Proteins and Enzymes

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Which level of protein structure is an alpha helix?

Primary structure

Quaternary structure

Secondary structure (correct)

Tertiary structure

Above a pH 5, why does an alpha helix take on a random coil configuration?

Increase in hydrophobic interactions

Formation of disulfide bonds

Denaturation of the protein

Ionization of Aspartate residues (correct)

Why do the amino acid substitutions of Lysine to Arginine have little effect on the protein's function?

Lysine and Arginine have opposite charges (correct)

Lysine and Arginine have similar side chain structures

Lysine and Arginine have similar chemical properties

Lysine and Arginine have similar molecular weights

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 Signup and view all the answers

What is the function of red blood cells?

To deliver oxygen to body tissues Signup and view all the answers

How many oxygen molecules can each hemoglobin protein carry?

4 Signup and view all the answers

Why do red blood cells not contain a nucleus?

To make room for hemoglobin Signup and view all the answers

What is sickle cell anemia?

An inherited disorder causing fragile red blood cells Signup and view all the answers

What can happen if sickle cell anemia red blood cells block smaller vessels?

Pain and organ damage Signup and view all the answers

What can sickle cell anemia red blood cells damage over time?

Spleen, kidneys, brain, bones, and other organs Signup and view all the answers

During a sickle cell crisis, what causes the shape of hemoglobin to be altered irreversibly?

Low oxygenation levels Signup and view all the answers

What is the cause of sickle cell anemia?

A substitution of glutamate for Valine in the β hemoglobin subunit Signup and view all the answers

Why does the single amino acid substitution in sickle cell anemia result in significant problems?

It alters the interactions between hemoglobin molecules Signup and view all the answers

What are the symptoms of a sickle cell crisis?

Pain, worsening anemia symptoms, fever, and shortness of breath Signup and view all the answers

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 Signup and view all the answers

What is the characteristic shape of red blood cells during a sickle cell crisis?

Sickled shape Signup and view all the answers

What triggers a sickle cell crisis?

Anything that reduces the amount of oxygen in the blood Signup and view all the answers

What is the function of hemoglobin in red blood cells?

To carry oxygen Signup and view all the answers

What is the result of the substitution of glutamate for Valine in the β hemoglobin subunit?

Abnormal red blood cell shape Signup and view all the answers

What causes pain during a sickle cell crisis?

Occlusion of blood vessels Signup and view all the answers

During a sickle cell crisis, what is the primary cause of the altered shape of red blood cells?

Low oxygenation levels Signup and view all the answers

What is the result of the substitution of glutamate for Valine in the β hemoglobin subunit?

The red blood cell shape becomes abnormal Signup and view all the answers

Why does the single amino acid substitution in sickle cell anemia result in significant problems?

It alters the interactions between hemoglobin molecules Signup and view all the answers

What triggers a sickle cell crisis?

Anything that reduces the amount of oxygen in the blood Signup and view all the answers

What are the symptoms of a sickle cell crisis?

Pain, worsening anemia symptoms, fever, and shortness of breath Signup and view all the answers

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 Signup and view all the answers

What is the characteristic shape of red blood cells during a sickle cell crisis?

Sickled shape Signup and view all the answers

What causes pain during a sickle cell crisis?

Occlusion of blood vessels Signup and view all the answers

What can sickle cell anemia red blood cells damage over time?

Smaller blood vessels Signup and view all the answers

What is the cause of sickle cell anemia?

A substitution of glutamate for Valine in the β hemoglobin subunit Signup and view all the answers

Which level of protein structure is an alpha helix?

Secondary structure Signup and view all the answers

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. Signup and view all the answers

Why do the amino acid substitutions of Lysine to Arginine have little effect on the protein's function?

Lysine and Arginine have opposite charges. Signup and view all the answers

Why do the amino acid substitutions of Isoleucine to Leucine have little effect on the protein's function?

Isoleucine and Leucine have similar hydrophobicity. Signup and view all the answers

What is the characteristic shape of red blood cells during a sickle cell crisis?

Sickle-shaped Signup and view all the answers

What can happen if sickle cell anemia red blood cells block smaller vessels?

Pain, organ damage, and lack of oxygenation Signup and view all the answers

During a sickle cell crisis, what causes the shape of hemoglobin to be altered irreversibly?

Decreased oxygen levels Signup and view all the answers

During a sickle cell crisis, what triggers the alteration in the shape of hemoglobin?

Low oxygenation levels Signup and view all the answers

What is the primary cause of the altered shape of red blood cells during a sickle cell crisis?

Low oxygenation levels Signup and view all the answers

What are the symptoms of a sickle cell crisis?

Pain, worsening anemia symptoms, fever, and shortness of breath Signup and view all the answers

What is the cause of sickle cell anemia?

Substitution of glutamate (normal) for Valine (sickle cell) in the β hemoglobin subunit Signup and view all the answers

Why does the single amino acid substitution in sickle cell anemia result in significant problems?

It alters the shape of hemoglobin irreversibly Signup and view all the answers

What can happen if sickle cell anemia red blood cells block smaller vessels?

Tissue damage and pain Signup and view all the answers

After a sickle cell crisis, why can't the red blood cell simply replace the irreversibly altered hemoglobin?

The altered hemoglobin is permanently changed Signup and view all the answers

Why would the single amino acid substitution result in such a significant problem?

It changes the interactions between hemoglobin molecules Signup and view all the answers

Which of the following is not a level of protein structure?

Quaternary Signup and view all the answers

What is the term used to describe the disruption in folding/shape of a protein?

Denaturation Signup and view all the answers

Which type of bonds within proteins can be disrupted by strong acids or bases, organic solvents, salts, and heavy metal ions?

Salt bridges Signup and view all the answers

Which heavy metals can denature proteins based on their charge?

Mercury (Hg+2) and lead (Pb+2) Signup and view all the answers

Which type of amino acid side chain can heavy metals like mercury and lead bind to?

Charged side chains Signup and view all the answers

Which type of interaction within a protein would be disrupted by heavy metals like mercury and lead?

Ionic interactions Signup and view all the answers

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 Signup and view all the answers

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 Signup and view all the answers

What effect does temperature have on enzyme activity?

Increases enzyme activity Signup and view all the answers

How does changing the pH affect enzyme activity?

It decreases enzyme activity Signup and view all the answers

What is the function of a lysosome?

Main site of intracellular enzymatic degradation for a wide range of molecules Signup and view all the answers

At what pH are lysosomal enzymes active?

pH of ~45 Signup and view all the answers

How can the activity of enzymes be controlled?

Genetic regulation Signup and view all the answers

What is an example of genetic regulation of enzyme activity?

Inducing enzyme transcription and translation in times of need Signup and view all the answers

Which enzyme catalyzes the phosphorylation of glycogen phosphorylase kinase? Is the reaction reversible or irreversible?

Protein kinase A; reversible Signup and view all the answers

What is the role of covalent modification in enzyme regulation?

To change the conformation of enzymes Signup and view all the answers

Which type of enzyme regulation involves the binding of an effector molecule to an allosteric site?

Allosteric modification Signup and view all the answers

What effect does high levels of ATP have on phosphofructokinase-1 (PFK-1)?

Inhibition Signup and view all the answers

How does compartmentalization of enzymes via membrane-bound organelles contribute to enzyme regulation?

By separating enzymes from opposing pathways Signup and view all the answers

Which metabolic pathways are commonly compartmentalized in different areas of the cell?

Glycolysis and gluconeogenesis Signup and view all the answers

What triggers the irreversible covalent modification of enzymes?

Cleavage of peptide bonds in proenzymes or zymogens Signup and view all the answers

Which subunit of allosteric enzymes contains the allosteric site?

A different subunit from the active site Signup and view all the answers

What effect does an effector molecule have on the binding of the substrate to an allosteric enzyme?

Decreases binding of the substrate Signup and view all the answers

Enzymes are an example of a type of __________ protein.

globular Signup and view all the answers

Enzymes speed up a reaction by lowering the __________ energy of the reaction.

activation Signup and view all the answers

The minimal amount of energy needed to make/break the bonds necessary for a reaction to occur is called __________ energy.

activation Signup and view all the answers

Enzyme molecules contain a special cleft called the __________ site.

active Signup and view all the answers

Enzymes are highly specific and only a substrate of the correct __________ and shape can enter into the active site.

size Signup and view all the answers

Which amino acid side chain can function easily as an acid or a base?

Aspartic acid Signup and view all the answers

Enzymes often have help from cofactors and coenzymes. Cofactors are typically __________ cations.

metal Signup and view all the answers

Which enzyme is responsible for the phosphorylation of glycogen phosphorylase kinase?

Glycogen phosphorylase kinase Signup and view all the answers

What type of modification inhibits the activity of phosphofructokinase-1 (PFK-1)?

Allosteric modification Signup and view all the answers

What effect does high levels of ATP have on phosphofructokinase-1 (PFK-1)?

Inhibition Signup and view all the answers

What effect does high levels of AMP have on phosphofructokinase-1 (PFK-1)?

Activation Signup and view all the answers

What is the purpose of compartmentalization in enzyme regulation?

Both A and B Signup and view all the answers

Which metabolic pathway is commonly compartmentalized in different areas of the cell?

Glycolysis Signup and view all the answers

What type of modification involves the cleavage of peptide bonds in proenzymes or zymogens?

Covalent modification Signup and view all the answers

What effect does an effector molecule have on the binding of the substrate to an allosteric enzyme?

Increase binding of the substrate Signup and view all the answers

Which subunit of allosteric enzymes contains the allosteric site?

The subunit with the effector site Signup and view all the answers

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 Signup and view all the answers

Proteins and Enzymes

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Questions and Answers

Which level of protein structure is an alpha helix?

Above a pH 5, why does an alpha helix take on a random coil configuration?

Why do the amino acid substitutions of Lysine to Arginine have little effect on the protein's function?

Why do the amino acid substitutions of Isoleucine to Leucine have little effect on the protein's function?

What is the function of red blood cells?

How many oxygen molecules can each hemoglobin protein carry?

Why do red blood cells not contain a nucleus?

What is sickle cell anemia?

What can happen if sickle cell anemia red blood cells block smaller vessels?

What can sickle cell anemia red blood cells damage over time?

During a sickle cell crisis, what causes the shape of hemoglobin to be altered irreversibly?

What is the cause of sickle cell anemia?

Why does the single amino acid substitution in sickle cell anemia result in significant problems?

What are the symptoms of a sickle cell crisis?

Why can't the red blood cell simply replace irreversibly altered hemoglobin after a sickle cell crisis?

What is the characteristic shape of red blood cells during a sickle cell crisis?

What triggers a sickle cell crisis?

What is the function of hemoglobin in red blood cells?

What is the result of the substitution of glutamate for Valine in the β hemoglobin subunit?

What causes pain during a sickle cell crisis?

During a sickle cell crisis, what is the primary cause of the altered shape of red blood cells?

What is the result of the 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?

What triggers a sickle cell crisis?

What are the symptoms of a sickle cell crisis?

Why can't the red blood cell simply replace irreversibly altered hemoglobin after a sickle cell crisis?

What is the characteristic shape of red blood cells during a sickle cell crisis?

What causes pain during a sickle cell crisis?

What can sickle cell anemia red blood cells damage over time?

What is the cause of sickle cell anemia?

Which level of protein structure is an alpha helix?

Above a pH 5, why does an alpha helix take on a random coil configuration?

Why do the amino acid substitutions of Lysine to Arginine have little effect on the protein's function?

Why do the amino acid substitutions of Isoleucine to Leucine have little effect on the protein's function?

What is the characteristic shape of red blood cells during a sickle cell crisis?

What can happen if sickle cell anemia red blood cells block smaller vessels?

During a sickle cell crisis, what causes the shape of hemoglobin to be altered irreversibly?

During a sickle cell crisis, what triggers the alteration in the shape of hemoglobin?

What is the primary cause of the altered shape of red blood cells during a sickle cell crisis?

What are the symptoms of a sickle cell crisis?

What is the cause of sickle cell anemia?

Why does the single amino acid substitution in sickle cell anemia result in significant problems?

What can happen if sickle cell anemia red blood cells block smaller vessels?

After a sickle cell crisis, why can't the red blood cell simply replace the irreversibly altered hemoglobin?

Why would the single amino acid substitution result in such a significant problem?

Which of the following is not a level of protein structure?

What is the term used to describe the disruption in folding/shape of a protein?

Which type of bonds within proteins can be disrupted by strong acids or bases, organic solvents, salts, and heavy metal ions?

Which heavy metals can denature proteins based on their charge?

Which type of amino acid side chain can heavy metals like mercury and lead bind to?

Which type of interaction within a protein would be disrupted by heavy metals like mercury and lead?

What are some examples of agents that can disrupt the bonds within proteins and denature them?

Which of the following is NOT a way in which cofactors and coenzymes can help enzymes speed up reactions?

What effect does temperature have on enzyme activity?

How does changing the pH affect enzyme activity?

What is the function of a lysosome?

At what pH are lysosomal enzymes active?

How can the activity of enzymes be controlled?

What is an example of genetic regulation of enzyme activity?

Which enzyme catalyzes the phosphorylation of glycogen phosphorylase kinase? Is the reaction reversible or irreversible?

What is the role of covalent modification in enzyme regulation?

Which type of enzyme regulation involves the binding of an effector molecule to an allosteric site?

What effect does high levels of ATP have on phosphofructokinase-1 (PFK-1)?

How does compartmentalization of enzymes via membrane-bound organelles contribute to enzyme regulation?

Which metabolic pathways are commonly compartmentalized in different areas of the cell?

What triggers the irreversible covalent modification of enzymes?

Which subunit of allosteric enzymes contains the allosteric site?

What effect does an effector molecule have on the binding of the substrate to an allosteric enzyme?

Enzymes are an example of a type of __________ protein.

Enzymes speed up a reaction by lowering the __________ energy of the reaction.

The minimal amount of energy needed to make/break the bonds necessary for a reaction to occur is called __________ energy.

Enzyme molecules contain a special cleft called the __________ site.

Enzymes are highly specific and only a substrate of the correct __________ and shape can enter into the active site.

Which amino acid side chain can function easily as an acid or a base?

Enzymes often have help from cofactors and coenzymes. Cofactors are typically __________ cations.

Which enzyme is responsible for the phosphorylation of glycogen phosphorylase kinase?