Biology; Cell Structure and Mitosis

Cell grows and matures.

Stage G is cell growth, Cell S is when the DNA is duplicated, and G2 is the synthesis of organelles.

First phase of mitosis. Condenses into chromosomes, each consisting of two chromatids conntect by a centromere. At the end of this phase, the nuclear membrane dissolves.

The centromeres of each chromesone attatch to fibers that change in length, pulling the chromosomes into a line along the center of the cell.

Centromeres split and chromatids are pulled to the opposite poles (sides) of the cell by the fibers. Phase is over when chromatids reach the poles and stop moving. During this process chromatids are now called daughter chromosomes.

A nucleur membrane fomrs around each set of daughter chromosomes, and the nucleolus reappears in each nucleus. The daughter chromosomes now unwind into chromatin.

The dividing of two identical nuclei by spliting the cytoplasm and forming two daughter cells, each having a perfect copy of the parent cell's DNA

Interphase

Chromatin is composed of DNA and proteins that condense to form chromosomes.

Anaphase

Cytoskeletal structure that seperate chromatids between daughter cells.

To help form the spindle fibers.

Telophase

Metaphase

Prophase

To ensure the cell gets all of it’s parent cell’s DNA.

Interphase

Cancerous tumors can form.

The Surface Area to Volume ratio and effiniency of DNA replication/cell division.

A process of programmed cell death.

The cell cycle is controlled by regulatory proteins both inside and outside the cell.

A family of proteins that regulate the timing of the cell cycle in eukaryotic cells.

Internal Regulations

External Regulations

External Regulations

Internal Regulations

Wound healing and embryonic development

Uncontrolled cell growth; cells do not respond to signals that regulate cell division or growth.

1) A cell begins to divide abnormally.

2) Cells produce a tumor and start to displace normal cells and tissues.

3) Cancer cells move to other parts of the body.

Cancerous tumor.

Noncancerous tumor. Does not spread to healthy tissue.

They absorb nutrients needed by other cells, block nerve connections, and prevent organs from functioning.

Invasion of healthy tissue by cancer cells.

Defects in genes that regulate cell growth and division.

Examples: smoking tobacco, radiation exposure, defective genes, and viral infection.

Many tumors can be treated with targeted radiation.

The radiation is especially damaging to cancer cells because of their high rate of mitosis.

The larger a cell = more demands on its DNA.

The rate of exchange depends on the surface area of a cell.

The rate of food and oxygen use and waste product production depends on the cell’s volume

Asexual Reproduction

Must find a mate, fewer offspring, offspring may be less well adapted to current conditions.

If conditions change, offspring not well adapted.

In changing environments, genetic diversity can be beneficial.

Don’t need to find a mate, offspring strive if in a stable environment, many offspring produced at a time.

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Series of events that take place in a cell leading to its division and duplication. It consists of interphase (G1, S, and G2 phases) and mitosis (prophase, metaphase, anaphase, and telophase). During interphase, the cell grows, replicates its DNA, and prepares for division. Mitosis is the process of dividing the duplicated DNA and other cellular components equally into two daughter cells.