Mitosis and Cytokinesis 5.2 EQ: What are the stages of mitosis and what is its role in the formation of new cells?

A chromosome is a long continuous thread of numerous genes A chromosome is a long continuous thread of numerous genes. Your cells have 46 chromosomes each (23 from mom and 23 from dad)

Histones are proteins associated with chromosomes Histones are proteins associated with chromosomes. They help to condense DNA.

Chromatin is the combination of loose DNA and proteins.

One half of a duplicated chromosome is called a chromatid One half of a duplicated chromosome is called a chromatid. Sister chromatids are held together at the centromere.

The ends of DNA molecules form structures called telomeres The ends of DNA molecules form structures called telomeres. Telomeres prevent chromosomes from attaching to each other.

Mitosis divides a cell’s nucleus into 2 genetically identical nuclei Mitosis divides a cell’s nucleus into 2 genetically identical nuclei. It ONLY occurs in somatic cells. A somatic cell is any cell that does not form gametes. A gamete is a sex cell (sperm or egg).

Mitosis has 4 stages – Prophase, Metaphase, Anaphase, and Telophase.

1) Prophase – chromatic condenses into tightly coiled chromosomes, nuclear envelop breaks down,

2) metaphase – chromosomes are aligned along the cell equator.

3) anaphase – chromatids separate to opposite sides of the cell.

4) telophase – nuclear membranes begin to form; chromatids uncoil.

Cytokinesis – cytoplasm is divided Cytokinesis – cytoplasm is divided. Each new cells has a complete copy of identical DNA.

Regulation of the Cell 5.3 Essential Question (EQ): How is cell division regulated and what happens when this regulation is lost?

Growth factors are a broad group of proteins that stimulate cell division.

Apoptosis is programmed cell death.

Cancer – disease characterized by uncontrolled cell division Cancer – disease characterized by uncontrolled cell division. Cancer is the result of a breakdown of cell cycle regulation.

Cancer cells formed disorganized clumps called tumors Cancer cells formed disorganized clumps called tumors. Tumors are either benign – remains clustered and is relatively harmless; or malignant – likely to spread to other parts of the body.

Why are cancer cells harmful Why are cancer cells harmful? Because cancer cell do not perform their intended function…

Carcinogens – substances known to promote the development of cancer cells.

Standard cancer treatment involves often involves, radiation, chemotherapy, and sometimes surgical removal of a tumor.

Multicellular Life 5.5 Essential Question (EQ): How are cell’s organized to produce a multicellular organism?

Uni means “one”. Examples: universe, uno, unicycle, unibrow, unicorn, etc. Unicellular organisms have only one cell. Examples: Bacteria, Algae, amoeba

multi means “many”. Examples: multiply, multiple, multiyear, etc multi means “many”. Examples: multiply, multiple, multiyear, etc. multicellular organisms have many cells. Examples: Kate Beckensale, David Beckham, plants, spiders, sponges, whales, and … YOU!

How do we use one cell to make an entire multicellular organisms?

Tissue is a group of cells that work together to perform a similar function. Groups of tissues that work together to form a similar function are known as organs.

Organs that carry out a similar function are known as organs systems.

How do you go from one cell to the many types of cells found in different organs???

Cell differentiation is the process by which unspecialized cells develop into their mature forms and functions. What the heck does that mean, Mr. Allen?!

Most of he cells in your body have a full set of DNA Most of he cells in your body have a full set of DNA. However, the differentiated cells only use SOME of the DNA to function. Example: a muscle cell only uses the genes from DNA that it needs to contract and relax even though it has THOUSANDS of genes.

What are undifferentiated cells called What are undifferentiated cells called? Undifferentiated cells that can develop into specialized cells are known as stem cells.

Embryonic stem cells have given many people hope that some devastating diseases might be curable in the near future.