Term
|
Definition
| mechanical stability based on the distribution of tensional and compressive forces |
|
|
Term
|
Definition
| force transfer resulting in distant mechanical effects |
|
|
Term
| molecules, cells, and metazoans are all... |
|
Definition
| early requirements in the cells of living systems. |
|
|
Term
|
Definition
| the idea that mitochondria, chloroplasts, and possibly other organelles of a living cell originated as bacteria living outside the cell but were taken into the cell to live there in a symbiotic process. |
|
|
Term
| advantages of being multicellular |
|
Definition
1. ability to perform multiple/specialized functions
2. can be bigger and store more food
3. can survive in multiple media
4. longer lifespans |
|
|
Term
| evolution of cells is based on... |
|
Definition
| heritable phenotypic variation |
|
|
Term
| the evolution of cells is constrained by... |
|
Definition
| selection of highly conserved mechanisms by functional interactions between proteins and pathways - EMBEDMENT - basically, they can't change these things about themselves. |
|
|
Term
|
Definition
| when a specific mechanism is absolutely necessary and integral to a cell - a highly conserved mechanism (?) |
|
|
Term
| What is weak linkage? What is an example of weak linkage? Strong linkage? |
|
Definition
| weak linkage is when a process isn't very dependant on other processes, like signal transduction; metabolism has strong linkage, and therefore IS dependant on other processes. |
|
|
Term
| what are three things that reduce constraint on the evolution of cells? |
|
Definition
1. weak linkage (minimal dependance of a process on other processes)
2. exploratory mechanisms (allow the cell to move to new environments and adapt to them?)
3. compartmentation and redundancy (which reduces dependance) |
|
|
Term
|
Definition
| the biological process that causes an organism to change its shape. |
|
|
Term
| what was the probable basis of the first living cells? |
|
Definition
| spontaneous synthesis of organic molecules |
|
|
Term
| how many primary cellular ancestors are there? |
|
Definition
| just one - all cells are descended from one primordial ancestor |
|
|
Term
| describe the steps required to get from pre-biotic soup to living organisms |
|
Definition
1. organic molecules are spontaneously generated
2. these polymerize into macromolecules
3. these macromolecules become self-reproducing
4. proto-cells are organized by enclosure in a self-forming phospholipid bilayer |
|
|
Term
| Why is RNA assumed to have been the initial genetic system? |
|
Definition
| it is both informational (able to serve as a template) and conformational (able to catalyze a reaction) - therefore it is the only macromolecule that was able to self-replicate. |
|
|
Term
|
Definition
| an early stage of chemical evolution thought to be based entirely on self-replicating RNA molecules |
|
|
Term
| cellular self-assembly depends on... (3) |
|
Definition
1. amphipile concentration
2. pH
3. ionic content |
|
|
Term
|
Definition
| an amphipathic molecule made of a hydrocarbon bonded to a phosphate group |
|
|
Term
| how do you get phospholipids to spontaneously aggregate into a bilayer? |
|
Definition
|
|
Term
| describe photosynthesis chemically |
|
Definition
| the splitting of H2O molecules, releasing O2 gas |
|
|
Term
| what is evidence for the possible role of oxygen in the evolution of eukaryotes? |
|
Definition
| eukaryotic cells started to show up fairly soon after O2 started accumulating after Fe2+ was used up |
|
|
Term
| what is the full name of the molecule all cells use to get energy? |
|
Definition
| adenosine triphosphate (ATP) |
|
|
Term
|
Definition
| a method of energy aquisition evolved when the earth's atmosphere was anaerobic; it is the breakdown of glucose to lactic acid, with 2 ATP produced |
|
|
Term
| what is the most primitive photosynthetic pathway? |
|
Definition
| breaking down H2S to convert CO2 to organic molecules |
|
|
Term
| how did the change from photosynthetic organisms using H2O in photosynthesis rather than H2S change the earth's atmosphere? |
|
Definition
| for the first time, O2 gas was readily available |
|
|
Term
| what is the advantage of oxidative metabolism over glycolysis? |
|
Definition
| it's much more efficient, yielding 36-38 ATP molecules to glycolysis' 2. |
|
|
Term
| what is the primary structural difference between prokaryotes and eukaryotes? |
|
Definition
| eukaryotes have internal orginization - thier nucleus is seperated from the rest of the cell with a nuclear envelope. |
|
|
Term
| modern-day prokaryotes (2) |
|
Definition
| archaebacteria and eubacteria |
|
|
Term
|
Definition
| a single circular module in the nucleoid; isn't enclosed by a nuclear envelope (prokaryote) |
|
|
Term
| how is a eukaryotic cell similar to a prokaryotic cell? (2) |
|
Definition
| they both have a phospholipid bilayer plasma membrane and ribosomes |
|
|
Term
| what is the largest organelle in a eukaryotic cell? |
|
Definition
|
|
Term
|
Definition
| site of oxydative metabolism (energy / ATP production) |
|
|
Term
|
Definition
|
|
Term
|
Definition
- are only present in plant cells
- digest macromolecules
- store waste products and nutrients |
|
|
Term
|
Definition
- protein modification
- lipid synthesis
- (plants only) synthesizes cell wall proteins |
|
|
Term
|
Definition
| network of protein filaments that provides support and motility |
|
|
Term
| evidence that choloroplasts evolved from engulfed cyanobacteria (3) |
|
Definition
1. divide independantly from the cell
2. have their own genome (circular DNA with no histones)
3. have their own protein-synthesis machienery, which is blocked differently (by streptomycin rather than diphtheria) than in the cell itself |
|
|
Term
| what is the simplest eukaryote? |
|
Definition
|
|
Term
|
Definition
| cover the surface of the body and line internal organs |
|
|
Term
| connective tissue types (3) |
|
Definition
1. bone
2. cartilage
3. adipose tissue |
|
|
Term
| structural units of loose connective tissue |
|
Definition
|
|
Term
|
Definition
|
|
Term
| granculocytes, monocytes, macrophages, lymphocytes |
|
Definition
|
|
Term
| possible driving forces for multicellularity (2) |
|
Definition
1. to avoid predators - heterotrophs that would engulf other organisms (phagocytosis) to get nutrients
2. in order to not sacrifice motility for mitosis, organisms had to internalize cell division |
|
|
Term
| basic principles learned from experiements one one cell are generally applicable to other cells. Why is this? |
|
Definition
| because the fundamental properties of all cells have been conserved during evolution. |
|
|
Term
| what is the most commonly studied bacterium, and the one from which we derive most of our cellular knowledge? |
|
Definition
|
|
Term
| why are e.coli so useful to study? (4) |
|
Definition
| they're simple, they reproduce very quickly, they can carry out biosynthetic reactions in simple defined media, and their genome is very small. |
|
|
Term
| how do experiments on yeasts reveal the unity of cell biology? |
|
Definition
| the general principles of cell structure and function found in yeasts apply to all eukaryotic cells |
|
|
Term
| why is c. elegans so widely used to study multicellular organisms? (3) |
|
Definition
1. nearly the same amount of genes as in humans
2. relatively simple (only 959 somatic cells); the embryonic origin and lineage of each cell has been traced
3. based on common mutations and abnormalities being identified, it's easy to isolate and characterize the genes that control development and differentiation |
|
|
Term
| studied as a model of plant molecular biology |
|
Definition
|
|
Term
| largest, most complext prokaryotes in which photosynthesis evolved |
|
Definition
|
|
Term
| cell wall composition in a prokaryotic cell |
|
Definition
| polysaccharides and peptides |
|
|
Term
| composition of the plasma membrane in a prokaryotic cell |
|
Definition
| phospholipidbilayer and associated proteins |
|
|
Term
| what might explain the fact that most eukaryotic genes relating to informational processes are similar to those of archaebacteria, and most relating to the basic operational processes were derived from eubacteria? |
|
Definition
| if the genome of eubacteria had arisen from the fusion of archaebacterial and eubacterial genomes resulting from endosymbiosis of these two species. |
|
|
Term
| how do the cells of the green algae volvox suggest an evolutionary transition from single cells to multicellular organisms? |
|
Definition
| composed of colonies of single cells; increasing cell specialization could have caused the evolutional step from this to true multicellular organisms. |
|
|
Term
| three main tissue categories of plant cells: |
|
Definition
1. ground tissue
2. dermal tissue
3. vascular tissue |
|
|
Term
|
Definition
| plant tissue that contains metabolic reactions of the plant (like photosynthesis); also has cells that provide structural support |
|
|
Term
|
Definition
| covers the surface of the plant (epidermal cells) - protective coat, absorbance of nutrients |
|
|
Term
| vascular system in plants |
|
Definition
|
|
Term
| what method of studying vertebrate cells has elucidated the methods of DNA replication, gene expression, cell division, and protein synthesis? |
|
Definition
| using isolated cells in culture |
|
|
Term
| what is the usefulness of muscle cells in culture? |
|
Definition
| as highly differentiated (specialized) cells, they are useful for studying cell movement on a molecular level |
|
|
Term
| use of giant neurons in culture |
|
Definition
| useful for the studies of ion transport across the plasma membrane, and role of cytoskeleton in the transport of cytoplasmic organelles |
|
|
Term
| why is the frog xenopus laevis useful to study early vertebrate development? |
|
Definition
1. lots of eggs
2. eggs are large cells
3. that develop outside of the mother
4. can be observed in large numbers |
|
|
Term
| use of zebrafish for study |
|
Definition
- small
- reproduce rapidly
- embroyos develop outside the mother and are transparent
- can bridge the gap between humans and simpler invertebrate systems |
|
|
Term
| the suitability of the mouse as a model for human development (2) |
|
Definition
1. similarty of mouse and human genomes
2. mutations in homologous genes result in similar developmental defects in both species |
|
|
Term
|
Definition
| prepared directly from the tissue of an organism; with a finite lifespan |
|
|
Term
|
Definition
| each nerve fiber is an outgrowth from a single cell, not a product of cell fusion |
|
|
Term
|
Definition
- immortal cell lines, transformed to divide indefinitely, derived from pre-existing cultures
- derived from hyperprolific tumor tissue, or oncogenic viruses/chemicals |
|
|
Term
| fluorescence-activated cell sorting (FACS) |
|
Definition
| seperates cells one at a time based on fluorescent qualities |
|
|
Term
| how are cells prepared for FACS? |
|
Definition
- broken down through the use of proteases (cleaves extracellular matric components) and alteration of ionic conditions - low Ca2+ levels lead to the breakdown of intercellular junctions
- then cells are seperated based on physical properties (for example, through density centrifugation) |
|
|
Term
| requirements for animal cell culture |
|
Definition
- culture media with various salts, glucose, and amino acids/vitamens the cells can't make for themselves
- polypeptide growth factors (from serum, usually) |
|
|
Term
| what allows animal cells to grow on plastic or glass? |
|
Definition
they excrete their own extracellular matrix components (support structures) |
|
|
Term
| what are the two main sources of cell culture cells? |
|
Definition
|
|
Term
| what kind of cells have played an important function in both gene function in mouse development and offer the possibility of treating many human illnesses through transplant therapies? |
|
Definition
|
|
Term
| what are the only two sources of immortal cell lines? |
|
Definition
| embryonic stem cells and tumor cells |
|
|
Term
| why are immortal cell lines important for study? |
|
Definition
| provide a continuous and uniform line of cells |
|
|
Term
| contemporary light microscopes are allowed to magnify objects up to _________ times, which allows cells to be seen - they are usually between _____________ in diameter. |
|
Definition
| 1000 times; 1-100 nanometers |
|
|
Term
|
Definition
| the ability of a microscope to distinguish objects separated by small distances |
|
|
Term
| limit of resolution by a light microscope |
|
Definition
|
|
Term
| what two factors determine the resolution limits of light microscopy? |
|
Definition
1. the wavelength of visible light
2. light-gathering power of the microscope lens (NA) |
|
|
Term
|
Definition
| light passes directly through the cell, which is preserved with fixatives and stained with dyes to enhance the contrast. this can't be done to living cells. |
|
|
Term
| phase-contrast microscopy and differential interference-contrast microscopy |
|
Definition
| convert variations in density or thickness to differences in contrast in the final image |
|
|
Term
| video-enhanced differential interference-contrast microscopy |
|
Definition
| has allowed the visualization of organelles along microtubules |
|
|
Term
| used for molecular analysis - studying the intracellular distribution of molecules |
|
Definition
|
|
Term
| if you want to find the location of specific proteins throughout a cell and you have antibodies for it, you would use... |
|
Definition
| immunofluorescence, a kind of fluorescence microscopy |
|
|
Term
| if you wanted to analyze cellular proteins (for which you presumably didn't have antibodies), what would you do? |
|
Definition
| fuse GFP (green fluorescent protein) to the protein of interest; the proteins are now stained and can be detected by fluorescence microscopy |
|
|
Term
| fluorescence recovery after photobleaching (FRAP) |
|
Definition
| a region of interest in a cell expressing a GFP labeled protein is bleached by exposure to high-intensity light. unbleaches GFP-labelled molecules travel to the bleached region, allowing the rate at which the protein moves within the cell to be studied. |
|
|
Term
| how would one determine the interactions of two proteins with one another in the cell? |
|
Definition
| fluorescence resonance energy transfer (FRET) - which is when you take two proteins and couple them to two fluorescent dyes, one of which excites the other, and excite the first one to see if it interacts with the second. |
|
|
Term
| how do you get an image from fluorescence microscopy to be non-blurry? (on DEAD cells) |
|
Definition
| confocal microscopy - a pinpoint of light is focused on the specimen, and the emitted fluorescent light collected by a detector - but first it passes through a confocal aperture where the light emitted from that depth on the specimen comes into focus; therefore, only in-focus light is detected. |
|
|
Term
| how do you get a sharp image via fluorescence microscopy on a LIVING cell? |
|
Definition
| multi-photon excitation microscopy - the specimen is illuminated with light such that excitation of the fluorescenct dye requires the simultaneousabsorption of two or more photons. this will really only happen in places where the input laser is being focused, and automatically provides 3-d resolution and doesn't hurt the specimen |
|
|
Term
| what are two difficulties with using confocal microscopy? |
|
Definition
1. photobleaching
2. phototoxicity |
|
|
Term
| why can electron microscopy achieve so much greater resolution that light microscopy? why is resolution practically reduced in living specimens? |
|
Definition
| shorter wavelengths; because of the difference in contrast |
|
|
Term
| transmission electron microscopy |
|
Definition
| cells are stained with heavy metals, which provide contast by scattering electrons |
|
|
Term
| what technique would you use to find specific proteins in electron microscopy? |
|
Definition
| positively-stained antibodies in transmission electron microscopy |
|
|
Term
|
Definition
| combines (via computer analysis) a lot of two dimensional images obtained bia transmission electron microscopy |
|
|
Term
| how would one visualize the surface of isolated subcellular structures or macromolecules in a transmision electron microscope? |
|
Definition
| metal shadowing - where the specimen is coated with a thin layer of evaporated metal on an angle, which creates a shadowing effect in electron microscopes |
|
|
Term
| how would one study membrane structure? |
|
Definition
| freeze fracture metal shadowing - specimens are frozen in liquid nitrogen, then fractured with a knife blade. This splits the lipid bilayer, revealing the interior faces of a cell membrane, which is then shadowed with platinum. then the specimen is dissolved in acid, leaving a metal replica of the surface of the sample. this is then examined with an electron microscope. |
|
|
Term
| what would one do to study a whole cell using electron microscopy? |
|
Definition
| scanning electron microscopy (has a limited resolution) |
|
|
Term
| how would one isolate the organelles of eukaryotic cells? |
|
Definition
| differential centrifugation, which separates the cell componants based on size and density. |
|
|
Term
| what are the steps to subcellular fractionation? |
|
Definition
- disruption of the plasma membrane under conditions that doesn't mess up the inside of the cell, such as sonication
- then put in an ultracentrifuge, which rotates really really fast |
|
|
Term
| how would one purify the fractions obtained through differential centriguation? |
|
Definition
| density-gradient centriguation - organelles are separated by sedimentation through a gradient of a dense substance, such as sucrose. (they travel until they reach the density of sucrose which matches their own,which is known at any given position) |
|
|
Term
|
Definition
| organelles are seperated out through a density gradient as they move at different rates, and then can be seperated out |
|
|
Term
| how would one separate subcellular components, such as different types of membranes and/or molecules that are labelled with different isotopes, independant of size and shape? |
|
Definition
| equilibrium centrifugation in desity gradients - centrifuged until the particles reach a position at which their buoyant density is equal to that of the surrounding sucrose or cesium chloride solution |
|
|
Term
|
Definition
| the systemic analysis of cell genomes |
|
|
Term
|
Definition
| all the proteins expressed in a given cell |
|
|
Term
|
Definition
| the systemic analysis of all cell proteins- aims to identify all proteins are expressed in a cell, where they are expressed, and their interactions |
|
|
Term
| number of genes expressed in any given cell is thought to be around... |
|
Definition
|
|
Term
| how do the estimated 10,000 expressed genes in any given cell give rise to more like 100,000 proteins? |
|
Definition
| splicing and protein modifications |
|
|
Term
| large-scale separation of cell proteins based on charge and size |
|
Definition
|
|
Term
| gel electrophoresis is biased towards... |
|
Definition
| the most abundant proteins in a cell |
|
|
Term
| how can proteins that have been separated by gel electrophoresis be identified |
|
Definition
| mass spectronomy - cut out of the gel, cleaved by a protease into small peptides, ionized, and the mass spectrometer detects unique size-to-mass ratio |
|
|
Term
| how much of the cell mass to inorganic ions make up? |
|
Definition
|
|
Term
| what are the four classes of organic compounds? |
|
Definition
| carbohydrates, lipids, proteins, nucleic acids |
|
|
Term
| what are the major nutrients of the cell? |
|
Definition
| carbohydrates (such as glucose) |
|
|
Term
| what monosaccharide provides the principal source of cellular energy? |
|
Definition
|
|
Term
| how are monosaccharides linked, and what is the resulting bond called? |
|
Definition
| linked by dehydration reactions, and the resulting link is a glycocidic bond |
|
|
Term
|
Definition
| polymer of a few simple sugars |
|
|
Term
|
Definition
| macromolecule composed of hundreds or thousands of monosaccharides |
|
|
Term
| two storage polysaccharides with glucose molecules in the α formation |
|
Definition
| glycogen (storage in animals) and starch (storage in plants) |
|
|
Term
|
Definition
- principal structural componant of the plant cell wall
- composed of glucose molecules in the β formation |
|
|
Term
| three main lipids and thier functions |
|
Definition
1. triacylglycerides (energy storage)
2. phospholipids (cell membranes)
3. steroids (cell signaling - hormones/messanger molecules)
|
|
|
Term
| simplest form of lipid and its structure |
|
Definition
| fatty acids - hydrocarbon chains with a carboxyl group on one end (O=C-O) |
|
|
Term
| triacylglycerol structure and function |
|
Definition
| three fatty acid chains on a glycerol molecule; more efficient energy storage than carbohydrates; accumulate as fat molecules in the cytoplasm |
|
|
Term
| glycerol phospholipid structure |
|
Definition
| two fatty acid chains bound to a glycerol backbone; third glycerol carbon is bound to a phosphate group. |
|
|
Term
| a molecule that is part hydrophobic and part hydrophilic (like a phospholipid) is called: |
|
Definition
|
|
Term
| three types of lipids in the cell membrane |
|
Definition
| mostly phospholipids, but also glycolipids (same thing as phospholipid but with glucose) and cholesterol |
|
|
Term
|
Definition
| four hydrophobic hydrocarbon rings, but with an OH group that makes it amphipathic |
|
|
Term
| steroid hormones are derivatives of what lipid form? |
|
Definition
|
|
Term
| what carries information from DNA to the ribosomes? |
|
Definition
|
|
Term
| DNA and RNA monomers are called |
|
Definition
|
|
Term
| list the purines and pyrimidines of DNA |
|
Definition
purines: Adenine and Guanine
pyrimidines: Cytosine and Thymine |
|
|
Term
|
Definition
| a nitrogenous base bound to a sugar |
|
|
Term
| componants of a nucleotide (3) |
|
Definition
1. nitrogenous base
2. sugar
3. phosphate group (liked to 5' carbon sugar) |
|
|
Term
| define: phosphodiester bond |
|
Definition
| bond between nucleotides - linking the 5' phosphate of one nucleotide to the 3' hydroxyl (C-OH) of another |
|
|
Term
|
Definition
| small polynucleotides with only a few nucleotides involved |
|
|
Term
| polynucleotides are always synthesized in the _________ direction |
|
Definition
|
|
Term
| other than DNA and RNA, what are two important nucleotides and their functions within the cell? |
|
Definition
1. ATP (adenosine 5'-triphosphate) - main source of chemical energy within the cell
2. cyclic AMP - acts as a signalling molecule within the cell |
|
|
Term
| how many different amino acids are there? |
|
Definition
|
|
Term
|
Definition
carbon bonded to:
- a hydrogen
- a carboxyl group (O=C-O)
- an amino acid (NH3+)
- a side chain (R) |
|
|
Term
| what are the four side-chain based groupings of amino acids? |
|
Definition
1. polar side chains
2. nonpolar side chains
3. side chains with charged basic groups
4. side chains terminating in (acidic) carboxyl groups |
|
|
Term
| amino acids are joined by what sort of bonds? |
|
Definition
|
|
Term
| describe the two ends of a polypeptide chain |
|
Definition
N-terminus: end with an α amino group
C-terminus: end with an α carboxyl group |
|
|
Term
| what is the defining characteristic of polypeptide chains? |
|
Definition
|
|
Term
| what determines the unique sequence of amino acids in a polypeptide chain/protein? |
|
Definition
| the order of nucleotide bases in a gene |
|
|
Term
| how is the shape and function of a protein determined by its amino acid sequence? |
|
Definition
| function of a protein is determined by its structure, which is determined by the intermolecular interactions between the amino acids |
|
|
Term
| how does heating a protein make it lose its shape? (denaturation) |
|
Definition
| by breaking its intermolecular bonds |
|
|
Term
| define: x-ray crystallography |
|
Definition
- how you examine the 3d structure of a protein
- pass x-rays through the protein and observe the scattering pattern on x-ray film |
|
|
Term
| two types of protein secondary structure |
|
Definition
|
|
Term
| what is the basic unit of tertiary structure? |
|
Definition
|
|
Term
| membrane fluidity is determined by (2) |
|
Definition
1. temperature
2. membrane composition |
|
|
Term
| membranes containing shorter fatty acid chains are (more/less) likely to be fluid at lower temperatures? |
|
Definition
| more - they have fewer interactions with each other |
|
|
Term
| lipids containing unsaturated fatty acid are (more/less) fluid? |
|
Definition
| more, because double bonds mean kinks and kinks mean not packing well |
|
|
Term
| describe the structure of phosphatidylcholine |
|
Definition
| - phospholipid - two fatty acid chains attatched to a phosphate attatched to a choline group |
|
|
Term
| plasma membranes of cells contain how many kinds of phospholipids? |
|
Definition
| five (two outer, three inner) |
|
|
Term
of the five types of phospholipids, which are the outer layer ones?
- phosphotidylcholine
- phosphotidylethanolamine
- phosphotideylserine
- phosphotidylnositol
- sphingomyelin |
|
Definition
phosphotidylcholine
sphingomyelin |
|
|
Term
| describe glycolipids in the cell membrane (where found, orientation/structure) |
|
Definition
- only found in animal cells
- only found in the outer layer
- carbohydrate proteins exposed on the cell surface |
|
|
Term
| in which leaflet is cholesterol present? |
|
Definition
| equally present in both leaflets |
|
|
Term
| how does cholesterol affect membrane fluidity at different temperatures? |
|
Definition
high temperatures: ring structure interacts with hydrocarbon tails and keeps them more solid, keeping small molecules from getting through
low temperatures: ring structure interacts with hydrocarbon tails and keeps them from freezing, increasing the fluidity |
|
|
Term
| glycolipids in animal cells (composition and role) |
|
Definition
found in the outer leaflet
- protects cell surface
- interacts with other cells / extracellular molecules |
|
|
Term
| five kinds of integral membrane proteins |
|
Definition
1. single-pass transmembrane protein
2. multi-pass transmembrane protein
3. fatty acid chain attatchment to membrane
4. oligaro-saccharide attatchment to the membrane
5. noncovalent attatchment to protein anchor |
|
|
Term
| peripheral membrane proteins attatch to the membrane... |
|
Definition
| through protein-protein interactionst that often involve ionic bonds |
|
|
Term
| how do you get a peripheral membrane protein to dissociate from the cell membrane? |
|
Definition
| using a polar reagant (salts or extreme pH) |
|
|
Term
| what is the difference between a transmembrane protein and an integral protein? |
|
Definition
| a transmembrane protein is a kind of integral protein that spans the membrane and emerges on both sides |
|
|
Term
| what are the two membrane-spanning structures of integral proteins? |
|
Definition
1. a-helixes made up of 20-25 nonpolar amino acids
2. β-barrels made of beta sheets folded into a barrel stucture with polar on the inside and nonpolar on the outside |
|
|
Term
|
Definition
areas in the cell membrane made of sphingolipids which have long saturated hydrocarbon chains (promote self-association) and cholesterol
- greater thickness than surrounding membranes
- may include/exclude some proteins preferentially |
|
|
Term
| which kinds of molecules can cross the phospholipid bilayer? which can't? |
|
Definition
can cross: small polar molecules; small nonpolar molecules
can't cross: ions (small charged molecules); large nonpolar molecules |
|
|
Term
| _________ molecules diffuse according to their simple concentration gradient, whereas __________ molecules diffuse according to their electrochemical gradient |
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Definition
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Term
| ________ channels and _________ carriers support facilitated diffusion |
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Definition
| all channels; some carriers |
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Term
describe the three types of transporters:
- uniporter
- symporter
- antiporter |
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Definition
uniporter: transports one molecule at a time in one direction
symporter: transports two molecules at a time in the same direction
antiporter: transports two molecules at a time in opposite directions |
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Term
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Definition
| bind specific molecules and then undergo conformational change to get them across the membrane |
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Term
| a ligand-gated ion channel opens in response to... |
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Definition
| the binding of neurotransmitters or other signalling molecules |
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Term
| voltage-gated ion channels open in response to |
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Definition
| changes in electric potential across the cell membrane |
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Term
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Definition
ATP powered pump with two ATP binding sites and two transmembrane domains
- the binding sites are where ATP is hydrolized (and provides energy)
- transports many different ions and molecules |
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Term
| P-class pumps vs. F-class and V-class pumps |
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Definition
P-class only transports ions
the other two only transport protons |
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Term
| how does cancer resist hydrophilic drugs? hydrophobic ones? |
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Definition
| resists hydrophilic by mutating the carrier proteins; resists hydrophobic by pumping them out via MDR1 (an ABC ATP-powered pump) |
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Term
| Na--K+ ion P-class pump works via... |
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Definition
| ATP-driven conformational changes |
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Term
| for every ATP used by the sodium-potassium pump, ________ Na+ are pumped out and _______ K+ are pumped in. |
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Definition
| three sodiums; two potassiums |
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Term
| how does an enzyme alter the state of chemical equilibrium and the rate of conversion? |
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Definition
| rate of conversion is increased both forwards and backwards. chemical equilibrium isn't altered at all. |
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Term
| chemical equilibrium in the conversion between a product and a substrate is determined by the laws of.... |
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Definition
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Term
| what is the active site of an enzyme? |
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Definition
| the place to which the substrate binds |
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Term
| active sites are formed by what level of the enzyme's structure? |
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Definition
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Term
| define: feedback inhibition |
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Definition
| when the product of a reaction inhibits the enzyme involved in its synthesis |
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Term
| define: allosteric regulation |
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Definition
when small molecules bind to regulatory sites on the enzyme (NOT the catalytic site!)
- this alters the shape of the enzyme, and, by extension, the active site |
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Term
| phosphorylation of an enzyme |
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Definition
| addition of phosphate groups either stimulates or inhibits the activities of many different enzymes. |
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Term
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Definition
| the bonds between the phosphates in ATP, which release a lot of energy when broken |
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Term
| hydrolizing ATP to AMP+pp releases ___________ the energy that hydrolizing ATP to ADP does |
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Definition
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Term
| equation for the complete oxidative breakdown of glucose to CO2 and H2O |
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Definition
| C6H12O6 + 6O2 --> 6CO2 + 6H2O |
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Term
| the three major steps to the breakdown of glucose |
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Definition
1. glycolysis (anaerobic, happens in all cells)
2. citric acid cycle
3. oxydative phosphorylation |
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Term
| glycolysis (process and outcome) |
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Definition
glucose --> pyruvate (net gain: 2ATP)
ALSO
NAD+ --> NADH |
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Term
| the enzymes that catalyze glycolysis are inhibited by... |
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Definition
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Term
| what does NADH do in aerobic and anaerobic conditions? |
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Definition
aerobic: donates electrons to the electron transport chain
anaerobic: reoxidized to NAD+ by the conversion of pyruvate to lactate or ethanol |
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Term
| what happens to the 2pyruvate generated by glycolysis? |
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Definition
| it goes to the mitochondria to be completely oxidized (oxidative decarboxylation) by coenzyme A - forms acetyl CoA |
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Term
|
Definition
formed by oxidative decarboxylation by coenzyme A (reducing 1 NAD+ to NADH) (releasing CO2)
--> enters the citric acid cycle |
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