Bio 93 Exam Questions WitH 100% Verified Answers

Bio 93 Exam Questions WitH 100% Verified Answers which steroid is a component of the membrane? cholesterol in amino acid side chains, how do you know the classification? nonpolar side chains (hydrophobic): these are only carbons and hydrogens polar side chains (hydrophilic): these have oxygen with the exception of the one SH side chain electrically charged: they are hydrophilic; acidic being negatively charged and basic being positively charged what are the four levels of protein structure primary: its sequence of amino acids secondary: coils (alpha helix) and folds (beta pleated sheets) from hydrogen bonds between repeating constituents of polypeptide backbone tertiary: overall shape quaternary: overall protein structure amino acids - polypeptides - proteins what are the different types of proteins? enzymatic, defensive, storage, transport, hormonal, receptor, contractile/motor, structural what is the structure of an amino acid? amino group (N-terminus), hydrogen, carboxyl group (C-terminus), and an R group (one of the side chains) what is the structure of a plasma membrane? thin 8 nm thick barrier; lipids (phospholipids (amphiphile or amphipathic), bilayer, cholesterol to regulate membrane fluid), proteins embedded in bilayer, and carbohydrates on extracellular surface (cell-cell recognition on fluidity in the cellular membrane phospholipids drift laterally in plane of membrane held together by weak hydrophobic reactions; stabilized by cholesterol what functions can membrane proteins have? transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton/extracellular matrix traffic across the plasma membrane is...? selectively permeable hypertonic versus hypotonic hypertonic loses water (think when you hyperventilate you "lose" air) hypotonic gains water (think "hungry hungry HYpo" what are the ways across the cell membrane? describe them direct passage through lipid bilayer (diffusing down the concentration gradient takes NO ENERGY), passage mediated by transport proteins (active and passive transport), and vesicular/bulk transport (exocytosis and endocytosis) what is exocytosis versus endocytosis exocytosis is movement OUT of the cell endocytosis is movement INTO the cell what are the three types of ENDOCYTOSIS phagocytosis (cell engulfs particle), pinocytosis (cell "drinks" particle), receptor mediated endocytosis what are the three structural elements of the cytoskeleton? microfilaments (MF), microtubules (MT), and intermediate filaments (IF) cytoskeleton in animal cells versus plant cells animal cells: MF, IF, and MT plant cells: MF and MT describe MF crawling movement mediated by the interaction of myosin motors and microfilaments and the alternate polymerization and depolymerization of MF in different regions of the cytoplasm what type of IF forms the nuclear lamina? lamin describe the microtubule cytoplasmic tubules from the centrosome a positive end (growing tip) and a negative end near the centrosome or MTOC what moves to the POSITIVE end of MT? kinesins what moves to the NEGATIVE end of MT? dyneins what are motor proteins? (in terms of energy) ATPases in cilia and flagella, what do MT do? function in the movement of appendages (in attached cells, they move fluid over tissue. in unattached cells, they move cells form one place to another) what are the most abundant glycoproteins in the extracellular matrix of animal cells? collagen fibers what are the similarities between mitochondria and chloroplasts? they both are energy transformers of the cell, enclosed in membranes but not part of the rest of the cell's endomembrane system, they are semiautonomous, and the cell location is not fixed what is present in all eukaryotic cells? mitochondria what contains the genetic library of eukaryotic cells? the nucelus what does the synthesis of mRNA? chromatin (directly outside of nucleolus) what does the synthesis of rRNA? nucleolus what are nuclear pores composed of? nucleoporins what allows substances to travel through the pores of the nucleus? the substances that have the "nuclear localization signal" tags what is the difference between free and bound ribosomes?