Download WGU BIOCHEMISTRY OA CERTIFICATION SCRIPT 2026 QUESTIONS WITH SOLUTIONS GRADED A+ and more Exams Biochemistry in PDF only on Docsity!
WGU BIOCHEMISTRY OA CERTIFICATION
SCRIPT 2026 QUESTIONS WITH SOLUTIONS
GRADED A+
◍ Lipid (fat) soluble vitamins. Answer: A, D, E, K ◍ Which complex polysaccharide acts as an energy storing molecule in the liver?. Answer: Glycogen ◍ Which type of mammalian DNA damage repair requires the presence of the chromosome that is homologous to the damaged chromosome?. Answer: Recombination ◍ F1. Answer: At which part of ATP synthase is ATP produced? ◍ 4. Answer: The urea cycle involves ___ reactions (only those in the cyclic portion of the process). ◍ cytochrome c. Answer: What protein shuttles electrons from complex III to complex IV? ◍ Glycogenesis. Answer: -store glucose as glycogen (short term storage)-in liver ◍ Which level of protein structure is disrupted through the hydrolysis of peptide bonds?. Answer: Primary ◍ What occurs during the biochemical process of glucation?. Answer: A covalent bond forms between a sugar and a protein or liquid.
◍ false. Answer: T/F: FADH2 yields 2.5 ATP molecules after donating electrons and hydrogen atoms to the ETC.
◍ Which molecule is replenished by fermentation?. Answer: NAD+
◍ ability to hydrogen bonds with water and its high density of nitrogen in a small molecule. Answer: Urea is useful for excreting nitrogen from cells due to its
◍ How would lipid production in a cell change in order to maintain fluidity of its cell membrane as it adapts to lower temperatures?. Answer: Produce lipids with shorter fatty acid chains
◍ ornithine. Answer: What amino acid is the following structure?
◍ Nucleotides. Answer: -contain one or more phosphates-a 5 carbon sugar and a nitrogen base-always in the 5' to 3' direction
◍ Quaternary structure. Answer: Large, functional protein structure composed or smaller proteins with multiple subunits.
◍ Ionic bond. Answer: Actions share + & - charge
◍ 2, 3, BPG. Answer: -produced in our body naturally-similar function to H+ (stabilizes the T state)-produced in 2 cases (high altitudes & pregnancy)
◍ 4. Answer: How many complexes are associated with the ETC?
◍ Quaternary Structure. Answer: -only some proteins will get here-2 or more subunits
shorter protein
◍ Which metal ion is bound to the porphyrin ring in hemoglobin?. Answer: Iron
◍ false. Answer: T/F: In the production of ATP via ATP synthase, the H+ ions move from the mitochondrial matrix to the intermembrane space.
◍ Acetyl CoA. Answer: -2 carbons-attached to coenzyme A (to make sticky we need biotin)
◍ What occurs during aerobic respiration?. Answer: NADH & FADH2 are produced from NAD & FAD during citric acid cycles.-NADH & FADH2 donate electrons to the ETC, re-engineering NAD & FAD.-O2 accepts electrons, producing water
◍ What is the function of DNA polymerase in the process of PCR?. Answer: It recognizes the primers and uses the available dNTPs to replicate the template DNA sequence.
◍ complex IV. Answer: At which complex does the following reaction take place?O2 + 4 e-
◍ What stimulates beta-oxidation of fatty acids?. Answer: An increase in NAD+ concentration in the mitochondrial matrix
◍ Hydrophobic effect. Answer: Tendency of non polar substances to aggregate in an aqueous solution & exclude water molecules.
◍ CAC. Answer: Oxidative phosphorylation uses NADH and FADH2 generated from the ___.
◍ Dopamine. Answer: -neurotransmitter -variety of functions (including motor control)Parkinson's = decreases dopamine. Sinemet helps by increasing
dopamine levels.
◍ Xeroxerma Pigmentosum (XP). Answer: A recessive genetic disease that occurs when one or more of the genes that perform nucleotide excision repair are nonfunctional
◍ How do rising blood CO2 levels promote the deoxygenated confirmation of hemoglobin?. Answer: CO2 reacts with H2O in the blood & decreases pH, which promotes the dome confirmation of the heme group.
◍ Mismatch repair. Answer: -happens in mistakes with DNA replication-DNA polymerase proofreads to see if make a right choice, but makes a mistake. -remove big section of damage and replace all of it
◍ DNA organization. Answer: DNA is wrapped around proteins called histones -~nucleosomes-~chromatin fiber-~ chromosomes
◍ Endothermic reaction. Answer: Endo=absorbThermos=heat-absorbs more energy than it releases
◍ Function of cholesterol. Answer: Maintains membrane fluidity
◍ Hydrolysis. Answer: Broken peptide bonds
◍ Competitive inhibition. Answer: -medicine/drugs-competitive inhibitor will bind to active site to prevent substrate from binding-(overcome inhibition by adding more substrate)
◍ Promoter. Answer: Start line
◍ Missense mutation. Answer: -substitution of one amino acid for another-results in 10 different
behavior?. Answer: Protein aggregation
◍ Fatty acid structures. Answer: -made up of carbonyl groups
◍ Pairing. Answer: DNA= A—TRNA= A—U
◍ Which bond is weakest, but have most influence on protein structure because of how many there are?. Answer: Hydrophobic bond
◍ 1.5 ATP per FADH2. Answer: How many ATP molecules does FADH2 yield after donating electrons and hydrogen atoms to the electron transfer chain (ETC)?
◍ How can alteration in protein structure lead to a disease state?. Answer: A mutation replaces an isoleucine with an aspartic acid in a transcription factor protein, which blocks the normal folding of the protein & its function in the expression of certain genes.
◍ Primary. Answer: Level of protein structure established through the dehydration synthesis of peptide bonds
◍ Which feature of hemoglobin makes it an effective O2 transport molecule?. Answer: It's affinity for O2 is regulated by pH.
◍ How do the rates of enzyme catalyzed reactions compare to those of corresponding uncatalyzed reactions?. Answer: They are 10^6 to 10^12 times faster.
◍ What is the function of DNA polymerase in the process of PCR?. Answer: It recognizes the primers and uses the available dNTPs to replicate the template DNA sequence.
◍ The chemical reactions of the ETC, through the oxidation of coenzymes produced by the CAC, create energy that pumps H+ ions into the
intermembrane space of mitochondria. The accumulation of these H+ ions in the intermembrane space creates an H+ ion gradient. This H+ gradient provides the driving force for the rotation of ATP synthase, which results in the production of ATP. Therefore, the ETC is responsible for the production of ATP via oxidative phosphorylation.. Answer: According to the chemiosmotic theory, how is the ETC connected to ATP production? Explain in at least 4 complete sentences.
◍ Lysis. Answer: Break
◍ Primary structure. Answer: Sequence of amino acids that make up a protein
◍ Non-homologous end-joining. Answer: -happens before DNA replication-trim the ends-stuck back together
◍ What is occurring in surrounding tissues as the amount of hemoglobin saturated with oxygen increases?. Answer: The concentration of hydrogen ions decreases.
◍ Covalent bond. Answer: When atoms share electrons
◍ Secondary Structure. Answer: Sequence of amino acids fold.
◍ Enzyme structure. Answer: -they are proteins-twist, fold, bend to final shape-shape attracts specific molecules
◍ Non-competitive inhibition. Answer: -more effective-bind to allosteric site of enzyme-changes the shape of the protein
◍ Insulin. Answer: -increase glucose in blood-fed state(after we eat, increase glucose=pancreas releases insulin)-lets glucose into cells-signals for GluT
Answer: -use 2nd copy of the DNA to copy back the correct info- double strand (cut DNA in 2), break
◍ Transcription. Answer: -comes first! Transcribes DNA into message. (RNA polymerase will connect complementary bases. mRNA can go out of nucleus to attach to ribosome of rRNA)
◍ What facilitates the transition of hgb from the R state to the T state?. Answer: An increase in the concentration of H+
◍ Aggregation. Answer: -proteins clump together in abnormal way (d/t hydrophobic interactions)
◍ Which cellular condition prompts the cell to perform fermentation rather than the citric acid cycle?. Answer: Lack of O
◍ Chaperones. Answer: Help fold proteins
◍ Which pathway is triggered by the intake of carbs during exercise?. Answer: Glycolysis
◍ Exothermic reaction. Answer: Exo=to releaseThermo=heat-chemical reaction that releases more energy than it absorbs (as heat & light)
◍ Steps of DNA replication. Answer: -DNA is separated, creating a replication fork (by helicase)-primase attaches on RNA primer, where the replication starts-DNA polymerase adds bases to remaining of the strand until it reaches a stop codon. (This is done in fragments-"ozaki fragments"-DNA ligase seals the 2 strands forming a double helix
◍ aspartate. Answer: What amino acid is the following structure?
◍ Neo. Answer: New
◍ Chemical reaction. Answer: -absorb and release energy-activation energy-energy is released (heat & light) when bonds are broken.
◍ Myoglobin. Answer: - 1 subunit- tertiary- used for O2 storage- in muscles-high affinity (how tightly it holds onto something)
◍ RNA. Answer: -plays "messenger"-in & outside nucleus -ribose-Adenine, Uracil, Guarine, Cytosine-mRNA=messenger (takes message to ribosome)-rRNA=ribosomal RNA-tRNA=transfers amino acids
◍ Which force is most influential in determining the tertiary structure of a protein?. Answer: Hydrophobic effect
◍ RNA. Answer: -phosphate + ribose sugar + A/U/C/G-single strand (can fold back onto itself & form pairs between itself (stem-loop)
◍ Quaternary Structure. Answer: Protein has more than 1 polypeptide chain.
◍ false. Answer: T/F: There are 5 complexes associated with the ETC.
◍ Enzymes. Answer: -functional proteins-catalysts-reusable (can be recycled!)-specific-induced fit-work like assembly line (enzyme pathway)
◍ Point mutations. Answer: When one of the DNA bases (nucleotides) are replaced with another, results in a different protein.
◍ Lipids. Answer: -energy storage-signaling-high amount of C
◍ In which situation would altering a protein structure lead to a disease state?. Answer: A mutation aconitase blocks essential step in aerobic metabolism
◍ F and F2. Answer: Which of the following is not a part of ATP synthase?- F- Fo- F1- F
◍ false. Answer: T/F: The majority of the reactions of the urea cycle occur in the mitochondrial matrix.
◍ inner membrane. Answer: In mitochondria, the molecule that produces ATP is located in the
◍ coQ. Answer: What molecule transfers electrons and H+ from both complex I and complex II to complex III?
◍ Example of endothermic reaction. Answer: Photosynthesis- takes in light to break down to create glucose
◍ Sickle cell disease. Answer: Caused by mutation in the Hgb-beta gene. (Causes cells to become rigid, sticky, misshapen.)
◍ Elevated levels of AST & ALT. Answer: -indicates liver damage(When damaged, their protein contents can spill into blood stream)
◍ Essential. Answer: -we have to eat it (our bodies cannot make it)-omega 3-omega 6- essential for building other types of lipids
◍ 3. Answer: Oxidative phosphorylation occurs in ___ phases.
◍ How does insulin impact carbohydrate metabolism?. Answer: It stimulates the uptake of glucose from the blood by cells in the body.
◍ Hemoglobin. Answer: - 4 subunits -quaternary-for O2 transport-moving through blood from lungs to tissues-low affinity (because it gives O2 up)
◍ Catalyst. Answer: Substance that will decrease the activation energy needed to start a chemical reaction
◍ Factors that favor the oxygenated form of hemoglobin:. Answer: -increased pH-decreased CO
◍ Van der Waals interactions. Answer: Occur due to random, transient movements of electrons that at any given instant, give molecules regions of + & - charges.
◍ A. The mitochondrion is the main site of oxidative phosphorylation, which can be attributed to its two-membrane structure. - The outer membrane is a bilayer that contains porin proteins, which allow ions and molecules to cross into the intermembrane space. The intermembrane space is located between the inner and outer membrane and contains solution. - The inner membrane is also a bilayer but is highly selective, allowing only select ions and molecules to cross. This selective characteristic of the inner membrane is critical for maintaining the specific concentrations of H+, ATP, and other species within the mitochondrial matrix. - The matrix is the innermost space of the mitochondrion and is where the citric acid cycle as well as parts of beta oxidation and the urea cycle occur. This close proximity of reaction cycles is efficient because it allows NADH and FADH2, produced by the citric acid cycle, to also participate in the electron transport chain by donating electrons and hydrogen ions.B. The complexes of the ETC are located in the inner membrane and accept the electrons from the coenzymes..
Answer: -pH changes-salt changes
◍ Heme. Answer: -special molecule inside the protein-iron (Fe)-where O2 binds-in myoglobin, carries 1 O2-in hemoglobin carries 4 O
◍ Gluconeogenesis. Answer: -make new glucose(from lactate)-acetyl CoA~pyruvate~glucose-glycerol (from triglycerides)-amino acids(last resort!)
◍ Elements. Answer: Substance that cannot be broken down into another substance by chemical reaction.
◍ Fatty acid synthesis. Answer: - make fat from acetyl CoA-fats stored in triglycerides (3 fatty acids)-adipose tissue (long term storage)
◍ ornithine, arginine, and aspartate. Answer: What amino acids are involved in the urea cycle?
◍ Hydrogen bond. Answer: Forms when portion of a polar molecule that is partially positive interacts with portion of a polar molecule that is partially negative
◍ Degradation. Answer: Break peptide bonds(Hydrolysis)
◍ What occurs immediately after the appropriate molecule enters the active site of the enzyme?. Answer: The enzyme binds to the molecule to form an enzyme molecule complex.
◍ Which force is most influential in determining the secondary structure of a protein?. Answer: Hydrogen bonding
◍ Which metabolic pathway involves coenzyme A, NAD, & FAD?.
Answer: Beta oxidation
◍ Example of exothermic reaction. Answer: Cellular respiration- breaks down glucose to make cellular energy
◍ Nucleotide excision repair. Answer: -more than 1 nucleotide damaged-cut a sequence & replace that section
◍ malate. Answer: Fumarate reenters the mitochondrion as
◍ Anneal. Answer: -step 2 of PCR-use DNA primers that match the gene to find only the gene we want (ex: to find BRCA gene)
◍ Which molecule is pyruvate directly converted to under aerobic conditions?. Answer: Acetyl CoA
◍ How many ATP molecules are used in the conversion of pyruvate to glucose?. Answer: 6
◍ What difference in the regions of the SIRT1 & SIRT2 genes in people addicted to cocaine increases their expression?. Answer: The nucleosomes become more widely spaced.
◍ synthesis of ATP from ADP + Pi. Answer: Oxidative phosphorylation is the synthesis of ___ from ___.
◍ Active site. Answer: -location on enzyme where substrate binds
◍ NH4+ (amine group). Answer: Oxidative deamination results in the removal of ___ from amino acids.
◍ Beta oxidation. Answer: Break fats into acetyl CoA
flow of electrons from NADH and FADH2. What happens after this first phase is complete?
◍ 2.5 ATP per NADH. Answer: How many ATP molecules does NADH yield after donating electrons and hydrogen atoms to the electron transfer chain (ETC)?
◍ Assuming 100% reaction efficiency, how many DNA copies are created after the completion of 4 complete PCR cycles?. Answer: 16
◍ Proteases. Answer: -a class of enzymes-hydrolyze protein strands into smaller units-increase pH= significant decrease in protease activity
◍ true. Answer: T/F: ATP is invested in the urea cycle.
◍ Exonuclease. Answer: During DNA replication, if an error is detected, DNA polymerase removes the nucleotides and replaces them with correct ones.
◍ Translation. Answer: -2nd step-builds protein(tRNA leaves behind its amino acid, built chain of amino acids)
◍ What breaks hydrogen bonds?. Answer: -pH and salt changes(Disulfide bonds broken by reducing agent)
◍ Decreased expression. Answer: Not making proteins
◍ muscle twitches, muscles weakness, and degradation of nerve cells. Answer: An individual with the MERRF disease tends to have symptoms of
◍ Frameshift mutation. Answer: -insertion or deletion of 1 or 2 nucleotides
◍ Polypeptides.
Answer: -functional proteins-made of folded up polymers
◍ Glycogenolysis. Answer: Break glucose out of glycogen
◍ complex I. Answer: At which complex does the following reaction take place?NADH + H+ + coQ → NAD + coQH
◍ complexes I, III, IV. Answer: Which of the ETC complexes pump H+?
◍ Base excision repair. Answer: -only 1 nucleotide damaged - remove and replace
◍ Cori Cycle. Answer: -muscle cells produce lactate which is then converted to glucose in the liver
◍ Why do XP patients have a much higher incidence of skin cancer than the general population?. Answer: The mutation of all other genes is higher due to failure to repair.
◍ Denature. Answer: -step 1 of PCR -increase heat to separate the DNA
◍ Are enzymes specific?. Answer: Yes
◍ Tertiary Structure. Answer: -more folding in a 3D shape.-R groups (side chains)
◍ Unsaturated fats. Answer: -natural (veg oils)-1 double bond
◍ Bohr Effect chart (low pH). Answer: C- High CO2H- High H+A- AcidicR-Release of O2(rt. Shift)T- tense state (in tissues)
◍ Genesis.
