Chapter 3 Cells - Vocabulary Flashcards

Vocabulary-style flashcards covering key cell biology concepts, organelles, membrane structure, transport mechanisms, junctions, and diabetes from the lecture notes.

Cell

The basic structural and functional unit of living organisms.

Cell Theory

Four statements: cells are the basic unit of life; organisms depend on cell activities; cell activities are shaped by their form; new cells arise only from existing cells.

Plasma Membrane

The phospholipid bilayer surrounding the cell, regulating entry/exit and hosting membrane proteins; ~60% protein and ~40% lipid; contains cholesterol and glycocalyx.

Cytoplasm

All cellular material between the plasma membrane and nucleus, including cytosol, organelles, and inclusions.

Nucleus

Cell’s control center that houses genetic material (DNA) and regulates cellular activities.

Nuclear Envelope

Double membrane surrounding the nucleus with nuclear pores; continuous with the Rough Endoplasmic Reticulum.

Chromatin

DNA-protein complex that condenses into chromosomes during cell division.

Nucleolus

Nuclear substructure where ribosomal RNA (rRNA) is synthesized and ribosomes begin to form.

Rough Endoplasmic Reticulum (RER)

ER studded with ribosomes; synthesizes proteins destined for secretion or membranes and is continuous with the nuclear envelope.

Smooth Endoplasmic Reticulum (SER)

ER lacking ribosomes; synthesizes lipids and carbohydrates, detoxifies chemicals, stores calcium, and in liver cells helps convert glycogen to glucose; sarcoplasmic reticulum in muscle.

Ribosomes

Nonmembranous particles that synthesize proteins; free ribosomes synthesize soluble proteins while membrane-bound ribosomes make proteins for membranes or lysosomes.

Golgi Apparatus

Stacked membrane sacs that modify, concentrate, and package proteins and lipids from the ER; has cis (receiving) and trans (shipping) faces; directs final destinations.

Mitochondrion

Powerhouse of the cell; produces ATP; double membrane with cristae; contains its own DNA and ribosomes.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for respiration.

Matrix

Innermost mitochondrial compartment where Krebs cycle enzymes reside.

Lysosome

Spherical organelle with digestive enzymes that degrade bacteria, old organelles, and debris; autolysis can occur after injury.

Peroxisome

Detoxifying organelle containing enzymes that break down toxins and fatty acids; contains catalase to convert hydrogen peroxide to water.

Cytosol

Fluid portion of the cytoplasm where many metabolic reactions occur.

Cytoskeleton

Network of protein filaments that gives the cell its shape, offers support, and serves as tracks for movement; includes microfilaments, intermediate filaments, and microtubules.

Microfilaments

Thinnest cytoskeletal filaments (actin) involved in cell movement and shape.

Intermediate Filaments

Filaments (e.g., keratin) that provide mechanical strength.

Microtubules

Hollow tubes that provide structure and act as tracks for vesicle movement and form the mitotic spindle.

Centrioles

Paired cylindrical organelles that organize microtubules during cell division.

Centrosome

Region near the nucleus containing a pair of centrioles and acting as the microtubule-organizing center.

Glycocalyx

Glycoprotein/glycolipid-rich sugar coating on the cell surface that mediates cell recognition.

Cholesterol (in membrane)

Sterol in the plasma membrane that stabilizes the bilayer and modulates fluidity.

Phospholipid

Lipid with a glycerol backbone, two nonpolar fatty acid tails, and a polar phosphate head forming the membrane bilayer.

Phospholipid Bilayer

Two-layer arrangement of phospholipids forming the cell membrane's hydrophobic core and hydrophilic surfaces.

Integral Membrane Proteins

Proteins that span the membrane (transmembrane) and participate in transport, signaling, and structure.

Peripheral Membrane Proteins

Proteins attached to the membrane surface but not embedded in the bilayer.

Transmembrane Protein

An integral protein that extends across the entire phospholipid bilayer.

Receptors

Membrane proteins that bind specific molecules (e.g., hormones) to trigger cellular responses.

CAMs (Cell Adhesion Molecules)

Proteins that enable cell-cell binding and communication in tissues.

Tight Junctions

Impermeable junctions that seal neighboring cells together to prevent paracellular passage.

Desmosomes

Anchoring junctions that bind cells together and distribute tension via intermediate filaments.

Gap Junctions

Communicating junctions that form channels allowing ions and small molecules to pass between adjacent cells.

Diffusion

Movement of molecules from high to low concentration down their gradient; no energy required.

Simple Diffusion

Direct diffusion of nonpolar, lipid-soluble substances through the phospholipid bilayer.

Facilitated Diffusion

Passive transport of substances down their gradient via carrier or channel proteins.

Osmosis

Diffusion of water across a selectively permeable membrane.

Active Transport

Movement of substances across membranes against their concentration gradient, requiring energy (ATP) and carrier proteins.

Primary Active Transport

Direct use of ATP to move substances, as in the Na+/K+ pump.

Sodium-Potassium Pump (Na+/K+ pump)

Membrane transporter that moves 3 Na+ out and 2 K+ in per ATP hydrolyzed to maintain gradients.

Secondary Active Transport

Movement of substances against their gradient using energy from ion gradients created by primary active transport.

Vesicular Transport

Movement of large particles or fluids in vesicles; includes endocytosis, exocytosis, and transcytosis.

Endocytosis

Process of taking materials into the cell via vesicles; includes phagocytosis, pinocytosis, and receptor-mediated endocytosis.

Phagocytosis

Cellular ingestion of solid particles or microbes.

Pinocytosis

Cellular intake of fluids and solutes via vesicles (cell drinking).

Receptor-Mediated Endocytosis

Selective uptake of ligands via receptor binding and vesicle formation.

Exocytosis

Secretory vesicles fuse with the plasma membrane to release contents outside the cell.

Transcytosis

Transport of substances across the cell by endocytosis on one side and exocytosis on the other.

Diabetes Mellitus

Metabolic disorder characterized by altered carbohydrate metabolism due to insulin production or sensitivity issues.

Type I Diabetes Mellitus (IDDM)

Insulin-dependent, usually juvenile-onset; little to no insulin production by pancreatic beta cells.

Type II Diabetes Mellitus (NIDDM)

Non-insulin-dependent, typically adult-onset; insulin resistance or inadequate insulin production; often linked to overweight.

ATP

Adenosine triphosphate; primary energy currency of the cell.

Glycogen

Storage polymer of glucose found mainly in liver and skeletal muscle.

Calcium (Ca2+)

Ion critical for signaling and muscle contraction; stored in ER/sarcoplasmic reticulum and released as needed.

Sarcoplasmic Reticulum

Specialized smooth ER in muscle cells that stores and releases Ca2+ for muscle contraction.

Autolysis

Self-digestion of cells by their own enzymes, often after injury.

Nuclear Pores

Protein-lined openings in the nuclear envelope that regulate transport between the nucleus and cytoplasm.