A2.2: Cell Structure - Organelles

Organelles

Cell wall

found in prokaryotic cells, plant and fungi cells

protects prokaryotic cell from toxins, maintains shape of cell by resisting high osmotic pressure

plasma membrane

all cells

semi-permeable phospholipid bilayer that controls what enters and exits cell, separates cell interior from external environment

cytoplasm

all cells, jelly cell-fluid

site of metabolic reactions DNA organelles and ribosomes in all (+prokaryotic) (eukaryotic) cells

Naked DNA

prokaryotes

DNA is not associated with histones, free-floating, circular in nucleoid

Ribosomes

protein synthesis, 70s prokaryotes, 80s eukaryotes

plasmid

prokaryotes

transferrable pieces of circular DNA between prokaryotic cells

Mitochondria

double-membrane bound organelles that perform aerobic respiration to create energy

Nucleus

contains histone-associated DNA organized into chromosomes

has double membrane with pores allowing certain molecules to pass (glucose, RNA, ions)

Rough ER

has 80S ribosomes attached to produce proteins sent to Golgi apparatus via vesicles

Golgi apparatus

receives proteins from ER, packages them into secretory vesicles to deliver in or out of cell

Vesicle

small sac that transports and releases substances produced within cell by fusing with cell membrane

vacuole

maintains osmotic balance of cell

can function like lysosome sometimes