Cells and Membrane Transport

Vocabulary flashcards generated from lecture notes covering cell organelles, stages of mitosis and meiosis, cellular transport mechanisms (diffusion, osmosis, active transport), and types of endocytosis and exocytosis.

Cells

The basic building blocks of the body comprised of organelles including the nucleus, cytoplasm, plasma membrane, ribosomes, endoplasmic reticulum, mitochondria, and cytoskeleton.

Nucleus

Organelle that contains genetic information and is surrounded by its own membrane.

Chromatin

The threadlike form of DNA present inside the nucleus prior to condensation.

Chromosomes

Condensed chromatin formed during cell division to organize genetic material.

Plasma Membrane

The outer barrier of the cell that exhibits selective permeability.

Selective Permeability

The property of the plasma membrane that allows specific objects or molecules to pass through.

Ribosomes

Tiny spherical bodies composed of RNA and protein, floating free or attached to the rough ER, that serve as the actual sites of protein synthesis.

Endoplasmic Reticulum (ER)

A membranous system of tubules extending throughout the cytoplasm, existing as rough ER (studded with ribosomes for protein storage and transport) and smooth ER (site of steroid/lipid synthesis, lipid metabolism, and drug detoxification).

Golgi Apparatus

A stack of flattened sacs with bulbous ends and associated vesicles located near the nucleus that packages proteins and other substances for cellular export, plasma membrane incorporation, or lysosomal enzyme packaging.

Lysosomes

Membranous sacs of various sizes containing digestive enzymes, including acid hydrolases, that digest worn-out organelles and foreign substances.

Peroxisomes

Small lysosome-like membranous sacs containing oxidase enzymes that detoxify alcohol, hydrogen peroxide, and other harmful chemicals.

Mitochondria

Rod-shaped bodies with a double-membrane wall whose inner membrane is folded into cristae; they contain enzymes that oxidize foodstuffs to produce cellular energy (ATP) and are known as the powerhouses of the cell.

Centrioles

Paired, cylindrical bodies lying at right angles to each other near the nucleus; as part of the centrosome, they direct mitotic spindle formation and form the bases of cilia and flagella.

Microfilaments

Cytoskeletal elements formed largely of actin, a contractile protein, that are important in cell mobility, particularly in muscle cells.

Intermediate Filaments

Stable cytoskeletal elements composed of a variety of proteins that resist mechanical forces acting on cells.

Microtubules

Cytoskeletal elements that form the internal structure of centrioles and help determine cell shape.

Mitosis

Cell division process used for non-sex cells that results in two identical daughter cells.

Meiosis

Cell division process used for sex cells (gametes) that creates four genetically different daughter cells.

Interphase

Period preceding mitosis during which DNA is replicated, cell growth occurs, and DNA remains as chromatin.

Prophase

Stage of mitosis where chromosomes form, the nuclear membrane breaks down, centrosomes separate, and the mitotic spindle forms and attaches to kinetochores.

Kinetochore

The center region of chromosomes where spindle microtubules attach during prophase.

Metaphase

Stage of mitosis during which chromosomes line up along the middle of the cell.

Anaphase

Stage of mitosis during which the mitotic spindle retracts and sister chromatids are pulled apart.

Telophase

Stage of mitosis where two separate cells start to form, a cleavage furrow appears, and nuclear envelopes reform.

Cytokinesis

The final physical separation of the cytoplasm resulting in completely divided daughter cells.

Diffusion

Passive transport process in which objects or molecules move from high concentration to low concentration.

Dynamic Equilibrium

A state where molecules continuously move across a membrane but forward and reverse rates are equal, resulting in equal concentration on both sides.

Rates of Diffusion Factors

Variables affecting how fast particles or water move, including concentration, size, temperature, surface area, and polarity.

Osmosis

The diffusion of water molecules across a membrane toward areas of higher solute concentration.

Hypotonic Solution

A solution with a lower solute concentration than the cytoplasm, causing water to enter red blood cells and leading them to lyse.

Isotonic Solution

A solution with equal solute concentration to the cytoplasm, resulting in balanced water movement and normal red blood cell morphology.

Hypertonic Solution

A solution with a higher solute concentration than the cytoplasm, causing water to exit red blood cells and leading them to shrivel.

Active Transport

Cellular transport mechanisms that require energy (ATP) to move substances across membranes, including pumps, endocytosis, and exocytosis.

Exocytosis

Active transport mechanism where secretory vesicles fuse with the plasma membrane to release molecules out of the cell.

Endocytosis

Active transport mechanism where vesicles bring extracellular substances or fluid into the cell.

Phagocytosis

A type of endocytosis termed 'cell eating' where pseudopodia engulf solid particles into a phagosome.

Pinocytosis

A type of endocytosis termed 'cell drinking' that allows the cell to take in droplets of extracellular fluid within vesicles.

Receptor-Mediated Endocytosis

A specialized type of endocytosis utilizing membrane receptors and coated pits to allow specific target substances to be absorbed into coated vesicles.