Term
| True or False: All biological membranes are composed of lipids and glycoproteins. |
|
Definition
| FALSE; all bio membranes are composed of lipids and proteins. |
|
|
Term
| All membrane lipids are _________. Three types? |
|
Definition
-amphiphilic
-phospholipid, shpingolipid, cholesterol |
|
|
Term
| Sphingomyelin is made from ____ instead of glycerol and is (polar/unipolar). |
|
Definition
|
|
Term
| What is the key to bilayer formation in water? |
|
Definition
| -energetically favorable interaction |
|
|
Term
| Lipid bilayer is a (2D/3D) fluid. What two main factors does fluidity depend on? |
|
Definition
-2D
-temperature and composition |
|
|
Term
| Cholesterol (dec/inc) the permeability of the bilayer to water-soluble molecules and (facilitates/prevents) freezing. |
|
Definition
|
|
Term
| Which monolayer of the lipid bilayer are glycolipids exclusively found? |
|
Definition
| -non0cytoplasmic monolayer |
|
|
Term
| What are the two types of membrane proteins? |
|
Definition
-peripheral: loosely bound
-integral: covalent attachement |
|
|
Term
| True or False: all transmembrane proteins are amphiphilic. |
|
Definition
|
|
Term
| Definition: Glycoproteins |
|
Definition
| -membrane proteins that are glycosylated |
|
|
Term
| What is functionally unique about amphiphilic detergents? How is this accomplished? |
|
Definition
-they can solubilize proteins
-the hydrophobic end of detergent bind to hydrophobic rregion of protein that displaces them from membrane, and hydrophilic end interacts with water to solubilize them |
|
|
Term
| What maintaines the biconcave structure of RBCs? |
|
Definition
-cytoskeletal spectrin dimers
-spectrins are linked together into a netlike meshwork by junctional complexes
-cytoskeleton is linked to membrane through band3 and glycophorin tansmembrane protein |
|
|
Term
| Diffusion through the lipid bilayer depends on what? What kinds of molecules diffuse rapidly/easily? |
|
Definition
-hydrophobicity of the molecule
-mor hydrophobic or oil soluble molecules (O2 an CO2) and uncharged polar molecules in they are small enough |
|
|
Term
| What is the function of trhansmembrane proteins? |
|
Definition
| -transporter or channels, allows transfer of polar solutes across a membrane |
|
|
Term
| solutes can be transported across membrane passively (_____ dependent) or actively (_____ dependent). |
|
Definition
|
|
Term
| What drives the Sodium-potassium pump? What does it do? |
|
Definition
-driven by ATP hydrolysis to generate E
-pumps 3 Na out and 2 K in and THUS creates an electrical potential |
|
|
Term
| What is significant about the electrical potential created by the sodium-Potassium pump? |
|
Definition
| -gradient represents a storehouse of E because the excess Na tries to move inside the cell |
|
|
Term
|
Definition
| -the diffusive force of one molecule pushes itself along with other macromolecules |
|
|
Term
|
Definition
| -the process of net movement of water caused by a concentration difference |
|
|
Term
| Give a few examples of important cell organelles inside the cell that play a crucial function. |
|
Definition
-endoplasmic reticulum
-Golgi apparatus
-mitochondria
-lysosomes
-peroxisomes
-nucleus
-nucleolus |
|
|
Term
| The building blocks of microfilament is _____ and of microtubules is _____. |
|
Definition
|
|
Term
| Name an actin-based motor protein that assists in muscle contraction. |
|
Definition
|
|
Term
| During tubulin polymerization, GTP bound to beta-tubulin hydrolyzes to ___ that then allows assembly ofnew dimers. GTP in ______ has mostly structural role. |
|
Definition
|
|
Term
| What is the functional unit of a DNA? |
|
Definition
|
|
Term
| True or False: DNA in the genomes doesn't synthesize a protein directly, rather it uses RNA as an intermediary. |
|
Definition
|
|
Term
| Name a few ways in which RNA differs from DNA. |
|
Definition
-RNA has ribonucleotides (ribose), DNA has deoxyribonucleotides
-RNA is single-stranded, DNA is double-stranded
-RNA has uracil, DNA has thymine |
|
|
Term
| What is chromatin? When is it important in transcription? |
|
Definition
-a complex of DNA and protein
-its remodeling is a key step intranscription |
|
|
Term
| What type of enzyme performs transcription? What are the 3 types? What do they do? |
|
Definition
-RNA polymerases
-RNAP I: formation rRNA
-RNAP II: mRNA
-RNAP III: tRNA |
|
|
Term
| What is the function of a general transcription factor? |
|
Definition
| -binds to specific sites of DNA, and helps RNA polymerase to positionitself correctly at the promoter to allow transcription to begin |
|
|
Term
| Promoter is a region (downstream/upstream) of a particular gene to be transcribed. |
|
Definition
|
|
Term
| Translationis based on a genetic code read in consecutive groups of ___ successive nucleotids. RNA is a linear polymer of ___ nucleotides, so there are ___ possible combinations, thereby indicating that some AAs are specified by more than one set. |
|
Definition
|
|
Term
| True or False: mRNA recognizes an AA by itself. |
|
Definition
| FALSE, mRNA does not recognize an AA themselves but is mediated by tRNA |
|
|
Term
| What are the 4 binding site of ribosomes? |
|
Definition
-one for mRNA
-3 for tRNA: A, P, E |
|
|
Term
| What are release factors? What are they functionally an example of? |
|
Definition
-proteins that bind to any ribosome with a stop codon positioned in the A-site
-release factors are an example of molecular mimicry, wherein one type of macromolecule resembles the shape of a chemically unrelated molecule |
|
|
Term
| What are the structural components of a protein? What makes them chemically different? |
|
Definition
-polypeptide backbone + attached side groups
-the sequence of chemically different side chains makes each protein distinct |
|
|
Term
| The final folded structure of any polypeptide chain is called the ________ and what is its function? |
|
Definition
-conformation
-one that achieves an energetically favored state |
|
|
Term
| What are two regular common conformation patterns? How are they achieved? |
|
Definition
-alpha helix
-beta sheets
-result from hydrogen bonding b/n the N-H and C=O groups in polypeptide backbone |
|
|
Term
| Definition: Enzymes? What is their function? |
|
Definition
-a protein class that acts as catalysts
-enzymes achieve extremely high rates of chemical reaction by lowering the activation E required to achieve the most unstable transition state of substrates |
|
|
Term
| What is the Michaelis-Menton constant (Km)? |
|
Definition
-an approximate measure of substrate affinity for the enzymes
-it is numerically equal to concentration of substrates at which the reactine rate is half of maximum rate (Vmax) |
|
|
Term
| Low Km means (high/low) rates of reaction. |
|
Definition
|
|
Term
| what are the two types of inhibitors that regulate enzyme activity? Where do they bind? |
|
Definition
-competitive: bind to active site
-Non-competitive inhibitors: bind on any location (allosteric side) other than the active site of enzyme |
|
|
Term
|
Definition
-an ATP dependen protease apparatus dispersed throughout cytosol and nucleus to deliberately destroys proteins
-they act on proteins that have been specifically marked for destruction by the covalent attachment of a recognition tag from a protein called ubiquitin |
|
|
Term
| What is the purpose of the ubiquitin-conjugating system? Describe it. |
|
Definition
-marks proteins for destruction
-composed of ATP dependent ubiquitin activating enzyme (E1), set of ubiquitin-conjugating (E2), and accessory (E3) proteins |
|
|
Term
| The E2-E3 complex is called ____. |
|
Definition
|
|
Term
| What feature of the ubiquitin-conjugatine system allows for there to be hundreds of specific proteins it can mark? |
|
Definition
| -hundreds of different E3 proteins that form complexes with specific E2 enzymes |
|
|
Term
|
Definition
| -the delivery of newly synthesixed proteins, carbohydrates, or lipis to either the plasma membrane or extracellular space |
|
|
Term
|
Definition
| -the delivery of important nutrients or plasma membrane components to endosomes |
|
|
Term
| What are the 3 types of vesicles? |
|
Definition
-COPI-coated
-COPII-coated
-Clathrin-coated |
|
|
Term
|
Definition
-clathrin is a major protein component of clathrin coated vesicles
-adaptor proteins form a discreet second layer of the coat, posisitoned between the clathrin cage and the membrane, adaptor proteins bind the clathrin coat to the membrane and trap various transmembrane proteins or cargo receptors |
|
|
Term
| What is the function of Dynamin? |
|
Definition
| -assembles as a ring around the neck of budding vesicles to allow pinching off ad release from the membrane |
|
|
Term
| What coat(s) does Arf (monomeric CTPase) control? Sar1? |
|
Definition
|
|
Term
| What is the function of Rab proteins? |
|
Definition
| -direct the vesicles to specific spots on the corret target membrane |
|
|
Term
| What is the function of SNARE proteins? |
|
Definition
| -mediate the fusion of the vesicle to the lipid bilayer |
|
|
Term
| Most cholersterols are transported in the blood as cholesteryl esters in the form of lipid-protein particles known as _____. What happens if a cell is mutant in the production of this? |
|
Definition
-low-density lipoproteins (LDLs)
-if mutant, the cell cannot bind and ingest LDL by receptor-mediated endocytosis and this will caud an increased risk of heart attack (via atherosclerosis) |
|
|
Term
| What are the tow types of anchoring junctions and what are they responsible for? |
|
Definition
-Cadherin mediated: cell-cell adhesion
-Integrin mediataed: cell-matrix adhesions |
|
|
Term
| Definition: Homophilic adhesion |
|
Definition
| -forms when cadherin molecules of the same or closely related subtype bind to cadherin molecule of the same or closely related subtype on adjacent cell |
|
|
Term
| Definition: Heterophilic adhesion |
|
Definition
| -forms when cadherens molecules of different subtypes bind to each outher |
|
|
Term
| True or False: Mutation in extracellular matrix production cannot adversely affect morphogenesis because they are unrelated processes. |
|
Definition
| FALSE; mutations in extracellular matrix production can adversely affect morphogenesis |
|
|
Term
| Communication between cells is mediated mainly by ________. Reception of signals is by (general/specific) receptor proteins which in turn activates one or more intracellular signaling pathways. |
|
Definition
-extracellular signal molecules
-specific |
|
|
Term
| What are the 4 types of extracellular signaling and define them. |
|
Definition
-Contact dependent: one cell touches another
-Paracrine: chemical works on neighboring cell
-Endocrine: chemical works on distant cell
-Autocrine: chemical acts of itself |
|
|
Term
| Because endocrine signaling relies on diffusion an blood flow, it is relatively (fast/slow) compared to neural communication. |
|
Definition
|
|
Term
| True or False: NO gas directly regulates the activity of specific proteins inside the target cell by activating extracellular receptors. |
|
Definition
| FALSE; intracellular receptors. |
|
|
Term
| NO acts on the enzyme ________ in smooth muscle cells. This stimulates the production of _________ and cause the (contraction/relaxation) of smooth muscle cells. |
|
Definition
-guanylyl cyclase
-cyclic GMP
0relaxation |
|
|
Term
| Nuclear receptors are what kind of protein? Nickname? |
|
Definition
-ligand-modulated gene regulatory proteins
-called Orphan nuclear receptors |
|
|
Term
| LIgans binding to nuclear receptors activate ______. This constitutes the (primary/secondary) response. The protein products of these genes in turn activate other genes to produce a delayed (primary/secondary) response. |
|
Definition
-transcription
-primary
-secondary |
|
|
Term
| Definition: Signal transduction |
|
Definition
| -the process by which cell receptors convert extracellular signals into intracellular signals |
|
|
Term
| What are the three classes of cell surface receptors? |
|
Definition
-ion channel cpold
-G protein cpld
-enzyme cpld |
|
|
Term
| Trimeric CTP-binding protein mediates the interaction of _______ and ______ |
|
Definition
-G protein cpld receptors
-target protein |
|
|
Term
| What are the two general ways an enzyme coupled receptor can function? |
|
Definition
-function directly as enzymes
-associate directly with enzymes that they activate |
|
|
Term
| Most activated cell surface receptors relay signals via small molecules and a network of intracellular signaling protiens. the small intracellular signaling molecules are (primary/secondary) and three examples are what? |
|
Definition
-secondary
-cAMP, IP3, diacylflycerol |
|
|
Term
| True or False: Many intracellular signaling proteins behave as molecular switches. |
|
Definition
|
|
Term
| Two types of ISP's that act as molecular switches get activated by _________ and by ________. |
|
Definition
-phosphorylation
-GTP binding |
|
|
Term
| What is the function of protein kinases? |
|
Definition
| -covalently add one or more phosphate group to the signaling protein |
|
|
Term
| What is the function of a protein phosphatase? |
|
Definition
| -to remove phosphate group |
|
|
Term
| ISPs have intrinsic __TPase activity. They are activated when bound to (GDP/GTP) and can shut themselves off by hydrolyzing it to (GDP/GTP). |
|
Definition
|
|
Term
| Definition: G-protein coupled receptor |
|
Definition
| -singly polypeptide chain that thread back and forth across lipid bilayer seven times |
|
|
Term
| All GCPRs use ______ to relay the signal into the cell interior. |
|
Definition
|
|
Term
| Describe the structure of a G-protein and how it changes upon GPCR activation |
|
Definition
-alpha, beta, and gamma SUs
-inactive when alpha SU is GDP bound
--upon act by ligand binding, alpha SU is GTP bound=> alpha SU is GTPase and hydrolyses its bound GTP to GDP to become inactive |
|
|
Term
| What is the function of adenylyl cyclase? |
|
Definition
|
|
