BIO 220 FINAL EXAM 2024 WITH VERIFIED SOLUTIONS.

MHC II Proteins are found on what type of cells? Professional Antigen Presenting Cells Molecular Koch's Postulate are important for identifying: A gene involved in virulence Brainpower Read More Previous Play Next Rewind 10 seconds Move forward 10 seconds Unmute 0:01 / 0:15 Full screen Based on what we've discussed, why do you think you are supposed to get a flu shot each year? -Epitopes of flu strains are highly variable on an animal basis -No cross protection exists between flu strains Where do Antigen Presenting Cells Migrate to interact with B and T-Cells? Lymph Node What happens when your innate immune system doesn't recognize body cells as being "self"? Autoimmune Disorders Having an infected mosquito bite would result in: Acute inflammation Which part of our immune system do you think evolved first? Innate Why are gnotobiotic mice used in the above microbiome experiments? Don't want host microbiome to influence results Vibrio cholerae are: associated with copepod egg cases How does Iron make its way to the middle of the Atlantic Ocean? Winds from Africa carrying dust Dead zones in the GOM are mainly due to: High BOD that causes hypoxia In contrast to catabolism, biosynthesis always requires phosphorous. energy. glucose. the TCA cycle. nitrogen gas. Energy Mechanism(s) by which microorganisms minimize biosynthetic energy cost is A. genome loss and cooperation. B. regulation of gene expression. C. lithoautotrophy Both A and B are correct Both B and C are correct A. genome loss and cooperation. B. regulation of gene expression. The ________ pathway is utilized for carbon fixation in chloroplasts and cyanobacteria. acetyl-CoA Calvin cycle reverse TCA cycle glycolosis 3-hydroxypropionate cycle Calvin Cycle The structures marked with arrows in the following photo are ________ and are used to ________. carboxysomes; concentrate bicarbonate or carbon dioxide along with Rubisco Given what you know about nitrogen fixation and molecular regulation, the presence of which of the following molecules in the culture medium of a nitrogen fixing microbe would lead to decreased expression of nitrogenase genes? carbon dioxide. nitrogen gas. ammonium. FeMo protein. ammonium How many ATP equivalents are used in the enzymatic conversion of N2 to NH3? 16 64 28 None; only GTP is used. 48 28 ________ prevent transcription, whereas ________ stimulate transcription. Activators; repressors Regulators; repressors Inducers; corepressors Repressors; activators Corepressors; inducers Repressors; activators A feature common to all control mechanisms is quorum sensing. phosphorylation cascades. the sensing of a change to something inside or or outside the cell. housekeeping enzymes. increased or decreased gene expression. the sensing of a change to something inside or or outside the cell. In a two-component signal transduction system, a ________ is transferred from a sensor kinase to a ________ in response to an environmental signal. phosphate; sensor domain magnesium; sensor domain phosphate; sensor phosphatase magnesium; response regulator phosphate; response regulator phosphate; response regulator The following figure shows a regulatory protein being produced on the left. Based on the information in the figure, this protein must function in which of the following ways? When glucose binds to it, the protein binds to the regulatory sequence and prevents transcription of the target gene. This protein must influence a hairpin sequence and thus fine tunes the operon. In the presence of the end product of the operon, this protein will bind to the regulatory region and acts as an activator. It is unclear from this diagram if this regulatory protein acts as an activator or repressor. This protein would not have an effect on transcription of the target gene. It is unclear from this diagram if this regulatory protein acts as an activator or repressor. One benefit of operons in bacteria is that they allow for alterations in DNA sequence by flipping promoters around. allow for coordinated gene expression of related genes because they are all under the control of a single promoter. do not need ligands and regulatory proteins as single genes would. do not need any modification of the proteins after they are expressed. allow the bacteria to use a wide variety of carbon sources. allow for coordinated gene expression of related genes because they are all under the control of a single promoter. If a cell always needs a gene to be expressed for essential "day to day" maintenance purposes, the gene is most likely going to be ________ expressed. constitutively. derepressibly. inducibly. promotable. repressibly. constitutively. Inverted repeated sequence within 100-200 bases of a promoter suggests the presence of a ________ binding site which can be bound by a regulatory protein. DNA ribosome transcriptional regulator corepressor RNA transcriptional regulator The following image shows a bacterial growth curve. The curve represents ________ growth, which is caused by the ________. diauxic; growth on two carbon sources resulting in a lag after the preferred substrate is depleted; new genes are then induced and growth resumes The small amount of sigma H that is made at 30°C is shuttled by the DnaK/GrpE/DnaJ chaperones and subsequently ________ by enzymes. enhanced protected activated folded degraded degraded Which reservoir is in steady state or imbalance: A is in Steady State, B is imbalanced The best description of the initial step in the regulatory process shown below is a sigma factor mRNA is transcribed and forms secondary structures at lower temperatures. When heated, the structures melt and the mRNA for the heat-shock sigma factor, rpoH, can be translated. In an inducible operon (ie: lac operon), the inducer binds to a ___________. operator region. promoter region. enhancer region. corepressor molecule. repressor protein. repressor protein A co-repressor binds to a(n) ________ and causes it to ________ DNA. operator region; bind promoter region; release from activator protein; release from inducer molecule; release from aporepressor protein; bind aporepressor protein; bind A means of communication and coordinated action among bacteria when sufficient numbers are present is called two-component regulation. induction of activation. quorum sensing. phase variation. targeted sigma release. quorum sensing Which of these is involved in commercial chemical fertilizer production? lightning strikes nitrification the Haber-Bosch process denitrification cellular nitrogen fixation the Haber-Bosch process Which of the following is NOT a pathway used by microbes for carbon fixation: Calvin cycle Reverse TCA Cycle Acetyl CoA Pathway Krebs Cycle All of the above cycles are used by microbes for carbon fixation Krebs Cycle Which is the most extreme/ dramatic approach to minimizing energy usage related to cellular life processes: Molecular regulation Genome Loss and reliance on other microbes Competition and Predation Genome Loss and reliance on other microbes Where does the reducing power come from to enable the biosynthesis reactions in the Calvin Cycle? FADH2 from the TCA cycle NADH from the TCA cycle NADPH from the "light reactions" of photosynthesis GTP NADPH from the "light reactions" of photosynthesis The habitat, available resources, and interactions with other species in an ecosystem must be considered when determining the _______ of an organism. Environment Population Niche Community Niche Spatial orientation of different strains of microbes in a particle of organic matter FISH Count and sort cells based on size Flow Cytometry Determine "who" is using a substrate of interest Stable Isotope Probing Determine how fast a substrate is being consumed or produced Radioisotopes Determine which types of bacteria are in a sample 16S rRNA analysis two different organisms can survive on their own, but grow best in the presence of one another synerism one organism benefits and the other neither benefits nor is harmed (lion and vulture) commensal one organism benefits and the other is harmed (tapeworms) Parasitism one organism is harmed and the other is not harmed nor benefitted amensal both organisms rely on the other and may not be able to grow without the other (ie: lichen) mutualism What is a limitation of metagenomics? How do metatranscriptomics and metaproteomics address this limitation of metagenomics and provide the researcher with a better understanding of the processes being carried out by microbes in the sample of interest? Metatranscriptomics, the study of the RNA transcripts (or RNAseq) obtained from an environmental community, and metaproteomics, the study of proteins synthesized by environmental samples, both identify genes that are actually expressed by the target community. These techniques address a major limitation in metagenomics regarding the actual function of microbes in the environment. Explain how a repressor protein works with respect to a biosynthetic operon. What is generally the corepressor of a biosynthetic operon? Give an example of a biosynthetic operon we talked about in class. When the end product of the biosynthetic operon is high, the cell does not need those enzymes. Thus, the end product will bind to the inactive aporepressor and become an active repressor protein, which will shut down the transcription of the genes. As the end product gets low, there is not enough to bind to the aporepressor; thus, there will be no repression, and transcription of the needed genes will occur. As complexity increases, the cell is said to decrease in ________, or disorder. size pH enthalpy entropy Gibbs free energy entropy