The Cell and Cell Membrane (Video) Notes

Vocabulary flashcards covering key terms from the lecture notes on the cell, plasma membrane, transport mechanisms, organelles, cytoskeleton, and nucleus.

Cell

The basic unit of living things; organisms are made of trillions of cells.

Plasma Membrane

The membrane that separates the internal cell from the extracellular environment and regulates import/export.

Fluid Mosaic

Describes the cell membrane as a flexible, mosaic-like structure made of many components.

Phospholipids

Major membrane component forming a bilayer with hydrophobic tails inside and hydrophilic heads outside.

Cholesterol

Stabilizes the membrane and prevents phospholipid tails from crystallizing; makes up about 20% of membrane weight.

Carbohydrate (in membranes)

Carbohydrate groups attached to membrane components, contributing to cell recognition.

Glycocalyx

Carbohydrate-rich layer on the outer cell surface involved in recognition and attachment.

Integral Protein

Proteins that penetrate the membrane core or span the membrane.

Peripheral Protein

Proteins loosely attached to the membrane surface.

Glycolipids

Lipids with carbohydrate chains on the outer surface; part of the glycocalyx.

Glycoproteins

Proteins with carbohydrate chains on the outer surface; markers for recognition.

Channel Protein

Membrane protein that forms a pore allowing ions or water to pass; can be leaky or gated.

Carrier Protein

Transport proteins that move larger molecules (e.g., glucose) across the membrane.

Receptors

Proteins that detect chemical signals and trigger cellular responses.

Enzymes (membrane-related)

Proteins that catalyze chemical reactions at the membrane.

Phospholipid Bilayer

Two phospholipid layers forming the core structure of the cell membrane.

Membrane Proteins

Proteins embedded in or associated with the lipid bilayer that perform various functions.

Microvilli

Finger-like extensions of the cell membrane that increase surface area for absorption; anchored by actin.

Gap Junctions

Adjacent integral proteins form channels that allow ions and water to pass between cells.

Desmosomes

Anchoring junctions that resist tension and mechanical stress between cells.

Tight Junctions

Junctions that seal spaces between cells to create a water-tight barrier.

Endocytosis

Cell takes in material via vesicle formation.

Exocytosis

Cell expels material via vesicle fusion with the plasma membrane.

Pinocytosis

Cell drinking; uptake of fluids and dissolved solutes.

Phagocytosis

Cell eating; uptake of larger particles.

Diffusion

Passive movement of solutes down a concentration gradient.

Facilitated Diffusion

Diffusion of solutes through membrane proteins (channels or carriers); still passive.

Active Transport

Movement of solutes against a gradient; requires energy (ATP) and a carrier protein.

Sodium-Potassium Pump

A primary active transport pump moving Na+ out and K+ in to maintain gradients.

Isotonic

Solution with equal solute concentration inside and outside the cell; no net water movement.

Hypotonic

Lower solute concentration outside the cell; water moves in; cell swells.

Hypertonic

Higher solute concentration outside the cell; water moves out; cell shrinks.

Dialysis

Artificial process using diffusion and osmosis to remove wastes from the blood.

Cytoplasm

Material within the cell excluding the nucleus; site of most cellular activity; contains cytosol and inclusions.

Mitochondria

Organelle that generates ATP; contains cristae (inner membrane) and matrix; has its own DNA and ribosomes.

Cristae

Folded inner membrane of mitochondria that increase surface area for ATP production.

Matrix

Fluid interior of mitochondria where metabolic reactions occur.

Ribosomes

Ribonucleoprotein particles that synthesize proteins; free ribosomes manufacture intracellular proteins, bound ribosomes synthesize for export or membranes.

Endoplasmic Reticulum (ER)

Network of membranes continuous with the nuclear envelope involved in protein and lipid synthesis.

Rough Endoplasmic Reticulum (RER)

ER with ribosomes on its surface; site of protein synthesis for secretion and membranes.

Smooth Endoplasmic Reticulum (SER)

ER lacking ribosomes; involved in lipid synthesis and detoxification processes.

Golgi Apparatus

Stacks of membranes that modify, sort, and package proteins and lipids for secretion or delivery.

Lysosomes

Vesicles containing digestive enzymes for cellular digestion and autolysis.

Peroxisomes

Organelles containing enzymes that neutralize reactive oxygen species (e.g., H2O2) and other oxidative processes.

Vacuoles & Vesicles

Membrane-bound sacs for storage and transport of substances within the cell.

Cytoskeleton

Network of protein filaments providing shape, support, and movement for the cell.

Actin Filament (Microfilament)

Smallest cytoskeletal filament involved in cell movement and shape changes.

Intermediate Filaments

Medium-sized cytoskeletal filaments providing structural support and resilience.

Microtubules

Largest cytoskeletal filaments that support cell shape, transport, and mitotic spindle formation.

Cilia

Hair-like extensions with a 9+2 microtubule arrangement; help move fluids; common in respiratory tract and fallopian tubes.

Nucleus

Largest organelle that houses DNA and controls cellular activities.

Nuclear Membrane

Double-layered membrane surrounding the nucleus with pores.

Nucleolus

Region within the nucleus where ribosomal RNA is produced and assembled with proteins.

Histones

Protein cores around which DNA is wrapped to form chromatin; regulate gene expression.

Chromatin

DNA-protein complex inside the nucleus; can be loosely packed (euchromatin) or tightly packed (heterochromatin).

Nucleosomes

DNA wrapped around a core of histone proteins; basic unit of chromatin structure.

Euchromatin

Lightly stained, transcriptionally active chromatin that is less condensed.

Heterochromatin

Densely packed, transcriptionally inactive chromatin that stains darkly.

Chromosomes

DNA material visible during cell division; carries genetic information.