Cell Cycle Overview

Cell Cycle Overview

• Cells grow and reproduce through a cyclical process.
• Interphase is the time between cell divisions, where cells perform normal functions.
• Proto-oncogenes promote cell growth and division.
• Tumor suppressor genes monitor and control cell process.
• Checkpoints ensure the health of the cell before division. If a cell fails a checkpoint, it may undergo repair or programmed cell death.
• Cell division includes mitosis (nuclear division) and cytokinesis (cytoplasm division).

Interphase

• Interphase comprises three phases: G1, S, and G2.
• G1: Cell growth, normal cell activities.
• S: DNA replication.
• G2: Preparation for mitosis.
• Interphase is where the cell prepares for mitosis.
• DNA from each parent, mom and dad, is replicated during S phase to ensure a full set in each new cell. Two identical sets of DNA exist.

Mitosis

• Mitosis is a type of cell division that produces two genetically identical daughter cells from a single parent cell.
• Mitosis consists of 4 distinct phases: Prophase, Metaphase, Anaphase, and Telophase.
• Mitosis is critical for growth, repair, and asexual reproduction in multicellular organisms.
• During mitosis, the replicated chromosomes are separated and distributed to two new nuclei.

Mitosis-Prophase

• Chromosomes condense and become visible.

• Sister chromatids become attached together.

• Spindle fibers form, attaching to the centromere of each chromosome.

• Nuclear envelope breaks down.

• The cell has 4 chromosomes and 8 DNA strands at the start of Mitosis-Prophase.

Mitosis-Metaphase

• Chromosomes line up along the metaphase plate (the center of the cell).
• Sister chromatids remain attached together but are lined up.

Mitosis-Anaphase

• Spindle fibers pull sister chromatids apart, to the opposite sides of the cell.
• Two identical sets of chromosomes now exist on opposite sides of the cell.

Mitosis-Telophase

• Chromosomes arrive at the poles of the cell.
• Nuclear envelopes re-form around each set of chromosomes.
• Spindle fibers disappear.

Cytokinesis

• Cytoplasm divides, creating two separate daughter cells.
• Cytokinesis is the final step of cell division.

Plant Cell Division

• Plant cells, during cytokinesis, form a cell wall by creating vesicles that fuse to form a new cell wall at the center of the dividing plant cell. This contrasts with animal cell cytokinesis, where the cell membrane pinches inward.

Prokaryotic Cell Division

• Prokaryotic cells, like bacteria, divide through a process called binary fission.
• The process begins by replicating chromosomal DNA and separating the copied DNA molecules from each other.
• The cell elongates, eventually dividing into two new, genetically identical daughter cells.

Summary of Cell Division

• Daughter cells are genetically identical to the parent cell (and each other).
• The number of chromosomes in the parent cell remains constant after one round of cell division.

Explore the phases of the cell cycle, including interphase and mitosis. Understand the role of proto-oncogenes and tumor suppressor genes in cell regulation. This quiz covers key concepts necessary for studying cell division and its importance in biology.