Cell: The Building Block of Life - Review Flashcards

This set of vocabulary flashcards covers the fundamental concepts of cell biology, including the history of cell discovery, microscopy, cell structure (membrane and wall), transport mechanisms (osmosis and diffusion), and the classification of cell types based on the provided lecture transcript.

Puga Valley

A location in Ladakh, India, known for its hot springs with temperatures near the boiling point of water, reflecting environmental conditions similar to early Earth about $3.5$ billion years ago.

Thermophiles

Heat-loving, unicellular bacteria that live in extreme environments like hot springs.

Cell

The basic level at which life exists and the fundamental unit of structure and function in all living organisms.

Unicellular

Organisms consisting of only one cell, such as bacteria or yeast.

Multicellular

Organisms made up of millions of cells working together, such as plants, fish, birds, or humans.

Tissue

A group of similar cells performing similar functions.

Organ

A structure formed by different tissues organized together to perform specific functions.

Organ system

A group of several organs working together, such as the nasal pores, trachea, and lungs forming the respiratory system.

Limit of resolution of the human eye

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

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 clarity in an image produced by a microscope.

Contrast

The difference in brightness between various parts of an object viewed under a microscope.

Nanometre

A unit of measurement equal to one-billionth of a metre.

Electron microscope

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

Cell membrane (Plasma membrane)

A thin, selectively permeable boundary that surrounds a cell, protects its contents, and defines its individuality.

Selectively permeable

A property of a membrane that allows some substances to pass through while blocking others.

Osmosis

The diffusion of water across 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.

Concentration gradient

A difference in the concentrations of particles of matter between two areas.

Isotonic solution

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

Hypotonic solution

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

Fluid-mosaic model

A model of the cell membrane structure consisting of a lipid bilayer with embedded proteins that can move sideways, flip, and rotate.

Lipid bilayer

Two layers of fat molecules with water-attracting heads facing outwards and water-repelling tails facing inwards.

Cell wall

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

Cellulose

A type of carbohydrate formed by many glucose units linked together that primarily makes up the plant cell wall.

Cytoplasm

A semi-fluid, jelly-like substance within the cell that contains sub-cellular components.

Organelles

Sub-cellular components present in the cytoplasm, most of which are only visible with an electron microscope.

Prokaryotic cells

Cells that lack a well-defined nucleus and membrane-bound organelles; 'pro' means primitive and 'karyon' means nucleus.