Unit 2: Cell Structure and Function Flashcards
prokaryotic cell
a type of cell that has no organelles
eukaryotic cell
has organelles
cell wall
rigid sturcture outside plasma membrane in plants
plasma membrane
membrane enclosing the cytoplasm
bacterial chromosome
single stand of DNA enclosed by cell membrane
nucleoid
region where prokaryotic cell’s DNA is located
cytoplasm
fluid interior of cell
Why are cells so small?
To maximize their surface area to volume ratio. SA proportional to a^2 and V proportianal to a^3, so SA/V proportianal to 1/a. Smaller cells have a smaller a so a larger SA/V ratio. This allows more diffusion of substances through cell membranes
Nuclear envelope
double membrane that encloses the nucleus and seperates it from the cytoplasm
nuclear lamina
protein filaments that maintain the shape of the nuclear envelope and connects the two layers of the nuclear envelope
nuclear matrix
fibers in the nucleus that keeps its shape
Chromosomes
single structure of a long DNA strand and associated proteins
chromatin
complex of histone proteins and DNA
nucleoli
condensed regions of the nucleus where ribosomes are made
ribosomes
structures of large and small subunits that build and assemble proteins from mRNA
free ribosomes
ribosomes in the cytosol that make proteins that function in the cytoplasm
bound ribosomes
ribosomes in the endoplasmic reticulum or the nuclear envelope that makes proteins for membranes or secretion
What structures make up the endomembrane system?
Nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles, vacuoles, and plasma membrane
endoplasmic reticulum (ER)
membrane network emerging from the nuclear membrane
lumen
space inside cisterna of the rough ER
cisterna
“sac” of the rough ER
transport vesicles
membrane sacs that transport contents to other places in the cell
rough ER
has bound ribosomes; folds proteins for secretion and is a membrane factory for the cell
smooth ER
does not have bound ribosomes on it; synthesizes lipids, metabolized carbohydrates, and detoxifies drugs and poisons
Golgi apparatus
“post-office” for proteins; modifies incoming proteins and sends them out for final functioning
lysosome
membrane sac that has enzymes to break down macromolecules; breaks down particles from phagocytosis and autophagy
phagocytosis
cells “eating” or engulfing outside molecules
autophagy
breaking down damaged cell parts to be recycled later
vacuole
stores stuff like food or water for later use
food vacuole
store macromolecules from phagocytosis to later be used by the cell
contractile vacuole
pumps excess water out of the cell
central vacuole (plants)
stores nutrients like potassium and chloride, absorbs water to keep the shape of the plant cell, and helps with the growth of plant cell
endosymbiont theory
states that an early ancestor of mitochondria or chloroplast was engulfed by a larger cell, and both the smaller and larger cells became symbionts and benefitted. The smaller cell became mitochondria and chloroplast today