molecular biology questions
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- what processes occur in the mitochondria.
- TCA cycle, electron transport chain
- where is the site of glycosylation and protein processing
- Rough ER and the glogi
- what is an extension of the nuclear envelope
- the Rough ER
- what happens in the smooth ER?
- steroid biosynthesis and drug detoxification in the liver
- where would you find hydroxylases?
- in the peroxisome... lipid metabolism and metabolization of strange hydrocarbons occurs here
- what do secretory vesicles contain?
- protein cargo
- what would a secretory vessicle containing protein cargo to be fused with the plasma membrane be surrounded by?
- Clathrin
- a complex of rna and protein which is not membrane bound
-
ribosomes
40s and 60s subunits - what are microtubules composed of? and what would they do?
- tubulin. they are for cell protrusion extension. the centrioles and cell division spindles are also made up of microtubules.
- what is the macroarchetecture of the cell
- microtubules
- what is the microarcheticecture of the cell made up of?
- microfilaments which are composed of actin.
- contractile bundles in cytokinesis are made up of?
- mifcrofilaments
- what link microfilaments together
- intermediate filaments
- what is in the extracellular matrix and what is its purpose
- mostly secreted or transmembrane proteins. the ecm protects the cell from dehydration and holds their shape and connects cells together.
- what kind of junctions will you find between cells
- tight, gap and adherens
- list six cellular processes
- membrane trafficking and secretion, receptor mediated endocytosis, signal transduction, cell cycle-DNA replication, apoptosis, transcription and translation
- which macromolecules are informational? which are for storage and structural
-
informational-DNA RNA Protein
Structural= polysaccharides - what is the term used when monomers are being polymerized?
- condensation. water is lost and energy is required
- name 5 types of bonds
-
covalent
and noncovalent which can be broken down into ionic, hydrogen bonds, van der walls forces, and hydrophobic - what is the monomer of a polysaccharide and what kind of bond links these monomers
- monosaccharides are linked by glycosidic bonds
- what are the monomers of proteins and what bond links them
- amino acids linked by a peptide bond
- where would you find glycolipids and what is their usual function
- glycolipids are usually on the outer leaflets of a membrand. they usually serve as receptors
- where would you find phosphatidylserine. what is unique about it?
- usually on the inner side of a membrane. it is negatively charged- attracting proteins with lysine and arganine. it is important in forming the cytoskeletal framework.
- phosphatidylinositol is usually found where? what is its function?
- on the innner side of a membrane. it is important in signal transduction
- where would you find a membrane carbohydrate?
- linked to a transmembrane protein-called a glycoprotein.
- a ______ transmembrane protein penetrates both sides of the lipid bilayer. glycophorin A in the red blood cells is an example of this type of protein
- integral
- a peripheral protein on the cytosolic face of a membrane usually takes part in either ______ or ________ ________
- cytoskeleton or signal transduction
- the extracellular peripheral proteins usually are part of the ____________ ________
- Extracellular matrix or ECM
- ____ transmembrane proteins are recruited or released depending on conditions
- peripheral
- where would you find either of these lipid anchored membrane proteins? :ras or proteoglycans
-
ras-cytoplasmic side
proteogylcans- extracellular side - _______ proteins can function as either enzymes, tranporters, receptors, and structural
- membrane proteins
- high temps would cause a lipid membrane to become (more or less) fluid?
-
high temp=more fluid
low temp= less fluid - the transition temperature of a membrane is dependent on three factors. what are they?
- length of fatty acid, degree of unsaturation, and the amount of cholesterol present in the membrane
- what is meant by the term "homeoviscious adaptation"?
- regulation of membrane fluidity
- what happens on the apical side
- secretory and taking in substances, protection
- what happens on the lateral side
- connecting and communicating
- what happens on the basal side
- attaching
- in passive transport what types of molecules are mostly transported thru the membrane and which use pores?
- nonopolar molecules- ions are not permeable into the lipid bilayer so they use pores instead
- what happens in the alternating conformation model of facilitated diffusion
- the solute binds, the transporter can be phosphorylated-which causes it to change its shape
- give an example of facillitated diffusion
- glucose, via the GluT1 transporter. the concentration of glucose low inside of a cell - its then phosphorylated which essentially locks it in.
- active transport moves solutes up their gradient... what makes this possible
- the transporter is usually coupled with an energy yielding reaction.
- why is active transport important?
- it allows for the uptake of energy rich molecules which may be in low concentrations, it allows substances to be removed against the gradient, it allows cells to maintain constant levels of important compounds.
- give an example of active transport
- the Na/K atp ase pump. first 3Na+ are taken from the inside of the cell, atp phosphorylates the transporter which causes a conformational change expelling the sodium out and taking in two K+ from the outisde. the transporter is dephosphorylated and the two potassium ions come in.
- Cotransport is a form of active transport. explain symports and antiports
- symports need energy because both solutes are going up the gradient. an antiport has one solute going up its gradient and another solute going down its gradient (glucose cotransported with Na in intestinal cells)
- which is the rate limiting step of glycolosis?
- phosphofructokinase-which is allosterically inhibited by atp
- what is the enzyme which allosterically activates the glycolysis enzyme -Phosphofructokinase? This promotes the relaxed state, even at relatively high [ATP].
-
Fructose-2,6-bisphosphate whose concentration fluctuates in response to external hormonal signals, supercedes control by local conditions (ATP concentration).
Fructose-2,6-bisphosphate instead inhibits the gluconeogenesis enzyme Fructose-1,6-bisphosphatase. -
Aminotransferases (or transaminases) catalyse the
transfer of the a-amino group (NH3+) from an amino
acid to what? What gets produced most often from these transamination reactions? -
either pyruvate, oxaloacetate
or, most often, a-ketoglutarate
If the acceptor is a-ketoglutarate, then glutamate is
produced. - in the electron transfer chain which complexes releases enough energy to transfer H+ from the mitochondrial matrix to the intermembrane space.
- complexes I, III and IV
- in TCA where is NADH+H+ produced?
- going from pyruvate to acetyl CoA, TCA-3, TCA-4, TCA-8,
- in TCA where is FADH2 produced?
- at TCA-6
- in TCA where does water go in?
- 1,5,7
- where does CO2 come out?
- pyruvate to Acetyl-CoA, 3,4
- why does Oxidation of a NADH molecule produces almost 3 ATP, and FADH2 oxidation yields almost 2 ATP.
- The amount of ATP produced by ATP synthase is therefore related to the difference in H+ concentration across the membrane. Since NADH oxidation causes prroton efflux from the matrix in three protein complexes (I, III e IV), whereas FADH2 oxidation to FAD is only accompanied by such an efflux in two complexes (III e IV), more ATP can be produced from NADH than from FADH2.
- where is FADH2 produced?
- TCA-6
- where does the pyruvate-acetyl CoA conversion occur? what does this produce
- occurs in the matrix of the mitochondria, produces CO2 and NADH+H+
- the only membrane bound enzyme in the TCA cycle
- Succinate dehydrogenase
- what are the allosterically regulated steps in glycolysis
- 1,3,10
- Trace the sequence of chemical changes that occurs in mammalian brain tissue when the oxygen supply is cut off.
- The first change is that the cytochrome oxidase system becomes totally reduced since electrons can still flow from cytochrome c but there is no oxygen to accept electrons from cytochrome oxidase. In similar form, the entire electron transport chain backs up. In doing so there is nothing to oxidize NADH back to NAD+. Without NAD+ the Krebs Cycle backs up quickly, and so does glycolysis, shutting down the brain cells' ability to produce energy. Without energy, the brain tissue dies.
- Trace the sequence of chemical changes that occurs in mammalian muscle tissue when the oxygen supply is cut off.
- The same process happens in muscle tissue, except that when the NADH builds up, lactic acid fermentation starts up. With lactic acid fermentation, muscle cells can continue to oxidize NADH to NAD+, allowing glycolysis to produce limited amounts of energy. However, the muscle tissue cannot do this forever. For, after some time without oxygen, the lactic acid buildup in muscle tissue becomes toxic. This is what happens to your body when you put it through extreme enduring exercising stress.