OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What occurs during transcription?

1. DNA is copied into mRNA

2. Amino acids are linked together

3. Proteins are folded into their shapes

4. rRNA forms ribosomes

The correct answer is: DNA is copied into mRNA

Transcription is the process in which the information encoded in a specific segment of DNA is converted into messenger RNA (mRNA). During transcription, an enzyme called RNA polymerase binds to the promoter region of a gene on the DNA. It unwinds the DNA helix and assembles a strand of RNA by synthesizing a complementary sequence to the template DNA strand. The resulting mRNA strand carries the genetic instructions needed for protein synthesis from the nucleus to the ribosomes, where it will be translated into a specific protein. This process is essential for gene expression, as it enables the information stored in DNA to be utilized in the production of proteins, which are crucial for various functions in the cells and the entire organism. In contrast, the other choices refer to processes that occur later in the expression of genes. Linking amino acids occurs during translation, which follows transcription, while the folding of proteins also occurs post-translation, and the formation of ribosomes involves ribosomal RNA combining with proteins, which is a separate step not directly related to transcription.