Cell Structure and Function: Microscope Types, Cell Components, and Plant vs. Animal Cells

Cells

Small units that allow materials to move in and out quickly and are highly complex.

Resolving power

The ability to distinguish two objects that are close together.

Cell theory

The concept that all living things are made of cells, and all cells come from other cells.

Prokaryotes

Simple, small cells (e.g., bacteria, archaea) with no organelles and DNA located in a nucleoid region.

Pili

Short projections from a cell's surface that aid in attachment.

Flagella

Long filaments that move the cell with a motor at the base.

Cell wall

Rigid structure that protects the cell and maintains its shape.

Plasma membrane

Regulates the flow of molecules in and out of the cell.

Nucleoid

Region containing DNA but not enclosed by a membrane.

Ribosomes

Structures that build proteins from RNA.

Eukaryotes

Larger, more complex cells with organelles; include plants, animals, fungi, and protists.

Cell wall (plants)

Made of cellulose; provides structure and protection.

Cytoplasm

Region between the plasma membrane and nucleus.

Cytosol

The fluid portion of the cytoplasm.

Organelles

Membrane-bound compartments within eukaryotic cells.

Phospholipid

Molecule with two fatty acid tails and a phosphate head; forms membranes.

Phospholipid bilayer

Two layers of phospholipids with hydrophobic tails inward.

Fluid mosaic model

Describes a flexible bilayer with proteins floating within it.

Selective permeability

Allows some substances to pass while blocking others.

Transport proteins

Membrane proteins that allow passage of specific substances.

Nucleus

Organelle containing DNA and surrounded by a double membrane.

Nuclear envelope

Double membrane surrounding the nucleus with pores for material exchange.

Chromatin

Long fibers of DNA and associated proteins.

Chromosomes

Coiled DNA structures that contain genes.

Nucleolus

Region in the nucleus that produces ribosome components.

Mitochondria

Organelles that perform cellular respiration to produce ATP.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for ATP production.

Matrix

Fluid inside the inner mitochondrial membrane.

Chloroplasts

Organelles that perform photosynthesis in plants and some protists.

Stroma

Fluid inside the chloroplast.

Grana

Stacks of membranes that trap light for photosynthesis.

Cytoskeleton

Network of fibers that maintain cell shape and help movement.

Microtubules

Hollow protein tubes that act as tracks for organelle movement.

Cilia

Short, numerous appendages that move fluid or the cell.

Flagella (eukaryotic)

Long appendages that propel cells with a whip-like motion.

Plasmodesmata

Channels that allow water and small molecules to pass between plant cells.

Extracellular matrix

Sticky layer outside animal cells that supports and protects them.

Tight junctions

Seal cells together to prevent leakage.

Anchoring junctions

Attach cells while allowing some material passage.

Communicating junctions

Channels that let materials pass between animal cells.