Number of ori (origin of replication) in E.coli and Zea mays are______ and _______ respectively

Options

A. 10 and 1000
B. One and several thousands
C. `10^5` and `10^15`
D. One and two

Answer

To answer the question regarding the number of origins of replication (ori) in E. coli and Zea mays, we can break down the information as follows:

### Step-by-Step Solution:

1. **Understanding the Concept of Origin of Replication (ori)**:
- The origin of replication is the specific location on the DNA where replication begins. It is often referred to as the "ori" site.
- In prokaryotes, such as E. coli, there is typically one origin of replication due to their simpler, circular DNA structure.

2. **Number of ori in E. coli**:
- E. coli is a prokaryotic organism, and it has a single circular chromosome.
- Therefore, E. coli has **1 origin of replication**.

3. **Number of ori in Zea mays**:
- Zea mays, commonly known as maize or corn, is a eukaryotic organism.
- Eukaryotic organisms have multiple linear chromosomes, and as a result, they have multiple origins of replication.
- Zea mays can have **thousands of origins of replication** due to its complex genome structure.

4. **Final Answer**:
- The number of ori in E. coli is **1**, and in Zea mays, it is **thousands**.

### Summary:
The final answer to the question is:
- Number of ori in E. coli: **1**
- Number of ori in Zea mays: **thousands**

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