objectives: differentiate between prokaryote and eukaryote cell division predict chromosome...

Objectives:•Differentiate between prokaryote and eukaryote cell division•Predict chromosome changes during cell division•Compare offspring development between species

Unit V : Reproduction & Development

Asexual Reproduction

• The production of new organisms without the fusion of nuclei. The new organisms develop from a cell or cells of a single parent and have characteristics identical to that parent.

How many cells do you produce in one day? Check out your textbook page 118

Mitotic Cell Division• According to the cell theory, all cells

arise from other preexisting cells.Eukaryotes:• Mitosis- an orderly series of complex

changes in the nucleus, normally involving an exact duplication of the complete set of chromosomes (nuclei) and the separation of these chromosomes (nuclei) into 2 identical sets of chromosomes (nuclei).

Interphase (Normal LIFE FUNCTIONS): Growth, Respiration, Nutrition, Transport, Excretion, Regulation

Mitosis is a small part of a cell’s life. Skin cells, for example, reproduce 65 times a day! While a liver cell only reproduces once a year!

Cytoplasmic Division

• Cytokinesis – “cytoplasm splitting”

• Cells usually divide into two relatively equal cytoplasmic parts, each one having a nucleus and called daughter cells.

Interphase

• Replication (exact duplication) of each single-stranded chromosome during the non-dividing period, resulting in double-stranded chromosomes.

Chromatin

Nucleolus

Plant Cell

Animal Cell

Chromosomes

• Individual strands of a double-stranded chromosome are known as chromatids and are joined at the centromeres.

Prophase• Disintegration (breakdown)

of the nuclear membrane and nucleolus during the early stages of division.

• Synthesis of a spindle apparatus from centrioles (a network of fibers).

• Chromosomes coil & sister chromatids pair up.

Metaphase• Attachment of double-

stranded chromosomes to the spindle apparatus at the centromere region of the chromosome.

• Replication of each centromere which results in the formation of two single-stranded chromosomes.

Anaphase

• Migration (movement) of single-stranded chromosomes toward opposite ends of the cell. As a result, there is one complete set of chromosomes at each end of the cell.

Telophase

• Nuclear membrane formation around each set of chromosomes, forming two nuclei.

Summary• Interphase• Prophase• Metaphase• Anaphase• Telophase (IPMAT)• Cytokinesis• View Online Onion

Root Tips animation

• The major result of mitosis is the formation of two daughter nuclei which are identical to each other and to the original nucleus, in number and types of chromosomes.

Comparing plant and animal cellspart I

• Animals – centrioles aid in the formation and orientation of the spindle apparatus.

• Cytoplasmic division is accomplished by protein threads in the cell membrane “pinching in”, thus separating the two nuclei.

Comparing plant and animal cellspart II

• Plants – the golgi complex secretes vesicles until a cell plate is synthesized and grows from the center outward, separating the cytoplasm.

Mitosis

• Self-regulated, normal mitotic cell division produces new cells used for growth and repair.

• However, uncontrolled, abnormal, and rapid mitotic cell division is known as cancer. These abnormally produced cells do not function properly and may cause damage or death to an organism.

What causes cancer (or what causes cells to divide uncontrollably)?

Check your textbook page 127 to find out

Lung Cancer Cell Dividing. by Wes // February 6, 2013