Question 1

A student is testing for the presence of starch in a potato sample using iodine solution. Which of the following observations indicates a positive result for starch, and what is the expected color change?

Accepted Answer

The solution turns blue-black, indicating a positive result.

Question 2

In an experiment to test the effect of temperature on enzyme activity, which of the following is the dependent variable?

Accepted Answer

The rate of the enzyme-catalyzed reaction

Question 3

A cell is placed in a solution and water moves out of the cell, causing it to shrink. Which type of solution is the cell in?

Accepted Answer

Hypertonic

Question 4

Which of the following best describes the function of an enzyme in a biological reaction?

Accepted Answer

It lowers the activation energy required for the reaction.

Question 5

During a Benedict's test for reducing sugars, a student observes a brick-red precipitate. What does this indicate about the sample?

Accepted Answer

The sample contains a high concentration of reducing sugars.

Question 6

A scientist wants to measure the mass of a chemical sample. Which unit should they use?

Accepted Answer

Grams ($$g)$$

Question 7

In a scientific experiment, which of the following is an example of a control variable?

Accepted Answer

The pH of the solution kept constant in all test groups

Question 8

Which of the following best describes osmosis?

Accepted Answer

The movement of water molecules from an area of high water concentration to an area of low water concentration across a selectively permeable membrane.

Question 9

A student is using a Biuret test to detect proteins in a solution. What color change indicates a positive result?

Accepted Answer

Violet or purple

Question 10

A researcher wants to determine the effect of light intensity on the rate of photosynthesis in plants. Which is the independent variable in this experiment?

Accepted Answer

Light intensity

Question 11

Which of the following statements about diffusion is correct?

Accepted Answer

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.

Question 12

A student is measuring the volume of a liquid in a graduated cylinder. To ensure accuracy, where should they read the measurement?

Accepted Answer

At the bottom of the meniscus

Question 13

A red blood cell is placed in a hypotonic solution. What will happen to the cell?

Accepted Answer

Water will enter the cell, causing it to swell and possibly burst.

Question 14

Which of the following best explains why enzymes are specific to their substrates?

Accepted Answer

The active site of an enzyme has a unique shape that fits only specific substrates.

Question 15

A student adds Sudan IV to a food sample. Which result indicates the presence of lipids?

Accepted Answer

A red-stained oil layer forms on the surface.

Question 16

In a controlled experiment, why is it important to have a control group?

Accepted Answer

To provide a baseline for comparison with the experimental group

Question 17

A scientist is measuring the length of a plant root. Which unit is most appropriate for this measurement?

Accepted Answer

Centimeters ($$cm)$$

Question 18

Which of the following scenarios best illustrates the concept of an independent variable?

Accepted Answer

A researcher changes the amount of fertilizer given to different groups of plants to observe growth differences.

Question 19

A student is conducting an experiment to test the effect of pH on enzyme activity. They keep the temperature, enzyme concentration, and substrate concentration constant. What is the dependent variable in this experiment?

Accepted Answer

The rate of enzyme activity

Question 20

Which of the following best describes an isotonic solution with respect to a cell?

Accepted Answer

The concentration of solutes is equal inside and outside the cell, resulting in no net movement of water.

Biology Lab Exam Study Guide: Key Concepts and Practical Skills

Study Guide - Practice Questions

Study Guide - Flashcards