Case Based Problems Discussion

Chapter 1 : Organ Systems and Tissues

1.
In human development the brain and the spinal cord are derived from
- a.
  endoderm
- b.
  ectoderm
- c.
  mesoderm
- d.
  yolk sac
- e.
  none of the above
  
  The correct answer is b
2.
Oviducts and uterus are derived from
- a.
  myotome
- b.
  mesonephros
- c.
  Mullerian ducts
- d.
  endoderm
- e.
  all of the above
  
  The correct answer is c
3.
The human aorta gives rise to
- a.
  iliac artery
- b.
  renal vein
- c.
  hepatic vein
- d.
  vena cava
- e.
  none of the above
  
  The correct answer is a
4.
Pluripotent stem cells are a characteristic of the early stages of human development. One stage where pluripotent embryonic stem cells can be found is in the formation of the
- a.
  ectoderm
- b.
  endoderm
- c.
  gastrula
- d.
  blastocyst
- e.
  all of the above
  
  The correct answer is d
5.
The human adrenal glands are located
- a.
  above the pancreas
- b.
  proximate to the liver
- c.
  above the kidneys
- d.
  below the kidneys
- e.
  none of the above
  
  The correct answer is c
6.
Which of the following is not a precursor of the liver?
- a.
  blastocyst
- b.
  primitive gut
- c.
  endoderm
- d.
  mesoderm
- e.
  none of the above
  
  The correct answer is d

Chapter 2 : The Cell

1.
Which of the following is not part of a cell’s plasma membrane?
- a.
  cholesterol
- b.
  phospholipid
- c.
  fatty acid
- d.
  peroxisome
- e.
  none of the above
  
  The correct answer is d
2.
There are five histones and the class of histone that is bound in the linker region between nucleosomes is
- a.
  H3
- b.
  H1
- c.
  H2A
- d.
  H4
- e.
  none of the above
  
  The correct answer is b
3.
The G1 checkpoint in the cell cycle occurs during the
- a.
  mitotic phase
- b.
  first growth phase
- c.
  synthesis phase
- d.
  anaphase
- e.
  none of the above
  
  The correct answer is b
4.
In the process of cell division, the nuclear envelope breaks down during
- a.
  metaphase
- b.
  interphase
- c.
  prometaphase
- d.
  interphase
- e.
  anaphase
  
  The correct answer is c
5.
Which of the following is a part of the mitochondrion?
- a.
  DNA
- b.
  ribosomes
- c.
  ATP synthase
- d.
  cristae
- e.
  all of the above
  
  The correct answer is e
6.
The peroxisome contains the major enzyme
- a.
  xanthine oxidase
- b.
  succinate dehydrogenase
- c.
  urate oxidase
- d.
  hexokinase
- e.
  all of the above
  
  The correct answer is c

Chapter 3 : Introductory Discussion on Water, pH, Buffers, and General Features of Receptors, Channels, and Pumps

1.
Preprovasopressin after undergoing cleavages gives rise to mature peptides and proteins, such as
- a.
  neurophysin I
- b.
  β-endorphin
- c.
  oxytocin
- d.
  glycopeptide
- e.
  all of the above
  
  The correct answer is d
2.
Renal sodium and water retention can be developed through the action of
- a.
  oxytocin
- b.
  cortisol
- c.
  angiotensinogen
- d.
  erythropoietin
- e.
  all of the above
  
  The correct answer is c
3.
When water molecules course through an aquaporin water channel, water molecules leave the channel toward the cell cytoplasm with the oxygen atom facing
- a.
  downward
- b.
  upward
- c.
  upward and downward
- d.
  combined with extra positive charges
- e.
  none of the above
  
  The correct answer is a
4.
Water channels are formed in the apical membrane of a cell through hormone action. This allows more water vesicles to transit the cytoplasm and pass through channels on the basolateral membrane to access the extracellular fluid and ultimately the bloodstream. A channel involved in basolateral membrane transfer is
- a.
  aquaporin 1
- b.
  aquaporin 2
- c.
  aquaporin 3
- d.
  aquaporin 12
- e.
  all of the above
  
  The correct answer is c
5.
Metabolic water is derived from
- a.
  glycolysis
- b.
  gluconeogenesis
- c.
  alanine cycle
- d.
  citric acid cycle
- e.
  all of the above
  
  The correct answer is d
6.
Cellular hormone receptors are located in the
- a.
  plasma membrane
- b.
  nucleus
- c.
  cytoplasm
- d.
  chromatin
- e.
  all of the above
  
  The correct answer is e

Chapter 4 : Proteins

1.
PrP
- a.
  converts heme Fe ³⁺ to heme Fe ²⁺
- b.
  is primarily a monoamine oxidase
- c.
  is a cofactor for peroxidase
- d.
  is a binder of copper ion
- e.
  is primarily an infectious agent
  
  The correct answer is d
2.
Phenylketonuria is a disease that results from
- a.
  an aggregation of branched chain amino acids
- b.
  a mutation in the gene for phenylalanine hydroxylase
- c.
  an inability to convert DOPA to epinephrine
- d.
  a diet deficient in phenylalanine
- e.
  a failure in the alanine cycle
  
  The correct answer is b
3.
An asymmetric carbon atom is one in which
- a.
  there is a different substituent on each of its two bonds
- b.
  there needs to be one double bond
- c.
  there is a different substituent on each of its four bonds
- d.
  there can be two individual protons attached to the carbon
- e.
  there can be two hydroxyl groups attached to the carbon
  
  The correct answer is c
4.
The isoelectric point of a protein is
- a.
  a pH at which its positive and negative charges are equal
- b.
  the position of a protein in a gel
- c.
  equal to its sedimentation constant
- d.
  the point at which it binds maximally to protons
- e.
  the point at which it binds maximally to an uncharged surface
  
  The correct answer is a
5.
Glutathione is synthesized
- a.
  on a ribosome directed by its mRNA
- b.
  in an initial step by gamma-glutamylcysteine synthase
- c.
  by glutathione oxidase
- d.
  by glutamate dehydrogenase
- e.
  by glutaminase
  
  The correct answer is b
6.
The alpha helix of a protein is stabilized by
- a.
  hydrogen bonding between amide nitrogens and carbonyl carbons of peptide bonds
- b.
  interaction of water molecules with amino groups
- c.
  interaction of sulfhydryl groups with water
- d.
  interaction of side chain hydroxyl groups with chlorine ions
- e.
  none of the above
  
  The correct answer is a
7.
Hemoglobin is a protein having four subunits. The quaternary structure of this protein would show
- a.
  its amino acid composition
- b.
  its amino acid sequence
- c.
  its peptide chains before folding
- d.
  its subunit structure
- e.
  pyridoxal phosphate as cofactor
  
  The correct answer is d
8.
Chaperone proteins (HSPs) are proteins that
- a.
  hydrolyze tripeptides
- b.
  phosphorylate aquaporin subunits
- c.
  form deleterious complexes
- d.
  carry proteins to oxygen
- e.
  assist in protein folding
  
  The correct answer is e
9.
Posttranslational modification of a protein may involve
- a.
  methylation
- b.
  oxidation
- c.
  acetylation
- d.
  phosphorylation
- e.
  all of the above
  
  The correct answer is e

Chapter 5 : Enzymes

1.
When tissue injury occurs, soluble cytoplasmic enzymes can
- a.
  aggregate and form clots on the nuclear surface
- b.
  digest themselves as well as the nuclear membrane
- c.
  precipitate microsomes
- d.
  leak into the extracellular space and gain access to the bloodstream
- e.
  all of the above
  
  The correct answer is d
2.
If there is damage to muscle tissue, the best enzyme activity to measure in the blood to confirm this damage is
- a.
  hexokinase
- b.
  xanthine oxidase
- c.
  creatinine synthase
- d.
  tyrosinase
- e.
  creatine kinase
  
  The correct answer is e
3.
The Michaelis–Menten constant, km, can be expressed in terms of
- a.
  substrate concentration at maximal velocity
- b.
  free energy
- c.
  substrate concentration at half-maximal velocity
- d.
  product concentration at end of reaction
- e.
  initial velocity
  
  The correct answer is c
4.
1/ v = K _m (1/ V _max ) [1/S]+1/ V _max is a straight-line version of
- a.
  Michaelis–Menten equation
- b.
  Lineweaver–Burk equation
- c.
  equation showing saturation
- d.
  equation showing enzyme breakdown
- e.
  none of the above
  
  The correct answer is b
5.
Many drugs are used to inhibit the activity of a specific enzyme. The type of inhibition is usually
- a.
  competitive
- b.
  noncompetitive
- c.
  uncompetitive
- d.
  always allosteric
- e.
  involving a chemical reaction
  
  The correct answer is a
6.
Some enzymes have readily dissociable coenzymes. When a coenzyme has dissociated, what remains is a
- a.
  holoenzyme
- b.
  denatured enzyme
- c.
  apoenzyme
- d.
  enzyme–product complex
- e.
  precipitated enzyme
  
  The correct answer is c

Chapter 6 : Insulin and Sugars

1.
Insulin is split out of its precursor, preproinsulin to first form proinsulin. Proinsulin consists of
- a.
  insulin connected to zinc
- b.
  insulin connected to molybdenum
- c.
  insulin connected to albumin
- d.
  insulin connected to a connecting peptide
- e.
  none of the above
  
  The correct answer is d
2.
In the bloodstream insulin is usually found in the
- a.
  hexameric form
- b.
  dimeric form
- c.
  heptameric form
- d.
  monomeric form
- e.
  half monomeric form
  
  The correct answer is d
3.
Glucose enters the beta-cell of the pancreatic Islets of Langerhans through the
- a.
  GLUT 2 channel
- b.
  GLUT 4 channel
- c.
  potassium channel
- d.
  calcium channel
- e.
  snare-activated channel
  
  The correct answer is a
4.
Following ingestion of a meal, the cells of the duodenum and jejunum secrete
- a.
  glucagon and somatostatin
- b.
  glucose-dependent insulinotropic polypeptide and glucagon-like peptide
- c.
  ghrelin and pepsin
- d.
  ghrelin and diacylglycerol
- e.
  ghrelin and glucagon
  
  The correct answer is b
5.
In the process of evoking the release of insulin from the beta-cell of the pancreas, the ATP-dependent potassium channel is
- a.
  stimulated by ATP
- b.
  inhibited by the action of glucagon-like peptide
- c.
  stimulated by membrane depolarization
- d.
  stimulated by the action of glucose-dependent insulinotropic polypeptide
- e.
  stimulated by calcium ions
  
  The correct answer is b
6.
An anomeric center depends upon a carbon atom that is substituted by
- a.
  two hydroxyls and two protons
- b.
  two hydroxyls and two other groups
- c.
  four nonidentical substituents
- d.
  four identical substituents
- e.
  two identical and two nonidentical substituents
  
  The correct answer is c
7.
The formula of d -glucose can be written in
- a.
  only one form
- b.
  in two forms
- c.
  in three forms
- d.
  in four forms
- e.
  in five forms
  
  The correct answer is d
8.
There are five important GLUT transporters that move glucose from the extracellular space to the internal space of cells. The transporter that moves glucose to the interior of the hepatocyte is
- a.
  GLUT 4
- b.
  GLUT 5
- c.
  GLUT 2
- d.
  GLUT 1
- e.
  GLUT3
  
  The correct answer is c
9.
The pentose phosphate pathway develops a product that is used for the synthesis of nucleotides, DNA, and RNA. That product is
- a.
  arginine
- b.
  glucose-1-phosphate
- c.
  glucose-6-phosphate
- d.
  glucose-5-phosphate
- e.
  phosphoribosylpyrophosphate
  
  The correct answer is e
10.
Deoxyribose is needed for DNA synthesis. Deoxyribose is formed from
- a.
  ribose by ribose dehydrogenase
- b.
  glucose by decarboxylation
- c.
  glyceraldehyde-3-phosphate
- d.
  ribose nucleotide by ribonucleotide reductase
- e.
  fructose-1-phosphate
  
  The correct answer is d
11.
The blood group O antigen is the structure from which the A and B antigens are derived. The type A antigen is derived from the O antigen by the addition of
- a.
  fucose to the terminal galactose
- b.
  N -acetylgalactosamine to the terminal glucose
- c.
  Galactose to the terminal N -acetylglucosamine
- d.
  N -acetylglucosamine to the terminal galactose
- e.
  N -acetyl glucosamine to the terminal glucose
  
  The correct answer is d

Chapter 7 : Glycogen and Glycogenolysis

1.
In muscle cells, glucose can be metabolized to glycogen. Glucose enters the muscle cell through
- a.
  GLUT2
- b.
  hexokinase
- c.
  UDP-glucose
- d.
  GLUT4
- e.
  branching enzyme
  
  The correct answer is d
2.
Glycogenolysis is the process by which glucose is released from glycogen. The first enzymatic step in this process involves
- a.
  branching enzyme
- b.
  glycogen phosphorylase
- c.
  debranching enzyme
- d.
  glucose-1-phosphatase
- e.
  glucose-6-phosphatase
  
  The correct answer is b
3.
Glucokinase is an enzyme that can modify glucose by
- a.
  acetylation
- b.
  methylation
- c.
  glycosylation
- d.
  forming pyruvate
- e.
  phosphorylation
  
  The correct answer is e
4.
An Islet of Langerhans contains different cell types. For example, the beta-cell secretes insulin. The alpha-cell secretes
- a.
  somatostatin
- b.
  ghrelin
- c.
  pepsin
- d.
  glucagon
- e.
  insulin-like growth factor
  
  The correct answer is d
5.
Glucagon causes an increase in the blood level of glucose by
- a.
  increasing glycogen synthesis
- b.
  suppressing glycogen degradation
- c.
  dephosphorylating glycogen synthase b
- d.
  dephosphorylating glycogen phosphorylase a
- e.
  phosphorylating glycogen phosphorylase a
  
  The correct answer is e
6.
Epinephrine binds and activates an alpha-adrenergic receptor on the cell membrane of the hepatocyte to increase the level of glucose in the bloodstream. The signaling pathway mediating this response involves
- a.
  decreased cAMP
- b.
  blocking a calcium channel
- c.
  increasing cellular calcium ion from the cellular store
- d.
  decreasing the level of calmodulin
- e.
  inhibiting glycogen phosphorylase
  
  The correct answer is c
7.
The action of insulin is to reduce the level of glucose in the bloodstream. Insulin induces this effect by first binding to the insulin receptor. One result of insulin action is to
- a.
  increase glycogen degradation
- b.
  activate phosphoenolpyruvate carboxykinase
- c.
  inhibit glycogen synthase
- d.
  suppress glycogen degradation
- e.
  activate glycogen phosphorylase
  
  The correct answer is d

Chapter 8 : Glycolysis and Gluconeogenesis

1.
2,3- bis phosphoglycerate is a molecule that is important for the functioning of hemoglobin because
- a.
  it forms a complex with a subunit of pyruvate oxidase
- b.
  it forms a complex with methemoglobin
- c.
  it binds to a lysine residue forming a Schiff base in basic proteins
- d.
  it binds to the taut state of hemoglobin and facilitates the release of oxygen to the lungs
- e.
  all of the above
  
  The correct answer is d
2.
The pentose phosphate pathway
- a.
  connects to glycolysis through its intermediates that can enter the glycolytic pathway
- b.
  can provide NADPH when its concentration is low
- c.
  can produce ribose 5-phosphate for the synthesis of nucleic acids
- d.
  can adapt to a cell’s need for reducing equivalents
- e.
  all of the above
  
  The correct answer is e
3.
Hexokinase and glucokinase are two enzymes that phosphorylate glucose
- a.
  the difference between the two enzymes is that glucokinase aggregates to a large molecular weight before it becomes active
- b.
  hexokinase has a much smaller km for glucose than does glucokinase
- c.
  glucokinase is primarily used in muscle
- d.
  hexokinase is primarily used in the liver
- e.
  none of the above
  
  The correct answer is b
4.
The product of the glycolytic pathway enters the mitochondria for the aerobic production of ATP
- a.
  enol pyruvate enters the mitochondrion
- b.
  lactic acid enters the mitochondrion
- c.
  enol pyruvate spontaneously is converted to keto pyruvate that enters the mitochondrion
- d.
  alanine, produced by glycolysis, enters the mitochondrion
- e.
  none of the above
  
  The correct answer is c
5.
The difference between normal differentiated tissue and proliferative tumor tissue is
- a.
  normal tissue cells rely both on glycolysis and mitochondrial oxidative phosphorylation to produce about 38 molecules of ATP from glucose, whereas tumor tissue cells rely more on glycolysis for production of ATP
- b.
  tumor cells rely on glycolysis for the production of ATP even though they contain functional mitochondria
- c.
  in tumor cells some glucose is diverted for other uses, such as for macromolecular syntheses so it is not used in the glycolytic pathway
- d.
  the Warburg effect describes the preference for cancer cells to utilize the glycolytic pathway for the production of ATP compared to differentiated cells
- e.
  all of the above are correct
  
  The correct answer is e
6.
Certain stresses, such as fasting can lead to the breakdown of muscle protein. One of the products of muscle protein degradation is the amino acid alanine. Alanine can be converted to glucose to provide ATP through glycolysis. This can be accomplished
- a.
  by the pentose phosphate pathway cycle
- b.
  by the alanine cycle where alanine is transported to the pancreas
- c.
  by the alanine cycle where alanine is transported to the liver and converted to pyruvate by tyrosine aminotransferase for entry into gluconeogenesis
- d.
  by the alanine cycle where alanine is transported to the liver and converted to pyruvate by glutamate-pyruvate transaminase for entry into gluconeogenesis
- e.
  none of the above
  
  The correct answer is d

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Chapter 1 : Organ Systems and Tissues

Chapter 2 : The Cell

Chapter 3 : Introductory Discussion on Water, pH, Buffers, and General Features of Receptors, Channels, and Pumps

Chapter 4 : Proteins

Chapter 5 : Enzymes

Chapter 6 : Insulin and Sugars

Chapter 7 : Glycogen and Glycogenolysis

Chapter 8 : Glycolysis and Gluconeogenesis

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