Unit 2 Notes

Cell Theory

The fundamental concept that all living organisms are composed of one or more cells; cells are the smallest units of life; new cells arise from existing cells.

Resolution

The ability to observe two close objects as distinct; it increases with magnification.

Contrast

The difference in appearance (color) between structures, which can be improved with stains or dyes.

Magnification

The ratio between the size of a microscope image and its actual size.

Prokaryotes

Cells with a simple structure that lack a nucleus, found in Bacteria and Archaea.

Eukaryotes

More complex cells with DNA enclosed in a nucleus and other organelles, including plants, fungi, animals, and protists.

Cytoplasm

The region of a eukaryotic cell that is outside the nucleus but inside the plasma membrane, containing organelles and cytosol.

Cytosol

The intracellular fluid contained within the cytoplasm.

Endomembrane System

A network of membranes enclosing the nucleus, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles.

Mitochondria

Organelles that generate ATP through cellular respiration and are involved in the synthesis and breakdown of various molecules.

Chloroplasts

Organelles that capture light energy to produce organic molecules through photosynthesis, mainly found in plants and algae.

Osmosis

The passive diffusion of water through a membrane from an area of higher water concentration to an area of lower water concentration.

Active Transport

Energy-requiring process where molecules move through a membrane against a gradient, often using ATP.

Exocytosis

The process where materials inside the cell are packaged into vesicles and secreted into the extracellular space.

Endocytosis

The process where the plasma membrane invaginates to form a vesicle that brings substances into the cell.

Tissues

Groups of cells with similar structures and functions that work together to perform specific activities.

Extracellular Matrix (ECM)

A complex network of proteins and carbohydrates secreted by cells, providing structural support and facilitating cell communication.

Cell Junctions

Structures that adhere cells to each other and to the ECM, crucial for tissue integrity.

Apoptosis

Genetically controlled cell death that plays a vital role in development and homeostasis.

Fluid-mosaic model

The model describing the structure of cell membranes as a mosaic of various components that can move fluidly within the bilayer.

Isotonic Solution

A solution in which the solute and solvent concentrations are equal on both sides of a membrane, resulting in no net movement of water.

Hypertonic Solution

A solution with a higher solute concentration compared to another, which can cause a cell to lose water and shrink.

Hypotonic Solution

A solution with a lower solute concentration compared to another, causing a cell to gain water and potentially swell.

Cell/plasma membrane

Cell feature present in all cells on earth, outer layer of a cell that serves as protection

Phospholipids

Component molecules in the cell membrane

Ribosomes

Produces proteins from the info from DNA genes

Cholesterol

Stabilizes the fluidity/movement of molecules in the membrane, which strengthens the membrane

Tonicity

Describes the concentration differences on either side of the membrane (hypertonic, hypotonic, isotonic)