1. Which digestive enzyme is primarily responsible for breaking down proteins?

A. Pepsin
B. Lipase
C. Amylase
D. Maltase

Correct answer: A

Rationale: The correct answer is A: Pepsin. Pepsin is primarily responsible for breaking down proteins in the stomach. It is an enzyme produced by the gastric chief cells in the stomach lining and works in a highly acidic environment to break down proteins into smaller peptide fragments. Lipase, on the other hand, is responsible for breaking down fats, amylase for breaking down carbohydrates, and maltase for breaking down maltose (a type of sugar). Therefore, pepsin is the correct enzyme involved in the digestion of proteins.

2. What is the process of breaking down fatty acids into acetyl-CoA, a key molecule in cellular respiration, called?

A. Beta-oxidation
B. Lipolysis
C. Carbohydrate catabolism
D. Nucleic acid catabolism

Correct answer: A

Rationale: Rationale: A) Beta-oxidation is the process of breaking down fatty acids into acetyl-CoA molecules. This process occurs in the mitochondria and is a crucial step in fatty acid metabolism for energy production. B) Lipolysis is the breakdown of fats into fatty acids and glycerol, but it does not specifically refer to the conversion of fatty acids into acetyl-CoA. C) Carbohydrate catabolism involves the breakdown of carbohydrates into glucose for energy production and is not directly related to the conversion of fatty acids into acetyl-CoA. D) Nucleic acid catabolism refers to the breakdown of nucleic acids into nucleotides and does not involve the conversion of fatty acids into acetyl-CoA.

3. What is the function of introns in eukaryotic genes?

A. They code for protein sequences.
B. They are involved in gene regulation.
C. They are removed during mRNA processing.
D. They are non-functional remnants of ancient DNA.

Correct answer: C

Rationale: Rationale: A) Introns do not code for protein sequences. Exons are the segments of DNA that code for proteins. B) While introns can indirectly influence gene regulation, their primary function is not directly involved in gene regulation. C) Introns are non-coding regions of DNA that are transcribed into pre-mRNA but are removed during mRNA processing through a process called splicing. This allows only the exons to be included in the mature mRNA that will be translated into proteins. D) While introns were once thought to be non-functional remnants of ancient DNA, research has shown that they can have regulatory functions and play a role in gene expression.

4. What is the scientific name for the common housefly?

A. Musca domestica
B. Drosophila melanogaster
C. Apis mellifera
D. Anopheles gambiae

Correct answer: A

Rationale: Rationale: - Musca domestica is the scientific name for the common housefly. This species is known for being a common pest found in and around human habitations. - Drosophila melanogaster (option B) is a species of fruit fly commonly used in genetic research. - Apis mellifera (option C) is the scientific name for the western honeybee. - Anopheles gambiae (option D) is a species of mosquito known for being a vector of malaria.

5. When making a dilution, you...

A. Add more solute to a concentrated solution
B. Change the temperature of the solution
C. Decrease the concentration of a solution
D. All of the above

Correct answer: C

Rationale: The correct answer is C: 'Decrease the concentration of a solution.' When making a dilution, you decrease the concentration of a solution by adding more solvent, not solute. Adding more solute to a concentrated solution would increase the concentration, not dilute it. Changing the temperature of the solution does not directly relate to dilution. Therefore, the only correct statement related to the process of making a dilution is that you decrease the concentration of the solution by adding more solvent, making option C the correct answer.