Term
| what kind of proteins have disulfide bonds? |
|
Definition
| ones going outside of the cell |
|
|
Term
| protein molecules : the synthesis of almost all of them begins in the _________ |
|
Definition
|
|
Term
| The transfer of proteins from the cytosol to different compartments (organelles) is called ______________ |
|
Definition
|
|
Term
| Compartment through which endocytosed material passes on its way to lysosomes. |
|
Definition
|
|
Term
| _______ sort the ingested material and recycle some back to the plasma membrane. |
|
Definition
|
|
Term
| Peroxisomes' oxidative enzymes are called _____ and ______ |
|
Definition
| catalase and urate oxidase. |
|
|
Term
| Peroxisomes are small organelles which contain oxidative enzymes which break down ____________________ |
|
Definition
| lipids and destroy toxic molecules. |
|
|
Term
| Like mitochondria peroxisomes utilize ________ |
|
Definition
|
|
Term
| peroxisomes produce ______ which catalase then uses to _______________ |
|
Definition
| peroxide, break down alcohol |
|
|
Term
| peroxisomes break down ________ to acetyl CoA |
|
Definition
|
|
Term
| the interior of most organelles is topologically equivalent to the _______ of the cell. |
|
Definition
|
|
Term
| For some organelles, including the ____ ____ _____ _____ proteins are delivered directly from the cytosol. |
|
Definition
| mitochondria, the ER, peroxisomes and the interior of the nucleus, |
|
|
Term
| For ____ ____ ____ ____ proteins and lipids are delivered indirectly via the ______ (which is itself a major site of protein and lipid synthesis). |
|
Definition
| the Golgi apparatus,lysosomes, endosomes and the nuclear membranes, .....ER |
|
|
Term
| protein system: Cytosol >>> ______ >>> golgi |
|
Definition
|
|
Term
| Three mechanisms for protein movement: |
|
Definition
1. gated, through nuclear pores
2. across membranes using protein translocators
3. transport by vesicles |
|
|
Term
| what is the "signal sequence" in a protein destined to be exocytosed? |
|
Definition
| amino acids that make up the sorting sequence. |
|
|
Term
| the signal sequences which mediate import of proteins into the ER and mitochondria always contain the N-terminal ________________ |
|
Definition
|
|
Term
| three- dimensional arrangement of amino signal on the protein surface, called a _______ is always an _______ amino acid |
|
Definition
|
|
Term
| how do nuclear pore complexes transport things? |
|
Definition
| both directions, porin-style |
|
|
Term
| The signal sequence that directs a protein from the cytosol into the nucleus is called a nuclear ______ signal (it contains many _______ amino acid residues) |
|
Definition
| localization, positively charged |
|
|
Term
| Mitochondrial precursor proteins ________ into their native structures after they are synthesized on ribosomes: |
|
Definition
|
|
Term
| The ER has a central role in both lipid and protein biosynthesis, and it also serves as an intracellular ______ store that is used in many cell signaling responses. |
|
Definition
|
|
Term
| The ER serves as _________ for proteins destined for other organelles and those that will be secreted outside the cell. |
|
Definition
|
|
Term
Mammalian cells begin to import most proteins into the ER before complete synthesis of the polypeptide chain. This process is called _____________
In contrast, the import of proteins into ___________________ is a post-translational translocation. |
|
Definition
| co-translational translocation. ....mitochondria and peroxisomes |
|
|
Term
| In __________________, the ribosome that is synthesizing the protein is attached directly to the ER membrane, |
|
Definition
| co-translational translocation |
|
|
Term
| Membrane-bound ribosomes are attached to the __________ of the ER membrane. They are making proteins that are being translocated into the ______. Free ribosomes are making all of the other proteins. |
|
Definition
|
|
Term
| Membrane-bound and free ribosomes are structurally and functionally ___________ |
|
Definition
|
|
Term
| The ER signal sequence contains a stretch of 8-10 ________ residues |
|
Definition
|
|
Term
two kinds of proteins that are
transferred from the cytosol to the ER: |
|
Definition
water soluble
prospective transmembrane |
|
|
Term
| ____________________ are completely translocated across the ER membrane and are released into the ER lumen. These proteins are destined either for secretion or for the lumen of an organelle. |
|
Definition
|
|
Term
| These proteins are only partly translocated across the ER membrane and become embedded in it. The ____________ are destined to reside in either the ER membrane, the membrane of another organelle, or the plasma membrane. |
|
Definition
|
|
Term
| The ER signal sequence is guided to the ER with the aid of at least two components: |
|
Definition
1) a signal recognition particle (SRP) present in the cytosol; 2) an SRP receptor,
embedded in the ER membrane, which recognizes SRP. |
|
|
Term
| what is formyl-Met and how does our immune system use it? |
|
Definition
| neutrophils use it to find bacteria, bacteria use it to initiate protein translation. |
|
|
Term
| Signal transduction is .... |
|
Definition
the process whereby the message
(signal) is converted from one form to another |
|
|
Term
| The extracellular molecules that can serve as signals |
|
Definition
Proteins
Peptides
Amino acids
Nucleotides
Steroids
Fatty acid derivatives
Gas (NO)
Others |
|
|
Term
| name 4 hormones which use intracellular receptors |
|
Definition
Cortisol
Testosterone
Estradiol
Thyroxine |
|
|
Term
| NO catalyzes the transformation of.... |
|
Definition
|
|
Term
| what four things do intracellular signaling proteins do after signal transduction? |
|
Definition
| relay, amplify, integrate, distribute |
|
|
Term
| what are the three families of cell-surface receptors? |
|
Definition
ion-channel coupled
g-protein coupled
enzyme-coupled |
|
|
Term
Ion-channel-coupled receptors convert chemical signals into
___________ signals |
|
Definition
|
|
Term
| The acetylcholine receptor in the plasma membrane of muscle cells is an example of ______________ receptors |
|
Definition
|
|
Term
| Nicotine and Curare mimic the natural ligand _____________ |
|
Definition
|
|
Term
| Nicotinestimulates the _________-coupled receptors. |
|
Definition
| acetylcholine ion-channel-coupled |
|
|
Term
| Curare blocks the receptors. It causes the blockage of ___________ __________, resulting in paralysis. |
|
Definition
| neuromuscular transmission |
|
|
Term
| G-protein and enzyme-coupled receptors differ from ion coupled ones in that... |
|
Definition
| they use intracellular signal cascades of mostly proteins (molecular switches) |
|
|
Term
| what are the two classes of molecular switches? |
|
Definition
1.Proteins whose activity is controlled by direct phosphorylation or dephosphorylation.
2.Proteins whose activity is regulated by GTP binding. |
|
|
Term
| Only three amino acid residues can be phosphorylated by kinases: |
|
Definition
|
|
Term
| G proteins is a class of switch molecules whose activity is regulated by _________________ |
|
Definition
|
|
Term
| In the ______________ state, the alpha subunit has GDP bound and the G protein is inactive. |
|
Definition
|
|
Term
| The alpha subunit is a _________ |
|
Definition
| GTPase (i.e., it has an enzymatic activity and can hydrolyze its bound GTP to GDP). |
|
|
Term
| The two most frequent target enzymes for G proteins are ___________ & _________ |
|
Definition
| adenylylcyclase and phospholipase C. |
|
|
Term
| The target proteins for G-protein subunits are: |
|
Definition
1.Ion channels.
2.Membrane-bound enzymes |
|
|
Term
| The enzyme adenylyl cyclaseproduces the small intacellular signaling molecule ______________ |
|
Definition
|
|
Term
| cAMP is produced from ________ in the reaction of cyclization. |
|
Definition
|
|
Term
| The enzyme phospholipase Cproduces two small intracellular signaling molecules, __________ & ______________. |
|
Definition
| inositol triphosphate and diacylglycerol |
|
|
Term
| How do membrane-bound enzymes amplify the signal? |
|
Definition
| by generating many copies of 2nd messengers |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| name the effects of the fast and slow-response cAMP pathways |
|
Definition
1. glycogen breakdown > fast
2. transcription activation > slow |
|
|
Term
| gpcr activated....2ns most frequent g-protein.... a and bg breakage target enzyme produces small intracellular signaling molecules __________ ___________- |
|
Definition
| inositoltriphosphate(IP3 ) and diacylglycerol(DAG). (adenylyl cyclase> cyclic amp) |
|
|
Term
| name 2 end-effects of phospholipase C |
|
Definition
- activation of protein kinase C
- release of Ca from the ER |
|
|
Term
| _________ activates the Inositol Phospholipid Pathway |
|
Definition
|
|
Term
| activation of (phoslipid cleaved to dag and....) inositol triphosphate>> by phosphlipase C>> floats around to ER causes what end result? (dag works on other end) |
|
Definition
|
|
Term
| what is the largest class of enzyme-coupled receptors? |
|
Definition
| Receptor tyrosine kinases (RTKs) |
|
|
Term
| what do you call an enzyme which phosphorilates tyrosine? |
|
Definition
|
|
Term
| what is used to phosphorylate tyrosine, and what is produced by dephos? |
|
Definition
|
|
Term
| Ras (a small GTPase) is.... |
|
Definition
| a small monomeric GTP-binding protein which hydrolyzes GTP. |
|
|
Term
| what is the difference between Ras and GPTCR ? |
|
Definition
| Ras binds monomers and GPTCR binds trimers. |
|
|
Term
|
Definition
| mitogen-activated protein kinase |
|
|
Term
| what causes human cancer? |
|
Definition
| A constitutively active mutant form of Ras stimulates uncontrollable cell proliferation |
|
|
Term
| which cascade does insulin start? |
|
Definition
| PI 3-kinase >>> insitosol |
|
|
Term
| microtubules are not as strong as ... |
|
Definition
|
|
Term
|
Definition
| microtubule organizing center, biochemically the same but structurally different. They nucleate, anchor, and organize microtubules |
|
|
Term
| name the variations on the MTOC |
|
Definition
| centrosome, kinetochores (non-nucleating), basal bodies |
|
|
Term
| what does the kinetochore do? |
|
Definition
| anchor and organize microtubules (cell division - chromo organizing) |
|
|
Term
| centrosome and centriole - difference? |
|
Definition
| centrosome - the body in which the cetrioles reside |
|
|
Term
| what are the most important proteins in MTOC? |
|
Definition
| the gamma tubulin ring complex (present on centrosomes) which microtubules nucleate from |
|
|
Term
| what is analogus to he centriole? |
|
Definition
| basal body (activated into mtoc) |
|
|
Term
| what is the number of microtubules in flagella and cilia? |
|
Definition
|
|
Term
| microtubules are always fully formed and separate? |
|
Definition
| no, some can "piggyback" and use the wall of another |
|
|
Term
| what is dynamic instability in MTOCs? |
|
Definition
| their shrinkage back toward the centrosome (from the positive end) and later growth. (most common in active cells) |
|
|
Term
|
Definition
| the section of bound but not yet hydrolyzed GTP associated with tubulin's beta particle, ahead of the hydrolytic wave |
|
|
Term
| what is the significance of the overtaking of the GTP cap? |
|
Definition
| dissolving it makes the microtubule more susceptible to polymerization |
|
|
Term
| what is the cytoskeleton made of? |
|
Definition
|
|
Term
| how are protein subunits of the cytoskeleton held together? |
|
Definition
|
|
Term
| name the four components of the cytoskeleton |
|
Definition
The cytoskeleton is composed of :
* Intermediate filaments
* Microtubules
* Actin filaments (aka: microfilaments, F-actin)
* Accessory protein |
|
|
Term
_______ bind to filaments
or subunits to control sites of filament assembly, regulate filament assembly and disassembly, and control motility of cell and cytoplasmic components |
|
Definition
|
|
Term
| what does the cytoskeleton contribute? |
|
Definition
Cell motility (crawling, flagella/cilia)
* Intracellular motility; organelle
positioning; cytoplasmic order:
organelle, vesicle/ chromosome, mRNA,
ribosomes, protein, intracellular signals,
pathogen motility
* Cell shape and support,
tissue support |
|
|
Term
| importance of intermediate filaments: |
|
Definition
Impart tensile strength providing mechanical support and reinforcement of
cells and tissues (support plasma membrane; nuclear envelope; cytoplasmic
components; in epithelial tissue they span the cytoplasm from one cell-cell
junction to another, thereby strengthening the entire epithelium; hair, claws,
fingernails, horns, feathers
* Not found in all cell tissue types; in epidermal cells and axons intermediate
filaments are 10 X’s more abundant than microtubules and F-actin
* Not directly responsible for generating intracellular movements; no
known motor proteins
* Do not bind nucleotides
* Not polar filaments |
|
|
Term
in ____________ & __________ intermediate
filaments are 10 X’s more abundant than microtubules and F-actin |
|
Definition
| epidermal cells and axons |
|
|
Term
| Individual polypeptides are elongated molecules with three region, _____ ______ & _________ but only ________ is conserved. |
|
Definition
| central rod, amino terminal head, carboxyl terminal tail, .... central rod |
|
|
Term
| what is the function of keratin? |
|
Definition
| EPITHELIAL CELLULAR AND TISSUE SUPPORT |
|
|
Term
|
Definition
i. The family of intermediate filaments that form a 3-D mesh work throughout
the cytoplasm of epithelial cells
ii. Forms the structural network that links cytoplasmic components (e.g.,
plasma membrane, nucleus) and provides intercellular connections. |
|
|
Term
Epidermolysis Bullosa Simplex (EBS): A mutation in keratin gene produces
defective filament assembly resulting in weakened keratin network.
What does this cause? |
|
Definition
|
|
Term
|
Definition
i. Found in nuclei of all eucaryotic cells
ii. Major constituents of the the nuclear lamina underlies the inner nuclear membrane
iv. Provides mechanical support to the nuclear envelope and aids in organizing
peripheral chromatin
v. Involved in nuclear membrane disassembly and reassembly during mitosis |
|
|
Term
Nucleation, assembly (syn _____________), disassembly (syn ________________)
and stability are essential to function and under tight regulation in microtubules |
|
Definition
| polymerization depolymerization |
|
|
Term
| Microtubule nucleation for cilia & flagella occurs at the ____________ |
|
Definition
|
|
Term
Microtubule:
The _________ grows out from one centriole cylinder, |
|
Definition
|
|
Term
| the __________ end of a microtubule extends into the cytoplasm. |
|
Definition
|
|
Term
| GTP hydrolysis only occurs on ______-tubulin. |
|
Definition
|
|
Term
| proteins that have entered the ER and are destined for the Golgi apparatus or beyond are first packaged into small __________ transport vesicles. These vesicles bud from specialized regions of the ER called ______________, whose membranes lack bound ribosomes. |
|
Definition
| COPII-coated, ER exit sites |
|
|
Term
| _____________ in the ER have exit signals that attach them to transmembrane cargo receptors. |
|
Definition
|
|
Term
| After transport vesicles have budded from the ER exit sites and have shed their coat, they begin to fuse with one another. The structures that are formed are called __________________ |
|
Definition
| vesicular tubular clusters |
|
|
Term
| why do vesicular tubular clusters bud off transport vesicles which retrograde transport? |
|
Definition
| COPI-coated, they carry back to the ER: cargo receptors, and mistakenly taken proteins. |
|
|
Term
| The _________ present in vesicular tubular clusters and the Golgi apparatus captures the soluble ER resident proteins |
|
Definition
|
|
Term
| The Golgi apparatus is a major site of __________ synthesis. |
|
Definition
|
|
Term
| the cis face of the golgi is closer to... |
|
Definition
|
|
Term
the Golgi apparatus generates the
____________ __________ found in mature proteins. |
|
Definition
| oligosaccharide structures |
|
|
Term
| The resident proteins in the Golgi apparatus are all __________ _________ |
|
Definition
|
|
Term
|
Definition
| the enzymes that remove sugars in the golgi |
|
|
Term
| Glycosyl transferases are .... |
|
Definition
| the enzymes that catalyze the transfer (addition) of sugars]. |
|
|
Term
Two broad classes of N-linked oligosaccharides
are attached to mammalian glycoproteins (as a
result of modifications in the Golgi apparatus), what are they? |
|
Definition
1)
complex oligosaccharides
2)
high-mannose oligosaccharides |
|
|
Term
| The constitutive and regulated secretory pathway. These two pathways diverge in the ____ _____ _____ |
|
Definition
|
|
Term
| what is the difference between a regulated and a constituitive secretory pathway? |
|
Definition
regulated - stores for later
constituitive - goes out in a stream, no control |
|
|
Term
| How to pinocytosis and phagocytosis differ? |
|
Definition
phago - large, eat
pino - small, drink |
|
|
Term
| In mammals, two classes of white blood cells act as professional phagocytes – ???? |
|
Definition
| macrophages and neutrophils |
|
|
Term
| Binding of bacteria induces the phagocytic cell to extend projections of the plasma membrane, called _________ that engulf the bacterium and fuse at their tips to form a phagosome |
|
Definition
|
|
Term
| receptor-mediated endocytosis often uses _____ coating. |
|
Definition
|
|
Term
Lysosomes contain about 40 types of hydrolytic enzymes
including: |
|
Definition
Proteases (degrade proteins)
Nucleases (degrade nucleic acids)
Glycosidases (cleave oligosaccharides)
Phospholipases (cleave phospholipids). |
|
|
Term
| Most of the lysosomal membrane proteins are unusually ___________ |
|
Definition
|
|
Term
| _________ is a marker of lysosomes. |
|
Definition
|
|
Term
| enzymes destined for lysosomes are tagged with .... |
|
Definition
|
|
