Key Terms

amyloplasts
plastids that synthesize and store starch

anthocyanin
a type of flavonoid pigment

cell wall

rigid cell covering comprised of various molecules that protects the cell, provides structural support, and gives shape to the cell

central vacuole
rigid cell covering comprised of various molecules that protects the cell, provides structural support, and gives shape to the cell

centrosome
region in animal cells made of two centrioles that serves as an organizing center for microtubules

chloroplasts

organelle in which photosynthesis takes place

chromatin
protein-DNA complex that serves as the chromosomes’ building material

chromoplasts
plastids used in synthesizing and storing pigments

cytoplasm
entire region between the plasma membrane and the nuclear envelope, consisting of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals

cytoskeleton
protein fiber network that collectively maintains the cell’s shape, secures some organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently

endoplasmic reticulum
series of interconnected membranous structures within eukaryotic cells that collectively modify proteins and synthesize lipids

flavonoids
a class of biological pigments that is water soluble and found in plant vacuoles.

Golgi apparatus
eukaryotic organelle comprised of a series of stacked membranes that sorts, tags, and packages lipids and proteins for distribution

intermediate filaments
cytoskeletal component, comprised of several fibrous protein intertwined strands, that bears tension, supports cell-cell junctions, and anchors cells to extracellular structures

Janus Green B Stain
A stain used for microscopic viewing of certain components within cells, including mitochondria

lysosome
organelle in an animal cell that functions as the cell’s digestive component; it breaks down proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles

microfilaments
the cytoskeleton system’s narrowest element; it provides rigidity and shape to the cell and enables cellular movements

microtubules
the cytoskeleton system’s widest element; it helps the cell resist compression, provides a track along which vesicles move through the cell, pulls replicated chromosomes to opposite ends of a dividing cell, and is the structural element of centrioles, flagella, and cilia

Mitochondrion
cellular organelles responsible for carrying out cellular respiration, resulting in producing ATP, the cell’s main energy-carrying molecule

Nissl bodies
granules in the cytoplasm of nerve cells, visible by dying in microscopy

nucleolus
darkly staining body within the nucleus that is responsible for assembling ribosome subunits

nucleus
cell organelle that houses the cell’s DNA and directs ribosome and protein synthesis

nuclear envelope
double-membrane structure that constitutes the nucleus’ outermost portion

peroxisome
small, round organelle that contains hydrogen peroxide, oxidizes fatty acids and amino acids, and detoxifies many poisons

pigment

a compound which imparts color to tissues or cells

plasma membrane

phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, and separates the cell’s internal content from its surrounding environment

plasmodesmata

channel that passes between adjacent plant cells’ cell walls, connects their cytoplasm, and allows transporting of materials from cell to cell

plastid
a class of membrane-bound organelles (chloroplasts, amyloplasts, etc.) performing various functions within cells

ribosomes
cellular structure that carries out protein synthesis

rough endoplasmic reticulum (RER)
region of the endoplasmic reticulum that is studded with ribosomes and engages in protein modification and phospholipid synthesis

smooth endoplasmic reticulum (SER)
region of the endoplasmic reticulum that has few or no ribosomes on its cytoplasmic surface and synthesizes carbohydrates, lipids, and steroid hormones; detoxifies certain chemicals (like pesticides, preservatives, medications, and environmental pollutants), and stores calcium ions

statoliths
inclusions in plant cells, such as starch grains, used in responding to gravity

striated muscle
a type of muscle tissue that appears striped in microscopy

vacuole
membrane-bound sac, somewhat larger than a vesicle, which functions in cellular storage and transport