Eating undercooked meat can lead to food-borne disease via helminthic infection. What is the common host for Taenia saginata?

A. Mitochondria: Prokaryotic cells do not contain mitochondria. Instead, they generate energy through processes that occur across the plasma membrane. They are found exclusively in eukaryotic cells and are absent in prokaryotes.

B. Lysosomes: Lysosomes are membrane-bound organelles found only in eukaryotic cells. Prokaryotes lack these structures and instead rely on enzymes within the cytoplasm for breakdown processes.

C. Ribosomes: Ribosomes are present in prokaryotes and eukaryotes, serving as the site of protein synthesis. In prokaryotes, they are smaller (70S type) but functionally equivalent to those in eukaryotes.

D. All of the above: This is incorrect because prokaryotes do not contain mitochondria or lysosomes.

A. An enzyme speeds up a chemical reaction in living organisms: Enzymes function as catalysts by lowering the activation energy needed for reactions, allowing biological processes to occur more quickly and efficiently.

B. An enzyme is a biological catalyst: Enzymes are proteins that serve as catalysts in living systems, regulating the speed of biochemical reactions without being permanently altered.

C. An enzyme reacts with the reactants and becomes part of the products: Enzymes do not become part of the products; they bind substrates temporarily, facilitate the reaction, and are released unchanged, allowing them to be reused multiple times.

D. An enzyme is specific to the chemical reaction it catalyzes: Enzymes have a highly specific active site that matches particular substrates, making them selective for certain reactions or molecular interactions.