Cell: The Building Block of Life

A collection of vocabulary flashcards covering cell structure, organelles, transport mechanisms, division, and the history of cell biology based on the lecture transcript.

Puga Valley

A location in Ladakh, India, containing hot springs with temperatures near the boiling point of water, reflecting conditions similar to early Earth approximately $3.5\,\text{billion years}$ ago.

Thermophiles

Heat-loving, unicellular bacteria that thrive in high-temperature environments such as the hot springs of Puga Valley.

Limit of resolution of the human eye

The ability of the human eye to see two close objects as separate and distinct, which is approximately $0.1\,\text{mm}$ when viewed from about $25\,\text{cm}$.

Robert Hooke

The scientist who first observed and named 'cells' in $1665$ after examining a thin slice of cork using a self-designed microscope.

Total magnification

The result of multiplying the magnifying power of the eyepiece by the magnifying power of the objective lens in a microscope.

Electron microscope

A powerful instrument that uses a beam of electrons instead of light to produce highly magnified images at the nanometre scale.

Osmosis

The movement of water through a selectively permeable membrane from an area with more water (dilute solution) to an area with less water (concentrated solution).

Diffusion

The net movement of particles from a higher concentration to a lower concentration occurring even without a membrane.

Isotonic solution

A solution where the solute concentration of the extracellular medium is equal to the solute concentration of the intracellular medium.

Hypotonic solution

A solution where the solute concentration of the extracellular medium is less than the solute concentration of the intracellular medium, causing a cell to swell.

Hypertonic solution

A solution where the solute concentration of the extracellular medium is greater than the solute concentration of the intracellular medium, causing the cell to shrink.

Fluid-mosaic model

A model describing the cell membrane as a lipid bilayer with proteins embedded in it, where molecules can move sideways, flip, and rotate.

Cell wall

An additional rigid covering outside the cell membrane in plants, fungi, and bacteria that provides structural support and maintains cell shape.

Cellulose

A type of carbohydrate formed by linked glucose units that primarily composes the plant cell wall and acts as roughage in the human diet.

Organelles

Sub-cellular components within the cytoplasm, such as the nucleus and mitochondria, that perform specific jobs for the cell.

Prokaryotic cells

Cells that lack a well-defined nucleus and membrane-bound organelles, with genetic material located in a region called the nucleoid.

Eukaryotic cells

Complex cells with a well-defined nucleus and several membrane-bound organelles, found in plants and animals.

Cytoskeleton

A network of fine fibres in eukaryotic cells provide structural support, maintain cell shape, and enable movement.

Nucleolus

A dense round body within the nucleus where the synthesis of ribosomal subunits takes place.

Chromosomes

Rod-shaped structures visible during cell division that are composed of DNA and proteins and carry genetic information.

DNA (Deoxyribonucleic acid)

Molecules that contain the genetic information of a cell, with functional segments known as genes.

Chromatin

An entangled mass of thread-like structures in a non-dividing cell that organizes into chromosomes when the cell is about to divide.

Ribosomes

Tiny structures that serve as the sites of protein synthesis, found either freely in the cytoplasm or attached to the endoplasmic reticulum.

Rough Endoplasmic Reticulum (RER)

A part of the endoplasmic reticulum with ribosomes attached to its surface, primarily involved in protein synthesis and secretion.

Smooth Endoplasmic Reticulum (SER)

A part of the endoplasmic reticulum without ribosomes, involved in the synthesis and storage of fats (lipids) and hormones.

Golgi apparatus

Stacks of flattened, sac-like structures that modify, sort, and package proteins and lipids into vesicles for transport or secretion.

Lysosomes

Single membrane-bound sacs filled with enzymes that break down unwanted proteins, fats, carbohydrates, and damaged cell parts.

Mitochondria

Known as the 'powerhouses of the cell,' these organelles release energy through cellular respiration and store it as Adenosine Triphosphate (ATP).

Adenosine Triphosphate (ATP)

The energy currency of the cell produced by mitochondria used to fuel various cellular activities.

Plastids

Organelles in plant cells used for food synthesis and storage, categorized into chloroplasts, chromoplasts, and leucoplasts.

Chloroplasts

Double-membrane-bound plastids containing the green pigment chlorophyll used in the process of photosynthesis.

Chromoplasts

Plastids containing yellow, orange, or red pigments that provide bright colors to flowers and fruits to attract pollinators and aid seed dispersal.

Leucoplasts

Colourless plastids that store food materials such as starch, oils, or proteins.

Vacuoles

Organelles for storage and support; in mature plant cells, a large central vacuole filled with cell sap maintains internal pressure.

Mitosis

The most common type of cell division that produces two genetically identical daughter cells from one parent cell for growth and repair.

Meiosis

A two-step cell division process that produces four gametes with half the original number of chromosomes for sexual reproduction.

Cell culture

The process of taking cells from an organism and growing them outside the body in a nutrient-rich medium under sterile conditions.

Cell Theory

A unifying biology principle stating all organisms consist of cells, cells are the basic unit of life, and all cells arise from pre-existing cells.

Contact inhibition

A process in many animal cells where cell division stops upon contact with neighboring cells, a control mechanism lost in cancer cells.

Programmed Cell Death (PCD)

A genetically regulated process of selective cell destruction essential for normal development and immune function.

Totipotency

The ability of a living plant cell to develop into a complete plant if provided with suitable nutrients and conditions, as proposed by Gottlieb Haberlandt.

Camillo Golgi

The Italian scientist who first observed a thread-like network in nerve cells in $1898$, which was later named the Golgi apparatus.

J. Craig Venter

A scientist who in $2010$ successfully inserted chemically synthesised DNA into a living cell, showing that DNA controls cell activities.

Arun Kumar Sharma

A famous Indian botanist recognized for his extensive work on plant chromosomes, taxonomy, and evolution.