A biological catalyst is essentially:

Options

A. An enzyme
B. A carbohydrate
C. An amino acid
D. A nitrogeneous base

Explanation

To answer the question "A biological catalyst is essentially:", we can follow these steps:

### Step 1: Define a Catalyst
A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It achieves this by lowering the activation energy required for the reaction to occur.

**Hint:** Remember that catalysts are not consumed in the reaction; they can be used repeatedly.

### Step 2: Identify Biological Catalysts
In biological systems, catalysts that facilitate biochemical reactions are known as biological catalysts. These are primarily enzymes.

**Hint:** Think about the role of enzymes in living organisms and how they help in metabolic processes.

### Step 3: Describe Enzymes
Enzymes are proteins that act as biological catalysts. They speed up biological reactions by providing an alternative reaction pathway with a lower activation energy.

**Hint:** Consider the structure of enzymes and how their active sites interact with substrates.

### Step 4: Conclude the Definition
Thus, a biological catalyst is essentially an enzyme that accelerates biochemical reactions in living organisms.

**Hint:** Recall that enzymes are specific to their substrates and play crucial roles in various biological processes.

### Final Answer
A biological catalyst is essentially an enzyme that increases the rate of biological processes.