==Cytosol== is the semifluid, jellylike substance inside cells
In eukaryotic cells, most of the DNA is found in the ==nucleus==
In prokaryotic cells, DNA is focused in a region called the ==nucleoid== which is not membrane enclosed
The interior of either type of these cells is called cytoplasm
At the boundary of every cell the ==plasma membrane== functions as a selective border that allows oxygen, nutrients, and wastes to service the entire cell
==Microvilli== increase the surface area of an object due to the crevices
The nucleus contains most of the genes in a eukaryotic cell
The ==nuclear envelope== encloses the nucleus separating its contents from the cytoplasm
The nuclear side of the envelope is lined by the ==nuclear lamina==
DNA is organized into discrete components called ==genes==
The complex of DNA and proteins making up chromosomes is called ==chromatin==
A prominent structure in the nondividing nucleus is the ==nucleolus== (plural of nucleoli) which is a mass of densely stained granules and fibers adjoining part of the chromatin
==Ribosomes== are complexes made of ribosomal (RNA) proteins
Many of the different membrane-bounded organelles of the eukaryotic cell are part of the ==endomembrane system,==
The ==endoplasmic reticulum== is a large network of membranes that accounts for more than half of the plasmic membranes in eukaryotic cells
After leaving the endoplasmic reticulum in transport vesicles, they head to the Golgi Apparatus
A ==lysosome== is a membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest macromolecules
==Phagocytosis== is the process of engulfing smaller organisms or food particles
==Vacuoles== are large vesicles formed by the endoplasmic reticulum and Golgi Apparatus
==Food Vacuoles== are formed by phagocytosis
Many unicellular protists living in freshwater have ==contractile vacuoles== that pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell.
Mature plants generally contain a ==central vacuole==, which develops by the coalescence of smaller vacuoles
The ==endosymbiont theory== states that an early ancestor of eukaryotic cells engulfed an oxygen-using non-photosynthetic prokaryotic cell. Eventually, the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming an endosymbiont.
The inner folds of a phospholipid bilayer are called a ==cristae==
The ==cytoskeleton== is a network of fibers extending throughout the cytoplasm
Eukarya have ==microtubules==, hollow rods constructed from a globular protein called tubulin
In animal cells, microtubules grow out of a ==centrosome==, a region that is often located near the nucleus and is a “microtubule organizing center”
Within the centrosome is a pair of ==centrioles==, each composed of nine sets of triplet microtubules arranged in a ring
The microtubule assembly of a cilium or flagellum is anchored in the cell by the basal body
Bending involves large motor proteins called dynein
==Microfilaments== are thin, solid rods. They are also called actin filaments because they are built from molecules of actin.
Thousand of actin filaments and thicker filaments of a motor protein called ==myosin== interact to cause a contraction in a muscle cell
==Intermediate filaments== are named for their diameter, which is larger than the diameter of microfilaments but smaller than that of microtubules