Cell Biology, Metabolism, and Genetics Flashcards

Phospholipid Bilayer

A two-layered cell membrane structure composed primarily of lipids and proteins, featuring hydrophilic polar heads and hydrophobic nonpolar tails.

Hydrophilic Heads

The polar, water-loving heads of phospholipid molecules that face the fluid environments inside and outside the cell.

Hydrophobic Tails

The nonpolar, water-fearing tails of phospholipid molecules that face inward, making up the interior of the cell membrane.

Fluid Mosaic

A model describing the cell membrane structure where embedded proteins can move around within the double layer of lipids.

Cytosol

The fluid, gel-like portion of the cytoplasm in which cellular organelles are suspended.

Cytoskeleton

An internal framework formed of microfilaments and microtubules that helps a cell maintain its shape and anchors organelles.

Actin

A protein that forms tiny rods making up microfilaments, assisting with micro movements within the cell.

Ribosomes

Structures composed of RNA and protein where protein synthesis takes place, located floating in cytosol or attached to the rough endoplasmic reticulum.

Rough Endoplasmic Reticulum

A network of membrane-bound sacs and canals studded with ribosomes that conducts protein synthesis and protein folding.

Smooth Endoplasmic Reticulum

A network of membranous canals lacking ribosomes that is responsible for lipid and fat synthesis.

Golgi Apparatus

A stack of membranous sacs that refines, packages, and delivers proteins produced on the rough endoplasmic reticulum into vesicles.

Vesicles

Membranous sacs produced by the Golgi apparatus that package, transport, or store substances within or outside the cell.

Mitochondria

Known as the powerhouse of the cell; the organelle where cellular respiration occurs to produce ATP.

Lysosomes

Tiny membranous sacs containing digestive enzymes that act as the garbage disposal of cells by breaking down debris, bacteria, and macromolecules.

Peroxisomes

Enzyme-containing sacs that function as detoxifiers, breaking down harmful substances such as alcohol and hydrogen peroxide.

Cilia

Hair-like projections on the surface of certain cells that move substances across the cell surface in an upward motion.

Flagella

A long cellular projection that enables motility, found in human body structure exclusively on sperm cells.

Nucleolus

A dense body of RNA and protein inside the nucleus responsible for producing ribosomes.

Passive Transport

The movement of substances across a cell membrane without requiring cellular energy or ATP.

Diffusion

The passive movement of atoms, molecules, or ions from a region of higher concentration to a region of lower concentration until equilibrium is reached.

Facilitated Diffusion

The passive movement of substances across a cell membrane from high to low concentration using transport proteins or membrane channels.

Osmosis

The passive movement of water molecules across a selectively permeable membrane from an area of high water concentration toward an area of higher solute concentration.

Isotonic Solution

A solution containing an equal concentration of solutes compared to the inside of a cell, resulting in no net movement of water.

Hypertonic Solution

A solution with a higher solute concentration than inside the cell, causing water to leave the cell and the cell to shrivel.

Hypotonic Solution

A solution with a lower solute concentration than inside the cell, causing water to flow into the cell, which can cause it to swell or burst.

Filtration

The process in which molecules are forced through membranes from higher to lower concentration regions by physical or hydrostatic pressure.

Active Transport

The movement of substances against a concentration gradient from an area of low concentration to high concentration requiring energy in the form of ATP.

Sodium-Potassium Pump

An active transport carrier mechanism that uses ATP to pump sodium ions out of the cell and potassium ions into the cell.

Pinocytosis

A form of endocytosis where the cell membrane engulfs tiny droplets of liquid from its surroundings.

Phagocytosis

A form of endocytosis where the cell membrane engulfs solid particles.

Exocytosis

The process of releasing substances from a cell by fusing a membrane-bound vesicle with the cell membrane.