Chapter 2 (reading) Flashcards
structures that are not usually surrounded by a plasma membrane
inclusions
a lipid bilayer that forms the cell boundary as well as the boundaries of many organelles within the cell
plasma (cell) membrane
a region of endoplasmic reticulum associated with ribosomes and the site of protein synthesis and modification of newly synthesized proteins
rough endoplasmic reticulum
a region of endoplasmic reticulum involved in lipid and steroid synthesis but not associated with ribosomes
smooth endoplasmic reticulum
a membranous organelle composed of multiple flattened cisternae responsible for modifying, sorting, and packaging proteins and lipids for intracellular or extracellular transport
golgi apparatus
membrane-bounded compartments interposed within endocytotic pathways that have the major function of sorting proteins delivered to them via endocytotic vesicles and redirecting them to different cellular compartments for their final destination
endosomes
small organelles containing digestive enzymes that are formed from endosomes by targeted delivery of unique membrane proteins and enzymes
lysosomes
organelles that provide most of the energy to the cell by producing ATP in the process of oxidative phosphorylation
mitochondria
small organelles involved in the production and degradation of H2O2 and degradation of fatty acids
peroxisomes
form elements of the cytoskeleton together with actin and intermediate filaments and continuously elongate and shorten—-dynamic instability
microtubules
short, paired cylindrical structures found in the center of the microtubule-organizing center and whose derivatives give rise to basal bodies cilia
centrioles
structures essential for protein synthesis and composed of rRNA
ribosomes
protein complexes that enzymatically degrade damaged and unnecessary proteins into small polypeptides and amino acids
proteasomes
what does the membrane primarily consist of?
phospholipid, cholesterol, and protein molecules
Microdomains of the plasma membrane, known as ______________, control the movement and distribution of proteins within the lipid bilayer.
lipid rafts
What is the dynamic glue that holds the lipid raft together?
cholesterol
-regarded as the molecular markers of planar lipid rafts and are considered to be scaffolding proteins
-also participate in recruitment of specific membrane proteins into the rafts and work as active partners in various signaling pathways
flotillins
proteins that have the capacity to bind cholesterol and a variety of proteins that are involved in signal transduction
caveolins
What preparation technique allowed for the existence of integral membrane proteins?
freeze-fracture
The E-face is backed by__________and the P-face is backed by ______________.
extracellular space
cytoplasm
-transport certain ions such as Na+ actively across membranes
-also transport metabolic precursors of macromolecules
pumps
allow the passage of small ions, molecules, and water across the plasma membrane in either direction
channels
allow recognition and localized binding of ligands in processes such as hormonal stimulation, coated-vesicle endocytosis, and antibody reactions
receptor proteins
anchor the intracellular cytoskeleton to the extracellular matrix
linker proteins
the process by which extracellular stimuli are received, processed, and conveyed by the cell to regulate its own physiologic responses
cell signaling
Activation of cell surface receptors leads to _________________, which contributes to the amplification of the signal.
posttranslational modification
What are the 6 posttranslational modifications mentioned in the text?
-phosphorylation
-glycosylation
-acetylation
-methylation
-nitrosylation
-ubiquitination
-SUMOylation
How do small, fat-soluble, uncharged molecules, and gases cross the plasma membrane down their concentration gradient without expending metabolic energy or transport proteins?
simple or passive diffusion
-transfer small, water-soluble molecules
-highly selective
-after binding, these proteins undergo a series of conformational changes and release the molecule on the other side of the membrane
carrier proteins
-transfer small, water-soluble molecules
-made of transmembrane proteins with several membrane-spanning domains that create hydrophilic channels through the plasma membrane
-ion selective and regulated on the basis of the cell’s needs
channel proteins
partially penetrates the membrane bilayer and serves as an ion-selectivity filter due to regulation of its three-dimensional structure
pore domain
The major mechanism by which large molecules enter, leave, and move within the cell is called______________
vesicle budding
-the general term for processes of vesicular transport in which substances enter the cell
-controls composition of the plasma membrane and the cellular response to changes in the external environment
-key roles in nutrient uptake, cell signaling, and cell shape changes
endocytosis
-the general term for processes of vesicular transport in which substances leave the cell
-also the process by which all cells deliver the intracellular plasma membrane to the cell surface
exocytosis
What happens when exocytosis is abolished?
no endocytosis takes place because they are coupled together
Following endocytosis, the contents of endocytotic vesicles and their membrane components are either:
recycled to the cell surface or are transported to late endosomes for future degradation