Cofactors and Coenzymes

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

Primary (correct)

Quaternary

Secondary

Tertiary

Protein denaturation occurs when

Protein bonds are strengthened

Protein folding is disrupted

Protein bonds are disrupted (correct)

Protein bonds are formed

Which of the following can denature proteins?

Strong acids or bases

Reducing agents

Organic solvents

All of the above (correct)

What type of interaction within a protein would be disrupted by heavy metal ions?

Ionic bonds Signup and view all the answers

Which of the following can disrupt polar and charged interactions within proteins?

All of the above Signup and view all the answers

What type of amino acid side chain do heavy metals like mercury and lead bind to?

Positively charged Signup and view all the answers

Which of the following can disrupt salt bridges within proteins?

Heavy metal ions Signup and view all the answers

Which type of protein are enzymes an example of?

Globular protein Signup and view all the answers

What is the role of enzymes in biochemical reactions?

To lower the activation energy Signup and view all the answers

What is the function of the active site in an enzyme?

To bind substrates Signup and view all the answers

How does the induced fit model explain enzyme specificity?

Enzymes change shape to fit the substrate Signup and view all the answers

How can amino acids in the active site of an enzyme speed up reactions?

By acting as acids or bases Signup and view all the answers

What are cofactors often made of?

Metal cations Signup and view all the answers

What are coenzymes typically derived from?

Vitamins Signup and view all the answers

Which of the following is a coenzyme derived from vitamin B3?

NAD+ 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?

Increase the temperature of the reaction Signup and view all the answers

What types of bonds between the enzyme and substrate would potentially be disrupted by a change in pH?

Hydrogen bonds Signup and view all the answers

At what pH are lysosomal enzymes active?

pH of ~4.5 Signup and view all the answers

Which of the following is NOT a way in which enzyme activity can be controlled?

Compartmentalization Signup and view all the answers

What is a common group that can be added or removed from enzymes in reversible covalent modification?

Phosphate group Signup and view all the answers

Which enzyme in glycogenesis is de-activated by phosphorylation?

Glucokinase Signup and view all the answers

Which protein catalyzes phosphorylation initially?

Protein kinase A (PKA) Signup and view all the answers

What does phosphorylation do to a protein?

Adds a phosphate to the protein Signup and view all the answers

What prevents both pathways from running at the same time?

Phosphorylation Signup and view all the answers

Which type of enzyme regulation involves covalent modification?

Covalent modification Signup and view all the answers

What is an example of covalent modification in glycogen metabolism?

Protein kinase A Signup and view all the answers

Which type of enzyme regulation involves allosteric modification?

Allosteric modification Signup and view all the answers

What can an effector molecule do to an allosteric enzyme?

Both increase and decrease binding of the substrate Signup and view all the answers

What inhibits phosphofructokinase-1 (PFK-1) allosterically?

High levels of ATP Signup and view all the answers

What is the pH range in which lysosomal enzymes function?

Around 4.5-5 Signup and view all the answers