.
Dyad: One pair of homologous chromosomes resulting from the division of a tetrad during
meiosis.
Haploid: A single set of chromosomes (half the full set of genetic material), present in the egg
and sperm cells of animals and in the egg and pollen cells of plants. Human beings have 23
chromosomes in their reproductive cells. Compare diploid.
Diploid: A full set of genetic material, consisting of paired chromosomes one chromosome from
each parental set. Most animal cells except the gametes have a diploid set of chromosomes. The
diploid human genome has 46 chromosomes. Compare haploid.
Gamete: Mature male or female reproductive cell (sperm or ovum) with a haploid set of
chromosomes (23 for humans).