Chapter 3: Cell Structure & Function

Flashcards covering key vocabulary related to cell structure, function, organization, and membrane transport mechanisms discussed in Chapter 3 of the lecture notes.

Cell Theory

States that all living things are composed of cells, a single cell is the smallest unit of life, and all cells come only from preexisting cells.

Prokaryotic cells

A more 'primitive' cell type where the internal environment is not divided into membrane-bound compartments; includes Bacteria and Archaea.

Eukaryotic cells

A cell type where the internal environment is divided into membrane-bound compartments called organelles; includes animals, plants, fungi, and protists.

Plasma membrane

A selective barrier that encloses the cell, separating it from its environment and enabling information transfer.

Cytoplasm

The material or protoplasm within a living cell, excluding the nucleus.

Microvilli

Small projections of the cytoplasmic membrane that increase the cell's surface area.

Nucleus

The information center of the cell that contains the genetic information (DNA) and controls all cell activities.

Ribosomes

Particles made of RNA and protein that are responsible for synthesizing proteins.

Endoplasmic Reticulum (ER)

A network of membranes that serves as a manufacturing center within the cell.

Golgi apparatus

An organelle that refines, packages, and ships synthesized products within and out of the cell.

Vesicles

Membrane-bound storage and shipping containers within the cell.

Mitochondria

The 'powerhouse' of the cell, providing energy by being the sites of cellular respiration to generate ATP.

Chromosomes

Structures within the nucleus composed of DNA, carrying the cell's genetic information.

Nucleolus

The site within the nucleus where components of ribosomes are synthesized.

Smooth ER

A region of the endoplasmic reticulum that lacks ribosomes and functions in synthesizing lipids, metabolizing carbohydrates, detoxifying drugs and poisons, and storing calcium ions.

Rough ER

A region of the endoplasmic reticulum covered with ribosomes, involved in secreting glycoproteins, distributing transport vesicles, and serving as a membrane factory for the cell.

Glycoproteins

Proteins with carbohydrates covalently attached, often secreted by bound ribosomes on the Rough ER.

Transport vesicles

Membrane-bound sacs that move proteins and other substances from the ER to the Golgi and to other destinations.

Secretory vesicles

Vesicles that contain products destined for export from the cell.

Endocytic vesicles

Vesicles that contain substances imported from the external environment into the cell.

Peroxisomes

Vesicles containing enzymes that detoxify wastes produced by the cell.

Lysosomes

Membranous sacs that contain hydrolytic digestive enzymes that break down macromolecules, working best in an acidic environment.

Fat (Triglycerides)

A form of long-term energy storage in animals, stored in the cytoplasm of fat cells.

Glycogen

A form of short-term carbohydrate storage in animals, stored in the cytoplasm of muscle cells and liver cells.

Cytoskeleton

An internal scaffolding composed of microtubules and microfilaments that helps maintain cell shape and supports cellular structures.

Microtubules

Tiny hollow tubes of protein that are part of the cytoskeleton and involved in maintaining cell shape and movement.

Microfilaments

Thin solid fibers of protein that are part of the cytoskeleton and involved in cell movement and shape maintenance.

Cilia

Short, numerous hairlike structures specialized for movement, found in ducts/tubes.

Flagella

Long, single, whip-like structures specialized for movement, such as enabling spermatozoa to swim.

Centrioles

Short rod-like microtubular structures near the nucleus that play an important role in cell division.

Phospholipids

The primary component of the plasma membrane, forming a two-layered bilayer.

Cholesterol

A lipid component of the plasma membrane that increases mechanical strength and maintains fluidity at various temperatures.

Fluid mosaic

A model describing the plasma membrane as a nonrigid structure where phospholipids and proteins are not anchored and can drift relative to each other.

Passive transport

Movement of molecules across the plasma membrane that does not require the cell to expend energy; includes diffusion, osmosis, and facilitated diffusion.

Active transport

Movement of molecules across the plasma membrane that requires the cell to expend energy, often moving solutes against their concentration gradients.

Bulk transport

Movement of larger substances across the membrane via membranous vesicles, requiring energy; includes endocytosis and exocytosis.

Diffusion

The spontaneous movement of molecules to spread out evenly into an available space, down their concentration gradient.

Concentration gradient

A difference in the concentration of a substance across a distance or a membrane.

Osmosis

The diffusion of water across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration until equilibrium is reached.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water, affecting cell volume.

Isotonic solution

A solution where the solute concentration is the same as that inside the cell, resulting in no net water movement across the plasma membrane.

Hypertonic solution

A solution where the solute concentration is greater than that inside the cell, causing the cell to lose water and shrink.

Hypotonic solution

A solution where the solute concentration is less than that inside the cell, causing the cell to gain water and potentially lyse (burst).

Facilitated Diffusion

The passive movement of molecules down their concentration gradient across a membrane with the help of channel proteins or carrier proteins.

Channel proteins

Transmembrane proteins that form channels to allow specific molecules or ions to cross the membrane during facilitated diffusion.

Aquaporins

Specific channel proteins that facilitate the rapid diffusion of water across cell membranes.

Ion channels

Channel proteins that open or close in response to a stimulus (gated channels) to allow ions to pass through the membrane.

Carrier proteins

Transmembrane proteins that undergo a conformational change to translocate specific solute-binding sites across the membrane during facilitated diffusion.

Sodium-Potassium Pump

A specific active transport system that expends ATP to pump sodium ions out of the cell and potassium ions into the cell, against their concentration gradients.

Exocytosis

A process of bulk transport where transport vesicles migrate to the plasma membrane, fuse with it, and release their contents to the outside of the cell.

Endocytosis

A process of bulk transport where the cell takes in macromolecules and other substances by forming vesicles from the plasma membrane.

Phagocytosis

A type of endocytosis ('cellular eating') where a cell engulfs a large particle in a vacuole, which then fuses with a lysosome for digestion.

Pinocytosis

A type of endocytosis ('cellular drinking') where the cell 'gulps' extracellular fluid into tiny vesicles, taking in dissolved solutes.