Chapter10: Cell Growth and Division Ms. Nguyen Biology

Ch. 10: Cell Growth and Division Essential Question: How does a cell produce a new cell? Ch. 10.1: Why do cells divide? Ch.10.2: How do cells divide? Ch. 10.3: How does a cell control the process of cell division Ch.10.4: How does a single undifferentiated cell lead to a complex multicellular organism?

1. Information “overload”: The larger a cell gets, the more demands it places on its DNA. Eventually, the cell’s DNA cannot meet the cell’s needs. I. Why do cells divide? A. Limits to Cell Size

B. Cell Reproduction

I. Chromosomes Chromosomes hold a cell’s genetic information. a. Prokaryotic chromosomes consist of a single, circular strand of DNA. b. Eukaryotic chromosomes are highly organized structures. c. The DNA winds around histone proteins, forming chromatin. d. Chromosomes make the precise separation of DNA possible during cell division. I. Chromosomes A. What are chromosomes?

A. What are the main phases of the cell cycle? II. The Cell Cycle A. What are the main phases of the cell cycle? The cell cycle is the series of events in the growth and division of a cell  In the prokaryotic cell cycle, the cell grows, duplicates its DNA, and divides by pinching in the cell membrane.

The eukaryotic cell starts with stages of Interphase: In the G1 phase, the cell grows, the stage with the most growth. In the S phase, the cell replicates its DNA. In the G2 phase, the cell produces organelles and materials for division. Cell Division: In the M phase, the cell divides in two stages— a. mitosis, the division of the nucleus, b. cytokinesis, the division of the cytoplasm.

C. The 4 phases of Mitosis are: 1. Prophase : a cell’s genetic material condenses, a spindle starts to form, and the nuclear envelope breaks down. NFL, Football?

2. Metaphase : the duplicated chromosomes line up IN THE MIDDLE and spindle fibers connect to the centromeres.

3. Anaphase : sister chromatids separate and move toward the centrioles. (PULL APART)

4. Telophase : the chromosomes begin to unwind and a nuclear envelope reforms. (LOOKS LIKE A TELEPHONE)

10.3 Regulating the Cell Cycle Bell Ringer: Answer the following question into your IAN, left side. Describe how the cell cycle is regulated.

I. Controls on Cell Division 1. Controls on Cell Division Dozens of proteins regulate the cell cycle 2. Cyclins are proteins that regulate the timing of the cell cycle in eukaryotic cells  3. Regulatory proteins work both inside and outside of the cell. Internal regulators allow the cell cycle to proceed when certain events have occurred within a cell. External regulators called growth factors stimulate the cell cycle. Other external regulators cause the cell cycle to slow down or stop. I. Controls on Cell Division A. How do cells control division?

4. Apoptosis is programmed cell death (cell suicide) that plays a key role in the development of new replacement cells. Normal V Cancer

II. Cancer: Uncontrolled Cell Growth Cancer Cancer is a disorder in which cells divide uncontrollably, forming a mass of cells called a tumor.  Cancers are caused by defects in genes that regulate cell growth.  Treatments for cancer include: removal of cancerous tumors. radiation, which interferes with the copying of DNA in multiplying cancer cells. chemotherapy, which is the use of chemicals to kill cancer cells. II. Cancer: Uncontrolled Cell Growth Cancer A. What is the cause of cancer?

A. What is the process of cell differentiation? From One Cell to Many Multicellular organisms produced via sexual reproduction begin life as a single cell. Early cell divisions lead to the formation of a zygote, then embryo and fetus. Then, individual cells become specialized in both form and function through the process of differentiation.  Once cells of a certain type, such as nerve cells or muscle cells, have formed, the cells cannot develop into a different type of cell. Blastocyst is an embryonic stage that consists of a hollow ball of cells. These cells are able to become any type of body cell.

2. Unspecialized cells that can develop into differentiated cells are called stem cells. Stem cells are found in embryos and in adults. Embryonic stem cells are the pluripotent cells of an early embryo. Adult stem cells are multipotent, which means they can produce many, but not all, types of differentiated cells.