EEMB 157 Midterm 1 Questions with Correct Answers What is the relationship between eukaryotes and archea? - Correct Answer Eukaryotes evolved from a shared common ancestor with bacteria. Although there is a big distinction between the two since archea are still technically considered prokaryotes since they have no true nucleus What is the general Endosymbiotic Theory? - Correct Answer it is the theory the both the mitochondria and chloroplasts evolved from cyanobacteria that the proto-eukaryotic cell "engulfed" and developed a mutual symbiotic relationship What are some examples of the missing link between the Domain Archea and the Domain Eukarya? - Correct Answer Scientist discovered the asgard archeaum which had eukaryotic signature proteins encoded in the archea genes What have scientist discovered that proves that the Endosymbiotic Theory happened but not in the ways that they might have thought? - Correct Answer They discovered that some asgard archea did it through syntropy. They theorize that the proto-eukarya and the cyanobacteria found each other and began sharing each others nutrients What are some things that influence a cells size or shape? - Correct Answer A cell's shape or size can differ between species, within a multicellular organism or even in under different conditions (E. coli having a different growth rate under different conditions) What are some ways as to why a cell size matters? - Correct Answer Their surface area matters, cellular transport requires a constant speed. Diffusion is key ultimately diffusion will ultimately influence the size of the cell What are actin filaments? - Correct Answer Occur in bundles or mesh like networks that interact with motor proteins such as myosin and kinesin How can a cell with a large vacuole overcome diffusion limitation? - Correct Answer they have parts of the cell that are everywhere making up what looks like little neighborhoods, other times cells will have lots of DNA or even an invagination of the cell membrane that brings bits of the outside into the cell How does Thiomargarita magnifica differ from other bacteria cells? What other prokaryotic cell does something similar? - Correct Answer Most bacterial cells do ETC on the cell membrane but in this particular bacteria it is centered around an almost nucleus. Asgard Archea also do something similar 1 / 2
What is the Gibbs free energy for catabolism? - Correct Answer Delta G is negative as catabolism releases energy, is exothermic, and is spontaneous What is the Gibbs free energy for anabolism? - Correct Answer Delta G is positive as anabolism requires energy, is endothermic and is non-spontaneous In phosphorylation of DNA , what are some issues that might be encountered? - Correct Answer Due to their being a lots of electronegative oxygens, the kinase could have trouble as its very crowded Why is magnesium ions used in phosphorylation? - Correct Answer They are used to help stabilize the extremely electronegative oxygens, they are also cofactors because they facilitate the transfer of phosphate groups since their positive charge interacts with ATP What do enzymes give the cell? - Correct Answer They speed up a rxn causing the cell to be more efficient. They allow the cell to decide where, when, and what rxns occur (they give them control) What do enzymes do in biochemical pathways? - Correct Answer They essentially get the ball rolling allowing for the cell to determine which biochemical pathway it'll follow based on the outside environment What are prosthetic groups? - Correct Answer similar to cofactors, but they are bound to the enzyme, rather than being separate molecules or atoms making them more permanent. An example is biotin What are lysozymes? - Correct Answer Enzymes that hydrolyse the cell walls of certain bacteria specifically peptidoglycan Why is peptidoglycan such a strong molecule? - Correct Answer Cross-linking by peptide bonds and glycosidic bonds between amino acids in the layer of peptidoglycan forms a strong mesh-like structure that provides structure to the cell What is Vmax? - Correct Answer Maximum rate of reaction when all the enzymes are satruated with substrates
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