Cell components Flashcards
Nucleoid
region where prokaryotic cells DNA is located with no membrane
Nuclear envelope
double membrane for the nucleus nuclear pores dotted throughout
nuclear lamina
on the nuclear side a netlike array of protein filaments that maintains the shape of the nucleus
chromatin
complex of proteins and DNA
free ribosomes
cytosolic ribosomes that make proteins such as enzyme in sugar catabolism in cytosol
Bound ribosomes
ribosomes that are bound to the surface of the nuclear lamina or ER for secretion
endomembrane system
membrane organelles interact in the transport of molecules by vesicles
ER lumen
the space between nuclear membranes is continuous to the ER lumen
smoother ER
synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons depending on which organ they are present
Carbohydrate addition
carbohydrates are first added to proteins in the ER
golgi apparatus
modifies the phospholipids and proteins and readies them for secretion
lysosome
membranous sac of hydrolytic enzymes that either break down food particles by phagocytosis or damaged organelle
food vacuoles
protists use phagocytosis and lysosomes to digest smaller organisms
contractile vacuole
freshwater protists use this to pump excess water out of the cell
central vacuole
in mature plants this stores water and nutrients and allows growth of the cell without expanse of the cytoplasm
tonoplast
membrane that surrounds the central vacuole
peroxisome
do not bud from the ER membrane system but grow larger by adding lipids and proteins from cytosol
cytoskeleton structures
microtubules, microfilaments, and intermediate filaments
motor proteins
cytoskeletal elements move motor proteins with vesicles or other proteins throughout the cell or even vesicles with neurotransmitters
microtubules
largest; hollow tubes; cilia/flagella motility; compression resistance; organelle movements; chromosome retraction during cell division
microfilaments
smallest; actin filaments; tension bearing for cell shape; muscle contraction; cell shape movements; cleavage furrow; muscle contraction
intermediate filaments
cables of keratin; tension bearing; anchorage of nucleus and other organelles; nuclear lamina
eukaryotic flagella
9 outer doublets of microtubules and 2 single inner microtubules with dynein arms to provide the motor movement
basal body
attaches flagella to cell body and has 9 outer triplets of microtubules with no inner microtubules
collagen
part of ECM; fibers that are embedded in dense proteoglycan complex
fibronectin
attaches the ECM to integrins embedded in plasma membrane
plasmodesmata
water and small solutes pass between the cell wall of plants
tight junctions
form a seal around the cells preventing leakage of fluid across cell layers
desmosomes
fasten cells together strongly; attached to intermediate filaments in the cytoplasm
gap junctions
passage of water, ions, sugars, amino acids and other small molecules between cells
Low temp membrane
Unsaturated hydrocarbons and cholesterol block phospholipids from packing too closely together at low temps
Integral proteins
Penetrate the hydrophobic core of lipid bilayer; only transmembrane proteins span membranes
Peripheral proteins
Proteins loosely bound to membrane surface; often to integral proteins
Channel proteins
Have hydrophilic channel that allows molecules to use as a tunnel
Aquaporins
Passage of water molecules through specific channel protein
Carrier proteins
Hold onto molecules and change shape that allows molecules to pass through
Osmosis
Water moves from area of higher water concentration to lower water concentration
Tonicity
The ability of a solution to cause a cell to gain or lose water
Hypertonic
More nonpenetrating salutes outside; cell will lose water and die
Hypotonic solution
Water enters the cell faster than it leaves and will swell
Plasmolysis
Plant cell in hypertonic solution; cell will lose water and wilt
Turgid
Normal environment for plant is hypotonic solution because of plant wall
Active transport
Carrier proteins that expend energy to pump molecules against its gradient
Electrochemical gradient
Cytoplasm of a cell is negative in charge compared to extracellular fluid; inside is more negative than outside
Electrogenic pump
Transport protein that generates voltage across a membrane
Cotransport
Can couple downhill diffusion to uphill transport of second substance against concentration gradient
Endocytosis
Phagocytosis, pinocytosis, receptor mediated endocytosis
Receptor mediated endocytosis
Ligands of potentially low concentration binds to receptors in coated pits
