Biology Molecular & Cellular Biology Flashcards

Which of the following nitrogenous bases is found in RNA but NOT in DNA?

Answer: Uracil

RNA contains uracil instead of thymine; uracil pairs with adenine just as thymine does in DNA.

What is the function of the smooth endoplasmic reticulum (SER)?

Answer: Lipid synthesis and detoxification

The smooth ER lacks ribosomes and is specialized for lipid synthesis, steroid hormone production, and detoxification of drugs.

Which process produces NADH and pyruvate from glucose without oxygen?

Answer: Glycolysis

Glycolysis occurs in the cytoplasm and breaks down one glucose molecule into two pyruvate molecules, generating 2 ATP and 2 NADH.

In prokaryotes, DNA is located in which region of the cell?

Answer: Nucleoid region

Prokaryotes lack a membrane-bound nucleus; their circular DNA resides in an irregularly shaped nucleoid region in the cytoplasm.

Which macromolecule serves as the primary structural component of the cell wall in bacteria?

Answer: Peptidoglycan

Bacterial cell walls are composed of peptidoglycan, a mesh-like polymer of sugars and amino acids that provides rigidity.

What is the term for the entire set of proteins expressed by a cell at a given time?

Answer: Proteome

The proteome refers to the complete set of proteins expressed by a cell, tissue, or organism under specific conditions.

Which stage of mitosis is characterized by chromosomes aligning at the cell's equatorial plate?

Answer: Metaphase

During metaphase, chromosomes are maximally condensed and align along the metaphase plate before sister chromatids are separated.