CELL - THE BUILDING BLOCKS OF LIFE

Vocabulary-style flashcards covering the structural organization, history, and functions of the cell, its organelles, and division processes.

Cell

The smallest structural and functional unit of life that is capable of performing basic life processes.

Cytology

The scientific study of cells.

Robert Hooke

The scientist who discovered the cell in dead cork cells using a primitive microscope in $1665$.

Leeuwenhoek

The scientist who observed the first living cells using an improved microscope in $1674$.

Robert Brown

The scientist who discovered the Nucleus in the cell in $1831$.

Purkinje

The scientist who coined the term protoplasm in $1839$.

Schleiden & Schwann

The scientists who proposed the Cell theory in $1838-1839$.

Virchow

The scientist who revised the Cell theory in $1855$ and stated 'Omnis cellula-e-cellula' (cells arise from pre-existing cells).

Ruska & Knoll

The scientists who invented the electron microscope in $1940$.

Unicellular

Organisms made up of a single cell, such as $Euglena$ or $Amoeba$.

Multicellular

Organisms made up of more than one cell, such as humans and plants.

Thermophiles

Organisms that can withstand high temperature environments, such as thermophilic bacteria in natural springs.

Nerve cell

A long and branched cell designed to transmit electric signals over long distances.

Limit of resolution

The distance of $0.1\,mm$ at which two points can be seen as distinct by the human eye.

Plasma Membrane

A highly flexible, selectively permeable, living membrane made of proteins and lipids that protects the cell.

Fluid Mosaic Model

A model of the plasma membrane proposed by Singer and Nicolson in $1972$.

Diffusion

A passive process involving the movement of particles from a region of higher concentration to lower concentration until equilibrium is reached.

Osmosis

The passive movement of water molecules from a region of higher water concentration to lower water concentration through a selectively permeable membrane.

Hypotonic solution

A solution where the surrounding medium has a higher water concentration than the cell, causing the cell to gain water and swell.

Hypertonic solution

A solution where the surrounding medium has a lower water concentration than the cell, causing the cell to lose water and shrink (plasmolysed).

Isotonic solution

A solution where the water concentration is the same inside and outside the cell, resulting in no change in cell shape.

Endocytosis

The process that enables a cell to engulf food and other material from its external environment, categorized into Phagocytosis and Pinocytosis.

Active Transport

The movement of molecules 'pumped' against the concentration gradient (low to high), requiring energy in the form of $ATP$.

Cell Wall

A rigid, non-living, and fully permeable outer layer composed of cellulose, present only in plant cells.

Plasmolysis

The phenomenon of shrinkage or contraction of cell contents away from the cell wall when a plant cell loses water through osmosis.

Karyology

The study of the nucleus.

Nucleopores

Tiny pores in the nuclear membrane that surround the nucleus.

Chromatin

A network of thread-like coiled structures in the nucleoplasm made of $DNA$ and proteins that condense into chromosomes during cell division.

Genes

Functional segments of the chromosomes that act as carriers of hereditary information from one generation to the next.

Cytoskeleton

A network of fine fibres in eukaryotic cells that provides structural support and maintains cell shape.

Endoplasmic Reticulum (ER)

A membrane-bound network of cisternae and tubules used for central transport and synthesis within the cell.

Membrane Biogenesis

The process where proteins and lipids produced by the $ER$ are used to synthesize the cell's own membrane.

Ribosomes

Tiny structures known as 'protein factories' where protein synthesis occurs.

Golgi Apparatus

A membrane-bound organelle consisting of flattened sacs called cisternae that processes, sorts, and packages proteins and lipids into vesicles.

Lysosomes

Sacs filled with digestive enzymes known as 'suicide bags' because they destroy the entire cell if it is damaged or infected.

Mitochondria

Double-membrane structures known as the 'Power House of the cell' for generating $ATP$ for life processes.

ATP

$Adenosine\,Tri-Phosphate$, referred to as the energy currency of the cell.

Chloroplasts

Green plastids containing chlorophyll that are sites for photosynthesis.

Leucoplasts

Colorless plastids found in roots or potatoes that store starch, oils, and proteins.

Tonoplast

The membrane that surrounds the vacuole and separates it from the cytoplasm in a cell.

Cell sap

Watery fluid inside plant vacuoles that provides turgidity and rigidity by maintaining turgor pressure.

Mitosis

Cell division resulting in two genetically identical daughter cells, necessary for growth and repair.

Meiosis

A two-step cell division process creating four genetically unique gametes with half the chromosome number of the parent cell.

Contact Inhibition

A process where cell division stops when cells come into contact with neighboring cells.

Totipotency

The special ability of a living plant cell to develop into a complete plant if provided with suitable nutrients and conditions.