WGU Biochemistry Questions and Answers All Verified and Rated A+

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WGU Biochemistry Questions and Answers All Verified and Rated A+ A risk factor associated with the use of metformin in the treatment of diabetes is lactic acidosis. Acidosis is associated with [a d... ecrease] in blood pH, due to [an increase] in the concentration of hydrogen ions (H+). Given this change in blood pH, hemoglobin is more likely to [release] oxygen. Correct Answer- Acidosis is associated with a decrease in blood pH, due to an increase in the concentration of hydrogen ions (H+). Given this change in blood pH, hemoglobin is more likely to release oxygen. A small segment of Kevin's green opsin gene is shown below. What would be the resulting mRNA sequence? Kevin's opsin gene at nucleotide positions 936 to 941. 5'-G.C.C.T.A.G-3' (coding strand) 3'-C.G.G.A.T.C-5' (template strand) c. 5'-GCCUAG-3' Correct Answer- This sequence is the same as the coding sequence, and the "T" bases have been replaced with "U", as is found in RNA. A substrate binds to an enzyme at a specific site, referred to as a(n)_________________. b. Active site Correct Answer- The active site of an enzyme is the site where the substrate specifically binds to the enzyme and the reaction is carried out. Acetyl-CoA, a central molecule in metabolism, is produced in the mitochondrial matrix. However, it is used for the synthesis of fatty acids in the cytosol. The transport of the acetylCoA from the matrix to the cytosol occurs by the conversion of acetyl-CoA to_______________.a. citrate Correct Answer- Acetyl-CoA combines with oxaloacetate to produce Citrate. Note that citrate is the first product produced in the citric acid cycle by the same reaction. Cells have the ability to mobilize citrate across the mitochondrial membrane. Thus, acetyl-CoA moves out of the mitochondria to the cytosol in the form of citrate. Once in the cytosol, the citrate is converted back to oxaloacetate and acetyl-CoA, and acetyl-CoA is utilized in fatty acid synthesis. Addition of ______________________alters the shape of the iron-heme complex, and therefore its absorption of light as indicated by its color change from dark purple (the color of hemoglobin in venous blood) to brilliant scarlet (the color of hemoglobin in arterial blood). c. oxygen Correct Answer- Oxygen binding alters the shape of the iron-heme complex, and therefore its light absorption properties as indicated by a color change. Aerobic respiration requires oxygen. Oxygen has a role in which of the following pathways: b. Electron transport chain Correct Answer- Gluconeogenesis is building of new glucose molecules and is not involved in aerobic respiration. Oxygen has a role as the terminal electron acceptor in the electron transport chain. After consultation with a genetic counselor and an examination of extended family history, the following pedigree was generated. Who did Kevin most likely inherit this mutation from? a. Maternal grandfather Correct Answer- Red-green color blindness occurs more frequently in males than females because these genes are located on the X chromosome, and males inherit only one X chromosome and will express whatever alleles are on that chromosome. Females, on the other hand, inherit two X chromosomes, and thus have two alleles for each gene. If one of the alleles is mutated on one X chromosome, there is usually a correct allele on the other that can provide the needed gene. A woman must have two mutated opsin alleles to be color blind, while men need only one. This is known as sex-linked inheritance. Kevin inherited his Y chromosome from his father and his X chromosome from his mother, so his X chromosome with the defective opsin gene most likely came from his maternal grandfather and was passedto him by his mother. Thus, both grandfathers is not correct because his paternal grandfather would have contributed a Y chromosome. After learning about Alzheimer's disease and one of the drugs used in its treatment, what other drug design strategies could you use to offer a treatment for AD? a. Drugs that block the production of amyloid beta peptide b. Drugs that break up the amyloid plaques d. Drugs that inhibit the aggregation of protein structures Correct Answer- The more we are able to understand the molecular details of a disease and the enzymes involved in the disease pathway, the more opportunities one has to target the key molecules. Any of the options here could be a possible treatment in the case of AD. Alzheimer's disease is caused by aggregation of the Amyloid beta peptide and tangle formation by the tau protein. What kinds of amino acids are likely to drive the formation of these protein aggregates? c. Hydrophobic Correct Answer- Hydrophobic amino acids strive to avoid water and like to interact with other hydrophobic amino acids. Generally they are found in the interior of a protein. But, when there are too many misformed peptides with exposed hydrophobic surfaces, they tend to attract each other and result in protein aggregation. As carbon monoxide binds to hemoglobin, the protein subunits change conformation to allow carbon monoxide to bind faster. This process is called __________. d. positive cooperativity Correct Answer- Carbon monoxide does competitively inhibit the overall function of the hemoglobin protein. Note that the question is referring to how the binding of one carbon monoxide molecule influences the conformation of the other subunits and increases the overall binding affinity for the hemoglobin molecule. Such a cooperative behavior exhibited by the subunits is referred to as positive cooperativity.Below is a diagram of the four steps of the beta oxidation cycle. Drag the correct small molecule to the step in the pathway to which it contributes. Correct Answer- The four steps of beta oxidation each involve a small molecule other than the fatty acid in the process, as shown below: Below is a schematic showing the synthesis and degradation of acetylcholine, an important neurotransmitter. If you were to design a drug to keep the acetylcholine concentration high, where would you target a drug inhibitor? b. Acetylcholinesterase Correct Answer- Acetylcholine is the substrate of the reaction and the desired chemical to preserve. However, since acetylcholine does not control its own production, it is ideal to target enzymes that can impact its concentration. Enzymes that produce acetycholine could be targeted for increased production, but this type of regulation is difficult to achieve with a drug. Instead, drugs usually inhibit specific enzymes. Acetylcholinesterase is the enzyme which digests acetylcholine to acetate and choline. Acetylcholinesterase inhibition will decrease degradation of the acetylcholine, which will therefore increase the concentration of acetylcholine. Supplementation with excess acetate or choline may also help increase choline acetyltransferase activity and perhaps increase acetylcholine concentrations, but the only productive target for a drug inhibitor in this scheme is acetylcholinesterase. Beta oxidation of a C14 fatty acid will make_______________ acetyl-CoA units after________ rounds of beta-oxidation. a. seven, six Correct Answer- Each round of beta-oxidation results in the production of a twocarbon acetyl-CoA units, so the number of carbons in a fatty acid chain divided by two is how many acetyl-CoA units are made. The number of rounds needed is one less than the number of acetyl-CoA units produced because the last round of beta-oxidation produces two acetyl-CoA units. Thus, a C14 fatty acid will altogether make seven acetyl-CoA units after six rounds of beta oxidation. Blood type is an example of what type of inheritance?a. Codominance Correct Answer- The genes that produce the A and B antigen proteins can both be expressed independently, and a heterozygote (someone with both genes) will be produce both A and B proteins - neither will dominate the other. The is an example of codominance. Carbohydrate loading is a common practice among endurance athletes. Often, three days before a big endurance event, they are known to eat large amounts of complex carbohydrates which leads to the storage of glycogen in their muscles. The stored glycogen increases their endurance by providing a steady supply of glucose during the event by the process of _______________. d. glycogenolysis Correct Answer- Glycogenolysis is the breakdown of glycogen to release glucose. A further breakdown of glucose results in ATP production which helps with the prolonged physical activity in the athletes. Carbon monoxide outcompetes oxygen for attachment to the __________ group of hemoglobin where it is permanently, covalently attached. d. heme Correct Answer- Carbon monoxide has a higher binding affinity than oxygen to the heme group of hemoglobin. Such binding is irreversible. Carbon monoxide shifts the Oxygen-Hemoglobin Dissociation Curve to the left, while carbon dioxide shifts this curve to the right. Based on your knowledge of the Bohr Effect, which of the following statements is true? b. Carbon dioxide decreases hemoglobin's affinity for oxygen, while carbon monoxide increases it Correct Answer- Carbon dioxide, released by the respiring cells, combines with the water molecules of plasma to form carbonic acid. Carbonic acid increases the H+ ion concentration (low or acidic pH). H+ ions stabilize the deoxy-conformation (T state) of hemoglobin and allow oxygen release and delivery to the tissues. On the other hand, carbon monoxide, which has a very high affinity for hemoglobin than oxygen, binds and maintains hemoglobin in oxyconformation (R state). Oxy-conformation of HB is amenable to further binding of carbon monoxide and shifts the Oxygen-Hemoglobin Dissociation Curve to the left. [Show More]

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