CMLA Chemistry Basics 5 — Questions and Answers
Question 1: Which of the following monosaccharides is known as blood sugar and is the primary fuel for cellular respiration?
- Fructose
- Galactose
- Glucose (Correct answer)
- Ribose
Correct answer: Glucose
Glucose is the principal monosaccharide used by cells for energy production through glycolysis and the citric acid cycle.
Question 2: A laboratory solution that has more hydroxide ions (OH⁻) than hydrogen ions (H⁺) is classified as:
- Acidic
- Neutral
- Basic (alkaline) (Correct answer)
- Amphoteric
Correct answer: Basic (alkaline)
A basic or alkaline solution has a higher concentration of OH⁻ than H⁺, resulting in a pH greater than 7.
Question 3: What type of isomers have the same molecular formula and connectivity but differ in the spatial arrangement of atoms?
- Structural isomers
- Chain isomers
- Stereoisomers (Correct answer)
- Functional group isomers
Correct answer: Stereoisomers
Stereoisomers share the same molecular formula and bond connectivity but differ in the three-dimensional orientation of their atoms.
Question 4: In laboratory practice, 'pipetting to the mark' ensures:
- The pipette is completely filled with no air
- An accurate, reproducible volume of liquid is delivered (Correct answer)
- The reagent is properly mixed
- Contamination is prevented
Correct answer: An accurate, reproducible volume of liquid is delivered
Filling a volumetric pipette to the calibration mark ensures delivery of the precise volume for which the pipette is rated.
Question 5: Which of the following statements correctly describes osmosis?
- Movement of solute from low to high concentration
- Movement of water from high to low solute concentration across a semipermeable membrane (Correct answer)
- Active transport of ions against a gradient
- Diffusion of gases across a membrane
Correct answer: Movement of water from high to low solute concentration across a semipermeable membrane
Osmosis is the passive movement of water molecules across a semipermeable membrane from an area of lower solute concentration to higher solute concentration.
Question 6: Which analytical chemistry technique uses electrical current to separate charged molecules, commonly used for serum protein analysis?
- Chromatography
- Spectrophotometry
- Electrophoresis (Correct answer)
- Nephelometry
Correct answer: Electrophoresis
Electrophoresis separates charged molecules (such as serum proteins) based on their size and charge using an electric field.
Question 7: If a quality control (QC) sample result falls more than 2 standard deviations from the mean, this indicates:
- The patient sample must be redrawn
- A warning that the assay may be out of control (Correct answer)
- The instrument needs immediate replacement
- The result is definitely erroneous and must be discarded
Correct answer: A warning that the assay may be out of control
By Westgard rules, a result beyond ±2 SD is a warning flag suggesting the assay may be drifting, requiring investigation before reporting patient results.
CMLA Chemistry Basics 5
Which of the following monosaccharides is known as blood sugar and is the primary fuel for cellular respiration?