Cellular Physiology - Vocabulary Flashcards

Vocabulary flashcards covering core terms from the lecture notes on cellular structure and organelles.

Cell

The basic living unit of the body; each cell type is specialized to perform one or a few functions; an organ is an aggregate of many cells.

Organ

An aggregate of many different cells held together by intercellular supporting structures.

Nucleus

Control center of the cell; contains DNA and RNA; includes nuclear sap, chromosomes, and nucleolus.

Chromosome

DNA-containing structures; humans have 23 pairs per cell.

Nucleolus

Non-membrane-bound region inside the nucleus rich in RNA and ribosomal proteins.

Cytoplasm

Cellular contents outside the nucleus, consisting of cortex (ectoplasm), endoplasm, and cytosol.

Cortex (Ectoplasm)

Region immediately beneath the cell membrane; composed of microfilaments that support the membrane.

Endoplasm

Region between the cortex and the nuclear membrane where organelles are suspended.

Cytosol

Fluid portion of the cytoplasm in which organelles reside.

Hyaloplasm

Water-rich component of the cell comprising about 70–85% of cell mass; medium for dissolution, suspension, and reactions.

Structural Proteins

Proteins that provide cellular structure; include long filaments and cytoskeletal elements like microtubules and extracellular collagen/elastin.

Globular Proteins

Compact, typically soluble proteins that are the second major class of cellular proteins.

Nucleoproteins

Proteins associated with DNA/RNA within the nucleus.

Lipids

Major class of biomolecules insoluble in water; include phospholipids, sphingolipids, glycolipids, cholesterol, and triglycerides.

Phospholipids

Lipids with a glycerol backbone, two fatty acid tails, and a polar phosphate head; amphipathic (hydrophilic head, hydrophobic tails).

Sphingolipids

Lipids with a sphingosine backbone; fatty acid tails with diverse head groups (phospholipid or glycolipid).

Glycolipids

Lipids with covalently attached carbohydrate (glyco) groups on the outer leaflet of the membrane.

Cholesterol

Hydrophobic lipid intercalated between phospholipids; modulates membrane permeability and fluidity.

Membrane Carbohydrates

Carbohydrates making up 2–10% of the membrane mass; form the glycocalyx and include glycoproteins, glycolipids, and proteoglycans.

Glycocalyx

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

Cell Membrane (Plasma Membrane)

Envelops the cell; about 7.5–10 nm thick; primarily proteins and lipids (55% proteins, 25% phospholipids, 13% cholesterol, 4% other lipids, 3% carbohydrates).

Micelles

Small droplets with a single layer of phospholipids; interior is hydrophobic.

Liposomes

Larger spheres with bilayer phospholipid walls and an aqueous core for containing water-soluble substances.

Integral Proteins

Proteins that span the lipid bilayer (through & through); tightly bound to the membrane.

Peripheral Proteins

Proteins attached to the membrane surface or to integral proteins; mainly enzymes or intracellular regulators.

Inclusion Bodies

Non-membrane-bound storage particles in the cytoplasm in direct contact with cytoplasm.

Mitochondria

Powerhouse of the cell; double-membrane organelle with cristae; site of oxidative phosphorylation; self-replicating.

Golgi Apparatus

Stacks of flattened vesicles near the nucleus; modifies, sorts, and packages proteins and carbohydrates; adds carbohydrate moieties.

Endoplasmic Reticulum (ER)

Network of tubules and sacs continuous with the nuclear envelope; contains enzymes for metabolic functions; two forms: rough and smooth.

Rough Endoplasmic Reticulum

ER studded with ribosomes; synthesizes and glycosylates proteins for secretion or membrane insertion; vesicle transport.

Smooth Endoplasmic Reticulum

ER lacking ribosomes; synthesizes lipids (phospholipids and cholesterol) and participates in detoxification and glycogen metabolism.

Lysosomes

Digestive organelles containing hydrolytic enzymes; digest proteins, carbohydrates, fats; autolysis if enzymes leak.

Peroxisomes

Smaller detoxification organelles containing oxidases and catalase; involved in fatty acid oxidation and drug detoxification.

Secretory & Storage Vesicles

Vesicles formed by the ER-Golgi system that carry secretory products and replenish cellular membranes.

Nucleoli

Non-membrane-bound region of the nucleus where RNA and ribosomal proteins accumulate for ribosome synthesis.

Nuclear Sap

Fluids within the nucleus (nucleoplasm) containing solutes and RNA-protein complexes.