Processing of the mrna begins before transcription of eukaryotic mrna\'s is complete. the end of the mrna is prepared for recognition by the ribosomes of the cell and protected from exonuclease degradation by a process called \"capping\". during this multi-step process a nucleoside is added to the end of the mrna and then modified. complete the following statements about the capping process. capping occurs at the end of the mrna. the nucleoside added is . the nucleoside is connected to the mrna through a linkage. the added nucleoside is modified by methylation at atom. the mrna is modified by methylation of ribose residues at the -hydroxy position.

The correct answer is

1. 5' end.

2. guanosine

3. 5′ to 5′ triphosphate linkage.

4. On the 7th position.

5. 2′ hydroxy-groups of the first 2 ribose sugars.

Explanation:

The eukaryotic mRNA is processed or modified with a guanosine cap at 5' end and poly-A tail at 3'end before translation.

The process of adding a cap at 5' end of a growing mRNA is known as capping. The process of capping adds guanosine nucleotide at the 5'-end of mRNAs by 5′ to 5′ triphosphate linkage. This guanosine is modified by methylating at the  7th position of the atom. The mRNA is further modified by methylation of first two ribose sugars at their 2′ hydroxy-groups. This capping is advantageous to the sequence as it protects the end from phosphatases and nucleases.

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: