4.3

Question 1

Transcription

Answer 1

Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). DNA safely and stably stores genetic material in the nuclei of cells as a reference, or template.

Question 2

Difference between RNA and DNA

Answer 2

While both DNA and RNA have sugar molecules in their subunits, those sugars are slightly different. DNA uses deoxyribose, but RNA uses ribose, which has an extra hydroxyl group (OH−) tacked on. DNA and RNA also have nearly identical nitrogenous bases. Both have the bases adenine, cytosine, and guanine.

Question 3

The different parts of a eukaryotic gene

Answer 3

Most eukaryotic genes contain segments of coding sequences (exons) interrupted by noncoding sequences (introns). Both exons and introns are transcribed to yield a long primary RNA transcript. The introns are then removed.

Question 4

What happens during alternative splicing?

Answer 4

Alternative splicing is a cellular process in which exons from the same gene are joined in different combinations, leading to different, but related, mRNA transcripts. These mRNAs can be translated to produce different proteins with distinct structures and functions all from a single gene.