BIOL 1020: Carbohydrates and Cell Structure

Vocabulary practice flashcards covering carbohydrate classification and structure, prokaryotic versus eukaryotic cells, the endomembrane system, energy-converting organelles, the cytoskeleton, and intercellular connections based on BIOL 1020 lecture notes.

Monosaccharide

The simplest carbohydrate or single sugar, having a molecular formula that is generally a multiple of $\text{CH}_2\text{O}$.

Aldose

A monosaccharide classified by having its carbonyl group located at the end of the carbon skeleton (an aldehyde sugar).

Ketose

A monosaccharide classified by having its carbonyl group located within the carbon skeleton (a ketone sugar).

Disaccharide

A double sugar formed when two monosaccharides are joined by a dehydration reaction.

Glycosidic Linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

Polysaccharide

A carbohydrate macromolecule composed of many sugar monomers joined together, serving storage or structural roles.

Starch

A plant storage polysaccharide consisting entirely of glucose monomers linked by $\alpha$ glycosidic bonds, stored as granules within plastids such as chloroplasts.

Glycogen

An extensively branched storage polysaccharide in animals, found predominantly in liver and muscle cells, which releases glucose upon hydrolysis.

Cellulose

An unbranched structural polysaccharide made of $\beta$ glucose monomers connected by 1-4 linkages, serving as a major component of plant cell walls.

Chitin

A structural polysaccharide found in the exoskeletons of arthropods and used to provide structural support in fungal cell walls.

Cytosol

The semifluid, jellylike substance in the cytoplasm in which subcellular components are suspended.

Nucleoid

A non-membrane-enclosed region in a prokaryotic cell where the cell's DNA is concentrated.

Plasma Membrane

A selective phospholipid bilayer barrier enclosing the cytoplasm that allows sufficient passage of oxygen, nutrients, and wastes to support cell volume.

Nuclear Envelope

A double membrane perforated by pores that encloses the nucleus, separating its genetic contents from the cytoplasm.

Nuclear Lamina

A netlike array of protein filaments lining the inner surface of the nuclear envelope that mechanically maintains the shape of the nucleus.

Chromatin

The complex of DNA and proteins that constitutes eukaryotic chromosomes within the nucleus.

Nucleolus

A specialized structure inside the nucleus where ribosomal RNA (rRNA) is synthesized.

Ribosome

A cellular complex composed of ribosomal RNA and protein that carries out protein synthesis either free in the cytosol or bound to the endoplasmic reticulum.

Endomembrane System

A collection of interconnected cellular membranes—including the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and plasma membrane—that regulates protein traffic and performs metabolic tasks.

Smooth Endoplasmic Reticulum

The portion of the endoplasmic reticulum that lacks ribosomes, functioning in lipid synthesis, carbohydrate metabolism, drug detoxification, and calcium ion storage.

Rough Endoplasmic Reticulum

The portion of the endoplasmic reticulum studded with ribosomes that synthesizes glycoproteins and secretory proteins, produces transport vesicles, and acts as a membrane factory.

Golgi Apparatus

An organelle consisting of flattened membranous sacs (cisternae) that modifies products of the ER, manufactures macromolecules, and sorts and packages cargo into transport vesicles.

Cisternae

Flattened membranous sacs that comprise structures such as the endoplasmic reticulum and Golgi apparatus.

Lysosome

A membrane-enclosed sac of hydrolytic enzymes that digests macromolecules and functions optimally within an acidic interior environment.

Phagocytosis

A process of cellular eating wherein a cell engulfs another cell or large food particle, forming a food vacuole that fuses with a lysosome for digestion.

Autophagy

A lysosomal recycling process in which a cell breaks down and recycles its own damaged organelles and macromolecules.

Contractile Vacuole

A membranous organelle in many freshwater protists that pumps excess water out of the cell to maintain osmotic balance.

Central Vacuole

A large, prominent compartment in mature plant cells that holds water and organic compounds, hydrolyzes waste, and plays a major role in plant cell growth.

Endosymbiotic Theory

The evolutionary theory stating that mitochondria and chloroplasts originated as prokaryotic endosymbionts engulfed by ancestral eukaryotic host cells.

Cristae

Infoldings of the inner mitochondrial membrane that expand the surface area available for ATP synthesis enzymes.

Mitochondrial Matrix

The fluid-filled soluble compartment enclosed by the inner mitochondrial membrane containing enzymes for cellular respiration, free ribosomes, and circular DNA.

Thylakoid

A flattened, chlorophyll-containing membranous sac inside a chloroplast, organized into stacks called grana, where light energy is captured during photosynthesis.

Stroma

The fluid outside the thylakoids within the chloroplast inner membrane, containing chloroplast DNA, ribosomes, and metabolic enzymes.

Peroxisome

A single-membrane metabolic compartment containing enzymes that transfer hydrogen to oxygen, producing hydrogen peroxide ($\text{H}_2\text{O}_2$) and converting it to water ($\text{H}_2\text{O}$).

Cytoskeleton

A dynamic network of protein fibers extending throughout the cytoplasm that provides structural support, anchors organelles, and organizes cellular activities and motility.

Microtubule

A hollow cylinder measuring approximately $25\,\text{nm}$ in diameter composed of tubulin dimers ($\alpha$ and $\beta$) that shapes the cell, guides organelle movement, and separates chromosomes during division.

Centrosome

A structure near the nucleus that serves as the main microtubule-organizing centre of the cell, containing a pair of centrioles in animal cells.

Centriole

A cylindrical cellular structure composed of nine sets of triplet microtubules arranged in a ring; a pair exists within each animal cell centrosome.

Basal Body

A cellular structure with a "9 + 0" arrangement of microtubule triplets that anchors a motile cilium or flagellum into the cell.

Dynein

A motor protein with attached arms between microtubule doublets that drives the bending movement of cilia and flagella using ATP.

Microfilament

A solid rod measuring approximately $7\,\text{nm}$ in diameter formed from a twisted double chain of actin subunits that resists pulling forces within the cell.

Cortex

A 3-D network of microfilaments located immediately beneath the plasma membrane in the outer cytoplasm that helps support cell shape.

Pseudopodia

Cellular extensions that extend and contract through localized reversible assembly and interaction of actin filaments and myosin, enabling amoeboid movement.

Cytoplasmic Streaming

A circular flow of cytoplasm along actin filaments driven by myosin motors, speeding up the distribution of materials within plant cells.

Intermediate Filament

A fibrous cytoskeletal element measuring $8\text{--}12\,\text{nm}$ in diameter, composed of proteins like keratin, specialized for bearing tension, supporting cell shape, and permanently fixing organelle locations.

Extracellular Matrix (ECM)

A meshwork surrounding animal cells consisting of glycoproteins (such as collagen, proteoglycans, and fibronectin) that provides structural support, adhesion, movement, and regulation.

Integrin

A transmembrane receptor protein with two subunits that binds extracellular fibronectin on the outside and microfilaments on the inside, transmitting signals between the extracellular matrix and the interior.

Plasmodesmata

Open cytoplasmic channels through plant cell walls that connect neighboring cells, allowing free transit of water, small solutes, and certain macromolecules.

Tight Junction

An intercellular junction in animal cells where adjoining plasma membranes are bound by proteins, forming a continuous barrier that prevents extracellular fluid leakage.

Desmosome

An anchoring junction in animal epithelial sheets that rivets neighboring cells together using intermediate filaments made of keratin.

Gap Junction

A communicating junction in animal cells that provides open cytoplasmic channels between adjacent cells, allowing ions and small molecules to pass directly.