Cell: The Building Block of Life Lecture Flashcards

A comprehensive vocabulary review of cell biology concepts, including microscopy, organelle functions, membrane transport, and cell division based on the provided curriculum.

Thermophiles

Heat-loving unicellular bacteria that live in extreme environments such as the hot springs of Puga Valley in Ladakh.

Limit of resolution of the human eye

The ability to see two very close objects as separate and distinct; for the human eye, this is approximately $0.1\,mm$ at a distance of $25\,cm$.

Robert Hooke

The first person to observe a cell in $1665$ using a self-designed microscope to examine a thin slice of cork.

Resolution

A measure of the clarity of an image when using a microscope.

Contrast

The difference in brightness between various parts of an object observed under 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).

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 the 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 explaining the cell membrane structure as a lipid bilayer with embedded proteins where molecules can move sideways, flip, and rotate.

Cell wall

An additional rigid, permeable layer outside the cell membrane found in plants, fungi, and bacteria that provide protection and structural support.

Cellulose

A type of carbohydrate formed by many glucose units that serves as the primary component of the plant cell wall.

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

Cells that possess a well-defined nucleus and several membrane-bound organelles.

Cytoskeleton

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

Nucleolus

A dense round body within the nucleus responsible for the synthesis of ribosomal subunits.

Chromosomes

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

Genes

The functional segments of DNA that contain genetic information.

Ribosomes

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

Rough Endoplasmic Reticulum (RER)

A type of ER with ribosomes attached to its surface that is mainly involved in protein synthesis and secretion.

Smooth Endoplasmic Reticulum (SER)

A type of ER without ribosomes on its surface involved in the synthesis and storage of fats (lipids) and hormones.

Golgi apparatus

A stack of flattened sac-like structures that modifies, sorts, and packages proteins and lipids into vesicles for transport or secretion.

Lysosomes

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

Mitochondria

Often called the 'powerhouses of the cell', these organelles release energy from food via cellular respiration and store it as ATP.

Adenosine Triphosphate (ATP)

The molecule that acts as the energy currency for most cellular activities.

Chloroplasts

Double-membrane-bound plastids containing chlorophyll, the site of photosynthesis in plant cells.

Chromoplasts

Plastids containing yellow, orange, or red pigments that provide bright colours to flowers and fruits.

Leucoplasts

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

Vacuoles

Storage organelles filled with cell sap; large in plant cells to maintain pressure and firmness, and smaller in animal cells for temporary storage.

Mitosis

A type of cell division that produces two genetically identical daughter cells from one parent cell, used for growth and repair.

Meiosis

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

Contact inhibition

A process where normal animal cells stop dividing once they come into contact with neighbouring cells.

Programmed Cell Death (PCD)

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

Totipotency

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