Question 1. transposons: “jumping genes,” DNA segments that move around in the genome providing genetic variation. Lytic cycle: replicating genome of virus constantly to make new virus cells until bacterium bursts and releases new viruses. To make viral protein, it must first be converted into a positive sense RNA virus. The main components of prokaryotic cells that we’ll discuss are the cell membrane and cell wall, the propulsion mechanism, ribosomes, and DNA. Lysosomes can be thought of as a garbage disposal machine, which takes in unwanted items and breaks them down in a way that makes the molecules easier to dispose. Answer choice A is correct. Instead, its main function is the synthesis of lipids, particularly phospholipids that are part of the cell membrane. The question is asking which mechanism is used for the virus to enter the cells. There are 3 main components of the cytoskeleton that you should be familiar with: microfilaments, microtubules, and intermediate filaments. Binary fission occurs rapidly, and as a result, bacteria tend to grow exponentially. At 7 days post infection (dpi), the percentage of infected mosquitoes (a) and viral titers in the bodies (b) were determined to serve as indicators of the infection rate and of initial viral replication. Intermediate filaments: polymers of filament monomer for structural support and cellular adhesion; keratin is prominent example. The fact that prokaryote DNA is circular is an important distinguishing factor between prokaryotes and eukaryotes, and this is an important distinction to remember when reading MCAT passages. This means that the sedimentation is related to the ribosome’s mass, and a larger mass particle taking longer to sediment. Lag phase: before cells start growing and reproducing, they have to start the process, and little growth happens, Log phase: exponential growth of bacteria due to quick nature of binary fission, Stationary phase: peak of exponential growth, population size levels off due to absence of certain resources needed to reproduce further. No Related Subtopics. Which of the following are likely characteristics of the bacterial colony? The cis golgi is the side facing the RER, and the trans golgi faces the cell membrane (choice D is incorrect; choice B is correct). As a result, based on the tenets of cell theory mentioned earlier, they are not considered to be living on their own. Choice C wouldn’t apply to any type of bacteria. So, let's look at how this protein was created. Transposons, sometimes called jumping genes, are a specific class of DNA segments found in both prokaryotic and eukaryotic DNA capable of moving around within the genome. This finding has led to the endosymbiotic origin hypothesis, which suggests that mitochondria derived from an aerobic prokaryotic cell that was engulfed by another cell and formed an endosymbiotic relationship. It then says retroviruses have plus-strand RNA. Nerve impulse —The self-propagating change in electrical potential across the axon membrane. Viruses under the double stranded RNA classification must also be converted to a positive sense single stranded RNA virus before it … Researchers first generated mutant viruses deficient in production of sfRNA isoforms by introducing point mutations that abolish XRN-1 resistance into each or both xrRNAs (xrRNA1 and xrRNA2) of ZIKV. Compared to other cell types, viruses lack a nucleus and organelles. Cells are the building blocks of organisms, and similarly, they are an integral component of biology on the MCAT. Negative-strand (NS) RNA viruses encompass some of the most significant human and agricultural pathogens extant. Peptidoglycan contains cross-linked chains of sugars and amino acids. 7. Negative-sense (3′-to-5′) viral RNA is complementary to the viral mRNA, thus a positive-sense RNA must be produced by an RNA-dependent RNA polymerase from it prior to translation. Additionally, there are other structural differences between prokaryotes and eukaryotes that help antibiotics target bacteria specifically. PRACTICE QUESTIONS. Answer choice D is correct. Obligate anaerobes are organisms that require the absence of oxygen as oxygen is toxic for them. Positive sense RNA viruses are single stranded RNA viruses whose RNA can function as a template for mRNA synthesis which in turn leads to protein synthesis from that mRNA. As a result, aerobes use the cell membrane for aerobic respiration. ... 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