Cell Structure and the Plasma Membrane

Flashcards covering key vocabulary and concepts related to cell structure and the plasma membrane.

Cell

The smallest unit of life.

Plasma Membrane

The physical barrier that separates intracellular fluid from extracellular fluid and controls what enters and leaves the cell.

Selectively permeable

A characteristic of the plasma membrane that allows certain substances to cross more easily than others.

Glycocalyx

A coating formed by surface carbohydrates on the outer surface of the plasma membrane, which aids in cell recognition.

Phospholipid bilayer

The main structure of the plasma membrane, consisting of hydrophilic heads and hydrophobic tails.

Hydrophobic

Water-fearing; describes the tails of phospholipids that prevent water-soluble substances from crossing.

Hydrophilic

Water-loving; describes the heads of phospholipids that interact with water.

Carbohydrates

Molecules on the outer surface of the membrane that act as identity markers, allowing cells to recognize each other.

Integral proteins

Proteins embedded in the lipid bilayer that can extend across the membrane.

Peripheral proteins

Proteins that are anchored to the membrane's surface or to integral proteins.

Exocytosis

The process by which substances are expelled from the cell via vesicles that fuse with the plasma membrane.

Endocytosis

The process by which cells internalize substances by engulfing them in a vesicle.

Rough ER

Endoplasmic reticulum with ribosomes, involved in making membrane proteins and phospholipids.

Smooth ER

Endoplasmic reticulum without ribosomes, involved in lipid synthesis and detoxification.

Vesicle

A small membrane-bound structure that transports substances within a cell.

Cytoplasm

The watery environment inside the cell where organelles are suspended.

Nucleus

The membrane-bound structure in a cell that contains genetic material.

Lysosomes

Organelles containing digestive enzymes that break down waste materials and cellular debris.

Secretory vesicles

Vesicles that transport proteins to the plasma membrane for secretion.