Chapter 03 Part C: Cells - Vocabulary (Cytoplasm, Organelles, and Nucleus)

Vocabulary flashcards covering key terms and definitions related to the cytoplasm, organelles, endomembrane system, cytoskeleton, and nucleus as described in the lecture notes.

Cytoplasm

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

Cytosol

Gel-like solution of water and soluble molecules (proteins, salts, sugars) in which cellular components are suspended.

Inclusions

Insoluble molecules in the cytoplasm that vary by cell type (e.g., glycogen granules, pigments, lipid droplets, vacuoles, crystals).

Organelles

Membrane-bound or nonmembrane-bound structures that perform specific cellular functions.

Membranous organelles

Organelles enclosed by membranes, such as mitochondria, ER, Golgi, peroxisomes, and lysosomes.

Nonmembranous organelles

Organelles not enclosed by a membrane, such as ribosomes, cytoskeleton, and centrioles.

Mitochondria

Organelle that produces most of the cell’s ATP via aerobic respiration; has double membranes and cristae.

ATP

Adenosine triphosphate; the cell’s main energy currency.

Cristae

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

Mitochondrial DNA (mtDNA), RNA, and ribosomes

Genetic material and ribosomes contained within mitochondria used for mitochondrial protein synthesis.

Ribosomes

Nonmembranous organelles where protein synthesis occurs; made of protein and rRNA.

Free ribosomes

Ribosomes floating freely in cytosol; synthesize soluble cytosolic or organelle proteins.

Membrane-bound ribosomes

Ribosomes attached to the rough ER; synthesize proteins for membranes, lysosomes, or export.

Endoplasmic Reticulum (ER)

Network of parallel, cisterns continuous with the outer nuclear membrane; two forms: rough and smooth.

Rough ER

ER with external ribosomes; synthesizes secreted and membrane proteins; proteins are modified and packaged for Golgi.

Smooth ER

ER without ribosomes; functions include lipid metabolism, detoxification, glycogen-to-glucose conversion, and calcium storage.

Saroplasmic reticulum

Specialized smooth ER in skeletal and cardiac muscle cells involved in calcium storage and release.

Golgi apparatus

Stacked cisternae that modify, concentrate, and package proteins and lipids from the rough ER; acts as traffic director.

Transport vesicles

Vesicles that fuse with the Golgi’s cis face to deliver proteins and lipids for processing.

Peroxisomes

Membranous sacs that detoxify toxins and break down fatty acids; contain oxidases and catalase.

Oxidases

Enzymes in peroxisomes that convert toxins to hydrogen peroxide (H2O2).

Catalase

Enzyme in peroxisomes that breaks down H2O2 into water and oxygen.

Lysosomes

Spherical vesicles with acid hydrolases that digest bacteria, viruses, toxins, and old organelles.

Acid hydrolases

Digestive enzymes inside lysosomes that break down biomolecules.

Autolysis

Self-digestion of a cell when lysosomal enzymes are released intracellularly due to injury.

Endomembrane system

Interconnected membranous organelles (ER, Golgi, secretory vesicles, lysosomes) plus nuclear and plasma membranes that build, degrade, store, and export molecules.

Cytoskeleton

Network of protein filaments giving the cell its shape, support, and ability to move components.

Microfilaments

Thin actin filaments that support the cell’s shape and aid in movement.

Intermediate filaments

Mid-thickness filaments providing tensile strength and anchor points for organelles.

Microtubules

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

Centrosome

Microtubule-organizing center near the nucleus; contains a matrix and centrioles.

Centrioles

Paired, barrel-shaped organelles at right angles; form the basis of cilia and flagella.

Cilia

Whiplike, motile extensions that move substances across cell surfaces in one direction.

Flagella

Longer extensions that propel whole cells, such as sperm tails.

Basal bodies

Organize the formation of cilia and flagella at their bases.

Microvilli

Fingerlike projections that increase surface area for absorption; contain actin filaments.

Nucleus

Largest organelle containing the cell’s genetic library; oversees protein synthesis.

Nuclear envelope

Double-membrane barrier enclosing the nucleus; outer layer continuous with rough ER.

Nucleolus

Dense region within the nucleus where rRNA is synthesized and ribosome subunits assemble.

Chromatin

DNA-histone-RNA complex; condenses into chromosomes during cell division.

Chromosomes

Condensed chromatin visible during cell division; carries genetic information.

Nucleolar organizer regions (NORs)

DNA regions that code for rRNA and organize nucleolus formation.

Nuclear pores

Openings in the nuclear envelope that regulate transport; guarded by the nuclear pore complex.

Nuclear pore complex

Protein assemblies that regulate movement of large molecules into and out of the nucleus.

Nucleoplasm

Fluid inside the nuclear envelope surrounding the chromatin and nucleolus.

Anucleate

Having no nucleus; e.g., mature red blood cells.

Multinucleate

Cells with more than one nucleus, such as some skeletal muscle and liver cells.

Glycogenolysis

Conversion of glycogen to free glucose, a key energy-releasing process in Smooth ER.

Detoxification (in ER and peroxisomes)

Metabolic processes that neutralize or remove toxic substances from the cell.

Lipid metabolism

Processes of lipid synthesis, storage, and transport primarily by Smooth ER and related organelles.