Adaptive Immunity and Cellular Processes, Exams of Nursing

Download Adaptive Immunity and Cellular Processes and more Exams Nursing in PDF only on Docsity! AAMC FL 5 B/BC Adaptive immunity specific Two types of adaptive immunity Humoral immunity- B cells regulating antibodies Cell Mediated Immunity- T cells regulating innate immunity non-specific phosphodiester linkage covalent bonds that join adjacent nucleotides between the -OH group of the 3' carbon of one nucleotide and the phosphate on the 5' carbon of the next disulfide bonds 2 cysteine residues can covalently bond to form disulfide bonds which hold together tertiary structures if sufficient cysteine residues are available. Heat can disrupt these bonds Hydrogen bonds hold base-pairing nucleotides together, not nucleotides within a backbone. Glycosidic linkages bind carbohydrates together pI pI is the pH at which the overall charge is neutral - A matches this definition for NqrD, since equal cationic and anionic functional groups would cancel out to 0 net charge. At a pH greater than the pI, you can think of it as there being relatively low proton concentrations in the environment, so the molecule is deprotonated (more negative). Conversely, at a pH lower than the pI, you can think of the environment as being relatively highly concentrated in protons, so the molecule is more protonated (more positive). Ionophores Ionophores are compounds that bind to ions and facilitate their movements across membranes. succinate dehydrogenase succinate to fumarate FAD to FADH2 Isoelectric focusing separates proteins based on their pIs. The technique uses an electric field and a pH gradient which causes proteins to stop moving at a pH equal to their pI. Southern blotting Southern blotting is a technique to identify specific DNA fragments and does not require a pH gradient. Where is the active site located? on the enzyme Substrate similarity and active site binding are classical features of which inhibitor? competitive inhibitor Pain reflex arcs Pain reflex arcs integrate with the CNS at interneurons around the spinal cord Roman numeral I represents the dorsal root ganglion. Roman numeral II represents an interneuron, which serves as an intercommunication point for the afferent and efferent neurons within the CNS. Roman numeral III represents the ventral root. Roman numeral IV represents the effector muscle. refers to the difference in charge distribution on opposing sides of a cell membrane membrane potential Resting membrane potential is a result of The resting potential of a neuron is primarily a result of the Within a neuron, the resting potential is determined by is a result of differential ion concentrations maintained by leak channels and Na+/K+ ATPase. Within a neuron, the resting potential is determined by the normal, uneven distribution of ions between the outside and the inside of a cell. Contraction of the diaphragm results in Diaphragm contraction results in increased thoracic volume and reduced intrathoracic pressure, which causes inhalation. Diaphragm contraction results in flattening of the diaphragm "dome", and serves to increase the intrathoracic volume and reducing intrathoracic pressure - this results in airflow into the lungs - inhalation. In an enzyme-catalyzed reaction where enzyme concentration is held constant and substrate concentration is relatively low, which kinetic parameter will increase with the addition of more substrate? (Note: Other than substrate concentration, assume no other changes to reaction conditions.) A. KM B. kcat C. Vmax D. V0 These describe Michaelis Menten Kinetics - A/B/C are inherent immutable properties of a substrate- enzyme interaction that do not change with substrate concentration. However, the more substrate there is initially, the more enzymatic reactions that will occur (V0 increase). A) KM, the rate constant of a reaction, does not change with changes in substrate concentration. B) Kcat is the reaction turnover number and does not change with changes in substrate concentration. C) Vmax is the maximum velocity of a reaction and is a constant property which does not change with the addition of more substrate. D) V0 is the initial velocity of an enzymatic reaction. At low concentrations of substrate and constant enzyme concentration, adding more substrate will increase V0 until the maximal velocity is reached. You'll notice that as you increase the substrate concentration, the reaction velocity gets ____. You'll notice that as you increase the substrate concentration, the reaction velocity gets faster. It rises quickly until you start to approach Vmax at which point, the rate increase slows down and asymptotically approaches Vmax. This is because all the active sites on the enzymes are flooded with substrate. Meaning, it doesn't matter how much substrate you continue to add if all the active sites are already full. Substrate is no longer the rate limiting agent, enzyme is. At this point, we call the enzyme saturated because at that substrate value and higher, there are no available active sites. They are all fully saturated with substrate and as soon as product is formed and released, free excess substrate fills the spot. Conserved regions of the genome are due to these regions being critical for survival and fitness A particular diploid organism is heterozygous in each of 3 unlinked genes. Considering only these 3 genes, how many different types of gametes can this organism produce? Types of gametes = 2 to the power of n where n is the number of heterozygous loci. Answer: 8 if this organism is heterozygous for 3 independent/unlinked genes, then their genotype is aA, bB, cC. Each gamete they produce can inherit one allele of each gene - there are 2 possibilites for gene 1, multiplied by 2 possibilities for gene 2, multiplied by 2 possibilities for gene 3 result in 8 total unique gamete genotypes (abc,Abc,aBc,ABc,abC,AbC,aBC,ABC) https://www.youtube.com/watch?v=5YjOlgXIi9E&t=2s&ab_channel=biologyexams4u Heterozygous An organism that has two different alleles for a trait means produce 2 types of gametes for ex, Aa can produce A gamete and a gamete, forming two gametes during independent assortment How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCdd? possible no. of gametes = 2^n , where n is the number of heterozygous gene pairs there are two heterozygous gene pairs (Aa and Bb) so, 2^2 = 4. We have an expert-written solution to this problem! AAMC FL 1 alternative splicing Alternative splicing is a process that occurs during gene expression and allows for the production of multiple proteins (protein isoforms) from a single gene coding. Alternative splicing can occur due to the different ways in which an exon can be excluded from or included in the messenger RNA. It can also occur if portions on an exon are excluded/included or if there is an inclusion of introns. Alternative splicing allows for the production of multiple proteins based on whether exons are included or omitted adhesion proteins major families of cell adhesion receptors and define them allow cells to bind to other cells or surfaces Major families of cell adhesion receptors: cadherins, selectins, ig superfamily, integrins Cadherins are calcium dependent glycoproteins that hold similar cells together Integrins have two membrane-spanning chains and permit cells to adhere to proteins in the extracellular matrix Selectins allow cells to adhere to carbohydrates on the surface s of other cells are most commonly used in the immune system Adhesion proteins are glycoproteins that mediate cell-cell connections. They're found on the membranes of cells and interact in the space between the cells, holding the membranes together. Adhesion proteins act in binding with other cells or with the extracellular matrix, not protein folding chaperone proteins Chaperone proteins assist in folding parts of a protein function to stabilize and refold proteins which are functions of chaperone proteins. facilitates proper protein folding and inhibits the formation of nonfunctional protein aggregates. Proteins that perform this function are chaperone proteins Clathrin works to form vesicles to assist in transport within cells Clathrin functions in formation of vesicles for intracellar trafficking transmembrane proteins A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta- barrels) can be also extracted using denaturing agents. Transmembrane proteins require specific modifications that occur in the rough enodplasmic reticulum. reabsorbs ions, water, and nutrients; removes toxins and adjusts filtrate pH descending loop of henle reabsorption of water aquaporins allow water to pass from the filtrate into the interstitial fluid ascending loop of henle Portion of the nephron not permeable to water. A filtrate flows up the ascending limp through decreasing concentration of the interstitial fluid, Na+ is actively pumped out of the filtrate, decreasing filtrate concentration. reabsorbs Na+ and Cl- from the filtrate into the interstitial fluid distal tubule selectively secretes and absorbs different ions to maintain blood pH and electrolyte balance collecting duct reabsorbs solutes and water from the filtrate The collecting duct system can be divided into _____ and ______ ducts. The collecting duct system can be divided into cortical and medullary ducts. Cortical ducts will receive filtrate and filtrate will descend into medullary collecting ducts. The medullary portion of the collecting duct is the latter portion and the answer choice where glomerular filtrate reaches its highest concentration. glomular filtration Non selectively moves water, ions, and solutes from blood into the Bowman's Capsule. Glomerular filtrate is at its highest concentration near the bottom of the loop of Henle before the ascending loop, and again before it's excreted as urine. Na+/K+ ATPase Measuring the activity of the Na+K+ ATPase is an enzyme that functions to bring two K+ ions into the cell while removing three Na+ ions per ATP consumed - measuring the rate of ATP hydrolysis: If we have more ATP hydrolyzed, theres more Na+K+ ATPase activity -measuring the rate of ADP production: If we have a higher rate of ADP production, it is because we have increased Na+K+ ATPase activity. More ATP is being used and more ADP is being produced. - measuring the change in ion concentration within the liposome: Na+K+ ATPase is an enzyme that functions to bring two K+ ions into the cell while removing three Na+ ions per ATP consumed What is the function of the Na+K+ ATPase during a neuronal action potential? Restoration of the resting potential K+ channels close, and the Na+/K+ transporter restores the resting potential. K+ channels close, and the Na+/K+ transporter restores the resting potential. Were forcused near the bottom right of the figure. the K+ channels close, and the Na+/K+ transporter restores the resting potential. The restoration and maintenance of the resting potential relies on Na+/K+ ATPase. This is achieved by moving three Na+ out of the cell for every two K+ ions that are brought into the cell. stimulation of the AP A stimulus from a sensory cell or another neuron causes the target cell to depolarize toward the threshold potential. If the threshold of excitation is reached, voltage gated Na+ channels open, and the membrane depolarizes. Hyperolization of the membrane At the peak action potential, K+ channels open and K+ begins to leave the cell, At the same time, Na+ channels close. The membrane becomes hyperpolarized as K+ ions continue to leave the cell. The hyperpolarized membrane is in a refractory period and cannot fire. In which direction does the Na+K+ ATPase transport ions across the cell membrane upon ATP hydrolysis? Upon ATP hydrolysis, three Na+ are transported outside the cell and two K+ are transported inside the cell against their concentration gradient. Transcription factors bind to DNA The initial filtration step in the glomerulus of the mammalian kidney occurs primarily by A. passive flow due to a pressure difference. B. passive flow resulting from a countercurrent exchange system. C. active transport of water, followed by movement of electrolytes along a resulting concentration gradient. D. active transport of electrolytes, followed by passive flow of water along the resulting osmolarity gradient. A) There are three pressures that work together to regulate filtration in the glomerulus: glomerular capillary pressure, capsular hydrostatic pressure, and blood colloid osmotic pressure. The glomerular capillary pressure will force filtrate from a capillary into Bowman's capsule; the other two forces promote movement of the filtrate in the opposite direction. The first step of the formation of the urine is glomerular filtration in the glomerulus. The glomerulus is the site in the nephron where fluid and solutes are filtered out of the blood to form a glomerular filtrate. The process of glomerular filtration filters out most of the solutes, particularly large solutes like proteins, due to the high blood pressure and specialized membrane in the afferent arteriole. B) It is not a countercurrent exchange system; it is the difference in pressures that regulates the formation of the filtrate. C) Water is not actively transported from the glomerulus into Bowman's capsule. D) Electrolytes are not actively transported from the glomerulus into Bowman's capsule. How are you able to change the chirality of a molecule ( ex. a chiral reactant is converted to an achiral product or vice versa) An isomerase (epimerase and racemase), not a decarboxylase, is capable of changing the chirality of a molecule. What molecule enters the Krebs cycle? Acetyl CoA What molecule enters glycolysis? glucose Mature erythrocytes contain (protein or DNA) that help transport oxygen. Protein Protein in circulating erythrocytes is needed to help transport O2 through the capillaries. Erythrocytes do not contain a nucleus at maturity. Instead erythrocytes contain hemoglobin, a protein that uses iron to carry oxygen. Erythrocytes - RBC or erythrocytes are specialized cells that circulate through the body delivering oxygen to other cells. - Erythrocytes are formed from stem cells in the bone marrow. - In mammals, these red blood cells are small, biconcave cells that, at maturity, do not contain a nucleus or mitochondria. - Mature erythrocytes are enucleated cells that do not contain DNA. Cells that are most important in the exchange of O2 between the blood and the surrounding tissues Endothelial cells Endothelial cells are the cells that are in direct contact with blood and the surrounding matrix so these are the cells that play the most important role in gas exchange. ECs form barriers between blood vessels and the surrounding tissues. Endothelial cells are specialized cells that allow the permeability of selective materials through the walls of the blood vessels. They also help in the movement of chemicals that facilitate in vasoconstriction and vasodilation, such as epinephrine. Smooth muscle cells responsible for involuntary movement and is found on the walls of major organs Fibroblasts are cells that generate any connective tissue that the body needs, as they move throughout the body and can undergo mitosis to create new tissues. The process of culturing bacteria often involves inoculation of cells on a noncellular, agar-based medium. Such a methodology would NOT result in growth of animal viruses because animal viruses: A. are obligate parasites. High cortisol levels (increase, decrease) gluconegogensis increase Gluconeogenesis Gluconeogenesis is the pathway for the synthesis of glucose (a carbohydrate) from other metabolic compounds such as lipids and amino acids. Therefore, this pathway is activated when the body's stores of carbohydrates are low. Glucose transporter proteins in the liver do not require the presence of insulin to facilitate the uptake of glucose. However, insulin does stimulate the first step in the glycolytic pathway within the liver. Therefore, in liver cells, insulin most likely: A. hinders glucose uptake by increasing the cellular concentration of glucose. B. aids glucose uptake by decreasing the cellular concentration of glucose. C. hinders glucose uptake by using the ATP needed by the glucose transporter proteins. D. aids glucose uptake by providing the ATP needed by the glucose transporter proteins. A) The question states that insulin stimulates the first step in the glycolytic pathway in the liver. This will result in a decrease of the cellular concentration of glucose. To compensate for the low cellular glucose concentration, glucose uptake is increased. Glycolysis is a metabolic pathway that occurs in the cytosol of cells and breaks down glucose into two three- carbon compounds and generates energy. Insulin stimulates gylcolysis in hepatocytes which leads to decreased cellular concentration of glucose. To compensate, hepatocytes need to increase glucose uptake. During the production of insulin, the translated polypeptide is cleaved into the mature form and secreted from the cell. The cleavage most likely takes place in which of the following locations? A. Nucleus B. Ribosomes C. Endomembrane system D. Cytoplasm The endomembrane system is the portion of the cells that is in charge of modifying proteins that will be secreted. Thus, it is most likely that insulin cleavage will occur in the endomembrane system. Diabetes symptom of diabetes mellitus - increased appetite - sweet-tasting urine - unexplained weight loss (the body uses proteins and lipids as a source of energy) - feeling of fatigue (might occur as the body uses aa and lipids as a source of energy) In diabetes, many tissues metabolize fatty acids as an alternative energy source and there is also protein degradation. Protein degradation means feeling fatigue, and the body is not accustomed to utilizing fatty acids and ketone bodies as an energy source so there may be feelings of fatigue. A certain bacterium was cultured for several generations in medium containing 15N, transferred to medium containing 14N, and allowed to complete two rounds of cell division. Given that the bacterium's genome mass is 5.4 fg when grown in 14N media and 5.5 fg when grown in 15N medium, individual bacteria with which of the following genome masses would most likely be isolated from this culture? A. 5.4 fg only B. 5.4 fg and 5.45 fg C. 5.4 fg and 5.5 fg D. 5.45 fg only https://www.youtube.com/watch?v=yDQg7uXShUs&ab_channel=QuickBiochemistryBasics https://jackwestin.com/resources/mcat-content/aamc-mcat-practice-exam-1-bb-solutions Q54 Assume that K and M are two unlinked genes that affect hearing. The dominant K allele is necessary for hearing, and the dominant M allele causes deafness regardless of the other genes present. Given this, what fraction of the offspring of parents with the genotypes KkMm and Kkmm will most likely be deaf? A. 1/4 B. 3/8 C. 1/2 D. 5/8 #58 https://jackwestin.com/resources/mcat-content/aamc-mcat-practice-exam-1-bb-solutions So I was reading over the answers and didn't really understand so I realized a way to explain it if you're more math brained. So the question, because the genes are UNLINKED, means that it is essentially asking what is the probability that we have "M" OR "kk" (not AND). So to solve these you use: p(A) + p(B) - p(A and B) Enzyme-linked receptors participate in cell signaling through extracellular ligand binding and initiation of 2nd messenger cascades Which of the following is an example of a ligand-gated ion channel? A) Voltage-gated sodium channel B) Voltage-gated potassium channel C) GABA-A receptor D) Na+/K+ ATPase C Which type of transmembrane protein is involved in the initiation of intracellular signaling pathways? A) Ion channels B) Transporters C) Enzymes D) Receptors Which type of transmembrane protein is responsible for maintaining the resting membrane potential in neurons? A) Ion channels B) Transporters C) Enzymes D) Receptors A