Question 1

Which of the following statements best describes an isotope and its significance in medicine?

Accepted Answer

Isotopes are atoms with the same number of protons but different numbers of neutrons, and radioactive isotopes are used in medical diagnosis and treatment.

Question 2

A molecule of sodium chloride (NaCl) forms when sodium donates an electron to chlorine. What type of bond is formed, and what are the resulting ions called?

Accepted Answer

An ionic bond is formed, resulting in a cation (Na$$^+) $$and an anion (Cl$$^-).$$

Question 3

Which of the following best explains why water is a good solvent for many biological molecules?

Accepted Answer

Water molecules are polar, allowing them to form hydrogen bonds with hydrophilic substances.

Question 4

A scientist is analyzing a chemical reaction: $$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{energy}. $$Which of the following correctly identifies the reactants and products?

Accepted Answer

Reactants: $$\mathrm{C_6H_{12}O_6$}$$ and $$\mathrm{O_2$}$$; Products: $$\mathrm{CO_2$}$$, $$\mathrm{H_2O}$$, and energy

Question 5

Which of the following best describes a dehydration synthesis reaction?

Accepted Answer

A reaction in which two molecules are joined together and water is released as a byproduct.

Question 6

Which of the following statements about acids and bases is correct?

Accepted Answer

Acids release hydrogen ions ($$\mathrm{H^+}) in $$solution, lowering pH, while bases accept hydrogen ions or release hydroxide ions ($$\mathrm{OH^-}$$), raising pH.

Question 7

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

Accepted Answer

Saturated lipids have no double bonds and are usually solid at room temperature, while unsaturated lipids have one or more double bonds and are usually liquid at room temperature.

Question 8

A patient is given a radioactive isotope for imaging. Which property of isotopes makes this possible?

Accepted Answer

Isotopes of the same element have different numbers of neutrons, and some are unstable and emit radiation.

Question 9

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

Accepted Answer

Enzymes act as catalysts, lowering the activation energy required for reactions to proceed.

Question 10

Which of the following correctly matches a macromolecule with its building block?

Accepted Answer

Proteins – Amino acids

Question 11

A molecule has the formula $$\mathrm{C_6H_{12}O_6$}$$ and exists in two forms with different structures but the same formula. What are these forms called?

Accepted Answer

Isomers

Question 12

Which of the following best describes a phosphodiester bond?

Accepted Answer

A covalent bond linking nucleotides together in DNA and RNA, forming the sugar-phosphate backbone.

Question 13

Which of the following statements about protein structure is correct?

Accepted Answer

The tertiary structure is the overall three-dimensional shape of a single polypeptide chain.

Question 14

Which of the following best explains why phospholipids are important in cell membranes?

Accepted Answer

They are amphipathic, having both hydrophilic and hydrophobic regions, allowing them to form bilayers.

Question 15

Which of the following is true about the difference between deoxyribonucleotides and ribonucleotides?

Accepted Answer

Deoxyribonucleotides contain deoxyribose sugar and are found in DNA, while ribonucleotides contain ribose sugar and are found in RNA.

Question 16

A solution has a pH of 3. Which of the following statements is correct about this solution?

Accepted Answer

It is acidic because it has a high concentration of hydrogen ions ($$\mathrm{H^+}).$$

Question 17

Which of the following best describes a glycosidic bond?

Accepted Answer

A covalent bond that links monosaccharides together to form larger carbohydrates.

Question 18

Which of the following is an example of an endergonic reaction?

Accepted Answer

Photosynthesis, where energy is absorbed to build glucose from carbon dioxide and water.

Question 19

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule is formed when two or more atoms bond together, while a compound is a molecule made of more than one type of element.

Question 20

A researcher observes that a certain protein loses its function when its tertiary structure is disrupted, but its primary structure remains intact. What does this indicate about the importance of protein structure?

Accepted Answer

The three-dimensional shape (tertiary structure) is critical for protein function, even if the amino acid sequence (primary structure) is unchanged.

Biochemistry Basics for Microbiology

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