Which best describes the first step in genetic engineering? A. Fragments of DNA that have desired genes are isolated to form recombinant DNA for use in a host. B. All the DNA from a desired organism is isolated to form recombinant DNA for use in a host. C. Different sections of DNA from a desired organism are inserted into a host so that beneficial traits will be expressed. D. One strand of DNA is isolated and inserted into a host so recombinant DNA can be formed.

A. Fragments of DNA that have desired genes are isolated to form recombinant DNA for use in a host.

Explanation:

Genetic engineering, also known as genetic modification, is a technique that involves the manipulation of an organism's genome using biotechnology procedures. The purpose of genetic engineering is to create an organism with desirable traits.

Genetic engineering involves series of steps, however, the very first step is that of DNA EXTRACTION. The fragments of DNA that have desired genes are isolated from the involved organism. The extracted DNA called the recombinant DNA, which is inserted into the host genome.

a

explanation:

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation: