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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

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Nestor Rutherford
Nestor RutherfordLv2
28 Sep 2019

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