lab 2 plasma membrane

Vocabulary flashcards covering key plasma membrane structures, cytoplasmic components, and nuclear terminology from the lecture notes.

Plasma membrane

The cell’s outer boundary composed of a phospholipid bilayer with proteins, cholesterol, and carbohydrates; regulates what enters and exits the cell.

Phospholipid bilayer

Double layer of phospholipids whose hydrophobic tails face inward and hydrophilic heads face outward, forming the basic structure of the plasma membrane.

Hydrophobic tails

Non-polar fatty acid portions of phospholipids that face each other in the membrane interior and repel water.

Hydrophilic heads

Polar phosphate portions of phospholipids that face the aqueous extracellular fluid and cytosol.

Selective permeability

Property of the plasma membrane that controls which ions and molecules can pass through and in what amounts.

Fluid mosaic model

Concept describing the plasma membrane as a dynamic, fluid structure with proteins floating in or on a shifting sea of lipids.

Microvilli

Tiny finger-like projections of the plasma membrane that greatly increase a cell’s surface area for absorption, prominent in small intestine and kidney cells.

Glycoprotein

Membrane protein with attached carbohydrate chains; often functions as a channel, receptor, or cell-recognition molecule.

Integral (transmembrane) protein

Protein that spans the lipid bilayer and can form channels or transporters for polar substances.

Peripheral protein

Protein loosely attached to the inner or outer surface of the membrane, providing structural support or signaling functions.

Channel protein (pore)

Integral protein forming a hydrophilic passageway that allows small polar substances to diffuse through the membrane.

Cholesterol (in membrane)

Steroid lipid embedded between phospholipids that stabilizes membrane fluidity and integrity.

Cytoplasm

All cellular material between the nuclear envelope and plasma membrane, containing organelles and cytosol.

Cytosol

Aqueous intracellular fluid within the cytoplasm that contains dissolved solutes and suspended particles.

Nucleus

Membrane-bound organelle that coordinates cellular activities and houses genetic material (DNA).

Nuclear envelope

Double, porous membrane that surrounds and protects the nucleus.

Nucleoplasm

Gel-like internal fluid of the nucleus containing DNA, RNA, and nuclear proteins.

DNA (deoxyribonucleic acid)

Hereditary molecule composed of nucleotides that encodes genetic information.

Gene

Functional segment of DNA that directs synthesis of a specific protein or RNA molecule.

Chromosome

Rod-shaped structure of condensed DNA and associated proteins visible during cell division; humans have 46 in somatic cells.

Histone

Protein around which DNA coils to form nucleosomes, aiding chromosome packaging and regulation.

Chromatin

Loosely arranged complex of DNA and histones present when the cell is not dividing; condenses into chromosomes during mitosis.

Genome

The complete set of genetic information in a cell; in humans, the total of 46 chromosomes (23 from each parent).