Question

1. how does a positive feedback loop differ from a negative feedback loop?

a. it maintains cellular equilibrium.
b. it always involves the cell membrane.
c. it reduces the effect of an initial change.
d. it amplifies the effect of an initial change until a specific outcome is reached.

1. which of the following is a feature unique to eukaryotic cells?

a. cytoplasm for metabolic reactions
b. semi - permeable cell membranes
c. presence of ribosomes
d. presence of membrane - bound organelles

Explanation:

1. Negative feedback loops maintain stability and equilibrium, while positive feedback loops amplify an initial change until a specific outcome is reached. For example, in a biological context, blood clotting is a positive - feedback mechanism where the initial injury leads to a cascade of events that amplify the clotting process until the bleeding stops.
2. Enzymes are proteins that act as biological catalysts in metabolic reactions. They are not unique to anabolic reactions. Semi - permeable cell membranes are a feature of all cells and not unique to anabolic reactions. The presence of ribosomes is a general cell feature. Anabolic reactions are characterized by the synthesis of complex molecules from simpler ones and often require energy in the form of ATP. The presence of energy - storing molecules like ATP is not unique to anabolic reactions. However, anabolic reactions often involve the use of coenzymes for reversible reactions, which is a more unique feature compared to the other options.

Answer:

1. d. It amplifies the effect of an initial change until a specific outcome is reached.
2. a. Coenzymes for reversible reactions.