85 Questions
Which level of protein structure is an alpha helix?
Secondary structure
Above a pH 5, why does an alpha helix take on a random coil configuration?
Ionization of Aspartate residues
Why do the amino acid substitutions of Lysine to Arginine have little effect on the protein's function?
Lysine and Arginine have opposite charges
Why do the amino acid substitutions of Isoleucine to Leucine have little effect on the protein's function?
Isoleucine and Leucine have similar side chain structures
What is the function of red blood cells?
To deliver oxygen to body tissues
How many oxygen molecules can each hemoglobin protein carry?
4
Why do red blood cells not contain a nucleus?
To make room for hemoglobin
What is sickle cell anemia?
An inherited disorder causing fragile red blood cells
What can happen if sickle cell anemia red blood cells block smaller vessels?
Pain and organ damage
What can sickle cell anemia red blood cells damage over time?
Spleen, kidneys, brain, bones, and other organs
During a sickle cell crisis, what causes the shape of hemoglobin to be altered irreversibly?
Low oxygenation levels
What is the cause of sickle cell anemia?
A substitution of glutamate for Valine in the β hemoglobin subunit
Why does the single amino acid substitution in sickle cell anemia result in significant problems?
It alters the interactions between hemoglobin molecules
What are the symptoms of a sickle cell crisis?
Pain, worsening anemia symptoms, fever, and shortness of breath
Why can't the red blood cell simply replace irreversibly altered hemoglobin after a sickle cell crisis?
The altered hemoglobin cannot be replaced with relatively functional hemoglobin
What is the characteristic shape of red blood cells during a sickle cell crisis?
Sickled shape
What triggers a sickle cell crisis?
Anything that reduces the amount of oxygen in the blood
What is the function of hemoglobin in red blood cells?
To carry oxygen
What is the result of the substitution of glutamate for Valine in the β hemoglobin subunit?
Abnormal red blood cell shape
What causes pain during a sickle cell crisis?
Occlusion of blood vessels
During a sickle cell crisis, what is the primary cause of the altered shape of red blood cells?
Low oxygenation levels
What is the result of the substitution of glutamate for Valine in the β hemoglobin subunit?
The red blood cell shape becomes abnormal
Why does the single amino acid substitution in sickle cell anemia result in significant problems?
It alters the interactions between hemoglobin molecules
What triggers a sickle cell crisis?
Anything that reduces the amount of oxygen in the blood
What are the symptoms of a sickle cell crisis?
Pain, worsening anemia symptoms, fever, and shortness of breath
Why can't the red blood cell simply replace irreversibly altered hemoglobin after a sickle cell crisis?
The altered hemoglobin cannot be replaced with functional hemoglobin
What is the characteristic shape of red blood cells during a sickle cell crisis?
Sickled shape
What causes pain during a sickle cell crisis?
Occlusion of blood vessels
What can sickle cell anemia red blood cells damage over time?
Smaller blood vessels
What is the cause of sickle cell anemia?
A substitution of glutamate for Valine in the β hemoglobin subunit
Which level of protein structure is an alpha helix?
Secondary structure
Above a pH 5, why does an alpha helix take on a random coil configuration?
The pH change disrupts the hydrogen bonds stabilizing the alpha helix structure.
Why do the amino acid substitutions of Lysine to Arginine have little effect on the protein's function?
Lysine and Arginine have opposite charges.
Why do the amino acid substitutions of Isoleucine to Leucine have little effect on the protein's function?
Isoleucine and Leucine have similar hydrophobicity.
What is the characteristic shape of red blood cells during a sickle cell crisis?
Sickle-shaped
What can happen if sickle cell anemia red blood cells block smaller vessels?
Pain, organ damage, and lack of oxygenation
During a sickle cell crisis, what causes the shape of hemoglobin to be altered irreversibly?
Decreased oxygen levels
During a sickle cell crisis, what triggers the alteration in the shape of hemoglobin?
Low oxygenation levels
What is the primary cause of the altered shape of red blood cells during a sickle cell crisis?
Low oxygenation levels
What are the symptoms of a sickle cell crisis?
Pain, worsening anemia symptoms, fever, and shortness of breath
What is the cause of sickle cell anemia?
Substitution of glutamate (normal) for Valine (sickle cell) in the β hemoglobin subunit
Why does the single amino acid substitution in sickle cell anemia result in significant problems?
It alters the shape of hemoglobin irreversibly
What can happen if sickle cell anemia red blood cells block smaller vessels?
Tissue damage and pain
After a sickle cell crisis, why can't the red blood cell simply replace the irreversibly altered hemoglobin?
The altered hemoglobin is permanently changed
Why would the single amino acid substitution result in such a significant problem?
It changes the interactions between hemoglobin molecules
Which of the following is not a level of protein structure?
Quaternary
What is the term used to describe the disruption in folding/shape of a protein?
Denaturation
Which type of bonds within proteins can be disrupted by strong acids or bases, organic solvents, salts, and heavy metal ions?
Salt bridges
Which heavy metals can denature proteins based on their charge?
Mercury (Hg+2) and lead (Pb+2)
Which type of amino acid side chain can heavy metals like mercury and lead bind to?
Charged side chains
Which type of interaction within a protein would be disrupted by heavy metals like mercury and lead?
Ionic interactions
What are some examples of agents that can disrupt the bonds within proteins and denature them?
Strong acids or bases, organic solvents, salts, and heavy metal ions
Which of the following is NOT a way in which cofactors and coenzymes can help enzymes speed up reactions?
Breaking covalent bonds in the enzyme structure
What effect does temperature have on enzyme activity?
Increases enzyme activity
How does changing the pH affect enzyme activity?
It decreases enzyme activity
What is the function of a lysosome?
Main site of intracellular enzymatic degradation for a wide range of molecules
At what pH are lysosomal enzymes active?
pH of ~45
How can the activity of enzymes be controlled?
Genetic regulation
What is an example of genetic regulation of enzyme activity?
Inducing enzyme transcription and translation in times of need
Which enzyme catalyzes the phosphorylation of glycogen phosphorylase kinase? Is the reaction reversible or irreversible?
Protein kinase A; reversible
What is the role of covalent modification in enzyme regulation?
To change the conformation of enzymes
Which type of enzyme regulation involves the binding of an effector molecule to an allosteric site?
Allosteric modification
What effect does high levels of ATP have on phosphofructokinase-1 (PFK-1)?
Inhibition
How does compartmentalization of enzymes via membrane-bound organelles contribute to enzyme regulation?
By separating enzymes from opposing pathways
Which metabolic pathways are commonly compartmentalized in different areas of the cell?
Glycolysis and gluconeogenesis
What triggers the irreversible covalent modification of enzymes?
Cleavage of peptide bonds in proenzymes or zymogens
Which subunit of allosteric enzymes contains the allosteric site?
A different subunit from the active site
What effect does an effector molecule have on the binding of the substrate to an allosteric enzyme?
Decreases binding of the substrate
Enzymes are an example of a type of __________ protein.
globular
Enzymes speed up a reaction by lowering the __________ energy of the reaction.
activation
The minimal amount of energy needed to make/break the bonds necessary for a reaction to occur is called __________ energy.
activation
Enzyme molecules contain a special cleft called the __________ site.
active
Enzymes are highly specific and only a substrate of the correct __________ and shape can enter into the active site.
size
Which amino acid side chain can function easily as an acid or a base?
Aspartic acid
Enzymes often have help from cofactors and coenzymes. Cofactors are typically __________ cations.
metal
Which enzyme is responsible for the phosphorylation of glycogen phosphorylase kinase?
Glycogen phosphorylase kinase
What type of modification inhibits the activity of phosphofructokinase-1 (PFK-1)?
Allosteric modification
What effect does high levels of ATP have on phosphofructokinase-1 (PFK-1)?
Inhibition
What effect does high levels of AMP have on phosphofructokinase-1 (PFK-1)?
Activation
What is the purpose of compartmentalization in enzyme regulation?
Both A and B
Which metabolic pathway is commonly compartmentalized in different areas of the cell?
Glycolysis
What type of modification involves the cleavage of peptide bonds in proenzymes or zymogens?
Covalent modification
What effect does an effector molecule have on the binding of the substrate to an allosteric enzyme?
Increase binding of the substrate
Which subunit of allosteric enzymes contains the allosteric site?
The subunit with the effector site
What is the reaction catalyzed by phosphofructokinase-1 (PFK-1)? Is it reversible or irreversible?
Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate
Test your knowledge on proteins with this quiz for BMS100. Answer questions about protein structure, including identifying the level of protein structure of an alpha helix. Get ready to ace your assignment!
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