Biochemistry Review Flashcards
(261 cards)
1
Q
Blood is maintained at a pH of about 7.4 through several mechanisms, such as the carbonic acid/bicarbonate buffering system and respiration removing carbon dioxide from the body. A laboratory measures the blood pH and bicarbonate ion concentration of trained endurance athletes performing high-intensity exercise under hypoxic conditions and normal conditions. The bicarbonate ion concentration drops under hypoxic conditions compared to normal conditions. What happens to the athletes’ blood pH under hypoxic conditions?
A
Lower
2
Q
A hospital lab indicates a urine sample pH of 5.0 in a patient presenting with symptoms of kidney stones. What is the actual hydrogen ion concentration of the urine sample?
A
10^-5 M
3
Q
The concentration of hydrogen ions [H+] in a solution is 1 x 10^-7 moles/L. What is the pH of the solution?
A
7
(pH of a solution can be calculated as: pH = -log[H+] = -log[H+]
4
Q
Which of the following levels of protein organization involves the interaction between multiple protein chains?
A
Quaternary
5
Q
When a protein is denatured, which of the following happens to its function?
A
It ceases to function
6
Q
What are proteins made of?
A
Amino acids
7
Q
What pair of functional groups is found in each of the 20 amino acids?
A
Amino group and carboxyl group
8
Q
What amino acid is composed of a bulky structure that includes aromatic residues?
A
Tryptophan
9
Q
What kind of bond is present between two amino acids?
A
Peptide bond
10
Q
A peptide bond forms through which process?
A
Dehydration synthesis
11
Q
When a peptide bond forms between two peptides to make a polypeptide, what does the carboxylic acid group of the amino acid bind to on another amino acid make this peptide bond?
A
Amino group
12
Q
Hemoglobinopathies may affect the structure or production of hemoglobin molecules.
Which of these diseases is divided by type, based on alpha and beta subunits, with disease severity ranging from mild to incompatible with life?
A
Thalassemia
13
Q
Allosteric moderators influence the oxygen affinity of hemoglobin.
Which moderator is known for T-state stabilization under hypoxic conditions?
A
Bisphosphoglycerate
14
Q
What phenomenon is observed with the binding and dissociation of oxygen in hemoglobin?
A
Positive cooperativity
15
Q
A protein in erythrocytes binds to oxygen and transports it from the lungs to tissues. How many oxygen molecules can be transported by a single molecule of hemoglobin?
A
4
16
Q
Which part of hemoglobin binds to oxygen?
A
Heme group
17
Q
Statins treat high cholesterol levels, placing them among the most commonly prescribed medications in the United States. Some statins, like atorvastatin and simvastatin, are primarily metabolized by CYP450 enzyme CYP3A4. Other statins, like pravastatin, are not significantly metabolized by CYP3A4. Cyclosporine, an immunosuppressant, is a strong inhibitor of CYP3A4. A patient receiving cyclosporine presents with high cholesterol. What statin regimen is best for this patient?
A
Pravastatin
18
Q
What substance is output by the liver following its metabolism of toxic ammonium ions?
A
Urea
19
Q
Where in the body is the cytochrome p450 protein found in the highest concentration?
A
Liver
20
Q
What bleeding disorder is characterized by a deficiency of factor VIII?
A
Hemophilia A
21
Q
What is the main function of fibrinogen in the blood coagulation cascade?
A
Initial blood clot formation
22
Q
What is the primary function of osteoclasts in relation to the structure and function of bone?
A
Reabsorption of bone
23
Q
What do osteoblasts manufacture during the bone formation process?
A
Osteocalcin
24
Q
A patient presents with a disease caused by the destruction of beta-cells of the pancreas and hyperglycemia.
What serum glucose level is likely to be observed?
A
150 mg/DL
25
What outcome related to alpha-cells is likely to result due to type I diabetes?
Increased glucagon secretion
26
A patient with diabetes demonstrates improper production of insulin. What consequence may occur?
Decreased glucose entry into muscle
27
A patient consumed a well-balanced meal several hours ago. What occurs inside liver tissue as a result of the time lapsed after eating?
Gluconeogenesis
28
A patient rests for 20 minutes after consuming a well-balanced meal. What occurs inside muscle tissue during this process?
Glucose entry
29
Multiple pathways enable energy currency to be derived from ingested food; this currency fuels vital cellular functions. What catabolic process results in the greatest amount of this currency?
Cellular respiration
30
Congestive heart failure is a large public health burden that may be treated with several types of hormones. Valsartan/sacubitril is a promising treatment for congestive heart failure. This medication degrades neprilysin, a peptidase that targets vasoactive peptides such as angiotensin. How does angiotensin cause a cellular response?
Initiating a signal transduction cascade and activating second messengers
31
Why are the target receptors of steroids often found within the nucleus of a cell?
Steroids alter gene expression
32
What system is responsible for the majority of hormone secretion and regulation in the body?
Endocrine
33
Improper activity of an epidermal growth factor receptor at the cell membrane may result in cancer. Which type of receptor may be involved?
Enzyme-linked receptor
34
A hormone binds to an adrenoreceptor during the "flight or fight" response. Which type of receptor facilitates this process?
G-protein-coupled receptor
35
A ligand binds to an external domain. A stepwise process ensues, resulting in a change in the electrical properties of the cell. Which type of receptor facilitates this process?
Ionotropic receptor
36
A ligand binds to a transmembrane protein and causes autophosphorylation of tyrosine in the cytoplasmic domain. This creates a binding site for effector proteins. What ligand may participate in this process?
Growth factors
37
A signaling molecule binds to a cell membrane receptor. In a stepwise process, the alpha subunit of the receptor dissociates from the beta and gamma subunits. Which portion of this receptor activates a target protein, as exemplified by the stimulation of adenylyl cyclase?
Alpha
38
The cytoplasmic face of a sodium-potassium pump has sodium bound and becomes phosphorylated. What is directly induced by this event?
Conformational change
39
Vesicles containing neurotransmitters are tethered to the plasma membrane. Their release is triggered by calcium. What type of transport is being performed?
Bulk transport
40
Carrier proteins facilitate solute transfer across the cell membrane. Which of these structures carries two different molecules in opposite directions?
Sodium potassium ATPase
41
The sodium-potassium pump of the cell membrane uses ATP to establish a transmembrane electrical potential, where the extracellular environment is more positive than the intracellular environment. What form of transport is performed when anything positively charged attempts to flow down this established gradient?
Secondary active transport
42
Which moiety of the plasma membrane typically demonstrates both intracellular and extracellular orientation?
Phospholipid head
43
Adenosine triphosphatases (ATPases) are ion pumps that span the lipid bilayer. Like all proteins, ATPases are composed of many amino acids. Where would you expect to find the most isoleucine residues in an ATPase?
Interacting with the hydrophobic lipids
44
What is the phospholipid bilayer structure comprised of, making it "dual in nature"?
Hydrophilic head and hydrophobic tail
45
What is the main function of the phospholipid bilayer in the cell membrane?
Protection
46
What is the main function of proteins in the cell membrane that create membrane channels?
Cellular transport
47
Insulin-degrading enzyme (IDE) is a promising target for therapeutics to treat type 2 diabetes and Alzheimer's disease. A kinetic study found that 1 mM ATP inhibits this reaction, but 1 mM magnesium relieves this inhibition. The Michaelis constant (KM) of the reaction in the absence of ATP and magnesium is approximately 2M. What might the KM be in the presence of ATP and in the presence of ATP and magnesium?
ATP: 3M, ATP and magnesium: 2M
48
The catalytic rate (rate limiting step) determines the rate of an enzyme-catalyzed reaction in which of the following situations?
Creating product with free enzyme
49
Considering the Michaelis-Menten equation, what is the value for the Michaelis constant (Km)?
1/2 V max
50
What category of enzyme is responsible for moving a functional group from one molecule to another?
Transferase
51
Sugars are easiest for the body to break down into quick energy. Which enzyme, found in saliva, can be used to obtain sugars from carbohydrates as soon as food enters the body?
Amylase
52
What process is taking place when aspirin is used to reduce the activity of the enzyme responsible for inflammation?
Enzyme inhibition
53
Once a substrate binds to the active site of the enzyme, what happens to the rate of the reaction?
Speeds up
54
Resveratrol, a compound found in red wine and grapes, may have anticancer properties. A laboratory study of resveratrol in hepatocellular carcinoma cell lines found that resveratrol activates an enzyme called sirtuin 1. Sirtuin 1 is a negative regulator of a kinase cascade that includes phosphatidylinositol 3'-kinase (PI3K) and AKT, a kinase downstream of PI3K. What effects does resveratrol treatment have on post-translational modifications of PI3K and AKT?
Decreased phosphorylation
55
What is the most common functional group added during post-translational modification?
Phosphate
56
Which post-translational modification is one of the most important and also non-reversible?
Proteolysis
57
A molecule is composed of a five-carbon sugar, a phosphate group, and four different nitrogenous bases. How can the structure of a molecule composed through polymerization of these units be described for eukaryotes?
Condensed
58
How many hydrogen bonds are formed between guanine and another of the four bases in a polynucleotide molecule?
3
59
Two strands of DNA are arranged in an antiparallel fashion. What is positioned across from the 5' end of one strand?
3' end of the opposite strand
60
Which of DNA bases can pair with adenine?
Thymine
61
What is composed of two polynucleotide molecules intertwining?
DNA
62
What replaces thymine when DNA is translated into RNA?
Uracil
63
Which type of mutation causes sickle cell disease?
Missense
64
How many sequence permutations are formed due to the degeneracy of the central dogma process?
64
65
What sequence of units marks the most common beginning of a protein sequence?
AUG
66
How many units compose the groups that specify amino acids during the central dogma process?
3
67
How many different base pairs have the potential to form a codon during the central dogma process?
4
68
A molecule enables RNA polymerase to bind to eukaryotic DNA. Where does this binding occur?
TATA box
69
What process protects the 5' end of a newly formed mRNA molecule from degradation?
Addition of 7-methylguanosine
70
Which transcription factor has a TATA-binding protein?
TFIID
71
What enzyme facilitates the three-step process that generates tRNA?
RNA polymerase III
72
What enzyme facilitates the three-step process that generates mRNA?
RNA polymerase II
73
What describes the complementary base pairing arrangement of a double-stranded helical polymer?
2 hydrogen bonds between 1 purine and 1 pyrimidine
74
During what phase is a double-stranded helical polymer compacted with scaffolding proteins?
Interphase
75
What basic unit, composed by a double-stranded helical polymer and its associated proteins, forms chromatin?
Nucleosome
76
What associates with a double-stranded helical polymer to facilitate compaction?
Histome
77
What binds to a double-stranded helical polymer and is crucial for its formation of higher-order structures, such as the solenoid and zigzag model?
H1
78
What genome is organized in the nucleus?
Eukaryotic genome
79
What must regulatory elements bind to for transcription to occur in eukaryotic cells?
TATA box
80
What codon is responsible for starting the process of translation?
AUG
81
What does the transcription process produce?
Antiparallel complementary RNA strand
82
HER2 is a well-known proto-oncogene. The HER2 gene encodes a tyrosine kinase receptor called human epidermal growth factor receptor 2 (HER2). HER2 has roles in cell growth and cell division, and HER2 overexpression has been reported in many types of human cancers. HER2 dimerization leads to autophosphorylation, which leads to the activation of HER2. Given this information, how might a laboratory target HER2 to develop a novel treatment for cancer?
HER2 inhibitor
83
The RAS genes are the most frequently mutated oncogenes observed in human cancer. RAS is part of the mitogen-activated protein kinase (MAPK) signaling pathway, and the downstream effects of MAPK signaling are cell cycle progression. RAS exists in a non-active form bound to GDP and an active form bound to GTP. The transition between RAS-GDP and RAS-GTP is regulated by guanine exchange factors and GTPase-activating proteins. A mutant RAS protein is identified as insensitive to cytosolic GAP. What effects will this mutant RAS protein have if left unchecked?
Activate MAPK signaling and cause cell proliferation
84
What process involves the entire protooncogene jumping from one position to another in the genome under the control of promoter?
Translocation
85
How do tumor suppressor genes contribute to a reduction in cancer?
Stop cell cycle progression
86
Tumor suppressor genes utilize which of the following mechanisms to slow or prevent the development of cancer?
Apoptosis
87
What type of event activates a protooncogene?
Chromosomal rearrangement
88
A cancer-associated variant has been discovered in a sequence of regulatory DNA. Which type of sequence is most likely to be mutated if it recruits RNA polymerase?
Transcription factor
89
A cancer-associated variant has been discovered in a sequence of regulatory DNA. Which type of sequence is most likely to be mutated if activation and repression functions of a multi-subunit assembly operate during both initiation and elongation?
Mediator coactivator
90
A cancer-associated variant has been discovered in a sequence of regulatory DNA. Which type of sequence is most likely to be mutated if abnormal silencing of tumor suppressors has occurred?
Long non-coding RNA
91
Mutation of a regulatory sequence has occurred. Which type of sequence is most likely to be mutated if DNA methylation targeting has become aberrant?
Non-coding RNA
92
Mutation of a regulatory sequence has occurred. Which type of sequence is most likely to be mutated if a failure to mobilize and modify nucleosomes occurs?
Chromatin regulator
93
What target might a researcher explore if they want to prevent release of RNA polymerase from a transcript?
Rho
94
Which subunit of this RNA polymerase has demonstrated mutations that account for rifamycin-resistant tuberculosis strains?
Beta
95
Which structure of RNA polymerase is prevent from forming when fidaxomicin is administered for a Clostridium difficile infection?
Open complex
96
Which part of RNA polymerase contains N-terminal and C-terminal domains that recognize the UP-element on the DNA molecule?
Alpha two
97
Which part of RNA polymerase pairs with the beta subunit to form the active site?
Beta prime
98
Based on the structural classification of hormones, which of the following hormones is derived from cholesterol?
Glucocorticosteroids
99
What hormone class is derived from lipids?
Steroid
100
What hormone is responsible for stimulated gamete production?
Follicle-stimulating hormone (FSH)
101
What characteristic is associated with hydrophilic hormones?
Targets cell surface receptors
102
What type of hormone is glucagon when classified according to the endocrine gland where it is synthesized?
Pancreatic hormone
103
Which hormone has a complex structure and a half-life of 60-90 minutes?
Steroid
104
Why do steroid hormones have an extended half-life?
Hydrophobicity
105
Where are steroid hormones like aldosterone and cortisol found in the body?
Adrenal cortex
106
What forms the backbone of all steroids, in addition to a single five-membered ring?
Three fused six-membered rings
107
What must occur before this thiamine can function?
Phosphorylation
108
If a patient has a deficiency of vitamin C, what may they present with?
Swollen and bleeding gums
109
What can result from deficiency of folate?
Neural tube defect
110
What is pantothenic acid a component of?
Coenzyme A
111
What form does niacin take during redox reactions?
NADP+
112
A patient of advanced age with a history of alcoholism presents with an inflamed tongue and demonstrates deficiency of a water-soluble micronutrient that is a cofactor of redox reactions. What is this compound a precursor for?
FAD
113
What vitamin is crucial for blood clotting?
Vitamin K
114
Which vitamin inhibits oxidation?
Vitamin E
115
Which vitamin is synthesized in the skin following exposure to sunlight?
Vitamin D
116
Which vitamin helps to maintain mucous membrane moisture?
Vitamin A
117
Which micronutrient has an activation function by enabling an enzyme (deiodinase) to convert T4 to T3?
Selenium
118
Which micronutrient is essential for the synthesis of thyroid hormone?
Iodine
119
Which micronutrient is highly involved in oxygen transport?
Iron
120
Which micronutrient is essential for neurotransmitter synthesis?
Copper
121
Adenosine triphosphate must complex with which micronutrient to be biologically active?
Magnesium
122
Which enzyme determines the rate-limiting step of cholesterol synthesis?
HMG-CoA reductase
123
What process of creating energy breaks down triglycerides into fatty acids and glycerol?
Lipolysis
124
What process marks the beginning of cholesterol biosynthesis?
HMG-CoA (3-hydroxy-3-methylglutaryl-coa) formation
125
Which type of eicosanoid is responsible for stimulating the contraction of smooth muscles during childbirth?
Prostaglandins
126
What is the main function of prostaglandins?
Induce fever and inflammation
127
Arachidonic acid metabolism involves the hydrolysis of the sn-2 position on the phospholipid backbone by what phospholipase?
A2
128
What unstable intermediary in the lipoxygenase pathway is converted to various leukotrienes?
Leukotriene A4
129
What type of eicosanoid biosynthesis is suppressed through the inhibition of cyclooxygenase by nonsteroidal anti-inflammatory drugs (NSAIDs)?
Prostanoids
130
What family of enzymes initiates the production of eicosanoids by releasing arachidonic acid?
Phospholipase a2
131
What transfers triacylglycerols to adipose tissue?
Chylomicron
132
What can be observed when abnormalities of lipoproteins occur due to diabetes?
Increased LDL
133
What is rich in triglyceride and cholesterol, synthesized in the liver, and used by other organs?
Very low-density lipoprotein
134
What performs reverse cholesterol transport?
High-density lipoprotein
135
What condition results when the heart fails to receive the proper amount of oxygen-rich blood due to this buildup?
Coronary artery disease
136
What condition is characterized by a temporary impediment of blood to the brain?
Transient ischemic attack
137
What condition is secondary to atherosclerosis and causes lasting neurological damage?
Ischemic stroke
138
What condition involves neurological symptoms from blockage of blood vessels by cholesterol?
Cerebrovascular disease
139
Where does the breakdown from glycogen to glucose occur?
Liver and muscles
140
What is the ATP usage and production in glycolysis?
2 used, 4 produced
141
Which key regulatory enzyme of glycogen synthesis catalyzes the α-1,4 linkage in glycogen?
Glycogen synthase
142
What molecule is the immediate donor of glucose for glycogen formation during glycogenesis?
Uridine diphosphate-glucose (UDP-Glucose)
143
In the final step of gluconeogenesis, which substrate undergoes hydrolyzation?
Glucose 6-phosphate
144
How does excessive alcohol consumption affect the gluconeogenesis pathway and subsequently lead to ethanol-induced hypoglycemia?
Accumulation of lactate
145
When would the body choose to switch from glycolysis to gluconeogenesis?
During starvation
146
What enzyme is used in both gluconeogenesis and glycolysis?
3-phosphoglycerate kinase
147
Fructose 1,6-bisphosphatase (FBP) catalyzes the removal of a phosphate group from fructose 1,6-bisphosphate to form fructose-6-phosphate, a key step in gluconeogenesis. FBP is regulated in several ways and is sensitive to both inhibitors and activators. A research team investigating potential therapies for type 2 diabetes has identified FBP as a therapeutic target. To treat type 2 diabetes, should the team focus on FBP inhibitors or activators, and why?
FBP inhibitors; to decrease gluconeogenesis and glucose levels
148
Glucose-6-phosphatase is an enzyme that removes the phosphate group from glucose-6-phosphate to produce glucose, a key step in gluconeogenesis. What are the primary locations where glucose-6-phosphate is expressed in the body?
Liver, kidneys, small intestine
149
Insulin stimulates glycolysis and represses gluconeogenesis, resulting in the consumption of glucose to produce energy in the form of ATP. If a pregnant mother develops gestational diabetes and insulin resistance, what would be the effect on gluconeogenesis and glucose availability to the fetus?
Gluconeogenesis would increase, making more glucose available
150
What is the first enzyme in the glycolysis path?
Hexokinase
151
```
Which of the following are intermediate component(s) of glycolysis? Select all that apply.
A. 1,3-Biphosphoglycerate
B. alpha-ketoglutarate
C. Isocitrate
D. Phosphoenolpyruvate
E. Uridine diphosphate glucose
```
A. 1,3-Biphosphoglycerate
| D. Phosphoenolpyruvate
152
In the process of glycolysis, after glucose is phosphorylated into glucose 6-phosphate (G6P), it is isomerized into fructose 6-phosphate (F6P) by what enzyme?
Glucose phosphate isomerase
153
Glycolysis is the process of converting the six-carbon molecule glucose into two three-carbon molecules, generating ATP and NADH. What three-carbon molecule is the final product of glycolysis?
Pyruvate
154
Pancreatic ductal adenocarcinoma is a highly lethal form of cancer that thrives in environments with little nutrients; research to elucidate how these cells adapt to metabolic stress is of interest. A microRNA that downregulates phosphofructokinase has been identified in these cells. What would be inhibited by this inhibition of phosphofructokinase?
Glycolysis
155
In some cancer types, the glycolytic enzyme hexokinase is upregulated in the tumor tissue compared to healthy tissues. Hexokinase expression levels may increase in more advanced stages of cancer. Hexokinase catalyzes the first step of glycolysis. Why is upregulated hexokinase an important advantage for a tumor cell?
Hexokinase produces glucose-6-phosphate, which cannot escape from the cell
156
What chemical reaction takes place when two carbohydrate molecules bond together to form one molecule?
Condensation
157
What type of reaction joins two monosaccharides to make a disaccharide?
Dehydration
158
What depiction of carbohydrates can clearly illustrate stereochemistry at each carbon center?
Fischer projection
159
What characteristic defines the naming convention based on glyceraldehyde enantiomers?
Position of the alcohol group relative to the chiral center
160
Which class of carbohydrates are furanoses and pyranoses?
Cyclic monosaccharides
161
Pyruvate dehydrogenase is the enzyme that converts pyruvate to acetyl CoA, which combines with oxaloacetate to form citrate in the TCA cycle. Hypoxia-inducing factors (HIFs) are transcription factors that are activated in many tumors. HIFs have been shown to activate pyruvate dehydrogenase kinase, which is a negative regulator of pyruvate dehydrogenase. What is the result of HIFs on the TCA cycle?
Inhibiting the TCA cycle
162
Isocitrate dehydrogenase (IDH) is a key enzyme in the citric acid cycle frequently involved in various cancers. Several IDH inhibitors are being developed as potential cancer treatments. What inhibits this enzyme in the citric acid cycle?
ATP
163
Why is oxygen needed for aerobic respiration in the Krebs cycle?
Electron transport chain
164
What is the final metabolite in the Krebs cycle that joins again to start the cycle?
Oxaloacetate
165
What compound is required to enter the Krebs cycle in an oxygen-rich environment?
Acetyl-CoA
166
What kind of process is the citric acid cycle?
Amphibolic
167
Where does the citric acid cycle occur in eukaryotes?
Mitochondria
168
Acetyl CoA undergoes oxidation in the Krebs cycle. Three molecules of which product of this process enter the electron transport chain?
NADH
169
Succinyl-CoA is formed during the Krebs cycle. What enzyme catalyzes its formation?
Alpha-ketoglutarate dehydrogenase
170
An enzyme catalyzes the oxidative decarboxylation of isocitrate. What stimulates the activity of this enzyme?
ADP
171
An enzyme catalyzes the oxidative decarboxylation of isocitrate. What inhibits this enzyme?
ATP
172
An enzyme catalyzes the oxidative decarboxylation of isocitrate. What enzyme catalyzes the step prior to this reaction?
Aconitase
173
Acetyl CoA enters the Krebs cycle. What enzyme acts upon it in the first step of this process?
Citrate synthase
174
An anabolic process results in the formation of glucose from fat and protein substrates. What reaction is occurring?
Gluconeogenesis
175
What hormone decreases gluconeogenesis?
Insulin
176
A period of fasting, lasting more than 2 days, has led to low blood sugar levels. What substrate will be most used to generate glucose?
Pyruvate
177
A short period of fasting triggers glucagon secretion and glycogen phosphorylase activation. What catabolic process will occur as a result?
Glycogenolysis
178
A catabolic process results in the formation of glucose-1-phosphate from glycogen. What hormone upregulates this process?
Epinephrine
179
An increase in blood glucose levels following digestion of a meal causes insulin secretion. What will occur next to reduce excess glucose in the blood?
Enhancement of cell proliferation
180
A reductase inside complex III accepts electrons from a carrier of complex II. What accepts these electrons next?
Cytochrome C
181
Flavin adenine dinucleotide (FAD) accepts two electrons inside complex II of the electron transport chain. What accepts these electrons after FAD transfers them to Fe-S clusters?
Coenzyme Q
182
Glucose enters a series of reactions that transfers some of the energy from it to ADP. Which product of this process enters the electron transport chain?
NADH
183
What is produced during the investment phase of glycolysis?
Glucose-6 phosphate
184
What respiratory enzyme is also known as complex I in the electron transport chain?
NADH dehydrogenase
185
Where does the majority of oxidative phosphorylation occur in the cell?
Mitochondria
186
During which stage(s) of cell respiration is NADP (nicotinamide adenine dinucleotide phosphate) created?
Glycolysis and the Krebs cycle
187
Tigecycline is an antibiotic that inhibits mitochondrial oxidative phosphorylation; it shows promise for treating many types of cancers. How would you expect tigecycline to affect ATP and energy levels of a cell?
Decrease both ATP and energy
188
To carry out oxidative phosphorylation, an electrochemical gradient must be established and maintained. The proteins involved in maintaining this electrochemical gradient may present a therapeutic target for acute myeloid leukemia. Where in the cell is this electrochemical gradient maintained, and where would therapies aimed at this system need to be targeted?
Inner mitochondrial membrane
189
What biochemical process is responsible for the buildup of compounds by use of ATP energy?
Anabolism
190
Oxidation-reduction reactions always occur together. Electrons are shared between these reactions. What happens to the oxidation side of the reaction?
Electrons are lost
191
What stage in the oxidation of foodstuffs involves the release of energy in the form of ATP from NADH and FADH2?
Tertiary metabolism
192
Where is the mitochondrial electron transport chain/respiratory chain located?
Inner mitochondrial membrane
193
What type of pyridine nucleotide redox system is responsible for the generation of nitric oxide?
Nicotinamide adenine dinucleotide phosphate
194
What molecule is the strongest oxidizing agent?
Ubiquinone
195
What type of pyridine nucleotide redox system plays an important role in apoptosis?
Nicotinamide adenine dinucleotide
196
ATP is most often used within the cell. What ATP function occurs outside the cell?
Inflammation
197
Which process to create ATP occurs in chloroplasts?
Photosynthesis
198
Where does ATP synthesis occur in a human body cell?
Cytoplasm and mitochondria
199
Where in the mitochondria is pyruvate converted into acetyl CoA?
Matrix
200
What process gets its energy from ATP synthase localized to plasma membranes?
Development of malignancy
201
What process provides the energy typically used for ADP phosphorylation?
Oxidative metabolism
202
Enhanced glucose levels induce a mitochondrial process and play a role in the pathophysiology of type 2 diabetes. Which process is thought to contribute through insulin resistance?
Oxidative phosphorylation
203
Pyruvate is converted to NADH, FADH2, and GTP. Where does this process take place with respect to the mitochondria?
Matrix
204
A glucose molecule is split into two pyruvate molecules. Where does this process take place with respect to the mitochondria?
Cytosol
205
In which part of the mitochondria are proteins of the electron transport chain located?
Inner membrane
206
Where are hydrogen ions deposited inside the mitochondria?
Intermembrane space
207
What is produced during lypolisis and enters gluconeogenesis?
Glycerol
208
What is produced through beta-oxidation during lipolysis?
Acetyl CoA
209
A metabolic process occurs to enable the human body to obtain the maximum amount of energy from proteins during a period of starvation. What is produced by deamination of glutamate during this process?
Alpha-ketoglutarate
210
Which enzyme of the Krebs cycle facilitates production of FADH2?
Succinate dehydrogenase
211
Which enzyme of the Krebs cycle facilitates formation of GTP?
Succinate thiokinase
212
Which enzyme of the Krebs cycle facilitates that combination of acetyl CoA and oxaloacetate?
Citrate synthase
213
What type of cells exhibits altered glucose levels upon treatment with an insulin receptor antagonist?
Myoblasts
214
The concentration of hydrogen ions [H+] in a solution is 1 x 10-7 moles/L. What is the pH of the solution?
7 (pH can be calculated as; pH = -log[H+]
215
What characteristic is associated with eicosanoids?
Mediation of fever
216
A 25-year-old patient presents with severe pain in the groin area and describes sighting blood in the urine. The patient reports no recent trauma, has a negative sexual history, and has not previously experienced these symptoms. What condition may be responsible for the patient's reported symptoms?
Cystinuria
217
An increased risk of hemorrhaging can be attributed to a deficiency in what vitamin?
Vitamin K
218
Vitamin B6 is involved in what function in humans?
Vitamin B6 helps in letting amino acids and Na+ out from the cell against a concentration gradient.
219
What vitamin deficiency is responsible for irreversible damage to the brain and the nervous system?
Cobalamin (B12)
220
The conversion of phenylalanine to tyrosine is catalyzed by what?
Phenylalanine hydroxylase
221
Research into polymers that inhibit insulin aggregation is important in the treatment of diabetes mellitus. These polymers are added to denatured insulin to help it regain its function. What does this indicate about the denaturation of insulin?
The denaturation of insulin is reversible
222
Birth defects, macrocytic anemia, and elevated homocysteine levels in the body are caused by a deficiency of what vitamin?
B9
223
The citric acid cycle is part of cellular respiration, breaking down glucose into energy the cell can use. The citric acid cycle also provides precursors for biosynthesis of fatty acids, amino acids, and other biomolecules. What kind of process is the citric acid cycle?
Amphibolic
224
Cholesterol oxidase is an enzyme that catalyzes the oxidation and isomerization of cholesterol. Cholesterol oxidase may have applications in synthesizing medicines, in the food industry, and as an insecticide. Using a Lineweaver-Burk plot, the Km was estimated to be 31 μM, with a Vmax of approximately 29 μmol/min/mL.
What would you expect the initial velocity of this reaction to be with a substrate concentration of 1 μM?
0.9 μmol/min/mL
225
The Notch signaling pathway is critical in development and cancer. Post-translational modifications are a key way the activity and output of this signaling pathway can be fine-tuned. Phosphorylation of the intracellular domain of Notch generally increases its ubiquitination and marks it for proteasomal degradation. Phosphatase Eya1 acts on a specific threonine residue in the Notch intracellular domain.
How would enhanced Eya1 activity affect Notch stability and Notch signaling?
Increased Notch stability, increased Notch signaling
226
In a 60-year-old patient with liver cirrhosis, detoxification of ammonia is impaired and damaging the brain. Which of the following can transport ammonia in a non-toxic form?
Glutamine
227
Hydrolysis of what bond releases energy from the ATP molecule?
Phosphoanhydride bond
228
Which of the following hemolytic anemias is due to an inborn error of metabolism?
Glucoso-6 phosphate dehydrogenase deficiency
229
After drinking a chocolate milk-based drink (sweetened with table sugar), what is/are the major carbohydrate product(s) that enter the blood after digestion?
Galactose, fructose, and glucose
230
Adenosine triphosphatases (ATPases) are ion pumps that span the lipid bilayer. Like all proteins, ATPases are composed of many amino acids. Where would you expect to find the most isoleucine residues in an ATPase?
Interacting with the hydrophobic lipids
231
Selenocysteine can only be incorporated into protein by recoding a UGA codon. This recoding requires a selenocysteine insertion sequence in the mRNA 3'UTR and the presence of what specific molecule?
The tRNA specific for selenocysteine
232
Serine is necessary for the proper formation of the myelin sheath (fatty tissue that wraps around the axons of nerve cells).
What problems can be caused by serine synthesis disorders in newborns?
Hypomyelination and microcephaly
233
How are polypeptide chains of silk fibroin, a fibrous protein, arranged?
ß-pleated sheets
234
The oxidative phosphorylation system is highly regulated to provide the appropriate level of ATP needed in the cell. ATP synthase is less active when phosphorylated. A mutation of protein kinase C, the enzyme that phosphorylates ATP synthase, has been identified as more active than normal. What would you predict would be the effect of this mutated protein kinase C on ATP synthase activity and ATP levels in the cell?
Decreased ATP synthase activity and ATP levels
235
The urea cycle takes place in the mitochondria of the liver, where excess ammonia is degraded into urea for excretion. In the initial step of the cycle, ammonia (along with bicarbonate and 2 molecules of ATP) is converted into which of the following molecules?
Carbamoyl phosphate
236
How do the antiparallel beta sheets in the mature mammalian cystatin-related epididymal spermatogenic protein differ from the parallel beta sheets in the immature protein?
The amino end of one beta strand is aligned with the carboxyl end of the next beta strand
237
For the reactions containing transaminases, which of the following is a common nitrogen acceptor?
α-ketoglutarate
238
Glycolysis is the process of converting the six-carbon molecule glucose into two three-carbon molecules, generating ATP and NADH. What three-carbon molecule is the final product of glycolysis?
Pyruvate
239
What explains anemia as a result of vitamin B6 deficiency?
The role of vitamin B6 in the production of delta-aminolevulinic acid
240
What pattern of inheritance would be expected for individuals affected by glucose-6-phosphate dehydrogenase deficiency?
Mostly males will be affected
241
Which cellular transporter is mostly responsible for transportation of vitamin C?
SVCT2
242
In SDS-polyacrylamide gel electrophoresis (SDS-PAGE), proteins are separated based on what?
Molecular mass
243
A 32-year-old man presents with severe muscle cramps. His laboratory result shows a deficiency of muscle glycogen phosphorylase. Which of the following is his most probable diagnosis?
McArdle's disease
244
What process is taking place when aspirin is used to reduce the activity of the enzyme responsible for inflammation?
Enzyme inhibition
245
What enzyme is found in both the glycolysis pathway and the gluconeogenesis pathway?
Phosphoglucoisomerase
246
Which of the following is a synthetic form of vitamin K?
Menadione
247
What enzyme is used in both gluconeogenesis and glycolysis?
3-phosphoglycerate kinase
248
Which intermediary of the cholesterol biosynthesis pathway plays an important role in protein prenylation?
Isopentenyl pyrophosphate
249
A hospital lab indicates a urine sample pH of 5.0 in a patient presenting with symptoms of kidney stones. What is the actual hydrogen ion concentration of the urine sample?
10^-5 M
250
Glycogen phosphorylase is the enzyme responsible for removing the terminal glucose residue from a glycogen chain, producing glucose-1-phosphate. Glycogen phosphorylase is activated by phosphorylation, which is carried out by the enzyme phosphorylase kinase. Glycogen phosphorylase has been investigated as a potential target for the treatment of type 2 diabetes. How would you expect a therapy for type 2 diabetes to affect this enzyme?
Effective therapy would dephosphorylate and inhibit glycogen phosphorylase.
251
Polyphenols have anti-inflammatory properties and act in a variety of ways to exert these functions. They are known to inhibit enzymes that produce reactive oxygen species, and they upregulate endogenous antioxidant enzymes. Polyphenols have an effect on catalase.
What effect do polyphenols have on catalase, and why?
Polyphenols inhibit catalase because it degrades hydrogen peroxide
252
Steroid hormones are synthesized from cholesterol, and some sex steroids can be converted into other sex steroids. In fact, the majority of estradiol in men is produced from testosterone in their fat tissue. What type of process converts estradiol to testosterone?
Aromatization
253
What clinical condition can result from folic acid deficiency?
Macrocytic anemia
254
Which of the following is a tryptophan-derived hormone?
Serotonin
255
What form of zinc is present in shampoos for the treatment of seborrhoeic dermatitis?
Zinc pyrithione
256
What vitamin B subtype is required as a precursor to coenzyme A?
Pantothenic acid (B5)
257
DPP-4 inhibitors work by stimulating insulin secretion and inhibiting the secretion of what other pancreatic hormone?
Glucagon
258
What is the term for the quantitive measure of the ability of a molecule to acquire electrons?
Reduction potential
259
A patient presents with poor wound healing, bleeding gums, and petechiae. Which of the following vitamins may be deficient?
Vitamin C
260
Howship's lacunae are a feature of what?
Osteoclasts
261
Cyclin-dependent kinase 9 (CDK9) is a key metabolic regulator and a candidate drug target for several types of cancer. CDK9 inhibitors have been shown to decrease the ability of prostate cancer cells to metabolize glucose, instead making them dependent on alternative energy sources. Given in combination with a CDK9 inhibitor, what would you predict would be lethal to prostate cancer cells?
Fatty acid oxidation inhibitors
