🏷️ LIMITED TIME OFFER: GET 20% OFF GRADE+ YEARLY SUBSCRIPTION →
Log in
Science
9
answers
1
watching
442
views

Describe the chemistry of two types of enzymes and explain how the apoenzyme forms.

Watch
9
answers
1
watching
442
views

For unlimited access to Homework Help, a Homework+ subscription is required.

Unlock all answers

Get 1 free homework help answer.
Already have an account? Log in
Share
Already have an account? Log in
Share
Already have an account? Log in
Share
Already have an account? Log in
Share
Already have an account? Log in
Share
Already have an account? Log in
Share
Already have an account? Log in
Share
Already have an account? Log in
Share
Already have an account? Log in
Share

Related questions

Do Enzymes Physically Attach to Their Substrates?
 
When scientists first began to examine the chemical activities of organisms, no one knew that biochemical reactions were catalyzed by enzymes. The first enzyme was discovered in 1833 by French chemist Anselme Payen. He was studying how beer is made from barley: First, barley is pressed and gently heated so its starches break down into simple two-sugar units; then yeasts convert these units into ethanol. Payen found that the initial breakdown requires a chemical factor that is not alive and that does not seem to be used up during the process-a catalyst. He called this first enzyme diastase (we call it amylase today).
 
Did this catalyst operate at a distance, increasing the reaction rate all around it, much as raising the temperature of nearby molecules might do? Or did it use physical contact, actually attaching to the molecules whose reaction it catalyzed (its "substrate")?
 
The answer was discovered in 1903 by French chemist Victor Henri. He saw that the hypothesis that an enzyme physically binds to its substrate makes a clear and testable prediction: In a solution of substrate and enzyme, there must be a maximum reaction rate. When all the enzyme molecules are working full tilt, the reaction simply cannot go any faster, no matter how much more substrate you add to the solution. To test this prediction. Henri carried out the experiment whose results you see in the graph, measuring the reaction rate (V) of diastase at different substrate concentrations (S).
 
Analysis
1. Making Inferences As S increases, does V increase? If so, in what manner-steadily, or by smaller and smaller amounts? Is there a maximum reaction rate?
2. Drawing Conclusions Does this result provide support for the hypothesis that an enzyme binds physically to its substrate? Explain. If the hypothesis were incorrect, what would you expect the graph to look like?
3. Further Analysis If the smaller amounts by which V increases are strictly the result of fewer unoccupied enzymes being available at higher values of S, then the curve in Henri's experiment should show a pure exponential decline in V-mathematically, meaning a reciprocal plot (1/V versus 1/S) should be a straight line. If some other factor is also at work that reacts differently to substrate concentration, then the reciprocal plot would curve upward or downward. Fill in the reciprocal values in the table to the right, and then plot the values on the lower graph (1/S on the x axis and 1/V on the y axis). Is a reciprocal plot of Henri's data a straight line?
Use the following information to answer the next two questions.
 
Beer making is complicated, multi-step process. Beer making depends on the metabolism of sugar by yeast. This process is known as fermentation. When yeast metabolizes sugar molecules, alcohol, carbon dioxide, and other by-products are produced.
1. First, malt barley is ground into small grains. It is then transferred to a mash mixer and mixed with water. At this point, the mixture is called griest.
2. The mash mixer and griest are steam-heated to a temperature of 43C.
3. The greist remains at this temperature to allow enzymes to break down complex protein molecules into simpler nitrogen compounds.
4. The greist is then heated to 63C.
5. At this temperature, enzymes in the griest convert the large, multibranched starch molecules into smaller chains of glucose.
6. After a specific amount of time, the griest is slowly heated to 68C.
7. A different enzyme breaks down the small glucose chains into monosaccharides and disaccharides. The longer the griest remains at this temperature, the more alcohol is produced by the yeast.
8. Finally the temperature is increased to 77C to stop the enzyme action in the griest.
 
Numerical Response
2. From the list above, identify which four of the steps involve a kinetic energy change in the griest. In numerical order, the numbers are _____, _____, _____, & _____.
(Record all four digits of your answer in the numerical-response section on the answer sheet.)
3. An endothermic reaction can be expressed by writing the enthalpy term
A. as a negative value on the product side in the equation.
B. as a negative value in , H notation.
C. On the product side of an equation.
D. On the reactant side of an equation.

Related Documents

LSCI 211 Lecture Notes - Lecture 9: Dna Ligase, Non-Covalent Interactions, Isomerase
periwinkleminnow302
BSC 161
Final Exam
Study Guide
BSC 161 Study Guide - Quiz Guide: Gram Staining, Cell Membrane, Microscope Slide
pucecrab859
01:119:131 Chapter Notes - Chapter 5: Metabolic Pathway, Photoheterotroph, Chemotroph
thegoldennotetaker07

Weekly leaderboard

Home
Homework Help 3,900,000
Science 1,000
Start filling in the gaps now
Log in