Lab 14- Mitosis and Meiosis
Cytokinesis
Division of the cytoplasm is not part of mitosis, but it usually occurs at the same time. Here, the cells divides in half. Each half receives approximately half of the cytoplasm.
prophase I
MEIOSIS PHASE chromatin condenses to form the chromosomes. the homologous chromosomes form pairs in an event called "synapsis". chromosomes can cross over during synapsis. during cross over, the chromatids of homologous chromosomes can exchange segments of the chromatids. the result of cross over is sister chromatids of one chromosomes are no longer genetically identical. cross over is one of the mechanisms that generates genetic variability. the nuclear envelope disappears and the spindle apparatus forms during late prophase I.
meiosis II
MEIOSIS PHASE consists of prophase, metaphase, anaphase, and telophase. the only notable event to occur is the separation of the two chromatids of each chromosome. the results in four haploid cells, each containing 23 different chromosomes. otherwise, and its very similar to mitosis.
interphase
MEIOSIS PHASE the chromosomes take the form of chromatin during this phase, and they replicate to produce the two chromatids.
metaphase I
MEIOSIS PHASE the homologous chromosomes pair along the equatorial plane of the cell so each homolog is on the opposite side of the plane.
telophase I
MEIOSIS PHASE the homologous chromosomes reach the opposite poles of the cell, and cytokinesis occurs. the resulting two cells each have the haploid numbers of chromosomes
anaphase I
MEIOSIS PHASE the homologous chromosomes separate, and are drawn to the opposite poles of the cell
Prophase
MITOSIS PHASE Chromosomes condense from chromatin and the nuclear membrane disappears
Metaphase
MITOSIS PHASE Chromosomes line up along the cell's equator
Telophase
MITOSIS PHASE Chromosomes reach the poles of the cells, begin to unwind, and then assume the form of chromatin
Anaphase
MITOSIS PHASE Sister chromatids on each chromosome separate, and begin to move towards the poles of the cells.
Interphase - Mitosis
MITOSIS PHASE period of time between nuclear division. resting phase. undergoes its normal activity for the majority of its life cycle. - chromosomes unwound into chromatin
G1 phase
PART OF INTERPHASE normal cellular activity, including cell growth, organelle replication, and protein synthesis
S phase
PART OF INTERPHASE DNA replication
G2 phase
PART OF INTERPHASE protein synthesis and the production of cellular products
homologous chromosomes
chromosomes identical in size, shape, and posses the same genes. humans have 23 pairs of homologous chromosomes.
diploid
having two haploid sets of homologous chromosomes. the normal number of chromosomes in body cells. humans have a diploid number of 46 chromosomes
chromatin
it literally means "colored material" this is the term for the uncoiled DNA in the nucleus when the cell is undergoing its normal activity. the chromatin coils form the chromosomes.
chromosomes
literally means the "colored bodies" these are the rod shaped structures of DNA present in the cell during cell division
produce eggs sperm and gametes
purpose of meiosis
produce two identical daughter cells
purpose of mitosis and cytokinesis
haploid
the number of chromosomes found in eggs or sperm. it is one half of the diploid number of chromosomes. the haploid number of chromosomes in humans is 23
Chromatids
the two identical strands of DNA which form a chromosome after DNA replication. the chromatids are separated into two different cells during mitosis