The enzyme lactase converts the disaccharide lactose into the monosaccharides glucose and galactose.
To test its activity a researcher puts 1ml of 1mg/ml lactase into a 5ml volume of 1mg/ml lactose and measures the amount of glucose at the end of a five minute time period. During the experiment the temperature is set to 37C. He repeats the experiment at pH 6, 7 and 8 and then creates a graph of the data.
In the following experiment indicate whether each of the following is a dependent, independent (experimental), or controlled variable (if it is none of these select that instead).
glucose concentration
[ Choose ] independent controlled dependent none of these
lactase concentration
[ Choose ] independent controlled dependent none of these
oxygen in ml
[ Choose ] independent controlled dependent none of these
temperature
[ Choose ] independent controlled dependent none of these
pH
The enzyme lactase converts the disaccharide lactose into the monosaccharides glucose and galactose.
To test its activity a researcher puts 1ml of 1mg/ml lactase into a 5ml volume of 1mg/ml lactose and measures the amount of glucose at the end of a five minute time period. During the experiment the temperature is set to 37C. He repeats the experiment at pH 6, 7 and 8 and then creates a graph of the data.
In the following experiment indicate whether each of the following is a dependent, independent (experimental), or controlled variable (if it is none of these select that instead).
glucose concentration
[ Choose ] independent controlled dependent none of these
lactase concentration
[ Choose ] independent controlled dependent none of these
oxygen in ml
[ Choose ] independent controlled dependent none of these
temperature
[ Choose ] independent controlled dependent none of these
pH
Related textbook solutions
Related questions
It refers to some of the Project titles only helpme thank you
QUESTION 1
Student A carried out an experiment to test for the presence of protein in skim milk. He used a chemical indicator called Biuret reagent which turns purple in the presence of proteins (the reagent is blue). He also identified egg white as an example of a solution containing protein and verified that egg white does cause the Biuret reagent to turn purple. For his milk experiment, Student A added the following items to a test tube and heated it for 3 minutes: 1 mL skim milk, 1 mL distilled water, 0.5 mL of egg white, 0.5 mL Biuret reagent. The solution turned purple and the student concluded that the milk contained protein.
What is the function of the egg white?
| it is the negative control | ||
| it is the experimental group | ||
| egg white serves no purpose in this experiment | ||
| it is a positive control |
0.66 points
QUESTION 2
You've just read a research project titled: "The activity of alcohol dehydrogenase enzyme is affected by pH."
What is the control?
| A. | pH = 1 | |
| B. | temperature | |
| C. | zero pH | |
| D. | the type of alcohol used | |
| E. | neutral pH |
0.67 points
QUESTION 3
You've just read a research project titled: "Prolonged cell phone use causes brain tumors."
What is the dependent variable?
| A. | number of patients with brain tumors | |
| B. | medical history of these patients | |
| C. | length of cell phone use | |
| D. | age of patients | |
| E. | type of cell phone used |
0.67 points
QUESTION 4
Which of the following would be standardized variables in the "pine trees on hillsides" study? Mark all that apply.
| elevation above sea level | ||
| same lattitude | ||
| counting trees at the same time of year | ||
| similar climate | ||
| angle of the hill slope | ||
| same size area | ||
| same history of logging activity (environmental succession) |
0.67 points
QUESTION 5
Which of the following would be standardized variables in the "cell phones cause brain tumors" experiment? Mark all that apply.
| same history of phone use in each group | ||
| same age distribution in each group | ||
| similar medical backgrounds and family histories | ||
| same number of males and females in each group | ||
| same type of phone | ||
| same amount of time on the phone | ||
| holding phone at the same distance and on the same side of the head |
0.67 points
QUESTION 6
Student A carried out an experiment to test for the presence of protein in skim milk. He used a chemical indicator called Biuret reagent which turns purple in the presence of proteins (the reagent is blue). He also identified egg white as an example of a solution containing protein and verified that egg white does cause the Biuret reagent to turn purple. For his milk experiment, Student A added the following items to a test tube and heated it for 3 minutes: 1 mL skim milk, 1 mL distilled water, 0.5 mL of egg white, 0.5 mL Biuret reagent. The solution turned purple and the student concluded that the milk contained protein.
What is wrong with this experiment? (select the single best answer)
| Student A should not have heated the samples. | ||
| Student A should not have added the distilled water. | ||
| Student A should have used a different test that gives quantitative data. | ||
| Student A combined the milk with a substance known to contain protein in a single tube. |
0.67 points
QUESTION 7
You've just read a research project titled: "Pine trees are more numerous on hillsides."
What is the independent variable?
| A. | logging activity | |
| B. | number of pine trees | |
| C. | slope of the land | |
| D. | size of geographic area | |
| E. | average rainfall |
0.67 points
QUESTION 8
You've just read a research project titled: "Prolonged cell phone use causes brain tumors."
What is the independent variable?
| A. | medical history of these patients | |
| B. | age of patients | |
| C. | length of cell phone use | |
| D. | number of patients with brain tumors | |
| E. | type of cell phone used |
0.66 points
QUESTION 9
You've just read a research project titled: "The activity of alcohol dehydrogenase enzyme is affected by pH."
What is the dependent variable?
| A. | pH | |
| B. | enzyme activity | |
| C. | substrate concentration | |
| D. | enzyme concentration | |
| E. | temperature |
0.66 points
QUESTION 10
You've just read a research project titled: "Pine trees are more numerous on hillsides."
What was used as a control?
| A. | average rainfall | |
| B. | lowland flat environment | |
| C. | number of pine trees | |
| D. | area at a different lattitude | |
| E. | logging activity |
0.67 points
QUESTION 11
You've just read a research project titled: "The activity of alcohol dehydrogenase enzyme is affected by pH."
What is the independent variable?
| A. | pH | |
| B. | substrate concentration | |
| C. | enzyme activity | |
| D. | enzyme concentration | |
| E. | temperature |
0.66 points
QUESTION 12
You've just read a research project titled: "Pine trees are more numerous on hillsides."
What is the dependent variable?
| A. | average rainfall | |
| B. | size of geographic area | |
| C. | number of pine trees | |
| D. | logging activity | |
| E. | environment and elevation |
0.66 points
QUESTION 13
Which of the following would be standardized variables in the "alcohol dehydrogenase" study? Mark all that apply.
| type of alcohol used | ||
| type of container used (beaker, flask, or plastic cup) | ||
| pH | ||
| substrate concentration | ||
| temperature | ||
| enzyme concentration | ||
| amount of time to react |
0.67 points
QUESTION 14
Student A carried out an experiment to test for the presence of protein in skim milk. He used a chemical indicator called Biuret reagent which turns purple in the presence of proteins (the reagent is blue). He also identified egg white as an example of a solution containing protein and verified that egg white does cause the Biuret reagent to turn purple. For his milk experiment, Student A added the following items to a test tube and heated it for 3 minutes: 1 mL skim milk, 1 mL distilled water, 0.5 mL of egg white, 0.5 mL Biuret reagent. The solution turned purple and the student concluded that the milk contained protein.
What should Student A use as a negative control for this experiment?
| 1 mL distilled water + 0.5 mL Biuret reagent | ||
| 1 mL skim milk + Biuret reagent | ||
| 1 mL Biuret reagent + 1 mL distilled water + 1 mL skim milk | ||
| 1 mL egg white + Biuret reagent |
0.67 points
QUESTION 15
You've just read a research project titled: "Prolonged cell phone use causes brain tumors."
What would be an appropriate control in this experiment?
| A. | a group of patients limited to a small number of short-duration calls per day | |
| B. | patients with a family history of cancer | |
| C. | patients that are the same age | |
| D. | a group of patients that already have brain tumors |
