Problem 2 - Campbell Biology Concepts & Connections

Question

Which of the following would be considered a transgenic organism? a. a bacterium that has received genes via conjugation b. a human given a corrected human blood-clotting gene c. a fern grown in cell culture from a single fern root cell d. a rat with rabbit hemoglobin genes

Step-by-Step Solution

Answer

d. a rat with rabbit hemoglobin genes

Step 1 - Understanding Transgenic Organisms

A transgenic organism contains a gene or genes that have been artificially inserted instead of the organism acquiring them through reproduction. These genes can come from another species, leading to new proteins and traits not found in the original organism.

Step 2 - Examine Option A

Option A discusses a bacterium that has received genes via conjugation. Conjugation is a natural form of genetic exchange between bacteria, not typically involving artificial insertion of genes, and usually involves genes from the same or similar species.

Step 3 - Examine Option B

Option B describes a human given a corrected human blood-clotting gene. While this involves gene therapy, it is not considered transgenic as the genes are not from a different species.

Step 4 - Examine Option C

Option C involves a fern grown from a single root cell. This process is natural and does not involve the insertion of genes from a different species, so it is not a transgenic organism.

Step 5 - Examine Option D

Option D describes a rat with rabbit hemoglobin genes. This involves the artificial insertion of genes from a different species, making the rat a transgenic organism.

Step 6 - Conclusion

Comparing all options, only option D describes an organism with genes artificially inserted from a different species, fulfilling the criteria for a transgenic organism.

Key Concepts

genetic engineering

Genetic engineering is a process where scientists alter the genetic material of an organism. This involves the manipulation of DNA to add, remove, or modify genes in a living organism.

Key Steps of Genetic Engineering:

• Isolation: Identifying and isolating the gene of interest.
• Insertion: Using vectors (like plasmids) to insert the gene into the host organism's genome.
• Expression: Ensuring the inserted gene is expressed in the host organism to produce the desired trait.

Genetic engineering is used in various fields, including agriculture, medicine, and research. For example, it helps in developing crops resistant to pests or diseases and producing insulin for diabetic patients.

recombinant DNA

Recombinant DNA (rDNA) technology is a fundamental tool in genetic engineering. It involves combining DNA from two or more sources to create new genetic combinations.

Process of Creating Recombinant DNA:

• Cutting DNA: Restriction enzymes are used to cut DNA at specific sequences.
• Combining DNA: The cut DNA fragments from different sources are joined together using ligase enzymes.
• Inserting Recombinant DNA: The new rDNA is introduced into a host organism, often using a vector like a plasmid.

This process allows for the development of organisms with desirable traits. For instance, bacteria with rDNA can produce human insulin, which is used in treating diabetes.

gene therapy

Gene therapy is a medical technique that involves modifying or replacing defective genes to treat or prevent diseases.

Types of Gene Therapy:

• Somatic Gene Therapy: Targets non-reproductive cells, so changes are not passed to offspring.
• Germline Gene Therapy: Targets reproductive cells, so changes can be inherited by the next generation.

Steps in Gene Therapy:

• Identifying the defective gene: Determine which gene is causing the problem.
• Creating a vector: Typically a virus is used to carry the correct gene into the patient's cells.
• Inserting the vector: The vector introduces the correct gene into the patient’s cells, where it becomes part of their DNA.

Gene therapy holds promise for treating genetic disorders like cystic fibrosis, hemophilia, and certain cancers. It aims to correct or replace the faulty genes responsible for these conditions.