Biochemistry Exam 4

A detailed illustration of biochemical pathways related to metabolism, vitamins, and hormones, with visual elements like DNA strands, enzymes, and dietary components in a vibrant style.

Essential Biochemistry Quiz

Test your knowledge of essential biochemistry concepts with our comprehensive quiz! This quiz covers a variety of topics including metabolic pathways, nutrition, hormones, and vitamin deficiencies.

Whether you're a student looking to revise for your exams or an educator seeking to test your understanding, this quiz is perfect for you. Key features include:

  • 81 multiple-choice questions
  • Focused on important biochemistry principles
  • Immediate feedback on your answers
81 Questions20 MinutesCreated by LearningBiochem247
It is recommended that women take folic acid supplements before and during the first trimester of pregnancy to prevent neural tube defects in the developing fetus because:
The synthesis of the cholesterol precursor HMGCoA requires folic acid.
Porphyrin and heme synthesis during development requires high concentrations of folic acid.
Oxygen transfer from maternal to fetal hemoglobin is accentuated by folic acid
Some of the enzymes in phospholipid biosynthesis use folate derivatives as substrates.
Folate derivatives are required for the synthesis of nucleotides.
What two things could counter ketoacidosis in a patient with uncontrolled diabetes who visits a hospital emergency room?
insulin and no carbohydrates in the diet
Bicarbonate given intravenously and insulin
Glucagon and glucose given intravenously
Insulin and glucose given intravenously
It is not possible to reverse ketoacidosis once the condition becomes severe.
AMP can accumulate from prolonged, vigorous activity. What would be the result of increased leptin concentrations in the liver and muscle as a response to high AMP?
Increased nucleoside diphosphate kinase activity
Increased protein kinase A activity, favoring glycolysis and glycogenolysis
increased glycolysis and fatty acid oxidation vi AMP-dependent kinase activation
increased adenylate kinase activity and stimulation of glycogen synthesis
stimulation of lactate fermentation and the glucose-alanine cycle
Oxytocin, insulin, and vasopressin are all proteins, and they all coordinately regulate metabolic functions in several tissues. How else are they related, biochemically?
They all increase glucose storage, but in different tissues
They all act on different tissues but all signal through tyrosine kinase receptors
They are all released by the same endocrine tissue but bind to different receptors
They are all very small and contain internal disulfide linkages.
They are all endocrine hormones that have similar signaling effects on target tissue
Insulin promotes many metabolic effect in different tissues. Which statement is TRUE?
In the liver, insulin promotes glycolysis, glycogenesis but decreases fatty acid synthesis
In the adipose tissue, insulin promotes glycolysis and glycogenesis.
In the muscle, insulin promotes glycogenolysis and gluconeogenesis
In the liver, insulin promotes glycolysis and glycogenesis but increases fatty acid synthesis.
In the adipose tissue, insulin inhibits glycolysis and glycogenesis
What metabolic advantage does brown fat provide over white fat?
generation of heat, rather than ATP, which is a desired outcome
faster generation of ATP via oxidative phosphorylation
a higher level of β oxidation because brown fat cells contain more unsaturated fatty acids with even numbers of carbons
Location within and near the liver, providing extremely rapid transport of fats during times of physiological or metabolic stress.
Membrane receptors for more classes of hormones and other signaling molecules
Insulin receptor activation stimulates the phosphorylation of each of the following proteins except:
Insulin receptor.
IRS-1
IRS-2
PDK1
Akt
Beta blockers are drugs that inhibit beta-adrenergic receptors and are used to control tachycardia (high heart rate) and anxiety disorders by countering the effects of epinephrine. Which of the following intracellular second messengers would be expected to decrease in a patient treated with a beta blocker?
CAMP
DAG
IP3
Ca2+
CGMP
Where is the kinase catalytic domain of the receptor tyrosine kinases found?
On the extracellular surface of the receptor, immediately adjacent to the ligand binding domain
On the cytoplasmic domain of the receptor
On an independent protein that rapidly binds the receptor upon binding
Within the transmembrane spanning portion of the receptor
Which hormone is secreted by α-cells in the pancreas in response to low blood glucose levels?
Insulin
Glucagon
Epinephrine
Cortisol
Norepinephrine
A blood sample is taken from a 40-year old man who has been fasting completely for a week, drinking only water. Which of the following will be at a higher concentration than after a normal overnight fast?
Glucose
Insulin
Ketone bodies
Triacylglycerol
Nonesterified fatty acids
Asians and Native Americans may flush and feel ill after drinking a small amount of ethanol in alcoholic beverages. This reaction is due to genetic variation in an enzyme that metabolizes the liver metabolite of alcohol, which is
Methanol
Acetone
Glycerol
Acetaldehyde
Pyruvate
Which of the following is the best definition of glycemic index?
The increase in the blood concentration of glucagon after consuming food compared with that after an equivalent amount of white bread
The increase in the blood concentration of glucose after consuming the food
The increase in the blood concentration of glucose after consuming food compared with that after an equivalent amount of white bread
The increase in the blood concentration of insulin after consuming the food
The increase in the blood concentration of insulin after consuming food compared with that after an equivalent amount of white bread
Which of the following will be elevated in the bloodstream about 1 to 2 hours after eating a highfat meal?
Chylomicrons
High density lipoprotein
Ketone Bodies
Nonesterified fatty acids
Very low density lipoproteins
A 5-year old child arriving at the refugee center in East Africa is stunted in growth (90% of expected height) but not oedematous. Would you consider him to be:
Suffering from kwashiorkor
Suffering from marasmus
Suffering from diabetes
Suffering from undernutrition
Not considered to be clinically malnourished
A 5-year old child arriving at the refugee center in East Africa is stunted in growth (55% of expected height) but not oedematous. Would you consider him to be:
Suffering from kwashiorkor
Suffering from diabetes
Suffering from marasmus
Suffering from undernutrition
Not considered to be clinically malnourished
Deficiency of which one of these vitamins is a major cause of blindness worldwide?
Vitamin A
Vitamin B12
Vitamin B6
Vitamin D
Vitamin K
Deficiency of which one of these vitamins may lead to megaloblastic anemia?
Vitamin B6
Vitamin B12
Vitamin D
Vitamin E
Vitamin K
Which of the following statements about the fed and fasting metabolic states is correct?
In the fasting state, glucagon acts to increase the activity of lipoprotein lipase in adipose tissue.
In the fasting state, glucagon acts to increase the synthesis of glycogen from glucose
In the fed state, insulin acts to increase the breakdown of glycogen to maintain blood glucose
In the fed state, there is decreased secretion of insulin in response to increased glucose in the portal blood.
Ketone bodies are synthesized in the liver in the fasting state, and the amount synthesized increases as fasting extends into starvation
Which of the following statements about the fed and fasting metabolic states is correct?
In the fasting state, adipose tissue synthesizes glucose from the glycerol released by the breakdown of TAG
In the fasting state, adipose tissue synthesizes ketone bodies
In the fating state, the main fuel for red blood cells is fatty acids released from adipose tissue
Ketone bodies provide the main fuel for the central nervous system in the fasting state.
Plasma glucose is maintained in starvation and prolonged fasting by gluconeogenesis in the liver from the amino acids released by the breakdown of muscle protein
What percentage of the population will have met their requirement for a vitamin or mineral if their intake is equal to the average requirement?
5%
25%
50%
95%
100%
Which of the following is the best definition of the reference nutrient intake (RNI) or recommended daily amount (RDA), of a vitamin or mineral?
One standard deviation above the average requirement of the population group under consideration
One standard deviation below the average requirement of the population group under consideration
The average requirement of the population group under consideration
. Two standard deviations above the average requirement of the population group under consideration
Two standard deviations below the average requirement of the population group under consideration
Which of the following does NOT occur in people with untreated diabetes?
Fatty acids become the main fuel for most tissues.
Ketone body formation is stimulated
Excess glucose is stored as glycogen.
Triacylglycerol breakdown is stimulated.
Which of the following vitamins provides the cofactor for reduction reactions in fatty acid synthesis?
Folate
Niacin
Riboflavin
Thiamin
Biotin
Which one is NOT an electrolyte?
Magnesium
Sodium
Potassium
Sulfur
Bicarbonate
Which one is Dr. Y’s favorite diet?
South Beach Diet
Atkins Diet
Ketogenic Diet
Mediterranean Diet
Paleo Diet
Which of the following minerals is involved in the synthesis of thyroid hormones triiodothyronine (T3) and thyroxin?
Zinc
Manganese
Iodine
What is the most common complication of insulin therapy in Type I Diabetes?
Hyperglycemia caused by excess insulin
Hyperglycemia caused by excess glucose
Hypoglycemia caused by an insulin deficit
Hypoglycemia caused by excess insulin
What leads to type 2 Diabetes?
Only insulin resistance
Combination dysfunctional Beta-cells and ketone bodies
Ketone bodies
Combination of insulin resistance and dysfunctional Beta-cells.
What fat is most metabolically active
Visceral adipocytes
Subq adipocytes
White fat
Brown fat
In the presence of insulin in a healthy person, what is a likely result for amino acids circulating in the blood?
Increased formation of ketone bodies by the liver
increased tendency toward hyperglycemia
Increased its uptake in peripheral tissues
Increased tendency toward nephropathy
Increased in more alanine and glutamine than other amino acids
Which micronutrient is responsible for the formation of γ-carboxyglutamyl residue?
Iodine
Ferrous ion
Vitamin K
Tetrahydrofolate
Vitamin B12
What is one compound that is made in the kidney, which can be used as a substrate for gluconeogenesis?
Acetyl coA
Alpha ketoglutarate
Leucine
Glucose
Lysine
Which of the following best describes Type I Diabetes?
Absolute deficiency of insulin due to autoimmune attack of beta cells of the pancreas.
Slight deficiency of insulin due to autoimmune attack of alpha cells of the pancreas.
Absolute deficiency of insulin due to autoimmune attack of alpha cells of the pancreas.
Patients with Type 2 diabetes are found to have a combination of insulin resistance and dysfunctional beta cells. Treatment often works towards maintaining blood glucose concentrations within normal limits. Which hypoglycemic agent should be used in order to decrease hepatic gluconeogenesis?
SGLT inhibitors
Alpha-glucosidase inhibitors
Metformin
Sulfonylureas
thiazolidinediones
Release of FFA and secretion of pro-inflammatory cytokines is found in obesity. Such proinflammatory cytokines include:
IL-4 and TNF-alpha
IL-4 and TNF-beta
IL-6 and TNF-alpha
IL-6 and TNF-beta
IL-6 only
A folic acid deficiency in early pregnancy can cause what to develop in the developing fetus?
Scurvy
Wernicke-Korsakoff Syndrome
Pernicious Anemia
Spina Bifida
Which one of the following is true about the function GLUT-1?
GLUT1 is primarily located in the heart.
GLUT 1 is involved with both insulin-dependent and insulin-independent transport within blood brain barrier.
GLUT 1 is involved with insulin- independent transport in the blood brain barrier.
GLUT 1 primarily located in the liver.
Which answer below is NOT one of the forms of weight reduction?
Caloric Restriction
Physical Activity
Surgical Treatment
Ghrelin Activation Therapy
€Homeoviscous adaptation” is the process whereby bacteria adjust the fatty-acid composition of their phospholipids to maintain constant membrane fluidity when incubated at non-standard temperatures. Which of the following describes the lipid content of cells cultured at 30°C compared with control cells incubated at 23°C
Fatty acids are more polyunsaturated than in control cells
Fatty acids are, on the average, shorter than in control cells
Fatty acids are identical in composition to those in control cells.
Fatty acids have fewer double bonds than those in control cells.
Fatty acid content is similar, but the amount of PE is decreased.
Increased Insulin levels result in the increase synthesis of which of the following enzymes?
Fatty Acid Synthase
Glucose 6 Phosphatase
Phosphoenolpyruvate Carboxykinase
Glutamate Dehydrogenase
Glutamate Dehydrogenase
The major, defining difference between a type 1 diabetic and a type 2 diabetic is which of the following?
Weight
Ability to produce insulin
LDL Levels
Blood glucose levels
Serum triglyceride levels
Both Hashimoto's Disease and Graves Disease present with goiter, but through different mechanisms. What is the main cause of goiter in Hashimoto's and Graves Disease respectively:
Lack of PLP and Overproduction of T4
Lack of dietary Iodine and hypersecretion of TSHthe major
Over secretion of TSH and Iodine insufficiency
Autoimmune destruction of TPO and autoantibodies binding TSH receptors
Which of the following is not a symptom of type 1 diabetes mellitus?
Polyuria
Polydipsia
hypodipsia
Polyphasia
Fatigue
What processes performed by the liver in fasting are responsible for maintaining blood glucose through the production of glucose?
Fatty Acid Synthesis and Gluconeogenesis
Gluconeogenesis and Glycogenolysis
Glycolysis and Gluconeogenesis
The Citric Acid Cycle and Glycolysis
Which would not be an appropriate process of the fasting state?
Release of glucagon by alpha cells of the pancreas
Hydrolysis of stored triacylglycerol to form free fatty acids in adipose tissue
Use of ketone bodies as energy by tissues
Synthesis of VLDL in the liver
Which of the following is not a fat soluble vitamin?
Vitamin A
Vitamin D
Vitamin C
Vitamin K
Vitamin E
What role does Adiponectin play in fat regulation?
Increase free fatty acid levels in the body
Increase fatty acid oxidation in muscle
Regulates appetite
Stimulates inflammation in patients with diabetes
Which is not associated with Leptin?
Leptin secretion is proportional to size of fat storage
Leptin is a complex carbohydrate involved in insulin regulation
Leptin levels are upregulated in a caloric surplus
Leptin resistance is common among overweight individuals.
Insulin and Leptin suppress appetite through regulation of hypothalamic neuron signaling.
A deficiency of thiamine produces the disease known as
Beri-Beri
Scurvy
Catarct
Anemia
The major cause of hypoglycemia in people who drink more alcohol is that, excess alcohol
Increases the activity of alcohol dehydrogenase
Suppresses glucagon secretion
induces production of abundant NADH
Stimulates excess insulin secretion
A deficiency in which of the following vitamins will lead to a functional folate deficiency?
Thiamine
Niacin
Riboflavin
B12
Vitamin C
Which of the following do adipocytes NOT secrete?
Leptin
Adiponectin
Ghrelin
IL-6
TNF-alpha
The liver cannot use ketone bodies as fuel due to the fact that it lacks
Fructose 1,6 - Bisphosphate
Glycogen phosphorylase
Thiophorase
Glycogenphosphorylase
Acetylase
Folic acid consists of the
Base pteridine, p-amino benzoic acid, and aspartic acid
Base purine, p-amino benzoic acid, and glutamate
Base pteridine, p-amino benzoic acid, and glutamate
Base purine, p-hydroxy benzoic acid, and glutamate
Which of the following most accurately describes the insulin-dependent glucose transporter (GLUT-2) of hepatocytes?
Has a high affinity for glucose
Has a low affinity for glucose
Has a high affinity for glucose and uptakes glucose when blood glucose is low
Has a low affinity for glucose and uptakes glucose when blood glucose is high
Which of the following enzymes converts glucose to glucose-6-phosphate in carbohydrate Metabolism?
Hexokinase
Phosphokinase
Glycogen phosphorylase kinase
Phosphorylase kinase
Glucose-6-phosphate kinase
A patient with a BMI of 27 is considered ______ and has _________ levels of adiponectin and_______ levels of leptin.
Healthy, increased, decreased
Overweight, decreased, increased
Obese, increased, increased
Overweight, decreased, decreased
What are the hallmark indicators of untreated type 1 diabetes mellitus (T1D)?
Hypoglycemia and increased levels of ketone bodies
Hyperglycemia and increased levels of ketone bodies
Hypoglycemia and decreased levels of ketone bodies
Hyperglycemia and decreased levels of ketone bodies
Hypoglycemia and decreased levels of insulin
Ketogenesis is favored when the concentration of which of the following molecules exceeds the oxidative capacity of the TCA cycle?
Acetyl-CoA
B-hydroxybutyrate
Citrate
Dihydroxyacetone phosphate
Enolase
Thiazolidinediones are hypoglycemic agents used in the treatment of type II diabetes that primarily serve to:
Decease peripheral insulin sensitivity
Increase Insulin secretion
Decrease FFA levels
Decrease renal absorption of glucose
Which one of the following represents the correct order of reactions involved in absorption and transport of vitamin A?
Retinal binding proteins attached to receptors of peripheral tissue, chylomicron storage, hydrolysis, re-esterification
Retinal esters hydrolyzed, re-esterified, chylomicron storage in liver, retinal binding protein complex attachment to the extra hepatic tissue
Chylomicron storage in liver, hydrolyzed retinyl esters, re-esterified, retinol binding complex attachment to extra hepatic tissue
LCFA re-esterified, hydrolyzed retinyl esters, chylomicron storage, retinol binding protein complex attachment to peripheral tissue
Most obesity is due to increased fat cell size which is called:
Hypertrophy
Hyperplasia
Hyperlipidemia
Hypergraphia
Hypertonia
Type 2 diabetes is best characterized as?
Autoimmune destruction of alpha cells of the pancreas
Autoimmune destruction of beta cells of the pancreas
Containing a strong genetic component, resulting in a combination of insulin resistance and dysfunction beta cells.
Containing a strong genetic component, resulting in a combination of insulin resistance and dysfunction alpha cells.
In the absorptive state, which of the following covalently regulated enzymes is dephosphorylated and active?
Glycogen phosphorylase kinase
Glycogen phosphorylase
Glycogen Synthase
Hormone sensitive lipase
N fasting state, the main target of glucagon is the liver, where it promotes the release of energy generating molecules into the blood by all the following except
Nhibiting glycogen synthase and activating glycogen phosphorylase.
Promoting gluconeogenesis.
Increasing uptake of amino acids.
Promoting ketone body formation.
Increase glucose uptake into cells (mediated by GLUT4).
Leptin
increases secretion of alpha-MSH and decreases secretion of NPY
increases secretion of alpha-MSH and increases secretion of NPY
Decreases secretion of alpha-MSH and increases secretion of NPY
has no effect on alpha-MSH or NPY
Ic syndromes due to how they enter portal circulation. Which of the following portal circulation patterns correlates with “pear-shaped” and “apple-shaped”?
(A) “Pear-shaped” individuals have their FFA deposited into a portal vein where it has direct access to the liver while “apple-shaped” individuals have their FFA deposited into general circulation, where it can reach the liver in lower concentrations
“Pear-shaped” individuals have their FFA deposited into general circulation, where it reaches the liver in lesser concentrations while “apple-shaped” individuals have their FFA deposited directly into the portal vein
Both body shapes have equal risk of developing diabetes and metabolic syndrome because they both deposit directly into the liver
Both body shapes have reduced risk of developing diabetes and metabolic syndrome because FFA’s are injected into general circulation
Ascorbic acid roles include all of the following EXCEPT..... (S
Reducing Agent
Coenzyme in hydroxylation reactions
Maintenance of connective tissue, wounding healing, and absorption of iron
Systemic free radical production
Prevention of Scurvy
Vitamin K exists in intestinal bacterial flora as which form?
Phylloquinone
Menaquinone
menadione
Pyridoxine
Elevated levels of what metabolites are the hallmarks of untreated Type 1 Diabetes?
Blood Glucose and Ketone Bodies
FFA and Glycerol
FFA and Amino Acids
Acetyl - CoA and Alanine
Which vitamin is required for the following transamination reaction: Oxaloacetate + glutamate ⇌ aspartate + a-ketoglutarate
Thiamine (B1)
Riboflavin (B2)
Niacin (B3)
Pyridoxine (B6)
Cobalamin (B12)
Hich of the following is true regarding the regulation of serum Ca2+ and Pi levels?
Parathyroid hormone and calcitriol respond to elevated serum Ca2+ levels
1,25-dihydroxycholecalciferol is produced in large quantities by small intestine following a meal
Calcitonin responds to elevated serum Ca2+ levels
PTH decreases serum Ca2+ by increasing bone resorption
What do decreased plasma levels of glucose, amino acids, and TAG NOT trigger in the fasted state?
Decrease in insulin secretion
increase in glucagon secretion
Decrease in epinephrine secretion
Increase in cortisol secretion
Which of the following is true about consumption of soluble dietary fiber?
Dietary fibers decreases bowel motility
Dietary fibers hardens stool and increases the risk for constipation
Dietary fibers has shown to increase LDL-C levels and increase plasma cholesterol
Dietary fibers decreases plasma cholesterol by increasing bile acid secretion
Dietary fibers provide large amounts of energy
You are treating a patient with a fat malabsorption problem, and you suggest that the patient switch his or her diet to one that contains which of the following?
Triglycerides with long-chain fatty acids
Triglycerides with medium-chain fatty acids
Triglycerides with a mixture of long-chain and short-chain fatty acids
Triglycerides with a mixture of long-chain and medium-chain fatty acids
Which micromineral does not act as an enzyme cofactor?
Copper
Iron
Chromium
Zinc
Ascorbic acid does NOT play a role in which of the following:
Wound healing Copper
Maintenance of connective tissue
absorption of vitamin D
absorption of iron
Which of the following is true about the glycemic index?
He glycemic index ranks carbohydrate-rich foods on a scale of 0–100 based on the metabolic response (MR).
Food with a high GI tends to create a sense of satiety over a longer period of time.
A high GI is considered >55
Low-GI diet improves glycemic control in diabetic individuals.
Carbohydrates with a low GI are digested and metabolized quicker, hence causing a faster rise in blood glucose.
Wilson’s Disease involves a mineral accumulating in the liver that ultimately leaks into the blood and is deposited into the brain, eyes, kidney, and skin. What mineral is in excess?
Manganese
Magnesium
Calcium
Copper
Chromium
Caffeine prolongs and intensifies the effects of epinephrine. Which of the following potential mechanisms of action of caffeine is consistent with this effect?
Inhibits cAMP phosphodiesterase
A competitive antagonist of cAMP binding to PKA
Stimulates phospholipase C
Inhibits sarcoplasmic/endplasmic reticulum Ca2+-ATPase
Activates PKC
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