Chapter 1-8: Cellular Structure and Tissues (Vocabulary Flashcards)

Vocabulary flashcards covering key cell biology topics (organelles, transport, mitosis, and epithelial tissues) from the lecture notes.

Plasma membrane

The phospholipid bilayer that encloses the cell, separating intracellular fluid (ICF) from extracellular fluid (ECF); contains receptors and transport proteins; hydrophobic tails face inward and hydrophilic heads face outward.

Cytoplasm

The contents of the cell excluding the nucleus; includes cytosol and all organelles.

Cytosol

The fluid component of the cytoplasm, high in potassium, where many metabolic reactions occur.

Intracellular fluid (ICF)

Fluid inside the cell.

Extracellular fluid (ECF)

Fluid outside the cell.

Rough endoplasmic reticulum (RER)

Ribosome-studded ER where protein synthesis occurs and proteins are folded and processed.

Smooth endoplasmic reticulum (SER)

ER without ribosomes; involved in lipid synthesis and detoxification processes.

Ribosome

RNA-protein complexes that are the sites of protein synthesis; can be free in the cytoplasm or attached to the rough ER.

Free ribosome

Ribosomes suspended in the cytosol that synthesize cytoplasmic and nuclear proteins.

Golgi apparatus

Organelle that modifies, tags, and ships proteins; has cis (receiving) and trans (shipping) faces and contributes to membrane maintenance.

Lysosome

Digestive organelle containing enzymes that break down waste, with potential to cause cell death if ruptured.

Peroxisome

Organelle containing catalase and peroxidases that detoxify hydrogen peroxide and break down fatty acids.

Mitochondrion

Powerhouse of the cell; produces most ATP via oxidative phosphorylation; contains its own DNA, often maternally inherited.

Nucleus

Cell’s control center containing DNA; surrounded by a nuclear envelope with pores; houses the nucleolus and chromatin.

Nucleolus

Dense region within the nucleus where ribosomal RNA (rRNA) synthesis and ribosome subunit assembly occur.

Chromatin

DNA packaged with histone proteins; appears as red fuzz in cells and condenses into chromosomes during mitosis.

Nuclear envelope

Double membrane enclosing the nucleus; contains nuclear pores for transport.

Nuclear pore

Openings in the nuclear envelope that regulate traffic between the nucleus and cytoplasm.

Centrosome

Microtubule-organizing center for the cell, important for mitosis; contains the pair of centrioles in animal cells.

Centriole

A cylindrical structure within the centrosome; organizes spindle fibers during cell division.

Cytoskeleton

Network of protein filaments (microfilaments, intermediate filaments, microtubules) that gives the cell shape and enables movement.

Microfilament

Actin-based filaments involved in cell movement and shape changes; contribute to cleavage furrow during cytokinesis and support microvilli.

Microtubule

Tubular filaments that form the mitotic spindle, enable chromosome movement via kinetochores, and build cilia/flagella.

Cilia

Hair-like projections that move substances across a surface; common in the respiratory tract.

Microvilli

Small finger-like projections that increase surface area for absorption, notably in the gut.

Stereocilia

Long, nonmotile microvilli-like projections found in certain tissues (e.g., parts of the reproductive system and inner ear).

Gap junctions

Intercellular channels (formed by connexons) that allow direct exchange of ions and small molecules between neighboring cells.

Intercalated discs

Specialized cell junctions in cardiac muscle containing gap junctions for coordinated contraction.

Receptor

Transmembrane protein that binds a signaling molecule (ligand) and initiates intracellular signaling cascades.

Ligand

A molecule that binds to a receptor to trigger a cellular response.

Glycocalyx

Carbohydrate-rich layer on the cell surface formed by glycoproteins and glycolipids involved in cell recognition and protection.

Diffusion

Passive movement of molecules from high to low concentration across a membrane or space.

Osmosis

Diffusion of water across a selectively permeable membrane from higher to lower water concentration.

Facilitated diffusion

Passive transport that requires membrane proteins to move substances down their concentration gradient.

Active transport

Movement of substances against their concentration gradient that requires energy (ATP) and transporter proteins.

Na+/K+ ATPase pump

Membrane pump that moves 3 Na+ out and 2 K+ in, consuming ATP to maintain ion gradients.

Endocytosis

Cellular uptake of material via vesicle formation from the plasma membrane.

Phagocytosis

Cell eating; engulfment of large particles or microbes by pseudopods to form a phagosome.

Pinocytosis

Cell drinking; uptake of extracellular fluid and dissolved solutes via vesicles.

Receptor-mediated endocytosis

Highly specific endocytosis triggered by ligand binding to cell-surface receptors; receptors are often recycled.

Exocytosis

Process by which vesicles fuse with the plasma membrane to secrete contents outside the cell.

Vesicular transport

Movement of materials between organelles via membrane-bound vesicles.

Lysosomal digestion

Degradation of biomolecules by lysosomal enzymes, essential for recycling and defense.

Apoptosis

Programmed cell death; a controlled, energy-dependent process that eliminates cells without causing inflammation.

Mitosis

Nuclear division yielding two genetically identical daughter cells; includes prophase, metaphase, anaphase, and telophase.

Prophase

Chromosomes condense and become visible; the mitotic spindle forms.

Metaphase

Chromosomes align at the metaphase plate; kinetochores attach to spindle fibers.

Anaphase

Sister chromatids separate and migrate to opposite poles as the spindle shortens.

Telophase and cytokinesis

Nuclei reform around separated chromosomes; cytoplasm divides via a cleavage furrow to form two cells.

DNA replication

Occurs prior to mitosis; semi-conservative duplication of the genome.

Epithelium

Tissue that lines surfaces and cavities; avascular but nourished by diffusion from underlying connective tissue.

Simple vs. Stratified epithelium

Simple: one cell layer; Stratified: multiple layers, providing protection.

Squamous

Flat, scale-like epithelial cells.

Cuboidal

Cube-shaped epithelial cells with round nuclei.

Columnar

Tall, column-shaped epithelial cells.

Transitional epithelium

Epithelium that can stretch and is found in the urinary system, capable of changing shape.