Cell Biology and Membrane Transport Flashcards

A set of vocabulary flashcards covering cell structure, organelles, membrane composition, and transport mechanisms based on the lecture notes.

Eukaryotes

Cells that contain a membrane-bound nucleus and organelles, literally translating to "little nut" in Latin due to the nucleus appearing like a nut under early microscopes.

Prokaryotes

Organisms such as bacteria that lack a membrane-bound nucleus and have freely floating DNA, with the name translating to "no nut".

Red Blood Cell Maturation

The cellular maturation process where a cell destroys its nucleus and organelles, causing it to collapse into a biconcave shape that maximizes surface area for oxygen and carbon dioxide transport.

Interstitial Fluid

The fluid located in the spaces between individual cells or between tissues in the body.

Cytosol

The fluid portion of the cytoplasm composed of $70\%$ to $80\%$ water along with dissolved glucose, proteins, amino acids, and electrolytes.

Lysosomes

Membrane-bound organelles containing digestive enzymes used to break down cellular material, derived from the Latin word "lice" meaning to cut.

Peroxisomes

Specialized membrane-bound vacuoles containing hydrogen peroxide that function to disinfect, digest toxins, and break down cellular waste.

Inclusion

A tiny vacuole within a cell that stores specialty substances such as pigments, glycogen, or triglycerides.

Nucleolus

A dense structure inside the nucleus that stores extra amino acids and RNA components required for protein synthesis.

Cisternae

Specialized inner membrane structures within mitochondria that enable the production of $36$ ATP per glucose molecule.

Flagellum

A long, whip-like extension of the plasma membrane used for cell movement, found exclusively on sperm cells in the human body.

Cilia

Short membrane extensions on stationary cells that beat to move fluid and surrounding material past the cell surface.

Microvilli

Specialized extensions of the plasma membrane designed specifically for cellular absorption.

Hydrophilic Heads

The polar, water-loving phosphate portions of phospholipids that face the liquid environments inside and outside the cell.

Hydrophobic Tails

The fat-based, water-avoiding internal portions of the phospholipid bilayer that repel water-based substances.

Glycolipids

Molecules made of sugar and lipid embedded in the plasma membrane that extend outward to serve as cellular flags, identifiers, and receptors.

Integral Proteins

Proteins that span completely across the phospholipid bilayer to function as channels or gates for transport.

Peripheral Proteins

Proteins attached loosely to only the inner or outer surface of the plasma membrane that assist with local chemical processes.

Osmosis

The passive movement of water across the plasma membrane through aquaporin channels without requiring energy input.

Simple Diffusion

The passive movement of small molecules directly between the phospholipids of the plasma membrane without requiring a channel.

Facilitated Diffusion

Passive membrane transport that utilizes a channel protein or helper carrier molecule to move substances down their concentration gradient.

Phagocytosis

A form of active vesicular transport in which a cell engulfs solid particles, literally meaning "cell eating".

Pinocytosis

A form of active vesicular transport in which a cell takes in fluid and dissolved solutes, literally meaning "cell drinking".

Sodium-Potassium Pump

An active transport protein pump in the plasma membrane essential for nerve cells to maintain ion gradients required for electrical conduction.

Rough Endoplasmic Reticulum

A ribbon-like membrane organelle studded with ribosomes that assembles amino acids into preliminary protein chains.

Smooth Endoplasmic Reticulum

A ribbon-like membrane organelle lacking ribosomes that processes fats, metabolizes lactic acid, and detoxifies drugs and poisons.

Golgi Apparatus

A membrane-bound organelle that receives amino acid chains, folds them into final functional proteins, and packages them into transport vesicles.

Autophagy

The cellular process of self-eating where lysosomes digest damaged or old organelles to clean up the cell and maintain health.

$70\text{S}$ Ribosomes

Bacterial-style ribosomes found inside mitochondria that support their evolutionary origin as ancient engulfed bacteria.

Centrosome

An organelle composed of a pair of centrioles that serves as an anchor pulling chromosomes and cellular contents apart during cell division.