Lecture 12 Mitosis Cell Cycle

Mitosis

Mitosis

The process of cell division in which a single cell divides into two identical daughter cells.

Cell Cycle

The series of events that take place in a cell leading to its division and duplication.

Prokaryotic Genome

The genetic material of prokaryotic cells, which consists of a single circular DNA molecule.

Eukaryotic Genome

The genetic material of eukaryotic cells, which consists of multiple linear DNA molecules.

Phases of the Cell Cycle

The different stages of the cell cycle, including interphase (G1, S, G2) and mitotic phase (mitosis and cytokinesis).

Phases of Mitosis

The stages of mitosis, including prophase, prometaphase, metaphase, anaphase, and telophase.

Mitotic Spindle

The structure composed of microtubules that helps to separate the chromosomes during mitosis.

Centrosomes

The structures that organize the microtubules of the mitotic spindle.

Kinetochore Microtubules

Microtubules that attach to the kinetochores of chromosomes and help to move them during mitosis.

Nonkinetochore Microtubules

Microtubules that do not attach to the kinetochores and help to elongate the cell during mitosis.

Asters

Radial arrays of short microtubules that extend from the centrosomes during mitosis.

Cytokinesis

The division of the cytoplasm that follows mitosis and results in the formation of two separate daughter cells.

Binary Fission

The process of cell division in prokaryotic cells, which is similar to mitosis.

Cancerous Cells

Cells that undergo abnormal cell division and escape normal cell cycle controls.

Benign Tumor

A noncancerous tumor that does not invade nearby tissues or spread to other parts of the body.

Malignant Tumor

A cancerous tumor that can invade nearby tissues and spread to other parts of the body.

Metastatic Tumor

A tumor that has spread from its original site to other parts of the body.

Genome

The complete set of genetic material in an organism.

Chromosomes

Structures composed of DNA and proteins that carry the genetic information of an organism.

Sister Chromatids

Two identical copies of a chromosome that are held together by a centromere.

Centromere

The region of a chromosome where the two sister chromatids are most closely attached.

Interphase

The phase of the cell cycle where the cell grows and prepares for cell division.

S Phase

The phase of interphase where DNA is synthesized and chromosomes are duplicated.

G1 Phase

The phase of interphase where the cell grows and carries out normal metabolic activities.

G2 Phase

The phase of interphase where the cell continues to grow and prepares for mitosis.

Meiosis

A type of cell division that produces gametes (sperm and egg cells) with half the number of chromosomes as the parent cell.

Walther Flemming

The German anatomist who developed dyes to observe chromosomes during mitosis and cytokinesis.

Microtubules

Tubular structures involved in various cellular processes, including cell division.

Chromosomes

Thread-like structures that contain genetic information.

Sister chromatids

Two identical copies of a chromosome that are held together by a centromere.

Aster

A star-shaped structure formed during cell division that helps position the spindle fibers.

Metaphase plate

An imaginary plane in the center of the cell where chromosomes align during metaphase.

Centrosome

A cellular organelle that helps organize microtubules and is involved in cell division.

Kinetochore

A protein structure on the centromere of a chromosome that attaches to spindle fibers.

Kinetochore microtubules

Microtubules that attach to the kinetochore and help move chromosomes during cell division.

Overlapping nonkinetochore microtubules

Microtubules that overlap with each other and help elongate the cell during cell division.

Anaphase

The stage of cell division where sister chromatids separate and move towards opposite ends of the cell.

Depolymerizing

The process of breaking down a polymer into its individual subunits.

Spindle pole

A structure involved in the formation and organization of the spindle fibers during cell division.

Chromosome movement

The movement of chromosomes during cell division.

Motor protein

A protein that uses ATP energy to move along microtubules and transport cellular components.

Tubulin subunits

The individual building blocks of microtubules.

Cleavage furrow

A groove that forms during cytokinesis in animal cells, leading to cell separation.

Cell plate

A structure that forms during cytokinesis in plant cells, eventually becoming the cell wall.

Nucleus

The central organelle of a eukaryotic cell that contains genetic material.

Prophase

The first stage of mitosis where chromatin condenses into visible chromosomes.

Prometaphase

The stage of mitosis where the nuclear envelope breaks down and spindle fibers attach to chromosomes.

Telophase

The final stage of mitosis where chromosomes decondense and two daughter nuclei form.

Binary fission

A type of cell division in prokaryotes where the chromosome replicates and the cell divides into two daughter cells.

Origin of replication

A specific site on the chromosome where DNA replication begins.

Eukaryotes

Organisms whose cells have a nucleus and other membrane-bound organelles.

Mitosis

The process of cell division in eukaryotic cells that results in two genetically identical daughter cells.

Cytoplasmic signals

Chemical signals present in the cytoplasm that drive the cell cycle.

Checkpoints

Specific points in the cell cycle where the cell stops and waits for a go-ahead signal before proceeding.

G1 checkpoint

The checkpoint in the G1 phase of the cell cycle where the cell decides whether to divide or enter a nondividing state.

G0 phase

A nondividing state that cells can enter if they do not receive a go-ahead signal at the G1 checkpoint.

Cyclins

Regulatory proteins involved in cell cycle control that fluctuate in concentration during the cell cycle.

Cyclin-dependent kinases (Cdks)

Enzymes that are activated by cyclins and help regulate the cell cycle.

MPF (maturation-promoting factor)

A cyclin-Cdk complex that triggers the cell's passage from the G2 phase to the M phase of the cell cycle.

MPF

Stands for Maturation Promoting Factor, a protein complex that regulates the cell cycle.

Cyclin

A family of proteins that regulate the progression of the cell cycle.

Cell cycle

The series of events that take place in a cell leading to its division and duplication.

Checkpoints

Points in the cell cycle where the cell checks for errors and ensures proper progression.

Kinetochores

Protein structures on chromosomes that attach to spindle microtubules during cell division.

Growth factors

Proteins released by certain cells that stimulate other cells to divide.

Platelet-derived growth factor (PDGF)

A specific growth factor that stimulates the division of human fibroblast cells.

Density-dependent inhibition

A phenomenon where crowded cells stop dividing.

Anchorage dependence

The requirement for animal cells to be attached to a substratum in order to divide.

Cancer cells

Abnormal cells that do not respond to normal cell cycle controls and can form tumors.

Transformation

The process by which a normal cell is converted into a cancerous cell.

Benign tumor

A mass of abnormal cells that remain at the original site and do not invade surrounding tissues.

Malignant tumor

A tumor that invades surrounding tissues and can spread to other parts of the body.

Metastasis

The spread of cancer cells from the original site to other parts of the body, where they can form secondary tumors.

Telophase

The final stage of mitosis, where the chromosomes decondense and nuclear envelopes reform.

Cytokinesis

The division of the cytoplasm to form two separate daughter cells.