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