Cell Structure and Function: Eukaryotic Cells Flashcards
plasma membrane
the phospholipid bilayer that forms the outer boundary of any cell, regulating the cell’s chemical composition
cell wall
a fairly rigid polysaccharide supportive and protective layer that lies outside the plasma membrane of all plant cells
cytoplasm
the contents of the cell enclosed by the plasma membrane, excluding the nucleus
cytosol
the water-based fluid component of the cytoplasm
cytoskeleton
a complex network of protein filaments found in the cytosol of eukaryotic cells that maintains a cell’s shape and is necessary for cell division, signaling, and movement
extracellular matrix
functions in the support and protection of the cell, as well as in cell-cell communication and association
organelle
a discrete, membrane-enclosed cytoplasmic structure with a specific function
nucleus
the organelle in a eukaryotic cell that contains the genetic blueprint of DNA organized into chromatin and chromosomes
histones
proteins found in the nucleus that function in the packaging of chromatin
nucleolus
a region of the nucleus that specializes in ribosomal RNA (rRNA) genes, ribosomal proteins (imported from the cytoplasmic site of rRNA synthesis), and ribosomal subunit assembly
Vesicle
a small, membrane-enclosed sac found in the cytosol of eukaryotic cells
Vacuole
a water-filled sac that serves various functions in the cell, including transport, structural support, and isolation of waste and harmful materials; formed from the fusion of smaller vesicles
central vacuole
a large membranous sac in a mature plant cell that helps to maintain cell shape and can be used to store nutrients and anti-herbivory chemicals
lysosome
specialized vesicle with an acidic lumen containing enzymes that break down macromolecules and bacterial cell walls
peroxisome
an organelle containing enzymes that transfer hydrogen (H2) from various substrates to oxygen (O2) producing and then degrading hydrogen peroxide (H2O2)
chloroplast
organelle found in plants and algae that is the primary site of photosynthesis and is also involved in the biosynthesis of amino acids and lipids; capable of autonomous replication
mitochondrion (pl. mitochondria)
an organelle with a double membrane that is the site of cellular respiration in eukaryotes and is also involved in regulated cell death; capable of autonomous replication
crista (pl. cristae)
folds in the inner membrane of mitochondria
ribosome
a cellular structure composed of proteins and RNA at which new proteins are synthesized; can be either attached to the endoplasmic reticulum (ER) or free in the cytosol
rough ER
a region of the endoplasmic reticulum that specializes in protein synthesis; “rough” because of the ribosomes attached to its surface
smooth ER
a region of the endoplasmic reticulum specialized for lipid synthesis; “smooth” because it lacks attached ribosomes
golgi apparatus
an organelle that routes proteins and lipids to various parts of the eukaryotic cell from the ER and synthesizes certain cellular products, notably non-cellulose carbohydrates
intermediate filaments
fibers that stabilize cell structure—for example, maintaining the position of the nucleus and other organelles—composed of helical subunits of fibrous proteins
microfilaments
two actin polymers that function in cell shape, muscle action with myosin, cytoplasmic streaming, cell division and motility, and anchoring proteins in the plasma membrane
microtubules
cylinders made of tubulin that function in motility (e.g.: flagella and cilia), support of cell shape, or transport of chromosomes and vesicles
cilium (pl. cilia)
a hair-like structure found in some eukaryotes that uses a rowing motion to propel the organism or to move fluid over cells
flagellum (pl. flagella)
a long cellular extension that lashes and enables that cell to move (structure differently than prokaryotic flagella)
