cell biology review (ch 2) Flashcards
what is the cell membrane?
Phospholipid bilayer containing cholesterol, proteins (integral and peripheral), and some carbohydrates (externally)
function of cell membrane?
Contains receptors for communication; forms intercellular connections; acts as physical barrier to enclose cell contents; regulates material movement into and out of the cell
what is cytoplasm?
Contains cytosol (a viscous fluid), inclusions, and organelles
function of cytoplasm?
Place of many metabolic processes of the cell; stores nutrients and dissolved solutes
what is the cytoskeleton?
Network of filaments and microtubules
function of cytoskeleton?
Provides structural support; helps cellular movement, transport of materials,
what is the mitochondria?
Double membrane structures with cristae; fluid matrix contents at center
function of mitochondria?
Synthesize most ATP during cellular respiration; “powerhouses of cell”
what is the rough endoplasmic reticulum?
membranous stacks called cisternae, has ribosomes
function of rough ER?
involved in the synthesis of protein secretion granules and lysosomes
what is the smooth ER?
membrane tubules
function of smooth ER?
mediates detoxification of poisons,
metabolizes lipids and sugars, and stores calcium ions
what is the golgi apparatus?
Stacked series of flattened, smooth membrane sacs with associated transport vesicles
function of golgi apparatus?
Modifies, packages, and sorts newly synthesized proteins
“go-gee”: tells proteins to “go!”
what are secretion granules?
Secretory granules contain specific proteins and other macromolecules that are destined for secretion into the extracellular space.
what are lysosomes?
Membrane sacs with digestive enzymes
function of lysosomes?
Digest materials or microbes ingested by the cell; remove old/damaged organelles
what are centrioles?
Paired perpendicular cylindrical bodies; composed of microtubule triplets
function of centrioles?
Organize microtubules during cell division for movement and separation of chromosomes
what is the nucleus?
Surrounded by double membrane nuclear envelope (each membrane is a phospholipid bilayer); contains nucleolus and chromatin within nucleoplasm (a fluid)
function of nucleus?
houses genetic information (DNA); site of ribosome subunit assembly
what is the nuclear envelope with pores?
Double membrane boundary between cytoplasm and nuclear contents
function of nuclear envelope?
Physical barrier that controls movement of materials between the nucleus and the cytoplasm
what is chromatin?
material that chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.
function of chromatin?
Site of genes in the DNA
what is the nucleolus?
- area inside the nucleus of a cell that is made up of RNA
- where ribosomes are made
function of nucleolus?
Synthesizes rRNA and assembles ribosomes in the nucleus
what is a chromosome?
The most organized level of genetic material; a single long molecule of DNA and associated proteins; becomes visible only when cell is dividing.
function of a chromosome?
make sure DNA is replicated and distributed evenly across cell
what is exocytosis?
aka cell secretion; large molecules move out of the cell using vesicles
what are the three forms of endocytosis?
phago-, pino- and receptor-mediated
what is endocytosis?
Bulk movement of substances into a cell by vesicles forming at the plasma membrane
what is phagocytosis?
Type of endocytosis in which particulate materials move into a cell after being engulfed by pseudopodia at the cell surface; vesicles form at the inside of the plasma membrane
*Think “phago equals pseudo”
what is pinocytosis?
the ingestion of liquid into a cell by the budding of small vesicles from the cell membrane.
phago = solid, pino = liquid
what is receptor-mediated endocytosis?
Type of endocytosis in which specific molecule-receptor complexes in the plasma membrane stimulate the clustering of bound molecule-receptor complexes
what are the three elements of the cytoskeleton?
microfilaments, microtubules, intermediate filaments
process of secretion granule release is ____
exocytosis
where does the golgi receive proteins from?
from rough ER
