Cell Structure
Complexes made of RNA and protein that are not membrane-bound and are freely scattered throughout the cytoplasm as well as attached to the nuclear envelope and endoplasmic reticulum
What are ribosomes?
Extracellular structure of plant cells that distinguishes them from animal cells and maintains shape
What is the cell wall?
Phospholipids are molecules that have both a hydrophilic region and a hydrophobic region
What is amphipathic?
Movement of particles of any substance as they spread out into available space
What is diffusion?
Diffusion gradient of an ion, which is affected by both the concentration difference of an ion across a membrane and the ion's tendency to move relative to the membrane potential
What is an electrochemical gradient?
The selective barrier at the boundary of every cell which allows the passage of certain substances for the use of the entire cell
What is the plasma membrane?
Perforations in plant cell walls that are membrane-lined channels filled with cytosol and which unify a plant into one living continuum
What is plasmodesmata?
The plasma membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids
What is the fluid mosaic model?
What is a concentration gradient?
Active transport requires energy to pump a solute against its concentration gradient
What is ATP hydrolysis?
Membranous sacs of hydrolytic enzymes found in many eukaryotic cells that hydrolyze macromolecules
What are lysosmes?
Specialized arrangement of microtubules that extend from certain eukaryotic cells and help propel them
What are cilia and flagella?
Passage of water molecules through the plasma membrane of certain cells is greatly facilitated by channel proteins
What are aquaporins?
Many polar molecules and ions impeded by the membrane bilayer diffuse passively with the help of transport proteins that span the membrane
What is facilitated diffusion?
Main electrogenic pump that actively transports hydrogen ions out of the cell
What is the proton pump?
The second compartment of the mitochondria that is enclosed by the inner membrane and contains different enzymes as well as mitochondrial DNA and ribosomes
What is the mitochondrial matrix?
Cytoplasmic channels from one cell to an adjacent one that allows ions, sugars, and amino acids to pass through
What is a gap junction?
Transport, Enzymatic Activity, Signal Transduction, Cell-Cell Recognition, Intracellular joining, and attachment to the cytoskeleton and extracellular matrix
What are the six major functions of proteins of the plasma membrane?
When a plant cell loses water to its surroundings and shrinks. As it shrinks the plasma membrane pulls away from the cell wall at multiple places
What is plasmolysis?
Coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient
What is cotransport?
Metabolic compartments bounded by a single membrane that contain enzymes that remove hydrogen atoms from certain molecules and transfer them to oxygen, producing hydrogen peroxide
What are peroxisomes?
Meshwork surrounding animal cells that consists of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by cells
Molecules wedged between phospholipids in the plasma membrane have different effects on the fluidity of the membrane
What is cholesterol?
The diffusion of free water across a selectively permeable membrane
What is osmosis?
A transport system that exchanges NA+ for K+ across the plasma membrane of animal cells
What is the sodium-potassium pump?