cell division

Cell Division

The fundamental biological process where a mother cell divides into two or more daughter cells.

Growth and Development

A reason for cell division that allows multicellular organisms to develop from a single-celled zygote into adults.

Repair and Maintenance

Cell division facilitates healing wounds and replacing old or worn-out cells.

Reproduction

In unicellular organisms, cell division is the primary means of reproduction.

Genetic Continuity

Cell division ensures the perpetuation of species.

Karyokinesis

The division of the nucleus during cell division.

Cytokinesis

The division of the cytoplasm during cell division.

The Cell Cycle

The entire sequence of events that takes place during cell growth and division.

Chromosome Cycle

Part of the cell cycle that involves DNA replication.

Cytoplasmic Cycle

Part of the cell cycle that involves growth and division of the cytoplasm.

Centrosome Cycle

Part of the cell cycle that involves duplication and separation of centrosomes.

Interphase

The resting stage of the cell cycle where the cell is metabolically busy.

G1 Phase (Gap-one)

Phase of the cell cycle with intensive biosynthesis, enlarging the cell and producing biomolecules.

S Phase (Synthetic phase)

Phase of the cell cycle where DNA replication occurs.

G2 Phase (Gap-two)

Phase of the cell cycle where the cell prepares for mitosis.

G0 Phase (Quiescent phase)

A state where cells are metabolically active but inactive until they re-enter the cell cycle.

M-phase (Mitotic phase)

Phase that includes the actual division of nuclear material and cytoplasm.

Direct Cell Division (Amitosis)

A form of asexual reproduction involving simple chromosome duplication.

Indirect Cell Division (Mitosis)

Division occurring in somatic cells resulting in daughter cells with the same chromosome number as the mother cell.

Prophase (Mitosis)

Phase where chromosomes condense and the nuclear membrane disappears.

Metaphase (Mitosis)

Phase where chromosomes align at the equatorial metaphasic plate.

Anaphase (Mitosis)

Phase where centromeres split, and daughter chromosomes move toward opposite poles.

Telophase (Mitosis)

Phase where chromosomes decondense and the nuclear membrane reappears.

Cytokinesis (Mitosis)

Occurs via peripheral furrowing in animals and cell plate formation in plants.

Significance of Mitosis

Ensures genetic stability, facilitates asexual reproduction, and controls cell size.

Reductional Cell Division (Meiosis)

Cell division occurring in specialized germ cells to produce haploid cells.

Meiosis I (Reductional Division)

First meiotic division that reduces the chromosome count by half.

Prophase I (Meiosis)

Stage including five sub-stages for chromosome pairing and crossing-over.

Interkinesis

Short resting phase between Meiosis I and II where no DNA replication occurs.

Meiosis II (Equational Division)

Second meiotic division similar to mitosis, leading to four haploid cells.

Significance of Meiosis

Maintains chromosome number, induces genetic variation, and enables alternation of generations.

Key Differences Between Mitosis and Meiosis

Includes aspects such as occurrence, daughter cells, and chromosome number changes.

Somatic Cells

Cells that undergo mitosis.

Reproductive Cells (Meiocytes)

Cells that undergo meiosis.

Genetically Identical Cells

Daughter cells produced by mitosis.

Genetically Different Cells

Daughter cells produced by meiosis.

Diploid

Chromosome number that remains the same in mitosis.

Haploid

Chromosome number that is reduced to half in meiosis.

Prophase Length (Mitosis vs Meiosis)

Mitosis has a short prophase, while meiosis has a long prophase with multiple sub-stages.

Growth and Repair

Main significance of mitosis.

Sexual Reproduction and Variation

Main significance of meiosis.

Chromosome Duplication

The process of replicating chromosomes during cell division.

Histone Proteins

Proteins synthesized during the S phase to ensure accurate genetic distribution.

Spindle Proteins

Proteins synthesized during G2 to prepare the cell for mitosis.

Furrowing

The method of cytokinesis in animal cells.

Cell Plate Formation

The method of cytokinesis in plant cells.

Phragmoplasts

Structures used in plant cells for cell plate formation during cytokinesis.

Crossing-over

Exchange of genetic material between homologous chromosomes during Prophase I.

Chiasmata

Points where two homologous non-sister chromatids exchange genetic material.

Reduced Chromosome Count

A key result of Meiosis I.

Sister Chromatids

Identical copies of a chromosome connected at the centromere.

Independent Assortment

Process that increases genetic variation during meiosis.

Cell Cycle Regulation

Ensures that cells divide in a controlled manner.

Astral Microtubules

Help position the spindle apparatus during cell division.

G1 Checkpoint

Regulates the cell's entry into the S phase.

G2 Checkpoint

Ensures DNA replication is complete and undamaged.

M Checkpoint

Ensures that chromosomes are properly aligned before division.

Centriole Duplication

Occurs during the S phase of the cell cycle.

DNA Repair Mechanisms

Processes that correct damaged DNA before cell division.

Hormonal Regulation

Influences cell division rates in different tissues.

Oncogenes

Genes that can promote cell division and lead to cancer if mutated.

Tumor Suppressor Genes

Genes that inhibit cell division and prevent tumor formation.

Cell Signaling Pathways

Molecules that regulate the cell cycle and division.

Cell Growth Signals

Stimuli that promote cell size increase before division.

Genetic Stability

Maintained by accurate DNA replication and segregation during cell division.

Asexual Reproduction

Reproduction that occurs through mitosis.

Sexual Reproduction

Reproduction that relies on meiosis.

Zygote

The initial cell formed when a sperm cell joins with an egg cell.

Organelles Duplicated in G2 Phase

Includes mitochondria and centrioles.

Chromatin

The form of DNA in the nucleus when the cell is not dividing.

Cell Proliferation

An increase in cell number due to cell division.

Apoptosis

Programmed cell death that maintains cellular health.

Cell Cycle Phases

Include interphase and mitotic phase.

Meiocytes

Specialized cells that undergo meiosis.

Diploid Cells

Cells with two complete sets of chromosomes.

Haploid Cells

Cells with one complete set of chromosomes.