---
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entity_type: "chapter"
id: "66def6423f8b4e9e69bd7905"
title: "Host-Vector System"
board: "CBSE"
curriculum: "CBSE"
class: "Class 12"
subject: "Biotechnology"
book: "Biotechnology"
chapter: "Host-Vector System"
chapter_slug: "host-vector-system"
canonical_url: "https://www.edzy.ai/cbse-class-12-biotechnology-host-vector-system"
markdown_url: "https://www.edzy.ai/okf/chapter/cbse-class-12-biotechnology-host-vector-system.md"
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source: "Edzy"
version: 1
last_updated: "2026-06-20"
---

# Host-Vector System
Recombinant DNA technology is a two-component system involving a compatible host and a vector. This chapter covers the fundamentals of different kinds of prokaryotic and eukaryotic hosts and vectors used in rDNA technology.

---

## Knowledge Snapshot

| Field | Details |
| :--- | :--- |
| Class | Class 12 |
| Subject | Biotechnology |
| Book | Biotechnology |
| Chapter | Host-Vector System |
| Pages | 9-26 |

---

## Chapter Summary

### Short Summary
This chapter discusses the essential components of recombinant DNA technology, focusing on hosts and vectors, and their significance in gene cloning.

### Detailed Summary
Recombinant DNA technology involves joining two different DNA molecules to isolate, propagate, characterize, and manipulate genes. It consists of two main steps: isolating the desired DNA molecule (insert) and inserting it into a carrier DNA molecule (vector). The vector containing the insert is termed recombinant DNA (rDNA) and is introduced into a host organism, where it is propagated and expressed. A variety of prokaryotic (like E. coli) and eukaryotic hosts (like yeast) are employed for gene cloning, supported by various vectors, which must possess specific features to function effectively in this capacity. The chapter further explores plasmids, bacteriophages, cosmids, and artificial chromosomes as different types of vectors utilized in gene cloning.

---

## Topic-Wise Explanation

### Two Key Components of Recombinant DNA Technology
Recombinant DNA technology utilizes a compatible host and vector to form a system for gene cloning, needing specific functionalities from both for effective propagation and expression.

### Host
Prokaryotic and eukaryotic hosts are used; E. coli is the primary prokaryotic host due to its rapid growth, while yeast serves as the main eukaryotic host, allowing the desired rDNA to enter without degradation.

### Vector
Vectors are DNA molecules that replicate inside host cells. They must be small, have an origin of replication, possess unique restriction sites, and include selectable markers for screening transformants.

### Eukaryotic Host Vector System
These systems accommodate larger DNA fragments due to eukaryotic genes containing introns, utilizing vectors like Yeast Artificial Chromosomes (YACs) to clone larger DNA sizes.

### Expression Vectors
Expression vectors are special types of vectors that allow the inserted DNA to be expressed in a host, containing elements that regulate gene expression such as promoters and terminators.

### Shuttle Vectors
These vectors can replicate in two different host types (prokaryotic or eukaryotic) and allow for flexibility in experimental design.

---

## Core Ideas

| Idea | Explanation |
| :--- | :--- |
| Recombinant DNA Technology | A system involving a host and vector for gene cloning and manipulation. |

---

## Key Concepts

| Concept | Meaning |
| :--- | :--- |
| Recombinant DNA (rDNA) | DNA that has been artificially created by combining genetic material from different sources. |
| Vector | A DNA molecule used as a vehicle for transfer of genetic material into another cell. |
| Host | An organism that supports the growth of the vector containing recombinant DNA. |
| Expression Vector | A vector containing necessary elements for transcription and translation of a gene. |

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## Important Points for Revision

* Recombinant DNA technology uses hosts and vectors for gene cloning.
* E. coli is a common prokaryotic host; Saccharomyces cerevisiae is a common eukaryotic host.
* Vectors must be small, autonomous, and have selectable markers.
* Plasmids can replicate independently and provide drug resistance.
* Lambda phage is a common bacteriophage vector.
* YACs can clone larger DNA fragments due to eukaryotic gene structure.
* Expression vectors ensure that the cloned gene is expressed correctly in the host.
* Shuttle vectors work in both prokaryotic and eukaryotic systems.

---

## Practice Questions

### Short Answer Questions
1. What are the two components of recombinant DNA technology?
2. Name one prokaryotic and one eukaryotic host used for gene cloning.
3. What role do selectable markers play in vectors?
4. Describe the structure of a plasmid.
5. Explain the function of lambda phage in gene cloning.

### Long Answer Questions
1. Discuss the characteristics that a vector must have to be effective in rDNA technology.
2. Explain the differences between high-copy and low-copy plasmids. Give examples of their use.
3. Describe the process and significance of using Yeast Artificial Chromosomes for cloning large DNA segments.

---

## Source Attribution

| Field | Value |
| :--- | :--- |
| Source | Edzy |
| Reference Type | examSubjectBookChapter |
| Reference ID | 66def6423f8b4e9e69bd7905 |
| Canonical URL | https://www.edzy.ai/cbse-class-12-biotechnology-host-vector-system |
| Markdown URL | https://www.edzy.ai/okf/chapter/cbse-class-12-biotechnology-host-vector-system.md |