Bio 1101 Chapter 10 Cell Division, Cancer Development, and Treatment Strategies in Biology

Genome

A Complete Set of Genetic Material/DNA in an Organism.

46

Total number of chromosomes humans have, consisting of 23 sets.

The exact same set of DNA

Every somatic cell in the body has this.

Different Proteins

Cells in the body express these, resulting in different structures and functions.

Replicate

Every time a cell divides to create a new cell, it needs to do this to its DNA.

Carcinogen

A substance that can cause cancer.

BRCA Genes

Genes that encode proteins important for repairing damaged DNA; inheriting a mutation in BRCA1 or BRCA2 significantly increases the chance of developing cancer.

Tissue

A group of cells working together to carry out a specific function.

Cell Division

Process by which a cell reproduces itself.

Embryonic Development

A phase where one fertilized egg cell and its daughter cells continuously divide to create trillions of cells.

Cell Replacement

Replaces dying cells and maintains healthy tissues; most cells have a finite lifespan.

Wound Healing

The process of replacing damaged cells; injury triggers cell division.

Cell Cycle

An ordered sequence of events that a cell goes through to divide.

Two identical daughter cells

The result of one parent cell undergoing cell division.

How do cells divide?

A cell doesn't simply split in half to form two new cells; each new cell would be smaller than the original cell.

Interphase

Preparatory phase where the cell makes a copy of its contents.

Mitotic Phase

Division phase where one parent cell divides into two new daughter cells.

Interphase - G1 phase

The cell enlarges, produces additional cytoplasm, and begins to produce new organelles.

Interphase - S phase

DNA replication occurs, each chromosome is replicated to produce two sister chromatids.

DNA Replication

Results in two DNA molecules with one original strand and one new strand, known as semi-conservative replication.

Sister Chromatids

The two identical DNA molecules that make up a replicated chromosome following DNA replication.

Centromere

The specialized region of a chromosome where the sister chromatids are joined, critical for proper alignment during mitosis.

Interphase - G2 phase

Cell continues to grow and prepares and produces molecules needed for cell division.

Stages of the Cell Cycle

Includes the mitotic phase, which consists of mitosis and cytokinesis.

Mitosis

Nuclear division involving the separation of sister chromatids.

The Phases of Mitosis (PMAT)

Mitosis occurs in a series of phases: Prophase, Metaphase, Anaphase, and Telophase.

Prophase

Replicated chromosomes begin to coil and become visible under a microscope; the nuclear envelope begins to disassemble.

Mitotic Spindle

A structure that separates sister chromatids during mitosis, made of microtubules (spindle fibers).

Metaphase

Spindle fibers attach to the sister chromatids via kinetochore, aligning replicated chromosomes along the middle of the cell.

Anaphase

Spindle fibers shorten and pull sister chromatids to opposite ends of the cell, making them individual chromosomes.

Telophase

Identical set of chromosomes reaches each pole, spindle fibers disassemble, and the nuclear membrane begins to form around each set of chromosomes.

Cytokinesis

The division of the cytoplasm that divides the cell into two daughter cells, each containing a full complement of organelles and DNA in the nucleus.

Cell Walls

A question regarding whether animal cells or plant cells have a cell wall.

Animal cell cytokinesis

Cleavage furrow (cell membrane pinches).

Plant cell cytokinesis

Cell plate (new cell wall).

Completion of Cell Cycle

Cell cycle starts over; Interphase then on to Mitotic phase unless cell cycle arrest.

G0 phase

Resting phase where cell no longer divides and usually has specialized function.

Cell Division Regulation

Cell cycle checkpoints ensure stages of cell cycle are completed correctly.

Cell cycle checkpoints

Prevent cell from progressing to next stage until accurately finished with current stage.

Growth factors

Molecules that signal a cell to divide when appropriate.

Apoptosis

Programmed cell death that occurs if irreparable damage is detected at a checkpoint.

Proteins in Cell Cycle Regulation

Cell cycle checkpoints involve proteins that promote or inhibit cell division.

Proto-oncogene

Genes that produce proteins providing signals that lead to cell division and accelerate growth.

Tumor suppressor genes

Genes that produce proteins that slow down cell division, repair DNA mistakes, and trigger apoptosis.

Cancer

A disease of unregulated cell division leading to mistakes in DNA replication and during mitosis.

Gene mutation effects

May result in protein with altered function or nonfunctional protein; mutations can also affect regulatory regions.

Mutations causing cancer

Mutations that affect proto-oncogenes and tumor suppressor genes result in non-functional cell cycle proteins.

Oncogene

A mutated proto-oncogene that is permanently turned on, stimulating cells to divide all the time.

Tumor Suppressor gene mutation

When these genes mutate, tumor suppressor proteins lose normal function, leading to no control over checkpoints.

Cancerous cells

For cells to become cancerous, multiple mutations in several genes that regulate the cell cycle are required.

Multi-hit model

Multiple mutations arising over time, including inherited mutations and errors in DNA replication.

Environmental insults

Can cause errors in DNA replication

Mutations

Once you have several mutations in cell cycle regulatory proteins, an abnormal cell begins to divide uncontrollably, producing a tumor.

Tumor

Mass of tissue formed by accumulation of abnormal cells.

Benign tumor

Noncancerous tumor that does not spread throughout the body.

Malignant tumor

Cancerous tumor that spreads and invades other tissues (metastasize).

Malignancy

Occurs when cells lose contact inhibition, meaning healthy cells stop dividing once they come into contact with neighboring cells.

Anchorage dependence

Healthy cells normally need physical contact with other cells in tissue to divide.

Angiogenesis

Cancer cells promote the growth of new blood vessels.

How does Cancer Kill?

Cancer can crowd out normal cells, invade other organs, and secrete poisonous chemicals.

Conventional Treatment

Includes surgery, radiation, chemotherapy, targeted therapies, and immunotherapy.

Surgery

Removing cancerous tumor is effective for certain solid tumors but not effective for blood cancers or metastatic tumors.

Chemotherapy

Drugs that interfere with cell division to treat cancer, killing all dividing cells, not just cancerous cells.

Chemotherapy side effects

Includes nausea, vomiting, hair loss, and immune deficiency.

Radiation Therapy

High-energy radiation beams are used to kill dividing cells by severely damaging molecules and DNA to trigger apoptosis.

Targeted Therapies

Drugs designed specifically for cancer cells and not harmful to normal cells dividing.

Immunotherapy

Drugs or treatments used to stimulate our own immune cells to recognize and destroy cancer cells.

High-risk mutations

People who have inherited high-risk mutations start life with at least one cancer-predisposing mutation and need fewer additional mutations to get cancer.

Germ cell mutation

Mutation that was in germ cell leading to higher cancer risk.

Sporadic cancer

Caused by non-inherited (acquired) mutations and occurs in mutations of somatic cells.