Q: A solution has a pH of 4. What is the concentration of hydrogen ions $$[\mathrm{H}^+] in $$the solution? Use the formula $$\mathrm{pH} = -\log_{10}[\mathrm{H}^+].$$

$$[\mathrm{H}^+] = 1 \times 10$$^{-4}$$ \ \mathrm{M}$$

Question 1

A student is conducting an experiment to test the effect of a new fertilizer on plant growth. Which of the following best represents the correct sequence of steps in the scientific method?

Accepted Answer

Make observations, form a hypothesis, conduct an experiment, analyze data, draw conclusions

Question 2

A biologist uses a standard curve to determine the pH of an unknown solution. If the absorbance of the unknown is $$0.35$$, and the standard curve equation is $$y = 0.5x + 0.1 ($$where $$y is $$absorbance and $$x is pH$$), what is the pH of the unknown solution?

Accepted Answer

Question 3

Which of the following best explains how a buffer works in a biological system?

Accepted Answer

A buffer resists changes in pH by absorbing excess hydrogen or hydroxide ions.

Question 4

Which of the following molecules is considered organic?

Accepted Answer

Glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6)$$

Question 5

A student performs Benedict's test on four unknown solutions. Which result indicates the presence of reducing sugars?

Accepted Answer

A color change from blue to orange-red

Question 6

Which of the following best describes the basic structure of an amino acid?

Accepted Answer

A central carbon atom bonded to an amino group ($$-\mathrm{NH}_2$$), a carboxyl group ($$-\mathrm{COOH}$$), a hydrogen atom, and a variable R group

Question 7

Which of the following is NOT a function of proteins in living organisms?

Accepted Answer

Storing genetic information

Question 8

A student observes a cell under a compound light microscope and notices the presence of a large central vacuole, chloroplasts, and a cell wall. What type of cell is this?

Accepted Answer

Plant cell

Question 9

Which part of the compound light microscope is responsible for focusing light onto the specimen?

Accepted Answer

Condenser

Question 10

Which of the following statements correctly compares plant and animal cells?

Accepted Answer

Plant cells have a cell wall and chloroplasts, while animal cells do not.

Question 11

A solution has a pH of 4. What is the concentration of hydrogen ions $$[\mathrm{H}^+] in $$the solution? Use the formula $$\mathrm{pH} = -\log_{10}[\mathrm{H}^+].$$

Accepted Answer

$$[\mathrm{H}^+] = 1 	imes 10$$^{-4}$$ \ \mathrm{M}$$

Question 12

Which test would you use to detect the presence of starch in a biological sample, and what is a positive result?

Accepted Answer

Iodine test; a blue-black color indicates starch is present

Question 13

A student is using a microscope and wants to increase the magnification of the specimen. Which part should they adjust?

Accepted Answer

Objective lens

Question 14

Which of the following is a correct metric conversion?

Accepted Answer

1 liter = 1000 milliliters

Question 15

A student adds a drop of Sudan III to a food sample and observes a red-stained oil layer. What does this indicate?

Accepted Answer

Lipids are present in the sample

Question 16

Which of the following best describes the function of the coarse adjustment knob on a compound light microscope?

Accepted Answer

It brings the specimen into general focus by moving the stage up and down.

Question 17

Which of the following is a similarity between plant and animal cells?

Accepted Answer

Both have mitochondria.

Question 18

A scientist wants to test the effect of temperature on enzyme activity. Which of the following is the best example of a controlled variable in this experiment?

Accepted Answer

The pH of the solution

BIO 121 Lab Midterm Review: Key Concepts and Applications

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