Bio

Cell division must be controlled

Unregulated cell division can lead to cancer, regulated by checkpoints, cyclins, and other proteins.

Cellular structures

Cells contain organelles with specialized functions essential for maintaining homeostasis.

Magnification formula

M = I/A, where magnification equals image size divided by actual size.

Fluid mosaic model

Describes how phospholipids and proteins move within the membrane for flexibility and function.

Passive transport

Movement of materials without energy, including diffusion and osmosis.

Active transport

Movement of materials requiring energy, including endocytosis and exocytosis.

Stem cells

Undifferentiated cells capable of becoming specialized cell types, used in regenerative medicine.

Endosymbiotic theory

Explains the origin of eukaryotic cells from prokaryotic ancestors.

Amphipathic

Molecules that have both hydrophobic and hydrophilic regions.

Asexual reproduction

Production of genetically identical clones without gametes.

Binary fission

A form of asexual reproduction in prokaryotic cells resulting in two identical cells.

Cytokinesis

The division of cytoplasm to form two daughter cells after mitosis.

Diffusion

Passive movement of molecules from an area of high concentration to low concentration.

Eukaryotic cell

A cell with membrane-bound organelles, including a nucleus.

Homeostasis

Maintenance of a stable internal environment within a cell or organism.

Metabolism

The sum of all chemical reactions occurring within an organism.

Mitosis

Cell division resulting in two genetically identical daughter cells.

Multicellular

Organism made of many cells performing specialized functions.

Organelle

Specialized structure within a cell that carries out a specific function.

Osmosis

Passive movement of water across a selectively permeable membrane.

Prokaryotic cell

A simple cell without membrane-bound organelles or a nucleus.

Sexual reproduction

Process of producing offspring through the combination of gametes.

Unicellular

Organism composed of a single cell performing all functions of life.

Cell Theory

A widely accepted explanation of the relationship between cells and living things.

Giant algae (Acetabularia)

Large, unicellular organisms that challenge the concept that all cells are small.

Phagocytosis

Active transport method for engulfing solid particles.

Pinocytosis

Active transport method for engulfing liquid droplets.

Davson-Danielli model

Proposed a static, protein-layered membrane before the fluid mosaic model.

Singer-Nicholson model

Fluid mosaic model showing proteins embedded in a dynamic phospholipid bilayer.

C1 phase of cell cycle

Cell growth phase.

S phase of cell cycle

DNA replication phase.

G2 phase of cell cycle

Preparation for division phase.

M phase of cell cycle

Mitosis and cytokinesis phase.

Control of cell cycle

Checkpoints regulated by cyclins.

Cell size limitations

Limited by surface area-to-volume ratio affecting transport efficiency.

Totipotent stem cells

Can become any cell type, such as a zygote.

Pluripotent stem cells

Can become most cell types, such as embryonic stem cells.

Multipotent stem cells

Limited differentiation potential, like bone marrow stem cells.

Therapeutic uses of stem cells

Utilized in treatments like bone marrow transplants and neuron regeneration.