BISC 1125 Lecture Notes - Lecture 4: Glucose Oxidase, Horseradish, Reaction Rate
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Enzymes Lab Report
Biology 1408
- Temperature and Enzyme Activity
- Based on Lab, Section III, Exercise 3 record the relative colorintensity at five-minute intervals to determine the temperaturerange for catechol oxidase.
| Time (min) | Tube 1 4oC | Tube 2 23oC | Tube 3 40oC | Tube 4 60oC | Tube 5 80oC | Tube 6 100oC |
0 | ||||||
5 | ||||||
10 |
- Construct a bar graph of the data for the ten-minute readings.Label axes and provide units. Sign, date and prepare an image ofyour graph and include it with this lab report.
- What is the optimal temperature range for catechol oxidaseactivity?
- pH and Enzyme Activity
- Within what pH range will catechol oxidase catalyze catecholand oxygen to form benzoquinone?
4-12
- Define pH.
- What is the role of catechol in the experiment?
- Which test tube contains the most acidic buffer solution?
- Cofactors and Enzyme Activity
- What is a cofactor?
- What cofactor is necessary for catechol oxidase activity?
Summary Questions
- What was the role of catechol oxidase in the experiments?
- What was the purpose of developing a color intensityscale?
- Identify three factors that influence the rate of enzymaticreactions.
- Examine the data in Exercise 3 and suggest a hypothesisexplaining why people with a fever feel tired and listless.
With high fever, enzymestructure changes and no longer act as a catalyst
- People who have been suddenly submerged in cold water andremained for long periods of time have survived. Examine the datain Exercise 3 and explain how this is possible.
Low temperature ranges willinhabit the reaction of the speed of chemical reaction incells
- How does pH range affect the function and structure of catecholoxidase?
Help the enzymes functionbetter
- The stomach maintains a pH of approximately 3 to 5. Do allenzymes function at this pH level? Examine the data in Exercise 4and determine if catechol oxidase would function in the stomach.
No, most enzymes functionbetter at ph 6-8
- What is enzyme specificity? Give an example.
A specific substrate fits aspecific enzyme.
QUESTION 10
If you can drink milk as an adult, it means that you have inherited a mutation in the promoter of your lactase gene (the gene that encodes the enzyme you need to break down lactose). Predict the effect of this mutation:
| The mutation changes the number of domains in the enzyme, which makes it work more efficiently | ||
| The mutation changes the amino acid sequence of the lactase protein | ||
| The mutation increases the number of copies of the lactase gene that will be found in your genome | ||
| The mutation changes whether the lactase sequence is found in an intron or exon | ||
| The mutation affects the expression of the lactase gene |
1.2 points
QUESTION 11
A competitive inhibitor is decreasing the activity of an enzyme. Predict the effect of adding more substrate to the reaction.
| The substrate will increase the reaction rate by binding to the allosteric site | ||
| The substrate will increase the reaction rate by competing with the inhibitor for the active site | ||
| The reaction rate will not change unless the inhibitor can be removed | ||
| The enzyme adjusts its shape so that the substrate, but NOT the competitive inhibitor, can bind | ||
| The substrate will bind to the competitive inhibitor and block its ability to bind to the enzyme |
1.2 points
QUESTION 12
What determines where in the genome a transcription regulator will bind?
| Transcription regulators bind to the 5' UTR region of a gene | ||
| Regulators bind via complementary base-pairing to certain DNA molecules | ||
| Covalent bonds form between the transcription regulator and the atoms of the DNA backbone | ||
| Every eukaryotic gene has a different transcription regulator that will bind to the 5' end of the gene | ||
| Transcription regulators bind to specific DNA sequences via multiple weak non-covalent interactions |
1.2 points
QUESTION 13
What is the basic premise of cell theory?
| DNA -> RNA -> protein | ||
| All cells arise from pre-existing cells | ||
| DNA provides the complete instructions to create a cell | ||
| The identity of a cell is determined through gene expression patterns | ||
| All cells contain the same four basic macromolecules |
1.2 points
QUESTION 14
What is the benefit of using BOTH the lac activator and the lac repressor to control gene expression?
| Using both an activator and repressor enables cells to more accurately determine the amount of lactose available in the environment | ||
| Enzymes to digest lactose are only made when energy is low and lactose is available | ||
| The activator can override the inhibition of the lac operon by the repressor | ||
| The repressor can control the enhancer, while the activator can control the promoter | ||
| When neither the lac activator or repressor is present, expression of the lac operon is too high |
1.2 points
QUESTION 15
What is the histone code used for?
| Phosphorylation and acetylation of DNA affect its ability to be compacted | ||
| Changes to the sequence of DNA change whether DNA will wrap around histone proteins | ||
| Covalent modifications of histones affect the ability of the transcription initiation complex to form | ||
| Histones provide the codon sequences needed for translation to occur | ||
| The histone code affects which amino acids will get added to a polypeptide |