Biology - Eukaryotic Cell Structures and their Descriptions

nucleus

large structure surrounded by double membrane; contains nucleolus and chromosomes

nucleolus

granular body within nucleus; consists of RNA and protein

chromosomes

composed of chromatin, a complex of DNA and protein; condense during cell division, becoming visible as rodlike structures

plasma membrane

membrane boundary of cell

endoplasmic reticulum

network of internal membranes extending through cytoplasm

smooth endoplasmic reticulum

lacks ribosomes on outer surface

rough endoplasmic reticulum

ribosomes stud outer surface

ribosomes

granules composed of RNA and protein

golgi complex

stacks of flattened membrane sacs

lysosomes

membranous sacs (in animals)

vacuoles

membranous sacs (mostly in plants, fungi, algae)

peroxisomes

membranous sacs containing a variety of enzymes

mitochondria

sacs consisting of two membranes; inner membrane is folded to form cristae and encloses matrix

chloroplast

double-membrane structure enclosing internal thylakoid membrane; chloroplasts contain chlorophyll in thylakoid membrane

microtubules

hollow tubes made of subunits of tubulin protein

microfilaments

solid, rodlike structures consisting of actin protein

intermediate filaments

tough fibers made of protein

centrioles

pair of hollow cylinders located near nucleus; each centriole consists of nine microtubule triplets

cilia

relatively short projections extending from surface of cell

flagella

long projections made of two central and nine pairs of peripheral microtubules