Cell Structure and Function

Chromosome

a single DNA molecule associated with proteins

Chromatin

all of the DNA and proteins of a cell

Gene

a section of DNA that codes for a trait

Nucleoid

contains most of prokaryotic DNA (which is circular)

Endosymbiosis theory

theory stating that chloroplasts and mitochondria have evolved from ancient bacteria

Mitochondria

sites of cellular respiration, containing 2 membranes and circular DNA

Chloroplast

sites of photosynthesis, containing chlorophyll and enzymes

Nucleus

contains most of the cell’s genes, enclosed by a double membrane

Ribosomes

organelles that carry out protein synthesis

Endoplasmic Reticulum

a network directly connected with the nuclear envelope

Golgi Apparatus

modifies and stores products from the ER before sending them out

Lysosome

membranous sac of enzymes that digest macromolecules

Vacuoles

large vesicles derived from ER and Golgi, with various functions

Cytoskeleton

network of protein fibers that maintain cell shape and organelle position

Extracellular Matrix

supports, moves, and regulates animal cells

Plasmodesmata

cytoplasmic channels through cell walls in plant cells

Gap Junction

provides cytoplasmic channels between adjacent animal cells

Phospholipids

primary lipid in the cell membrane, amphipathic in nature

Fluid Mosaic Model

describes the structure of the plasma membrane

Membrane Transport Mechanisms

passive and active transport processes in cells

Membrane Potential

voltage across a membrane, maintained by ion pumps

Electrochemical Gradient

combination of forces driving ion diffusion across a membrane

Bulk Flow

overall movement of a fluid in an organism

Tonicity

ability of a surrounding solution to cause a cell to gain or lose water

Plasmolysis

Plant cell loses water causing the membrane to detach from the cell wall.

Osmoregulation

Process that maintains water balance and controls internal solute composition.

Membrane Transport

Movement of molecules across membranes to sustain growth and homeostasis.

Water Potential

The force driving water movement; low water potential indicates less force.

Solute Potential

High water potential has more free water molecules than low water potential.