Cell Biology Membrane Structure and Transport Dynamics (copy)

Cell

The smallest, most fundamental structural and functional unit of a living thing.

Organism

Any living entity, which can be single-celled (unicellular) or multi-celled (multicellular).

Unified Cell Theory Postulates

1. All living organisms are composed of one or more cells. 2. The cell is the fundamental, basic unit of life. 3. All new cells arise solely from pre-existing cells through division.

Magnification

The process of enlarging an object's physical appearance.

Resolving Power

The capacity of an optical system to distinguish two adjacent structures as distinct and separate entities.

Antony van Leeuwenhoek

A Dutch shopkeeper known for early observations of single-celled organisms and the term 'animalcules'.

Robert Hooke

Published Micrographia, coining the term 'cell' to describe box-like compartments observed in cork tissue.

Prokaryotes

Organisms that belong to the domains Bacteria and Archaea, mostly unicellular and lacking internal membrane-bound compartments.

Plasma Membrane

An outer phospholipid bilayer boundary separating internal cytoplasm from the external environment.

Cytoplasm

Jelly-like fluid cytosol containing dissolved cellular components.

Eukaryotic Cells

Cells characterized by a true membrane-bound nucleus and organelles performing specific metabolic functions.

Mitochondria

Double-membrane organelles responsible for aerobic cellular respiration and ATP production.

Chloroplasts

Double-membrane photosynthetic organelles found in plants and algae that absorb light energy.

Microtubules

Hollow tubes composed of tubular dimers that form tracks for vesicle transport and are involved in cell division.

Endocytosis

The process of engulfing extracellular material to form internal membrane-bound vesicles.

Exocytosis

The process of exporting bulk materials from the internal cytoplasm to the extracellular space.

Passive Transport

The movement of substances across membranes without the need for energy input.

Active Transport

The movement of solutes across plasma membranes against their concentration gradient requiring energy.

Osmolarity

Total solute concentration of a solution expressed as total number of solute particles per liter.

Tonicity

The ability of an external solution to affect a cell's volume through osmosis.

Aquaporins

Channel proteins that facilitate rapid water transport across membranes.

Lysosomes

Acidic hydrolytic organelles found in animal cells containing digestive enzymes for degrading substances.

Pap Smear Test

A test collecting cervical cell samples to examine for abnormalities like dysplasia or malignancy.

Cytotechnologist

Medical laboratory professionals trained to examine cellular morphology to identify disease.

Cell Wall

A rigid structural boundary external to the plasma membrane found in plants, fungi, and some protists.

Glycocalyx

Carbohydrate layer surrounding cell surfaces that aids in cell recognition and protection.

Electrochemical Gradient

The combined force driving ion movement across a membrane due to concentration and electrical differences.

Sodium-Potassium Pump

A critical membrane antiporter that maintains ionic homeostasis by moving sodium out and potassium into the cell.

Symbiosis

A close, long-term physical interaction between two organisms of different species.

Endosymbiosis

A mutually beneficial relationship where one organism lives inside the cell of another.