Understanding the Cell Cycle and Cancer Biology

Cell Cycle

Series of stages in an organism's life.

Eukaryotic Cell Cycle

Includes interphase and mitotic phases.

Interphase

Longest phase; cell prepares for division.

G1 Phase

Cell growth and metabolic activity occur.

S Phase

DNA replication occurs during this phase.

G2 Phase

Preparation for mitosis; proteins synthesized.

Mitosis

Nuclear division maintaining chromosome number.

Cytokinesis

Division of cytoplasm after mitosis.

Diploid Cells

Cells with two sets of chromosomes.

Homologous Chromosomes

Chromosome pairs from each parent.

Sister Chromatids

Identical DNA molecules joined at centromere.

Checkpoint Proteins

Sensors that regulate cell cycle progression.

Apoptosis

Programmed cell death if errors persist.

Chromosome Structure

Consists of DNA and histone proteins.

Cell Division Purpose

Growth, repair, and asexual reproduction.

DNA Damage Response

Mechanisms that halt cycle for repair.

Centromere

Region where sister chromatids are joined.

Body Cells

Diploid cells forming tissues and organs.

Asexual Reproduction

Offspring produced from a single parent.

Transcription

Process of copying DNA to RNA.

Histones

Proteins that package and order DNA.

Cell Growth

Increase in cell size and mass.

Chromosome Condensation

Chromosomes pack tightly to prevent tangling.

Early Prophase

Mitosis starts; DNA condenses and nuclear envelope breaks.

Prophase

Chromosomes visible; spindle microtubules bind to centromeres.

Metaphase

Chromosomes align midway between spindle poles.

Anaphase

Sister chromatids separate to opposite poles.

Telophase

Chromosomes reach poles; nuclear envelope reforms.

Centrosome

Dense cytoplasm region containing centrioles.

Spindle

Temporary structure moving chromosomes during division.

Spindle Poles

Areas where spindle originates on cell sides.

Cytokinesis

Mechanism of cytoplasmic division post-mitosis.

Contractile Ring

Microfilaments and proteins forming around dividing cell.

Cleavage Furrow

Visible indentation during animal cell cytokinesis.

Plant Cell Cytokinesis

Involves formation of a cell plate.

Cell Plate

Membrane structure separating two plant cells.

Telomeres

Noncoding DNA at chromosome ends in eukaryotes.

Microtubules

Tubulin structures forming spindle during mitosis.

Vesicles

Transport membrane components to division plane.

Cell Cortex

Cytoskeletal mesh under animal cell membrane.

Fusion of Vesicles

Creates membranes separating daughter cells.

Motor Proteins

Proteins aiding in contractile ring function.

Nuclear Envelope

Membrane surrounding the nucleus during mitosis.

Telomere

Short DNA sequence, TTAGGG, repeated thousands of times.

Cell division limit

Maximum divisions before a cell becomes senescent.

Senescent cell

Metabolically active but cannot divide due to damage.

p53

Checkpoint gene product halting cell cycle in G1.

Telomerase

Enzyme that lengthens telomeres by adding repeats.

Stem cells

Cells that divide indefinitely by producing telomerase.

Oncogene

Gene with a mutation that causes tumors.

Proto-oncogene

Normal gene that can become an oncogene.

EGFR

Proto-oncogene encoding a receptor for EGF.

EGF

Epidermal growth factor stimulating cell division.

Tumor suppressor genes

Genes preventing tumor formation when functional.

BRCA1

Tumor suppressor gene involved in DNA repair.

BRCA2

Checkpoint gene acting as a tumor suppressor.

Neoplasm

Tumor formed by uncontrolled cell division.

Mitosis

Process of cell division producing two daughter cells.

Cell cycle arrest

Halting of cell cycle due to damage.

Checkpoint gene products

Proteins monitoring cell cycle for damage.

Reproductive cell mutations

Mutations passed to offspring affecting future generations.

Growth factor genes

Genes that promote cell division when activated.

Chromosome structure maintenance

Role of BRCA genes during cell division.

Tumor-causing mutations

Mutations leading to uncontrolled cell growth.

Hormone receptors

Proteins binding hormones to regulate cell functions.

HPV

Human papillomavirus linked to tumor suppressor disruption.

Tumor Suppressors

Proteins that prevent uncontrolled cell growth.

Warts

Skin growths caused by HPV infection.

Neoplasms

Abnormal tissue growths, benign or malignant.

Benign Neoplasms

Grow slowly, remain in home tissue, non-dangerous.

Malignant Neoplasms

Grow rapidly, invade tissues, dangerous to health.

Cell Division

Malignant cells divide uncontrollably, causing overcrowding.

Cellular Structure

Malignant cells have altered cytoplasm and membranes.

Metastasis

Process of malignant cells invading other body parts.

Anchoring to Tissue

Benign cells properly anchored; malignant cells defective.

Cancer

Disruption of tissues by abnormally dividing cells.

Iain Couzin

Researches collective behavior in cancer cell migration.

Collective Behavior

Cancer cells sense environment and change behavior.

HeLa Cells

Immortal human cell line used in medical research.

George and Margaret Gey

Created HeLa cell line from Henrietta Lacks.

Paclitaxel

Drug that prevents microtubule disassembly in cells.

Aurora B Kinase

Protein linked to chromosome distribution in cell division.

Chromosome Overexpression

Correlated with poor survival rates in cancer patients.

Microtubule Poison

Drugs targeting microtubules more effective on cancer cells.

Cell Lineages

Immortal cells allow study of diseases without human trials.

Tendril Growth

Brain tumors extend into surrounding tissues.

Cancer Cell Migration

Movement of cancer cells during metastasis.