Q: A solution has a pH of 3. What is the concentration of hydrogen ions ($$[\mathrm{H^+}]) in $$this solution?

$$[\mathrm{H^+}] = 1 \times 10$$^{-3}$$\ \mathrm{M}$$

Question 1

Which of the following best describes the function of a buffer in biological systems?

Accepted Answer

A buffer resists changes in pH by accepting or donating hydrogen ions ($$\mathrm{H^+}) as $$needed.

Question 2

A solution has a pH of 3. What is the concentration of hydrogen ions ($$[\mathrm{H^+}]) in $$this solution?

Accepted Answer

$$[\mathrm{H^+}] = 1 	imes 10$$^{-3}$$\ \mathrm{M}$$

Question 3

Which of the following is a correct sequence of steps in the scientific method?

Accepted Answer

Question → Hypothesis → Experiment → Data → Conclusion

Question 4

Which of the following laboratory practices is essential for preventing chemical exposure to the skin and eyes?

Accepted Answer

Wearing gloves, safety goggles, and a lab coat

Question 5

Which of the following statements about the metric system is correct?

Accepted Answer

1 liter (L) equals 1000 milliliters (mL)

Question 6

Which of the following best explains why cellulose cannot be digested by most animals?

Accepted Answer

Cellulose contains beta-D-glucose with glycosidic bonds that mammalian enzymes cannot break.

Question 7

Which of the following is a monomer of proteins?

Accepted Answer

Amino acid

Question 8

Which of the following best describes the amphipathic nature of phospholipids in cell membranes?

Accepted Answer

They have both hydrophilic heads and hydrophobic tails.

Question 9

A scientist observes that a protein loses its function after being exposed to high temperatures. What is the most likely explanation?

Accepted Answer

The protein is denatured due to disruption of hydrogen bonds and other interactions in its tertiary structure.

Question 10

Which of the following best describes the role of enzymes in biological reactions?

Accepted Answer

Enzymes decrease the activation energy, speeding up reactions.

Question 11

Which of the following is a correct application of the Beer-Lambert Law in a spectrophotometry experiment?

Accepted Answer

Absorbance ($$A) is $$directly proportional to concentration ($$c) $$when path length ($$l) $$and extinction coefficient ($$\varepsilon) $$are constant: $$A = \varepsilon c l$$

Question 12

Which of the following best explains why glucose enters cells via facilitated diffusion?

Accepted Answer

Glucose is a large, polar molecule that requires a protein transporter to cross the membrane.

Question 13

Which of the following is a real-world example of the importance of buffers in the human body?

Accepted Answer

Buffers in blood maintain pH near 7.4, preventing dangerous swings in acidity or alkalinity.

Question 14

Which of the following best describes the difference between saturated and unsaturated fats?

Accepted Answer

Saturated fats are solid at room temperature due to the absence of double bonds; unsaturated fats are liquid due to the presence of double bonds.

Question 15

Which of the following is a function of carbohydrates on the cell surface?

Accepted Answer

They are critical for cell recognition and immune defense.

Question 16

Which of the following best describes the role of the sodium-potassium pump in cells?

Accepted Answer

It uses ATP to move sodium out of the cell and potassium into the cell against their concentration gradients.

Question 17

Which of the following is a correct statement about the structure of amino acids?

Accepted Answer

The R group determines the identity and properties of each amino acid.

Question 18

Which of the following best explains why enzymes are substrate-specific?

Accepted Answer

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

Question 19

Which of the following is a correct application of the concept of homeostasis in cells?

Accepted Answer

Homeostasis refers to the maintenance of constant internal conditions, such as pH and ion concentration, necessary for enzyme function.

General Biology Study Notes: Scientific Method, Chemistry of Life, Macromolecules, and Cell Structure

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