Problem 11 - Biology Today and Tomorrow with Physiology

Question

A gene that is knocked out is ___________. a. deleted b. inactivated c. expressed d. either a or b

Step-by-Step Solution

Answer

d. either a or b

Step 1: Understanding the Term 'Knocked Out'

In genetics, 'knocked out' refers to the process of deactivating a gene. This can be done by deleting the gene or by inactivating it in some way, rendering it unable to perform its usual function.

Step 2: Analyzing the Options

Let's explore the options given: - **a. deleted:** This is one way a gene can be knocked out. - **b. inactivated:** This is another method of knocking out a gene, by making it non-functional but without necessarily deleting it. - **c. expressed:** This is the opposite of knocking out a gene, as an expressed gene is active and functional. - **d. either a or b:** This encompasses both possible strategies to knock out a gene.

Step 3: Identifying the Correct Answer

Given that a gene can be knocked out by either being deleted or inactivated, the option that includes both possibilities is 'd. either a or b.' This makes option d the correct answer, as it appropriately covers both potential methods of knocking out a gene.

Key Concepts

Genetic Inactivation

Genetic inactivation is a technique used in genetics to render a gene non-functional. This can occur through various methods. A common form involves mutation introduction, which causes changes in the DNA sequence of the target gene. When a gene is inactivated, it no longer produces the protein it usually does, affecting the organism's traits. Genetic inactivation is crucial in research and medicine because it helps scientists understand gene functions and relations to diseases.

• **Techniques**: Methods like CRISPR-Cas9 can inactivate genes by introducing mutations.
• **Research**: Inactivation helps uncover the role of specific genes in biological processes.

It doesn't always involve complete gene removal, meaning the genetic material stays intact within the cell, just inactive.

Gene Deletion

Gene deletion is another approach to knocking out a gene, involving the complete removal of a gene from an organism's genome. This leads to a total absence of the gene's functions, opposed to simply inactivating them. By deleting a gene, scientists can study the effects of its absence on an organism's growth, development, and physiology.

• **Process**: Techniques involve cutting out the gene using specific enzymes or genetic technologies.
• **Purpose**: Understanding what happens to an organism when a gene is completely removed is essential for genetic research.

Gene deletion is more drastic than inactivation since the DNA region coding for the gene is entirely lost.

Gene Expression

Gene expression refers to the process by which information from a gene is used to synthesize functional products like proteins. It's a key mechanism through which genes exert their effects on an organism. When a gene is expressed, it undergoes transcription into RNA and then translation into a protein. This biological process is essential for maintaining cellular function and responding to environmental changes.

• **Components**: Involves both transcription (DNA to RNA) and translation (RNA to protein).
• **Regulation**: Gene expression is tightly regulated to ensure proteins are produced at the right time and in the right amount.

Unlike genetic inactivation or deletion, where genes are either shut down or removed, gene expression represents an active and essential stage of genetic function.