You are interested in examining the different kinetics of two isozymes of malate dehydrogenase (MDH). Isozymes are two similar enzymes that catalyze the same reaction but are from different genes or splice variants, giving them different properties. One of the MDH isozymes is located in the mitochondria, whereas the other is located in the cytoplasmic fraction. Your goal is to simply separate the two isozymes and test the samples in the partially purified state. Your research partner has centrifuged the cell extract at 10,000g for 10 minutes, but is not sure which fraction (pellet or supernatant) contains MDH. What should you tell your research partner?A. The pellet contains the heavy proteins, and MDH will be found in that fraction. B. Both the pellet (mitochondrial MDH) and the supernatent (cytoplasmic MDH) contain MDH. C. The pellet contains only the nuclear fraction, and thus both mitochondrial and cytosolic MDH proteins are still in the supernatant. D. The pellet has both the nuclear and the mitochondrial fractions, and thus the preparation is ruined.

Match the descriptions / definitions with the term they best describe 1. three dimensional relationship of the different polypeptide chains in a multisubunit protein or protein complex 2. common folding pattern in proteins in which a linear sequence of amino acids folds into a right-handed coil stabilized by internal hydrogen-bonding between polypeptide backbone atoms. 3. the amino acid sequence of a protein 4. a region on the surface of a protein that can interact with another molecule through noncovalent bonding. 5. three-dimensional arrangement of alpha-helices and beta-sheets within a single polypeptide, typically stabilized by a variety of noncovalent bonds, including ionic and hydrogen bonds, and nonpolar interactions / hydrophobic force. 6. the chain of repeating carbon and nitrogen atoms, linked by peptide bonds, in a protein. 7. common structural motif in proteins in which different sections of the polypeptide chain run alongside each other and are joined together by hydrogen bonding between atoms of the polypeptide backbone. 8. portion of a polypeptide chain that has a discrete tertiary structure of its own and can often fold independently of the rest of the chain 9. regular local folding patterns in a protein, including alpha-helix and beta-sheet a. primary structure b. beta-sheet c. protein d. coiled-coil e. polypeptide backbone f. secondary structure g. side chain h. tertiary structure i. binding site j. alpha-helix k. quaternary structure l. protein domain

Select the situation bellow that would produce a total displacement of zero. a. a trip to the moon and then to mars b. a horse galloping from one end of a field to another c. the criss-crossing path of a bug as it flies from flower to flower d.a round-trip ride to school and back

Which feature of a human community is similar to a niche in a biological community